muzika-gromche/MuzikaGromche/Plugin.cs

using BepInEx;
using BepInEx.Configuration;
using BepInEx.Logging;
using HarmonyLib;
using LethalConfig;
using LethalConfig.ConfigItems;
using LethalConfig.ConfigItems.Options;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Security.Cryptography;
using System.Text;
using Unity.Netcode;
using UnityEngine;

namespace MuzikaGromche
{
    [BepInPlugin(MyPluginInfo.PLUGIN_GUID, MyPluginInfo.PLUGIN_NAME, MyPluginInfo.PLUGIN_VERSION)]
    [BepInDependency("ainavt.lc.lethalconfig", "1.4.6")]
    [BepInDependency("watergun.v72lightfix", BepInDependency.DependencyFlags.SoftDependency)]
    [BepInDependency("BMX.LobbyCompatibility", BepInDependency.DependencyFlags.SoftDependency)]
    public class Plugin : BaseUnityPlugin
    {
        private static Harmony Harmony = null!;
        internal static ManualLogSource Log = null!;
        internal new static Config Config { get; private set; } = null!;

        // Not all lights are white by default. For example, Mineshaft's neon light is green-ish.
        // We don't have to care about Light objects lifetime, as Unity would internally destroy them on scene unload anyway.
        internal static Dictionary<Light, Color> InitialLightsColors = [];

        public static ISelectableTrack[] Tracks => Library.Tracks;

        private static int GetCurrentSeed()
        {
            var seed = 0;
            var roundManager = RoundManager.Instance;
            if (roundManager != null && roundManager.dungeonGenerator != null)
            {
                seed = roundManager.dungeonGenerator.Generator.ChosenSeed;
            }
            return seed;
        }

        static (ISelectableTrack[], Season?) GetTracksAndSeason()
        {
            var today = DateTime.Today;
            var season = SeasonalContentManager.CurrentSeason(today);
            var tracksEnumerable = SeasonalContentManager.Filter(Tracks, season);
            if (Config.SkipExplicitTracks.Value)
            {
                tracksEnumerable = tracksEnumerable.Where(track => !track.IsExplicit);
            }
            tracksEnumerable = tracksEnumerable.Where(track => track.Enabled);
            var tracks = tracksEnumerable.ToArray();
            return (tracks, season);
        }

        public static ISelectableTrack ChooseTrack()
        {
            var seed = GetCurrentSeed();
            var (tracks, season) = GetTracksAndSeason();
            int[] weights = tracks.Select(track => track.Weight.Value).ToArray();
            var rwi = new RandomWeightedIndex(weights);
            var trackId = rwi.GetRandomWeightedIndex(seed);
            var track = tracks[trackId];
            Log.LogInfo($"Seed is {seed}, season is {season?.Name ?? "<none>"}, chosen track is \"{track.Name}\", #{trackId} of {rwi}");
            return tracks[trackId];
        }

        // This range results in 23 out of 33 tracks (70%) being selectable with the lowest overlap of 35% in the vanilla 35-40 seconds range.
        internal const float CompatModeAllowLongerTrack = 3f; // audio may start earlier (and last longer) than vanilla timer
        internal const float CompatModeAllowShorterTrack = 3f; // audio may start later (and last shorter) than vanilla timer

        // Select the track whose wind-up timer most closely matches target vanilla value,
        // so that we have a bit of leeway to delay the intro or start playing it earlier to match vanilla pop-up timing.
        public static IAudioTrack? ChooseTrackCompat(float vanillaPopUpTimer)
        {
            var seed = GetCurrentSeed();
            var (tracks, season) = GetTracksAndSeason();
            // Don't just select the closest match, select from a range of them!
            var minTimer = vanillaPopUpTimer - CompatModeAllowShorterTrack;
            var maxTimer = vanillaPopUpTimer + CompatModeAllowLongerTrack;
            bool TimerIsCompatible(IAudioTrack t) => minTimer <= t.WindUpTimer && t.WindUpTimer <= maxTimer;

            // Similar to RandomWeightedIndex:
            // If everything is set to zero, everything is equally possible
            var allWeightsAreZero = tracks.All(t => t.Weight.Value == 0);
            bool WeightIsCompatible(ISelectableTrack t) => allWeightsAreZero || t.Weight.Value > 0;

            var compatibleSelectableTracks = tracks
                .Where(track => WeightIsCompatible(track) && track.GetTracks().Any(TimerIsCompatible))
                .ToArray();

            if (compatibleSelectableTracks.Length == 0)
            {
                Log.LogWarning($"Seed is {seed}, season is {season?.Name ?? "<none>"}, no compat tracks found for timer {vanillaPopUpTimer}");
                return null;
            }

            // Select track group where at least one track member is compatible
            int[] weights = compatibleSelectableTracks.Select(track => track.Weight.Value).ToArray();
            var rwi = new RandomWeightedIndex(weights);
            var trackId = rwi.GetRandomWeightedIndex(seed);
            var selectableTrack = compatibleSelectableTracks[trackId];

            // Select only compatible members from the selected group
            var compatibleAudioTracks = selectableTrack.GetTracks().Where(TimerIsCompatible).ToArray();

            // Randomly choose a compatible member from the group
            var rng = new System.Random(seed + (int)(vanillaPopUpTimer * 1000));
            var groupIndex = rng.Next();
            var audioTrack = Mod.Index(compatibleAudioTracks, groupIndex);

            Log.LogInfo($"Seed is {seed}, season is {season?.Name ?? "<none>"}, chosen compat track is \"{audioTrack.Name}\" with timer: {audioTrack.WindUpTimer}, vanilla timer: {vanillaPopUpTimer}");
            return audioTrack;
        }

        public static IAudioTrack? FindTrackNamed(string name)
        {
            return Tracks.SelectMany(track => track.GetTracks()).FirstOrDefault(track => track.Name == name);
        }

        // Max audible distance for AudioSource and LyricsEvent
        public const float AudioMaxDistance = 150;

        public static bool LocalPlayerCanHearMusic(EnemyAI jester)
        {
            var player = GameNetworkManager.Instance.localPlayerController;
            var listener = StartOfRound.Instance.audioListener;
            if (player == null || listener == null || !player.isInsideFactory)
            {
                return false;
            }
            var distance = Vector3.Distance(listener.transform.position, jester.transform.position);
            return distance <= AudioMaxDistance;
        }

        public static void DisplayLyrics(string text)
        {
            HUDManager.Instance.DisplayTip("[Lyrics]", text);
            // Don't interrupt the music with constant HUD audio pings
            HUDManager.Instance.UIAudio.Stop();
        }

        void Awake()
        {
            Log = Logger;

            // Sort in place by name
            Array.Sort(Tracks.Select(track => track.Name).ToArray(), Tracks);

#if DEBUG
            JesterPatch.DedupLog = new DedupManualLogSource(Logger);
            GlobalBehaviour.Instance.StartCoroutine(PreloadDebugAndExport(Tracks));
#endif
            Config = new Config(base.Config);
            DiscoBallManager.Load();
            PoweredLightsAnimators.Load();
            Harmony = new Harmony(MyPluginInfo.PLUGIN_NAME);
            Harmony.PatchAll(typeof(GameNetworkManagerPatch));
            Harmony.PatchAll(typeof(JesterPatch));
            Harmony.PatchAll(typeof(PoweredLightsAnimatorsPatch));
            Harmony.PatchAll(typeof(AllPoweredLightsPatch));
            Harmony.PatchAll(typeof(DiscoBallTilePatch));
            Harmony.PatchAll(typeof(DiscoBallDespawnPatch));
            Harmony.PatchAll(typeof(SpawnRatePatch));
            Harmony.PatchAll(typeof(DeathScreenGameOverTextResetPatch));
            Harmony.PatchAll(typeof(ScreenFiltersManager.HUDManagerScreenFiltersPatch));
            Harmony.PatchAll(typeof(ClearAudioClipCachePatch));
            NetcodePatcher();
            Compatibility.Register(this);
        }

#if DEBUG
        static IEnumerator PreloadDebugAndExport(ISelectableTrack[] tracks)
        {
            foreach (var track in tracks.SelectMany(track => track.GetTracks()))
            {
                AudioClipsCacheManager.LoadAudioTrack(track);
            }
            yield return new WaitUntil(() => AudioClipsCacheManager.AllDone);
            Log.LogDebug("All tracks preloaded, exporting to JSON");

            foreach (var track in tracks)
            {
                track.Debug();
            }
            Exporter.ExportTracksJSON(tracks);
            AudioClipsCacheManager.Clear();
        }
#endif

        private static void NetcodePatcher()
        {
            var types = Assembly.GetExecutingAssembly().GetTypes();
            foreach (var type in types)
            {
                var methods = type.GetMethods(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
                foreach (var method in methods)
                {
                    var attributes = method.GetCustomAttributes(typeof(RuntimeInitializeOnLoadMethodAttribute), false);
                    if (attributes.Length > 0)
                    {
                        method.Invoke(null, null);
                    }
                }
            }
        }
    };

    public readonly record struct Language(string Short, string Full)
    {
        public static readonly Language ENGLISH = new("EN", "English");
        public static readonly Language RUSSIAN = new("RU", "Russian");
        public static readonly Language KOREAN = new("KO", "Korean");
        public static readonly Language JAPANESE = new("JP", "Japanese");
        public static readonly Language HINDI = new("HI", "Hindi");
    }

    public readonly record struct Easing(string Name, Func<float, float> Eval)
    {
        public static Easing Linear = new("Linear", static x => x);
        public static Easing InCubic = new("InCubic", static x => x * x * x);
        public static Easing OutCubic = new("OutCubic", static x => 1 - Mathf.Pow(1f - x, 3f));
        public static Easing InOutCubic = new("InOutCubic", static x => x < 0.5f ? 4f * x * x * x : 1 - Mathf.Pow(-2f * x + 2f, 3f) / 2f);
        public static Easing InExpo = new("InExpo", static x => x == 0f ? 0f : Mathf.Pow(2f, 10f * x - 10f));
        public static Easing OutExpo = new("OutExpo", static x => x == 1f ? 1f : 1f - Mathf.Pow(2f, -10f * x));
        public static Easing InOutExpo = new("InOutExpo", static x =>
            x == 0f
            ? 0f
            : x == 1f
            ? 1f
            : x < 0.5f
                ? Mathf.Pow(2f, 20f * x - 10f) / 2f
                : (2f - Mathf.Pow(2f, -20f * x + 10f)) / 2f);

        public static readonly Easing[] All = [Linear, InCubic, OutCubic, InOutCubic, InExpo, OutExpo, InOutExpo];

        public static readonly string[] AllNames = [.. All.Select(easing => easing.Name)];

        public static Easing FindByName(string Name)
        {
            return All.Where(easing => easing.Name == Name).DefaultIfEmpty(Linear).First();
        }

        public override string ToString()
        {
            return Name;
        }
    }

    public readonly record struct Palette(Color[] Colors)
    {
        public static readonly Palette DEFAULT = new([Color.magenta, Color.cyan, Color.green, Color.yellow]);

        public static Palette Parse(string[] hexColors)
        {
            Color[] colors = new Color[hexColors.Length];
            for (int i = 0; i < hexColors.Length; i++)
            {
                if (!ColorUtility.TryParseHtmlString(hexColors[i], out colors[i]))
                {
                    throw new ArgumentException($"Unable to parse color #{i}: {hexColors}");
                }
            }
            return new Palette(colors);
        }

        public static Palette operator +(Palette before, Palette after)
        {
            return new Palette([.. before.Colors, .. after.Colors]);
        }

        public static Palette operator *(Palette palette, int repeat)
        {
            var colors = Enumerable.Repeat(palette.Colors, repeat).SelectMany(x => x).ToArray();
            return new Palette(colors);
        }

        public Palette Stretch(int times)
        {
            var colors = Colors.SelectMany(color => Enumerable.Repeat(color, times)).ToArray();
            return new Palette(colors);
        }

        public Palette Use(Func<Palette, Palette> op)
        {
            return op.Invoke(this);
        }
    }

    public readonly struct TimeSeries<T>
    {
        public TimeSeries() : this([], []) { }

        public TimeSeries(float[] beats, T[] values)
        {
            if (beats.Length != values.Length)
            {
                throw new ArgumentOutOfRangeException($"Time series length mismatch: {beats.Length} != {values.Length}");
            }
            var dict = new SortedDictionary<float, T>();
            for (int i = 0; i < values.Length; i++)
            {
                dict.Add(beats[i], values[i]);
            }
            Beats = [.. dict.Keys];
            Values = [.. dict.Values];
        }

        public readonly int Length => Beats.Length;
        public readonly float[] Beats { get; } = [];
        public readonly T[] Values { get; } = [];

        public override string ToString()
        {
            return $"{nameof(TimeSeries<T>)}([{string.Join(", ", Beats)}], [{string.Join(", ", Values)}])";
        }
    }

    // An instance of a track which appears as a configuration entry and
    // can be selected using weighted random from a list of selectable tracks.
    public interface ISelectableTrack : ISeasonalContent
    {
        // Provide means to disable the track and hide it from user-facing config, while keeping it around in code and still exporting to JSON.
        public bool Enabled { get; init; }

        // Name of the track, as shown in config entry UI; also used for default file names.
        public string Name { get; init; }

        // Artist and Song metadata, shown in config description.
        public string Artist { get; init; }

        public string Song { get; init; }

        // Language of the track's lyrics.
        public Language Language { get; init; }

        // Whether this track has NSFW/explicit lyrics.
        public bool IsExplicit { get; init; }

        // How often this track should be chosen, relative to the sum of weights of all tracks.
        internal ConfigEntry<int> Weight { get; set; }

        internal IAudioTrack[] GetTracks();

        // Index is a non-negative monotonically increasing number of times
        // this ISelectableTrack has been played for this Jester on this day.
        // A group of tracks can use this index to rotate tracks sequentially.
        internal IAudioTrack SelectTrack(int index);

        internal void Debug();
    }

    // An instance of a track which has file names, timings data, palette; can be loaded and played.
    public interface IAudioTrack
    {
        // Name of the track used for default file names.
        public string Name { get; }

        // Wind-up time can and should be shorter than the Intro audio track,
        // so that the "pop" effect can be baked into the Intro audio and kept away
        // from the looped part. This also means that the light show starts before
        // the looped track does, so we need to sync them up as soon as we enter the Loop.
        public float WindUpTimer { get; }

        // Estimated number of beats per minute. Not used for light show, but might come in handy.
        public float Bpm
        {
            get
            {
                if (LoadedLoop == null || LoadedLoop.length <= 0f)
                {
                    return 0f;
                }
                else
                {
                    return 60f / (LoadedLoop.length / Beats);
                }
            }
        }

        // How many beats the loop segment has. The default strategy is to switch color of lights on each beat.
        public int Beats { get; }

        // Number of beats between WindUpTimer and where looped segment starts (not the loop audio).
        public int LoopOffset { get; }
        public float LoopOffsetInSeconds
        {
            get
            {
                if (LoadedLoop == null || LoadedLoop.length <= 0f)
                {
                    return 0f;
                }
                else
                {
                    return (float)LoopOffset / (float)Beats * LoadedLoop.length;
                }
            }
        }

        // MPEG is basically mp3, and it can produce gaps at the start.
        // WAV is OK, but takes a lot of space. Try OGGVORBIS instead.
        public AudioType AudioType { get; }

        public AudioClip? LoadedIntro { get; internal set; }
        public AudioClip? LoadedLoop { get; internal set; }

        public string FileNameIntro { get; }
        public string FileNameLoop { get; }

        public string Ext => AudioType switch
        {
            AudioType.MPEG => "mp3",
            AudioType.WAV => "wav",
            AudioType.OGGVORBIS => "ogg",
            _ => "",
        };

        // Offset of beats. Bigger offset => colors will change later.
        public float BeatsOffset { get; }

        // Offset of beats, in seconds. Bigger offset => colors will change later.
        public float BeatsOffsetInSeconds
        {
            get
            {
                if (LoadedLoop == null || LoadedLoop.length <= 0f)
                {
                    return 0f;
                }
                else
                {
                    return BeatsOffset / (float)Beats * LoadedLoop.length;
                }
            }
        }

        public float FadeOutBeat { get; }
        public float FadeOutDuration { get; }

        // Duration of color transition, measured in beats.
        public float ColorTransitionIn { get; }
        public float ColorTransitionOut { get; }

        // Easing function for color transitions.
        public Easing ColorTransitionEasing { get; }

        public float[] FlickerLightsTimeSeries { get; }

        public float[] LyricsTimeSeries { get; }

        // Lyrics line may contain multiple tab-separated alternatives.
        // In such case, a random number chosen and updated once per loop
        // is used to select an alternative.
        // If the chosen alternative is an empty string, lyrics event shall be skipped.
        public string[] LyricsLines { get; }

        public TimeSeries<float> DrunknessLoopOffsetTimeSeries { get; }
        public TimeSeries<float> CondensationLoopOffsetTimeSeries { get; }

        public Palette Palette { get; }

        public string? GameOverText { get => null; }
    }

    // A proxy audio track with default implementation for every IAudioTrack method that simply forwards requests to the inner IAudioTrack.
    public abstract class ProxyAudioTrack(IAudioTrack track) : IAudioTrack
    {
        internal IAudioTrack Track = track;
        string IAudioTrack.Name => Track.Name;
        float IAudioTrack.WindUpTimer => Track.WindUpTimer;
        int IAudioTrack.Beats => Track.Beats;
        int IAudioTrack.LoopOffset => Track.LoopOffset;
        AudioType IAudioTrack.AudioType => Track.AudioType;
        AudioClip? IAudioTrack.LoadedIntro { get => Track.LoadedIntro; set => Track.LoadedIntro = value; }
        AudioClip? IAudioTrack.LoadedLoop { get => Track.LoadedLoop; set => Track.LoadedLoop = value; }
        string IAudioTrack.FileNameIntro => Track.FileNameIntro;
        string IAudioTrack.FileNameLoop => Track.FileNameLoop;
        float IAudioTrack.BeatsOffset => Track.BeatsOffset;
        float IAudioTrack.FadeOutBeat => Track.FadeOutBeat;
        float IAudioTrack.FadeOutDuration => Track.FadeOutDuration;
        float IAudioTrack.ColorTransitionIn => Track.ColorTransitionIn;
        float IAudioTrack.ColorTransitionOut => Track.ColorTransitionOut;
        Easing IAudioTrack.ColorTransitionEasing => Track.ColorTransitionEasing;
        float[] IAudioTrack.FlickerLightsTimeSeries => Track.FlickerLightsTimeSeries;
        float[] IAudioTrack.LyricsTimeSeries => Track.LyricsTimeSeries;
        string[] IAudioTrack.LyricsLines => Track.LyricsLines;
        TimeSeries<float> IAudioTrack.DrunknessLoopOffsetTimeSeries => Track.DrunknessLoopOffsetTimeSeries;
        TimeSeries<float> IAudioTrack.CondensationLoopOffsetTimeSeries => Track.CondensationLoopOffsetTimeSeries;
        Palette IAudioTrack.Palette => Track.Palette;
        string? IAudioTrack.GameOverText => Track.GameOverText;
    }

    // Core audio track implementation with some defaults and config overrides.
    // Suitable to declare elemnents of SelectableTracksGroup and as a base for standalone selectable tracks.
    public class CoreAudioTrack : IAudioTrack
    {
        public /* required */ string Name { get; init; } = "";
        public /* required */ float WindUpTimer { get; init; } = 0f;
        public int Beats { get; init; }

        // Shorthand for four beats
        public int Bars
        {
            init => Beats = value * 4;
        }

        public int LoopOffset { get; init; } = 0;
        public AudioType AudioType { get; init; } = AudioType.MPEG;
        public AudioClip? LoadedIntro { get; set; } = null;
        public AudioClip? LoadedLoop { get; set; } = null;

        private string? FileNameIntroOverride = null;
        public string FileNameIntro
        {
            get => FileNameIntroOverride ?? $"{Name}Intro.{((IAudioTrack)this).Ext}";
            init => FileNameIntroOverride = value;
        }

        private string? FileNameLoopOverride = null;
        public string FileNameLoop
        {
            get => FileNameLoopOverride ?? $"{Name}Loop.{((IAudioTrack)this).Ext}";
            init => FileNameLoopOverride = value;
        }

        public float BeatsOffset { get; init; } = 0f;
        public float FadeOutBeat { get; init; } = float.NaN;
        public float FadeOutDuration { get; init; } = 2f;
        public float ColorTransitionIn { get; init; } = 0.25f;
        public float ColorTransitionOut { get; init; } = 0.25f;
        public Easing ColorTransitionEasing { get; init; } = Easing.OutExpo;

        public float[] _FlickerLightsTimeSeries = [];
        public float[] FlickerLightsTimeSeries
        {
            get => _FlickerLightsTimeSeries;
            init
            {
                Array.Sort(value);
                _FlickerLightsTimeSeries = value;
            }
        }

        public float[] LyricsTimeSeries { get; private set; } = [];

        // Lyrics line may contain multiple tab-separated alternatives.
        // In such case, a random number chosen and updated once per loop
        // is used to select an alternative.
        // If the chosen alternative is an empty string, lyrics event shall be skipped.
        public string[] LyricsLines { get; private set; } = [];
        public (float, string)[] Lyrics
        {
            set
            {
                var dict = new SortedDictionary<float, string>();
                foreach (var (beat, text) in value)
                {
                    dict.Add(beat, text);
                }
                LyricsTimeSeries = [.. dict.Keys];
                LyricsLines = [.. dict.Values];
            }
        }

        public TimeSeries<float> DrunknessLoopOffsetTimeSeries { get; init; } = new();
        public TimeSeries<float> CondensationLoopOffsetTimeSeries { get; init; } = new();

        public Palette Palette { get; set; } = Palette.DEFAULT;

        public string? GameOverText { get; init; } = null;
    }

    // Standalone, top-level, selectable audio track
    public class SelectableAudioTrack : CoreAudioTrack, ISelectableTrack
    {
        public bool Enabled { get; init; } = true;
        public /* required */ string Artist { get; init; } = "";

        public /* required */ string Song { get; init; } = "";
        public /* required */ Language Language { get; init; }
        public bool IsExplicit { get; init; } = false;
        public Season? Season { get; init; } = null;
        ConfigEntry<int> ISelectableTrack.Weight { get; set; } = null!;

        IAudioTrack[] ISelectableTrack.GetTracks() => [this];

        IAudioTrack ISelectableTrack.SelectTrack(int index) => this;

        void ISelectableTrack.Debug()
        {
            Plugin.Log.LogDebug($"Track \"{Name}\", Intro={LoadedIntro?.length:N4}, Loop={LoadedLoop?.length:N4}");
        }
    }

    public class SelectableTracksGroup : ISelectableTrack
    {
        public bool Enabled { get; init; } = true;
        public /* required */ string Name { get; init; } = "";
        public /* required */ string Artist { get; init; } = "";

        public /* required */ string Song { get; init; } = "";
        public /* required */ Language Language { get; init; }
        public bool IsExplicit { get; init; } = false;
        public Season? Season { get; init; } = null;
        ConfigEntry<int> ISelectableTrack.Weight { get; set; } = null!;

        public /* required */ IAudioTrack[] Tracks = [];

        IAudioTrack[] ISelectableTrack.GetTracks() => Tracks;

        IAudioTrack ISelectableTrack.SelectTrack(int index)
        {
            if (Tracks.Length == 0)
            {
                throw new IndexOutOfRangeException("Tracks list is empty");
            }
            return Mod.Index(Tracks, index);
        }

        void ISelectableTrack.Debug()
        {
            Plugin.Log.LogDebug($"Track Group \"{Name}\", Count={Tracks.Length}");
            foreach (var (track, index) in Tracks.Select((x, i) => (x, i)))
            {
                Plugin.Log.LogDebug($"    Track {index} \"{track.Name}\", Intro={track.LoadedIntro?.length:N4}, Loop={track.LoadedLoop?.length:N4}");
            }
        }
    }

    readonly record struct BeatTimestamp
    {
        // Number of beats in the loop audio segment.
        public readonly int LoopBeats;
        public readonly float HalfLoopBeats => LoopBeats / 2f;

        // Whether negative time should wrap around. Positive time past LoopBeats always wraps around.
        public readonly bool IsLooping;

        // Beat relative to the popup. Always less than LoopBeats. When not IsLooping, can be unbounded negative.
        public readonly float Beat;

        // Additional metadata describing whether this timestamp is based on extrapolated source data.
        public readonly bool IsExtrapolated;

        public BeatTimestamp(int loopBeats, bool isLooping, float beat, bool isExtrapolated)
        {
            LoopBeats = loopBeats;
            IsLooping = isLooping || beat >= HalfLoopBeats;
            Beat = isLooping || beat >= LoopBeats ? Mod.Positive(beat, LoopBeats) : beat;
            IsExtrapolated = isExtrapolated;
        }

        public static BeatTimestamp operator +(BeatTimestamp self, float delta)
        {
            if (delta < -self.HalfLoopBeats && self.Beat > self.HalfLoopBeats /* implied: */ && self.IsLooping)
            {
                // Warning: you can't meaningfully subtract more than half of the loop
                // from a looping timestamp whose Beat is past half of the loop,
                // because the resulting IsLooping is unknown.
                // Shouldn't be needed though, as deltas are usually short enough.
                // But don't try to chain many short negative deltas!
            }
            return new BeatTimestamp(self.LoopBeats, self.IsLooping, self.Beat + delta, self.IsExtrapolated);
        }

        public static BeatTimestamp operator -(BeatTimestamp self, float delta)
        {
            return self + -delta;
        }

        public readonly BeatTimestamp Floor()
        {
            // There is no way it wraps or affects IsLooping state
            var beat = Mathf.Floor(Beat);
            return new BeatTimestamp(LoopBeats, IsLooping, beat, IsExtrapolated);
        }

        public readonly override string ToString()
        {
            return $"{nameof(BeatTimestamp)}({(IsLooping ? 'Y' : 'n')}{(IsExtrapolated ? 'E' : '_')} {Beat:N4}/{LoopBeats})";
        }
    }

    readonly record struct BeatTimeSpan
    {
        public readonly int LoopBeats;
        public readonly float HalfLoopBeats => LoopBeats / 2f;
        public readonly bool IsLooping;
        // Open lower bound
        public readonly float BeatFromExclusive;
        // Closed upper bound
        public readonly float BeatToInclusive;
        // Additional metadata describing whether this timestamp is based on extrapolated source data.
        public readonly bool IsExtrapolated;

        public BeatTimeSpan(int loopBeats, bool isLooping, float beatFromExclusive, float beatToInclusive, bool isExtrapolated)
        {
            LoopBeats = loopBeats;
            IsLooping = isLooping || beatToInclusive >= HalfLoopBeats;
            BeatFromExclusive = wrap(beatFromExclusive);
            BeatToInclusive = wrap(beatToInclusive);
            IsExtrapolated = isExtrapolated;

            float wrap(float beat)
            {
                return isLooping || beat >= loopBeats ? Mod.Positive(beat, loopBeats) : beat;
            }
        }

        public static BeatTimeSpan Between(BeatTimestamp timestampFromExclusive, BeatTimestamp timestampToInclusive)
        {
            var isExtrapolated = timestampFromExclusive.IsExtrapolated || timestampToInclusive.IsExtrapolated;
            return new BeatTimeSpan(timestampToInclusive.LoopBeats, timestampToInclusive.IsLooping, timestampFromExclusive.Beat, timestampToInclusive.Beat, isExtrapolated);
        }

        public static BeatTimeSpan Between(float beatFromExclusive, BeatTimestamp timestampToInclusive)
        {
            return new BeatTimeSpan(timestampToInclusive.LoopBeats, timestampToInclusive.IsLooping, beatFromExclusive, timestampToInclusive.Beat, timestampToInclusive.IsExtrapolated);
        }

        public static BeatTimeSpan Empty = new();

        public readonly BeatTimestamp ToTimestamp()
        {
            return new(LoopBeats, IsLooping, BeatToInclusive, IsExtrapolated);
        }

        // The beat will not be wrapped.
        public readonly bool ContainsExact(float beat)
        {
            return BeatFromExclusive < beat && beat <= BeatToInclusive;
        }

        public readonly int? GetLastIndex(float[] timeSeries)
        {
            if (IsEmpty() || timeSeries == null || timeSeries.Length == 0)
            {
                return null;
            }

            if (IsWrapped())
            {
                // Split the search in two non-wrapping searches:
                // before wrapping (happens earlier) and after wrapping (happens later).

                // Check the "happens later" part first.
                var laterSpan = new BeatTimeSpan(LoopBeats, isLooping: false, beatFromExclusive: /* epsilon to make zero inclusive */ -0.001f, beatToInclusive: BeatToInclusive, IsExtrapolated);
                var laterIndex = laterSpan.GetLastIndex(timeSeries);
                if (laterIndex != null)
                {
                    return laterIndex;
                }

                // The "happens earlier" part is easy: it's just the last value in the series.
                var lastIndex = timeSeries.Length - 1;
                if (timeSeries[lastIndex] > BeatFromExclusive)
                {
                    return lastIndex;
                }
            }
            else
            {
                // BeatFromExclusive might as well be -Infinity

                var index = Array.BinarySearch(timeSeries, BeatToInclusive);
                if (index > 0 && index < timeSeries.Length && timeSeries[index] > BeatFromExclusive)
                {
                    return index;
                }
                else
                {
                    // Restore from bitwise complement
                    index = ~index;
                    // index points to the next larger object, i.e. the next event in the series after the BeatToInclusive.
                    // Make it point to one event before that.
                    index -= 1;
                    if (index >= 0 && timeSeries[index] > BeatFromExclusive && timeSeries[index] <= BeatToInclusive)
                    {
                        return index;
                    }
                }
            }
            return null;
        }

        public readonly float Duration(bool longest = false)
        {
            if (longest)
            {
                var to = BeatToInclusive;
                if (BeatFromExclusive >= 0f && BeatToInclusive >= 0f && to < BeatFromExclusive)
                {
                    // wrapped
                    to += LoopBeats;
                }
                return Mathf.Max(0f, to - BeatFromExclusive);
            }
            else if (IsEmpty())
            {
                return 0f;
            }
            else if (IsWrapped())
            {
                var beforeWrapping = LoopBeats - BeatFromExclusive;
                var afterWrapping = BeatToInclusive - 0f;
                return beforeWrapping + afterWrapping;
            }
            else
            {
                return BeatToInclusive - BeatFromExclusive;
            }
        }

        public readonly bool IsEmpty()
        {
            if (IsLooping)
            {
                var to = BeatToInclusive;

                // unwrap if needed
                if (BeatToInclusive < BeatFromExclusive)
                {
                    to = BeatToInclusive + LoopBeats;
                }

                // Due to audio offset changes, `to` may shift before `from`, so unwrapping it would result in a very large span
                return to - BeatFromExclusive > HalfLoopBeats;
            }
            else
            {
                // straightforward requirement that time is monotonic
                return BeatFromExclusive > BeatToInclusive;
            }
        }

        public readonly bool IsWrapped()
        {
            return IsLooping && !IsEmpty() && BeatToInclusive < BeatFromExclusive;
        }

        public readonly override string ToString()
        {
            return $"{nameof(BeatTimeSpan)}({(IsLooping ? 'Y' : 'n')}{(IsExtrapolated ? 'E' : '_')}, {BeatFromExclusive:N4}..{BeatToInclusive:N4}/{LoopBeats}{(IsEmpty() ? " Empty!" : "")})";
        }
    }

    class ExtrapolatedAudioSourceState
    {
        // AudioSource.isPlaying
        public bool IsPlaying { get; private set; }

        // AudioSource.time, possibly extrapolated
        public float Time => ExtrapolatedTime;

        // The object is newly created, the AudioSource began to play (possibly delayed) but its time hasn't advanced from 0.0f yet.
        // Time can not be extrapolated when HasStarted is false.
        public bool HasStarted { get; private set; } = false;

        public bool IsExtrapolated => LastKnownNonExtrapolatedTime != ExtrapolatedTime;

        private float ExtrapolatedTime = 0f;

        private float LastKnownNonExtrapolatedTime = 0f;

        // Any wall clock based measurements of when this state was recorded
        private float LastKnownRealtime = 0f;

        private const float MaxExtrapolationInterval = 0.5f;

        public void Update(AudioSource audioSource, float realtime)
        {
            IsPlaying = audioSource.isPlaying;
            HasStarted |= audioSource.time != 0f;

            if (LastKnownNonExtrapolatedTime != audioSource.time)
            {
                LastKnownRealtime = realtime;
                LastKnownNonExtrapolatedTime = ExtrapolatedTime = audioSource.time;
            }
            // Frames are rendering faster than AudioSource updates its playback time state
            else if (IsPlaying && HasStarted)
            {
#if DEBUG
                Debug.Assert(LastKnownNonExtrapolatedTime == audioSource.time); // implied
#endif
                var deltaTime = realtime - LastKnownRealtime;
                if (0 < deltaTime && deltaTime < MaxExtrapolationInterval)
                {
                    ExtrapolatedTime = LastKnownNonExtrapolatedTime + deltaTime;
                }
            }
        }

        public override string ToString()
        {
            return $"{nameof(ExtrapolatedAudioSourceState)}({(IsPlaying ? 'P' : '_')}{(HasStarted ? 'S' : '0')} "
                + (IsExtrapolated
                    ? $"{LastKnownRealtime:N4}, {LastKnownNonExtrapolatedTime:N4} => {ExtrapolatedTime:N4}"
                    : $"{LastKnownRealtime:N4}, {LastKnownNonExtrapolatedTime:N4}"
                ) + ")";
        }
    }

    class JesterAudioSourcesState
    {
        private readonly float IntroClipLength;

        // Neither intro.isPlaying or loop.isPlaying are reliable indicators of which track is actually playing right now:
        // intro.isPlaying would be true during the loop when Jester chases a player,
        // loop.isPlaying would be true when it is played delyaed but hasn't actually started playing yet.
        private readonly ExtrapolatedAudioSourceState Intro = new();

        private readonly ExtrapolatedAudioSourceState Loop = new();

        // If true, use Start state as a reference, otherwise use Loop.
        private bool ReferenceIsIntro = true;

        public bool HasStarted => Intro.HasStarted;

        public bool IsExtrapolated => ReferenceIsIntro ? Intro.IsExtrapolated : Loop.IsExtrapolated;

        // Time from the start of the start clip. It wraps when the loop AudioSource loops:
        // [...start...][...loop...]
        //              ^          |
        //              `----------'
        public float Time => ReferenceIsIntro
            ? Intro.Time
            : IntroClipLength + Loop.Time;

        public JesterAudioSourcesState(float introClipLength)
        {
            IntroClipLength = introClipLength;
        }

        public void Update(AudioSource intro, AudioSource loop, float realtime)
        {
            // It doesn't make sense to update start state after loop has started (because start.isPlaying occasionally becomes true).
            // But always makes sense to update loop, so we can check if it has actually started.
            Loop.Update(loop, realtime);

            if (!Loop.HasStarted)
            {
#if DEBUG
                Debug.Assert(ReferenceIsIntro);
#endif
                Intro.Update(intro, realtime);
            }
            else
            {
                ReferenceIsIntro = false;
            }
        }
    }

    // This class tracks looping state of the playback, so that the timestamps can be correctly wrapped only when needed.
    // [... ...time... ...]
    //            ^       |
    //            `---|---' loop
    //                ^ IsLooping becomes true and stays true forever.
    class AudioLoopingState
    {
        public bool IsLooping { get; private set; } = false;

        private readonly float StartOfLoop;
        private readonly float LoopLength;
        private readonly int Beats;

        public AudioLoopingState(float startOfLoop, float loopLength, int beats)
        {
            StartOfLoop = startOfLoop;
            LoopLength = loopLength;
            Beats = beats;
        }

        public BeatTimestamp Update(float time, bool isExtrapolated, float additionalOffset)
        {
            // If popped, calculate which beat the music is currently at.
            // In order to do that we should choose one of two strategies:
            //
            // 1. If start source is still playing, use its position since WindUpTimer.
            // 2. Otherwise use loop source, adding the delay after WindUpTimer,
            //    which is the remaining of the start, i.e. (LoadedStart.length - WindUpTimer).
            //
            // NOTE 1: PlayDelayed also counts as isPlaying, so loop.isPlaying is always true and as such it's useful.
            // NOTE 2: There is a weird state when Jester has popped and chases a player:
            //         Intro/farAudio isPlaying is true but stays exactly at zero time, so we need to ignore that.

            var offset = StartOfLoop + additionalOffset;

            float timeSinceStartOfLoop = time - offset;

            var adjustedTimeNormalized = (LoopLength <= 0f) ? 0f : timeSinceStartOfLoop / LoopLength;

            var beat = adjustedTimeNormalized * Beats;

            // Let it infer the isLooping flag from the beat
            var timestamp = new BeatTimestamp(Beats, IsLooping, beat, isExtrapolated);

            IsLooping |= timestamp.IsLooping;

#if DEBUG && false
            Plugin.Log.LogDebug(string.Format("t={0,10:N4} d={1,7:N4} {2} Time={3:N4} norm={4,6:N4} beat={5,7:N4}",
                Time.realtimeSinceStartup, Time.deltaTime,
                isExtrapolated ? 'E' : '_', time,
                adjustedTimeNormalized, beat));
#endif

            return timestamp;
        }
    }

    class BeatTimeState
    {
        private readonly IAudioTrack track;

        private readonly JesterAudioSourcesState AudioState;

        // Colors wrap from WindUpTimer
        private readonly AudioLoopingState WindUpLoopingState;

        // Events other than colors wrap from WindUpTimer+LoopOffset.
        private readonly AudioLoopingState LoopLoopingState;

        private float LastKnownLoopOffsetBeat = float.NegativeInfinity;

        private static System.Random LyricsRandom = null!;

        private int LyricsRandomPerLoop;

        private bool WindUpZeroBeatEventTriggered = false;

        public BeatTimeState(IAudioTrack track)
        {
            if (LyricsRandom == null)
            {
                LyricsRandom = new System.Random(RoundManager.Instance.playersManager.randomMapSeed + 1337);
                LyricsRandomPerLoop = LyricsRandom.Next();
            }
            this.track = track;
            AudioState = new(track.LoadedIntro?.length ?? 0f);
            var loadedLoopLength = track.LoadedLoop?.length ?? 0f;
            WindUpLoopingState = new(track.WindUpTimer, loadedLoopLength, track.Beats);
            LoopLoopingState = new(track.WindUpTimer + track.LoopOffsetInSeconds, loadedLoopLength, track.Beats);
        }

        public List<BaseEvent> Update(AudioSource intro, AudioSource loop)
        {
            var time = Time.realtimeSinceStartup;
            AudioState.Update(intro, loop, time);

            if (AudioState.HasStarted)
            {
                var loopOffsetTimestamp = Update(LoopLoopingState);
                var loopOffsetSpan = BeatTimeSpan.Between(LastKnownLoopOffsetBeat, loopOffsetTimestamp);

                // Do not go back in time
                if (!loopOffsetSpan.IsEmpty())
                {
                    if (loopOffsetSpan.BeatFromExclusive > loopOffsetSpan.BeatToInclusive)
                    {
                        LyricsRandomPerLoop = LyricsRandom.Next();
                    }

                    var windUpOffsetTimestamp = Update(WindUpLoopingState);
                    LastKnownLoopOffsetBeat = loopOffsetTimestamp.Beat;
                    var events = GetEvents(loopOffsetTimestamp, loopOffsetSpan, windUpOffsetTimestamp);
#if DEBUG
                    Plugin.Log.LogDebug($"looping? {(LoopLoopingState.IsLooping ? 'X' : '_')}{(WindUpLoopingState.IsLooping ? 'X' : '_')} Loop={loopOffsetSpan} WindUp={windUpOffsetTimestamp} Time={Time.realtimeSinceStartup:N4} events={string.Join(",", events)}");
#endif
                    return events;
                }
            }

            return [];
        }

        private BeatTimestamp Update(AudioLoopingState loopingState)
        {
            return loopingState.Update(AudioState.Time, AudioState.IsExtrapolated, AdditionalOffset());
        }

        // Timings that may be changed through config
        private float AdditionalOffset()
        {
            return Config.AudioOffset.Value + track.BeatsOffsetInSeconds;
        }

        private List<BaseEvent> GetEvents(BeatTimestamp loopOffsetTimestamp, BeatTimeSpan loopOffsetSpan, BeatTimestamp windUpOffsetTimestamp)
        {
            List<BaseEvent> events = [];

            if (windUpOffsetTimestamp.Beat >= 0f && !WindUpZeroBeatEventTriggered)
            {
                events.Add(new WindUpZeroBeatEvent());
                WindUpZeroBeatEventTriggered = true;
            }

            if (GetColorEvent(loopOffsetSpan, windUpOffsetTimestamp) is { } colorEvent)
            {
                events.Add(colorEvent);
            }

            if (loopOffsetSpan.GetLastIndex(track.FlickerLightsTimeSeries) != null)
            {
                events.Add(new FlickerLightsEvent());
            }

            // TODO: quick editor
            if (!Config.ReduceVFXAndHideLyrics.Value)
            {
                var index = loopOffsetSpan.GetLastIndex(track.LyricsTimeSeries);
                if (index is int i && i < track.LyricsLines.Length)
                {
                    var line = track.LyricsLines[i];
                    var alternatives = line.Split('\t');
                    var randomIndex = LyricsRandomPerLoop % alternatives.Length;
                    var alternative = alternatives[randomIndex];
                    if (alternative != "")
                    {
                        events.Add(new LyricsEvent(alternative));
                    }
                }
            }

            if (GetInterpolation(loopOffsetTimestamp, track.DrunknessLoopOffsetTimeSeries, Easing.Linear) is { } drunkness)
            {
                var value = Config.ReduceVFXAndHideLyrics.Value ? drunkness * 0.3f : drunkness;
                events.Add(new DrunkEvent(value));
            }

            if (GetInterpolation(loopOffsetTimestamp, track.CondensationLoopOffsetTimeSeries, Easing.Linear) is { } condensation)
            {
                events.Add(new CondensationEvent(condensation));
            }

            return events;
        }

        private SetLightsColorEvent? GetColorEvent(BeatTimeSpan loopOffsetSpan, BeatTimestamp windUpOffsetTimestamp)
        {
            if (FadeOut(loopOffsetSpan, windUpOffsetTimestamp) is { } colorEvent1)
            {
                return colorEvent1;
            }

            if (ColorFromPaletteAtTimestamp(windUpOffsetTimestamp) is { } colorEvent2)
            {
                return colorEvent2;
            }

            return null;
        }

        private SetLightsColorTransitionEvent? FadeOut(BeatTimeSpan loopOffsetSpan, BeatTimestamp windUpOffsetTimestamp)
        {
            var fadeOutStart = track.FadeOutBeat;
            var fadeOutEnd = fadeOutStart + track.FadeOutDuration;

            if (windUpOffsetTimestamp.Beat < 0f && track.FadeOutBeat < loopOffsetSpan.BeatToInclusive && loopOffsetSpan.BeatFromExclusive <= fadeOutEnd)
            {
                var t = (loopOffsetSpan.BeatToInclusive - track.FadeOutBeat) / track.FadeOutDuration;
                return new SetLightsColorTransitionEvent(/* use initial light color */null, Color.black, Easing.Linear, t);
            }
            else
            {
                return null;
            }
        }

        public SetLightsColorEvent? ColorFromPaletteAtTimestamp(BeatTimestamp timestamp)
        {
            if (timestamp.Beat <= -track.ColorTransitionIn)
            {
                return null;
            }

            // Imagine the timeline as a sequence of clips without gaps where each clip is a whole beat long.
            // Transition is when two adjacent clips need to be combined with some blend function(t)
            //     where t is a factor in range 0..1 expressed as (time - Transition.Start) / Transition.Length;
            //
            // How to find a transition at a given time?
            // First, we need to find the current clip's start and length.
            // - Length is always 1 beat, and
            // - start is just time rounded down.
            //
            // If time interval from the start of the clip is less than Transition.Out
            // then blend between previous and current clips.
            //
            // Else if time interval to the end of the clip is less than Transition.In
            // then blend between current and next clips.
            //
            // Otherwise there is no transition running at this time.
            const float currentClipLength = 1f;
            var currentClipStart = timestamp.Floor();
            var currentClipEnd = currentClipStart + currentClipLength;

            float transitionLength = track.ColorTransitionIn + track.ColorTransitionOut;

            if (transitionLength > /* epsilon */ 0.01)
            {
                if (BeatTimeSpan.Between(currentClipStart, timestamp).Duration() < track.ColorTransitionOut)
                {
                    return ColorTransition(currentClipStart);
                }
                else if (BeatTimeSpan.Between(timestamp, currentClipEnd).Duration() < track.ColorTransitionIn)
                {
                    return ColorTransition(currentClipEnd);
                }
            }
            // default
            return new SetLightsColorStaticEvent(ColorAtWholeBeat(timestamp));

            SetLightsColorTransitionEvent ColorTransition(BeatTimestamp clipsBoundary)
            {
                var transitionStart = clipsBoundary - track.ColorTransitionIn;
                var transitionEnd = clipsBoundary + track.ColorTransitionOut;
                var t = BeatTimeSpan.Between(transitionStart, timestamp).Duration() / transitionLength;
                if (track.ColorTransitionIn == 0.0f)
                {
                    // Subtract an epsilon, so we don't use the same beat twice
                    transitionStart -= 0.01f;
                }
                return new SetLightsColorTransitionEvent(ColorAtWholeBeat(transitionStart), ColorAtWholeBeat(transitionEnd), track.ColorTransitionEasing, t);
            }

            Color? ColorAtWholeBeat(BeatTimestamp timestamp)
            {
                if (timestamp.Beat >= 0f)
                {
                    int wholeBeat = Mathf.FloorToInt(timestamp.Beat);
                    return Mod.Index(track.Palette.Colors, wholeBeat);
                }
                else
                {
                    return float.IsNaN(track.FadeOutBeat) ? /* use initial light color */ null : Color.black;
                }
            }
        }

        private float? GetInterpolation(BeatTimestamp timestamp, TimeSeries<float> timeSeries, Easing easing)
        {
            if (timeSeries.Length == 0)
            {
                return null;
            }
            else if (timeSeries.Length == 1)
            {
                return timeSeries.Values[0];
            }
            else
            {
                int? indexOfPrevious = null;
                // Find index of the previous time. If looped, wrap backwards. In either case it is possibly missing.
                for (int i = timeSeries.Length - 1; i >= 0; i--)
                {
                    if (timeSeries.Beats[i] <= timestamp.Beat)
                    {
                        indexOfPrevious = i;
                        break;
                    }
                }
                if (indexOfPrevious == null && timestamp.IsLooping)
                {
                    indexOfPrevious = timeSeries.Length - 1;
                }

                // Find index of the next time. If looped, wrap forward.
                int? indexOfNext = null;
                for (int i = 0; i < timeSeries.Length; i++)
                {
                    if (timeSeries.Beats[i] >= timestamp.Beat)
                    {
                        indexOfNext = i;
                        break;
                    }
                }
                if (indexOfNext == null && timestamp.IsLooping)
                {
                    for (int i = 0; i < timeSeries.Length; i++)
                    {
                        if (timeSeries.Beats[i] >= 0f)
                        {
                            indexOfNext = i;
                            break;
                        }
                    }
                }

                switch (indexOfPrevious, indexOfNext)
                {
                    case (null, null):
                        return null;

                    case (null, { } index):
                        return timeSeries.Values[index];

                    case ({ } index, null):
                        return timeSeries.Values[index];

                    case ({ } prev, { } next) when prev == next || timeSeries.Beats[prev] == timeSeries.Beats[next]:
                        return timeSeries.Values[prev];

                    case ({ } prev, { } next):
                        var prevBeat = timeSeries.Beats[prev];
                        var nextBeat = timeSeries.Beats[next];
                        var prevTimestamp = new BeatTimestamp(timestamp.LoopBeats, isLooping: false, prevBeat, false);
                        var nextTimestamp = new BeatTimestamp(timestamp.LoopBeats, isLooping: false, nextBeat, false);
                        var t = BeatTimeSpan.Between(prevTimestamp, timestamp).Duration(longest: true)
                            / BeatTimeSpan.Between(prevTimestamp, nextTimestamp).Duration(longest: true);
                        var prevVal = timeSeries.Values[prev];
                        var nextVal = timeSeries.Values[next];
                        var val = Mathf.Lerp(prevVal, nextVal, easing.Eval(t));
                        return val;
                }
            }
        }
    }

    abstract class BaseEvent;

    abstract class SetLightsColorEvent : BaseEvent
    {
        // Calculate final color, substituting null with initialColor if needed.
        public abstract Color GetColor(Color initialColor);

        protected string NullableColorToString(Color? color)
        {
            return color is { } c ? ColorUtility.ToHtmlStringRGB(c) : "??????";
        }
    }

    class SetLightsColorStaticEvent(Color? color) : SetLightsColorEvent
    {
        public readonly Color? Color = color;

        public override Color GetColor(Color initialColor)
        {
            return Color ?? initialColor;
        }

        public override string ToString()
        {
            return $"Color(#{NullableColorToString(Color)})";
        }
    }

    class SetLightsColorTransitionEvent(Color? from, Color? to, Easing easing, float t) : SetLightsColorEvent
    {
        // Additional context for debugging
        public readonly Color? From = from;
        public readonly Color? To = to;
        public readonly Easing Easing = easing;
        public readonly float T = t;

        public override Color GetColor(Color initialColor)
        {
            var from = From ?? initialColor;
            var to = To ?? initialColor;
            return Color.Lerp(from, to, Mathf.Clamp(Easing.Eval(T), 0f, 1f));
        }

        private Color? GetNullableColor()
        {
            return From is { } from && To is { } to ? Color.Lerp(from, to, Mathf.Clamp(Easing.Eval(T), 0f, 1f)) : null;
        }

        public override string ToString()
        {
            return $"Color(#{NullableColorToString(GetNullableColor())} = #{NullableColorToString(From)}..#{NullableColorToString(To)} {Easing} {T:N4})";
        }
    }

    class FlickerLightsEvent : BaseEvent
    {
        public override string ToString() => "Flicker";
    }

    class LyricsEvent(string text) : BaseEvent
    {
        public readonly string Text = text;
        public override string ToString()
        {
            return $"Lyrics({Text.Replace("\n", "\\n")})";
        }
    }

    class WindUpZeroBeatEvent : BaseEvent
    {
        public override string ToString() => "WindUp";
    }

    abstract class HUDEvent : BaseEvent;

    class DrunkEvent(float drunkness) : HUDEvent
    {
        public readonly float Drunkness = drunkness;
        public override string ToString() => $"Drunk({Drunkness:N2})";
    }

    class CondensationEvent(float condensation) : HUDEvent
    {
        public readonly float Condensation = condensation;
        public override string ToString() => $"Condensation({Condensation:N2})";
    }

    // Default C#/.NET remainder operator % returns negative result for negative input
    // which is unsuitable as an index for an array.
    static class Mod
    {
        public static int Positive(int x, int m)
        {
            int r = x % m;
            return r < 0 ? r + m : r;
        }

        public static float Positive(float x, float m)
        {
            float r = x % m;
            return r < 0f ? r + m : r;
        }

        public static T Index<T>(IList<T> array, int index)
        {
            return array[Mod.Positive(index, array.Count)];
        }
    }

    readonly struct RandomWeightedIndex
    {
        public RandomWeightedIndex(int[] weights)
        {
            Weights = weights;
            TotalWeights = Weights.Sum();
            if (TotalWeights == 0)
            {
                // If everything is set to zero, everything is equally possible
                Weights = [.. Weights.Select(_ => 1)];
                TotalWeights = Weights.Length;
            }
        }

        private byte[] GetHash(int seed)
        {
            var buffer = new byte[4 * (1 + Weights.Length)];
            var offset = 0;
            Buffer.BlockCopy(BitConverter.GetBytes(seed), 0, buffer, offset, sizeof(int));
            // Make sure that tweaking weights even a little drastically changes the outcome
            foreach (var weight in Weights)
            {
                offset += 4;
                Buffer.BlockCopy(BitConverter.GetBytes(weight), 0, buffer, offset, sizeof(int));
            }
            var sha = SHA256.Create();
            var hash = sha.ComputeHash(buffer);
            return hash;
        }

        private int GetRawIndex(byte[] hash)
        {
            if (TotalWeights == 0)
            {
                // Should not happen, but what if Weights array is empty?
                return -1;
            }

            var index = 0;
            foreach (var t in hash)
            {
                // modulus division on byte array
                index *= 256 % TotalWeights;
                index %= TotalWeights;
                index += t % TotalWeights;
                index %= TotalWeights;
            }
            return index;
        }

        private int GetWeightedIndex(int rawIndex)
        {
            if (rawIndex < 0 || rawIndex >= TotalWeights)
            {
                return -1;
            }

            int sum = 0;
            foreach (var (weight, index) in Weights.Select((x, i) => (x, i)))
            {
                sum += weight;
                if (rawIndex < sum)
                {
                    // Found
                    return index;
                }
            }

            return -1;
        }

        public int GetRandomWeightedIndex(int seed)
        {
            var hash = GetHash(seed);
            var index = GetRawIndex(hash);
            return GetWeightedIndex(index);
        }

        public override string ToString()
        {
            return $"Weighted(Total={TotalWeights}, Weights=[{string.Join(',', Weights)}])";
        }

        readonly private int[] Weights;
        readonly public int TotalWeights { get; }
    }

    class Config
    {
        public static ConfigEntry<bool> ReduceVFXAndHideLyrics { get; private set; } = null!;

        public static ConfigEntry<float> AudioOffset { get; private set; } = null!;

        public static ConfigEntry<bool> SkipExplicitTracks { get; private set; } = null!;

        public static ConfigEntry<bool> OverrideSpawnRates { get; private set; } = null!;

        public static bool ShouldSkipWindingPhase { get; private set; } = false;
        public static bool VanillaCompatMode { get; private set; } = false;

        // Audio files are normalized to target -14 LUFS, which is too loud to communicate. Reduce by another -9 dB down to about -23 LUFS.
        private const float VolumeDefault = 0.35f;
        private const float VolumeMin = 0.2f;
        private const float VolumeMax = 0.5f;
        // Ranges from quiet 0.20 (-14 dB) to loud 0.5 (-6 dB)
        public static ConfigEntry<float> Volume { get; private set; } = null!;
#if DEBUG
        // Latest set track, used for loading palette and timings.
        private static IAudioTrack? CurrentTrack = null;
        // All per-track values that can be overridden
        private static float? BeatsOffsetOverride = null;
        private static float? FadeOutBeatOverride = null;
        private static float? FadeOutDurationOverride = null;
        private static float? ColorTransitionInOverride = null;
        private static float? ColorTransitionOutOverride = null;
        private static string? ColorTransitionEasingOverride = null;
        private static float[]? FlickerLightsTimeSeriesOverride = null;
        private static float[]? LyricsTimeSeriesOverride = null;
        private static TimeSeries<float>? DrunknessLoopOffsetTimeSeriesOverride = null;
        private static TimeSeries<float>? CondensationLoopOffsetTimeSeriesOverride = null;
        private static Palette? PaletteOverride = null;

        private class AudioTrackWithConfigOverride(IAudioTrack track) : ProxyAudioTrack(track), IAudioTrack
        {
            float IAudioTrack.BeatsOffset => BeatsOffsetOverride ?? Track.BeatsOffset;

            float IAudioTrack.FadeOutBeat => FadeOutBeatOverride ?? Track.FadeOutBeat;

            float IAudioTrack.FadeOutDuration => FadeOutDurationOverride ?? Track.FadeOutDuration;

            float IAudioTrack.ColorTransitionIn => ColorTransitionInOverride ?? Track.ColorTransitionIn;

            float IAudioTrack.ColorTransitionOut => ColorTransitionOutOverride ?? Track.ColorTransitionOut;

            Easing IAudioTrack.ColorTransitionEasing =>
                ColorTransitionEasingOverride != null
                    ? Easing.FindByName(ColorTransitionEasingOverride)
                    : Track.ColorTransitionEasing;

            float[] IAudioTrack.FlickerLightsTimeSeries =>
                FlickerLightsTimeSeriesOverride ?? Track.FlickerLightsTimeSeries;

            float[] IAudioTrack.LyricsTimeSeries => LyricsTimeSeriesOverride ?? Track.LyricsTimeSeries;

            TimeSeries<float> IAudioTrack.DrunknessLoopOffsetTimeSeries => DrunknessLoopOffsetTimeSeriesOverride ?? Track.DrunknessLoopOffsetTimeSeries;
            TimeSeries<float> IAudioTrack.CondensationLoopOffsetTimeSeries => CondensationLoopOffsetTimeSeriesOverride ?? Track.CondensationLoopOffsetTimeSeries;

            Palette IAudioTrack.Palette => PaletteOverride ?? Track.Palette;
        }
#endif

        internal Config(ConfigFile configFile)
        {
            OverrideSpawnRates = configFile.Bind("General", "Override Spawn Rates", true,
                new ConfigDescription("Deviate from vanilla spawn rates to experience content of this mod more often."));
            LethalConfigManager.AddConfigItem(new BoolCheckBoxConfigItem(OverrideSpawnRates, requiresRestart: false));

            ReduceVFXAndHideLyrics = configFile.Bind("General", "Reduce Visual Effects, Hide Lyrics", false,
                new ConfigDescription("Reduce intensity of certain visual effects, hide lyrics in the HUD tooltip when you hear the music."));
            LethalConfigManager.AddConfigItem(new BoolCheckBoxConfigItem(ReduceVFXAndHideLyrics, requiresRestart: false));

            SkipExplicitTracks = configFile.Bind("General", "Skip Explicit Tracks", false,
                new ConfigDescription("When choosing tracks at random, skip the ones with Explicit Content/Lyrics."));
            LethalConfigManager.AddConfigItem(new BoolCheckBoxConfigItem(SkipExplicitTracks, requiresRestart: false));

            Volume = configFile.Bind("General", "Volume", VolumeDefault,
                new ConfigDescription("Volume of music played by this mod.", new AcceptableValueRange<float>(VolumeMin, VolumeMax)));
            LethalConfigManager.AddConfigItem(new FloatSliderConfigItem(Volume, requiresRestart: false));

            AudioOffset = configFile.Bind("General", "Audio Offset", 0f, new ConfigDescription(
                "Adjust audio offset (in seconds).\n\nIf you are playing with Bluetooth headphones and experiencing a visual desync, try setting this to about negative 0.2.\n\nIf your video output has high latency (like a long HDMI cable etc.), try positive values instead.",
                new AcceptableValueRange<float>(-0.5f, 0.5f)));
            // too much configurability
            LethalConfigManager.SkipAutoGenFor(AudioOffset);

#if DEBUG
            SetupEntriesForGameOverText(configFile);
            SetupEntriesForScreenFilters(configFile);
            SetupEntriesToSkipWinding(configFile);
            SetupEntriesForPaletteOverride(configFile);
            SetupEntriesForTimingsOverride(configFile);
            SetupEntriesForVanillaCompatMode(configFile);
#endif

            var chanceRange = new AcceptableValueRange<int>(0, 100);
            var languageSectionButtonExists = new HashSet<Language>();

            foreach (var track in Plugin.Tracks)
            {
                if (!track.Enabled)
                {
                    // hide disabled tracks from user-facing config
                    continue;
                }
                var language = track.Language;
                string section = $"Tracks.{language.Short}";

                // Create section toggle
                if (!languageSectionButtonExists.Contains(language))
                {
                    languageSectionButtonExists.Add(language);
                    string buttonOptionName = $"Toggle all {language.Full} tracks";
                    string buttonDescription = "Toggle all tracks in this section ON or OFF. Effective immediately.";
                    string buttonText = "Toggle";
                    var button = new GenericButtonConfigItem(section, buttonOptionName, buttonDescription, buttonText, () =>
                    {
                        var tracks = Plugin.Tracks.Where(t => t.Language.Equals(language)).ToList();
                        var isOff = tracks.All(t => t.Weight.Value == 0);
                        var newWeight = isOff ? 50 : 0;
                        foreach (var t in tracks)
                        {
                            t.Weight.Value = newWeight;
                        }
                    });
                    LethalConfigManager.AddConfigItem(button);
                }

                // Create slider entry for track
                var seasonal = track.Season is Season season ? $"This is seasonal content for {season.Name}.\n\n" : "";
                string warning = track.IsExplicit ? "Explicit Content/Lyrics!\n\n" : "";
                string description = $"Song: {track.Song} by {track.Artist}\n\nLanguage: {language.Full}\n\n{seasonal}{warning}Random (relative) chance of selecting this track.\n\nSet to zero to effectively disable the track.";
                track.Weight = configFile.Bind(
                    new ConfigDefinition(section, track.Name),
                    50,
                    new ConfigDescription(description, chanceRange, track));

                LethalConfigManager.AddConfigItem(new IntSliderConfigItem(track.Weight, requiresRestart: false));
            }
        }

        internal static IAudioTrack OverrideCurrentTrack(IAudioTrack track)
        {
#if DEBUG
            CurrentTrack = track;
            return new AudioTrackWithConfigOverride(track);
#else
            return track;
#endif
        }

#if DEBUG
        private void SetupEntriesToSkipWinding(ConfigFile configFile)
        {
            var entry = configFile.Bind("General", "Skip Winding Phase", false,
                new ConfigDescription("Skip most of the wind-up/intro music.\n\nUse this option to test your Loop audio segment.\n\nDoes not work in Vanilla Compat Mode."));
            LethalConfigManager.AddConfigItem(new BoolCheckBoxConfigItem(entry, requiresRestart: false));
            entry.SettingChanged += (sender, args) => apply();
            apply();

            void apply()
            {
                ShouldSkipWindingPhase = entry.Value;
            }
        }

        private void SetupEntriesForVanillaCompatMode(ConfigFile configFile)
        {
            var entry = configFile.Bind("General", "Vanilla Compat Mode", false,
                new ConfigDescription("DO NOT ENABLE! Disables networking / synchronization!\n\nKeep vanilla wind-up timer, select tracks whose timer is close to vanilla.\n\nMay cause the audio to start playing earlier or later.\n\nIf you join a vanilla host you are always in compat mode."));
            LethalConfigManager.AddConfigItem(new BoolCheckBoxConfigItem(entry, requiresRestart: false));
            entry.SettingChanged += (sender, args) => apply();
            apply();

            void apply()
            {
                VanillaCompatMode = entry.Value;
            }
        }

        private void SetupEntriesForPaletteOverride(ConfigFile configFile)
        {
            const string section = "Palette";
            const int maxCustomPaletteSize = 8;
            // Declare and initialize early to avoid "Use of unassigned local variable"
            ConfigEntry<int> customPaletteSizeEntry = null!;
            var customPaletteEntries = new ConfigEntry<string>[maxCustomPaletteSize];

            var loadButton = new GenericButtonConfigItem(section, "Load Palette from the Current Track",
                "Override custom palette with the built-in palette of the current track.", "Load", load);
            LethalConfigManager.AddConfigItem(loadButton);

            customPaletteSizeEntry = configFile.Bind(section, "Palette Size", 0, new ConfigDescription(
                "Number of colors in the custom palette.\n\nIf set to non-zero, custom palette overrides track's own built-in palette.",
                new AcceptableValueRange<int>(0, maxCustomPaletteSize)));
            LethalConfigManager.AddConfigItem(new IntSliderConfigItem(customPaletteSizeEntry, requiresRestart: false));
            customPaletteSizeEntry.SettingChanged += (sender, args) => apply();

            for (int i = 0; i < maxCustomPaletteSize; i++)
            {
                string entryName = $"Custom Color {i + 1}";
                var customColorEntry = configFile.Bind(section, entryName, "#FFFFFF", "Choose color for the custom palette");
                customPaletteEntries[i] = customColorEntry;
                LethalConfigManager.AddConfigItem(new HexColorInputFieldConfigItem(customColorEntry, requiresRestart: false));
                customColorEntry.SettingChanged += (sender, args) => apply();
            }

            apply();

            void load()
            {
                var palette = CurrentTrack?.Palette ?? Palette.DEFAULT;
                var colors = palette.Colors;
                var count = Math.Min(colors.Count(), maxCustomPaletteSize);

                customPaletteSizeEntry.Value = colors.Count();
                for (int i = 0; i < maxCustomPaletteSize; i++)
                {
                    var color = i < count ? colors[i] : Color.white;
                    string colorHex = $"#{ColorUtility.ToHtmlStringRGB(color)}";
                    customPaletteEntries[i].Value = colorHex;
                }
            }

            void apply()
            {
                int size = customPaletteSizeEntry.Value;
                if (size == 0 || size > maxCustomPaletteSize)
                {
                    PaletteOverride = null;
                }
                else
                {
                    var colors = customPaletteEntries.Select(entry => entry.Value).Take(size).ToArray();
                    PaletteOverride = Palette.Parse(colors);
                }
            }
        }

        private void SetupEntriesForTimingsOverride(ConfigFile configFile)
        {
            const string section = "Timings";
            var colorTransitionRange = new AcceptableValueRange<float>(0f, 1f);
            // Declare and initialize early to avoid "Use of unassigned local variable"
            List<(Action<IAudioTrack?> Load, Action Apply)> entries = [];
            ConfigEntry<bool> overrideTimingsEntry = null!;
            ConfigEntry<float> fadeOutBeatEntry = null!;
            ConfigEntry<float> fadeOutDurationEntry = null!;
            ConfigEntry<string> flickerLightsTimeSeriesEntry = null!;
            ConfigEntry<string> lyricsTimeSeriesEntry = null!;
            ConfigEntry<string> drunknessTimeSeriesEntry = null!;
            ConfigEntry<string> condensationTimeSeriesEntry = null!;
            ConfigEntry<float> beatsOffsetEntry = null!;
            ConfigEntry<float> colorTransitionInEntry = null!;
            ConfigEntry<float> colorTransitionOutEntry = null!;
            ConfigEntry<string> colorTransitionEasingEntry = null!;

            var loadButton = new GenericButtonConfigItem(section, "Load Timings from the Current Track",
                "Override custom timings with the built-in timings of the current track.", "Load", load);
            LethalConfigManager.AddConfigItem(loadButton);

            overrideTimingsEntry = configFile.Bind(section, "Override Timings", false,
                new ConfigDescription("If checked, custom timings override track's own built-in timings."));
            LethalConfigManager.AddConfigItem(new BoolCheckBoxConfigItem(overrideTimingsEntry, requiresRestart: false));
            overrideTimingsEntry.SettingChanged += (sender, args) => apply();

            fadeOutBeatEntry = configFile.Bind(section, "Fade Out Beat", 0f,
                new ConfigDescription("The beat at which to start fading out", new AcceptableValueRange<float>(-1000f, 0)));
            fadeOutDurationEntry = configFile.Bind(section, "Fade Out Duration", 0f,
                new ConfigDescription("Duration of fading out", new AcceptableValueRange<float>(0, 10)));
            flickerLightsTimeSeriesEntry = configFile.Bind(section, "Flicker Lights Time Series", "",
                new ConfigDescription("Time series of loop offset beats when to flicker the lights."));
            lyricsTimeSeriesEntry = configFile.Bind(section, "Lyrics Time Series", "",
                new ConfigDescription("Time series of loop offset beats when to show lyrics lines."));
            drunknessTimeSeriesEntry = configFile.Bind(section, "Drunkness", "",
                new ConfigDescription("Time series of loop offset beats which are keyframes for the drunkness effect. Format: 'time1: value1, time2: value2"));
            condensationTimeSeriesEntry = configFile.Bind(section, "Helmet Condensation Drops", "",
                new ConfigDescription("Time series of loop offset beats which are keyframes for the Helmet Condensation Drops effect. Format: 'time1: value1, time2: value2"));
            beatsOffsetEntry = configFile.Bind(section, "Beats Offset", 0f,
                new ConfigDescription("How much to offset the whole beat. More is later", new AcceptableValueRange<float>(-0.5f, 0.5f)));
            colorTransitionInEntry = configFile.Bind(section, "Color Transition In", 0.25f,
                new ConfigDescription("Fraction of a beat *before* the whole beat when the color transition should start.", colorTransitionRange));
            colorTransitionOutEntry = configFile.Bind(section, "Color Transition Out", 0.25f,
                new ConfigDescription("Fraction of a beat *after* the whole beat when the color transition should end.", colorTransitionRange));
            colorTransitionEasingEntry = configFile.Bind(section, "Color Transition Easing", Easing.Linear.Name,
                new ConfigDescription("Interpolation/easing method to use for color transitions", new AcceptableValueList<string>(Easing.AllNames)));

            LethalConfigManager.AddConfigItem(new FloatSliderConfigItem(fadeOutBeatEntry, requiresRestart: false));
            LethalConfigManager.AddConfigItem(new FloatSliderConfigItem(fadeOutDurationEntry, requiresRestart: false));
            LethalConfigManager.AddConfigItem(new TextInputFieldConfigItem(flickerLightsTimeSeriesEntry, requiresRestart: false));
            LethalConfigManager.AddConfigItem(new TextInputFieldConfigItem(lyricsTimeSeriesEntry, requiresRestart: false));
            LethalConfigManager.AddConfigItem(new TextInputFieldConfigItem(drunknessTimeSeriesEntry, requiresRestart: false));
            LethalConfigManager.AddConfigItem(new TextInputFieldConfigItem(condensationTimeSeriesEntry, requiresRestart: false));
            LethalConfigManager.AddConfigItem(new FloatSliderConfigItem(beatsOffsetEntry, requiresRestart: false));
            LethalConfigManager.AddConfigItem(new FloatSliderConfigItem(colorTransitionInEntry, requiresRestart: false));
            LethalConfigManager.AddConfigItem(new FloatSliderConfigItem(colorTransitionOutEntry, requiresRestart: false));
            LethalConfigManager.AddConfigItem(new TextDropDownConfigItem(colorTransitionEasingEntry, requiresRestart: false));

            registerStruct(fadeOutBeatEntry, t => t.FadeOutBeat, x => FadeOutBeatOverride = x);
            registerStruct(fadeOutDurationEntry, t => t.FadeOutDuration, x => FadeOutDurationOverride = x);
            registerArray(flickerLightsTimeSeriesEntry, t => t.FlickerLightsTimeSeries, xs => FlickerLightsTimeSeriesOverride = xs, float.Parse, sort: true);
            registerArray(lyricsTimeSeriesEntry, t => t.LyricsTimeSeries, xs => LyricsTimeSeriesOverride = xs, float.Parse, sort: true);
            registerTimeSeries(drunknessTimeSeriesEntry, t => t.DrunknessLoopOffsetTimeSeries, xs => DrunknessLoopOffsetTimeSeriesOverride = xs, float.Parse, f => f.ToString());
            registerTimeSeries(condensationTimeSeriesEntry, t => t.CondensationLoopOffsetTimeSeries, xs => CondensationLoopOffsetTimeSeriesOverride = xs, float.Parse, f => f.ToString());
            registerStruct(beatsOffsetEntry, t => t.BeatsOffset, x => BeatsOffsetOverride = x);
            registerStruct(colorTransitionInEntry, t => t.ColorTransitionIn, x => ColorTransitionInOverride = x);
            registerStruct(colorTransitionOutEntry, t => t.ColorTransitionOut, x => ColorTransitionOutOverride = x);
            registerClass(colorTransitionEasingEntry, t => t.ColorTransitionEasing.Name, x => ColorTransitionEasingOverride = x);

            void register<T>(ConfigEntry<T> entry, Func<IAudioTrack, T> getter, Action applier)
            {
                entry.SettingChanged += (sender, args) => applier();
                void loader(IAudioTrack? track)
                {
                    // if track is null, set everything to defaults
                    entry.Value = track == null ? (T)entry.DefaultValue : getter(track);
                }
                entries.Add((loader, applier));
            }

            void registerStruct<T>(ConfigEntry<T> entry, Func<IAudioTrack, T> getter, Action<T?> setter) where T : struct =>
                register(entry, getter, () => setter.Invoke(overrideTimingsEntry.Value ? entry.Value : null));
            void registerClass<T>(ConfigEntry<T> entry, Func<IAudioTrack, T> getter, Action<T?> setter) where T : class =>
                register(entry, getter, () => setter.Invoke(overrideTimingsEntry.Value ? entry.Value : null));
            void registerArray<T>(ConfigEntry<string> entry, Func<IAudioTrack, T[]> getter, Action<T[]?> setter, Func<string, T> parser, bool sort = false) where T : struct =>
                register(entry,
                    (track) => string.Join(", ", getter(track)),
                    () =>
                    {
                        var values = parseStringArray(entry.Value, parser, sort);
                        if (values != null)
                        {
                            // ensure the entry is sorted and formatted
                            entry.Value = string.Join(", ", values);
                        }
                        setter.Invoke(overrideTimingsEntry.Value ? values : null);
                    });
            void registerTimeSeries<T>(ConfigEntry<string> entry, Func<IAudioTrack, TimeSeries<T>> getter, Action<TimeSeries<T>?> setter, Func<string, T> parser, Func<T, string> formatter) =>
                register(entry,
                    (track) =>
                    {
                        var ts = getter(track);
                        return formatTimeSeries(ts, formatter);
                    },
                    () =>
                    {
                        var ts = parseTimeSeries(entry.Value, parser);
                        if (ts is { } timeSeries)
                        {
                            entry.Value = formatTimeSeries(timeSeries, formatter);
                        }
                        setter.Invoke(overrideTimingsEntry.Value ? ts : null);
                    });

            // current restriction is that formatted value can not contain commas or semicolons.
            TimeSeries<T>? parseTimeSeries<T>(string str, Func<string, T> parser)
            {
                try
                {
                    if (string.IsNullOrWhiteSpace(str))
                    {
                        return null;
                    }

                    List<float> beats = [];
                    List<T> values = [];
                    foreach (var pair in str.Split(","))
                    {
                        if (string.IsNullOrWhiteSpace(pair))
                        {
                            continue;
                        }
                        var keyvalue = pair.Split(":");
                        if (keyvalue.Length != 2)
                        {
                            throw new FormatException($"Pair must be separated by exactly one semicolon: '{pair}'");
                        }
                        var beat = float.Parse(keyvalue[0].Trim());
                        var val = parser(keyvalue[1].Trim());
                        beats.Add(beat);
                        values.Add(val);
                    }
                    var ts = new TimeSeries<T>(beats.ToArray(), values.ToArray());
                    return ts;
                }
                catch (Exception e)
                {
                    Plugin.Log.LogError($"Unable to parse time series: {e}");
                    return null;
                }
            }
            string formatTimeSeries<T>(TimeSeries<T> ts, Func<T, string> formatter)
            {
                StringBuilder strings = new();
                for (int i = 0; i < ts.Length; i++)
                {
                    var beat = ts.Beats[i];
                    var value = formatter(ts.Values[i]);
                    strings.Append($"{beat}: {value}");
                    if (i != ts.Length - 1)
                    {
                        strings.Append(", ");
                    }
                }
                Plugin.Log.LogDebug($"format time series {ts} {strings}");
                return strings.ToString();
            }
            T[]? parseStringArray<T>(string str, Func<string, T> parser, bool sort = false) where T : struct
            {
                try
                {
                    T[] xs = str.Replace(" ", "").Split(",").Select(parser).ToArray();
                    Array.Sort(xs);
                    return xs;
                }
                catch (Exception e)
                {
                    Plugin.Log.LogError($"Unable to parse array: {e}");
                    return null;
                }
            }

            void load()
            {
                foreach (var entry in entries)
                {
                    entry.Load(CurrentTrack);
                }
            }

            void apply()
            {
                foreach (var entry in entries)
                {
                    entry.Apply();
                }
            }
        }

        private void SetupEntriesForGameOverText(ConfigFile configFile)
        {
            const string section = "Game Over";
            var gameOverTextConfigEntry = configFile.Bind(section, "Game Over Text", DeathScreenGameOverTextManager.GameOverTextModdedDefault,
                new ConfigDescription("Custom Game Over text to show."));
            LethalConfigManager.AddConfigItem(new GenericButtonConfigItem(section, "Game Over Animation",
                "Run Death Screen / Game Over animation 3 times.", "Trigger", () =>
                {
                    HUDManager.Instance.StartCoroutine(AnimateGameOverText(gameOverTextConfigEntry.Value));
                }));
            LethalConfigManager.AddConfigItem(new TextInputFieldConfigItem(gameOverTextConfigEntry, requiresRestart: false));
        }

        static IEnumerator AnimateGameOverText(string text)
        {
            yield return new WaitForSeconds(1f);
            for (int i = 0; i < 3; i++)
            {
                DeathScreenGameOverTextManager.SetText(text);
                HUDManager.Instance.gameOverAnimator.SetTrigger("gameOver");
                yield return new WaitForSeconds(5f);
                HUDManager.Instance.gameOverAnimator.SetTrigger("revive");
                yield return new WaitForSeconds(1f);
            }
            DeathScreenGameOverTextManager.Clear();
        }

        private void SetupEntriesForScreenFilters(ConfigFile configFile)
        {
            const string section = "Screen Filters";

            var drunkConfigEntry = configFile.Bind(section, "Drunkness Level", 0f,
                new ConfigDescription("Override drunkness level in Screen Filters Manager."));
            LethalConfigManager.AddConfigItem(new FloatSliderConfigItem(drunkConfigEntry, requiresRestart: false));
            drunkConfigEntry.SettingChanged += (sender, args) =>
            {
                ScreenFiltersManager.Drunkness = drunkConfigEntry.Value;
            };

            var condensationConfigEntry = configFile.Bind(section, "Condensation Level", 0f,
                new ConfigDescription("Override drunkness level in Screen Filters Manager."));
            LethalConfigManager.AddConfigItem(new FloatSliderConfigItem(condensationConfigEntry, new FloatSliderOptions()
            {
                Min = 0f,
                Max = 0.27f,
                RequiresRestart = false,
            }));
            condensationConfigEntry.SettingChanged += (sender, args) =>
            {
                ScreenFiltersManager.HelmetCondensationDrops = condensationConfigEntry.Value;
            };
        }
#endif
    }

    [HarmonyPatch(typeof(GameNetworkManager))]
    static class GameNetworkManagerPatch
    {
        const string JesterEnemyPrefabName = "JesterEnemy";

        [HarmonyPatch(nameof(GameNetworkManager.Start))]
        [HarmonyPrefix]
        static void StartPrefix(GameNetworkManager __instance)
        {
            var networkPrefab = NetworkManager.Singleton.NetworkConfig.Prefabs.Prefabs
                .FirstOrDefault(prefab => prefab.Prefab.name == JesterEnemyPrefabName);
            if (networkPrefab == null)
            {
                Plugin.Log.LogError("JesterEnemy prefab not found!");
            }
            else
            {
                networkPrefab.Prefab.AddComponent<MuzikaGromcheJesterNetworkBehaviour>();
                Plugin.Log.LogInfo("Patched JesterEnemy");
            }
        }
    }

    class MuzikaGromcheJesterNetworkBehaviour : NetworkBehaviour
    {
        const string IntroAudioGameObjectName = "MuzikaGromcheAudio (Intro)";
        const string LoopAudioGameObjectName = "MuzikaGromcheAudio (Loop)";

        // Number of times a selected track has been played.
        // Increases by 1 with each ChooseTrackServerRpc call.
        // Resets on SettingChanged.
        private int SelectedTrackIndex = 0;

        internal IAudioTrack? CurrentTrack = null;
        internal BeatTimeState? BeatTimeState = null;
        internal AudioSource IntroAudioSource = null!;
        internal AudioSource LoopAudioSource = null!;

        void Awake()
        {
            var farAudioTransform = gameObject.transform.Find("FarAudio");
            if (farAudioTransform == null)
            {
                Plugin.Log.LogError("JesterEnemy->FarAudio prefab not found!");
            }
            else
            {
                // Instead of hijacking farAudio and creatureVoice sources,
                // create our own copies to ensure uniform playback experience.
                // For reasons unknown adding them directly to the prefab didn't work.
                var introAudioGameObject = Instantiate(farAudioTransform.gameObject, gameObject.transform);
                introAudioGameObject.name = IntroAudioGameObjectName;

                var loopAudioGameObject = Instantiate(farAudioTransform.gameObject, gameObject.transform);
                loopAudioGameObject.name = LoopAudioGameObjectName;

                IntroAudioSource = introAudioGameObject.GetComponent<AudioSource>();
                IntroAudioSource.maxDistance = Plugin.AudioMaxDistance;
                IntroAudioSource.dopplerLevel = 0;
                IntroAudioSource.loop = false;
                IntroAudioSource.volume = Config.Volume.Value;

                LoopAudioSource = loopAudioGameObject.GetComponent<AudioSource>();
                LoopAudioSource.maxDistance = Plugin.AudioMaxDistance;
                LoopAudioSource.dopplerLevel = 0;
                LoopAudioSource.loop = true;
                LoopAudioSource.volume = Config.Volume.Value;

                Config.Volume.SettingChanged += UpdateVolume;

                Plugin.Log.LogInfo($"{nameof(MuzikaGromcheJesterNetworkBehaviour)} Patched JesterEnemy");
            }
        }

        public override void OnDestroy()
        {
            Config.Volume.SettingChanged -= UpdateVolume;

            DeathScreenGameOverTextManager.Clear();
            Stop();
        }

        private void UpdateVolume(object sender, EventArgs e)
        {
            if (IntroAudioSource != null && LoopAudioSource != null)
            {
                IntroAudioSource.volume = Config.Volume.Value;
                LoopAudioSource.volume = Config.Volume.Value;
            }
        }

        public override void OnNetworkSpawn()
        {
            ChooseTrackDeferred();
            foreach (var track in Plugin.Tracks)
            {
                track.Weight.SettingChanged += ChooseTrackDeferredDelegate;
            }
            Config.SkipExplicitTracks.SettingChanged += ChooseTrackDeferredDelegate;
            base.OnNetworkSpawn();
        }

        public override void OnNetworkDespawn()
        {
            foreach (var track in Plugin.Tracks)
            {
                track.Weight.SettingChanged -= ChooseTrackDeferredDelegate;
            }
            Config.SkipExplicitTracks.SettingChanged -= ChooseTrackDeferredDelegate;
            base.OnNetworkDespawn();
        }

        // Batch multiple weights changes in a single network RPC
        private Coroutine? DeferredCoroutine = null;

        private void ChooseTrackDeferredDelegate(object sender, EventArgs e)
        {
            SelectedTrackIndex = 0;
            ChooseTrackDeferred();
        }

        private void ChooseTrackDeferred()
        {
            if (DeferredCoroutine != null)
            {
                StopCoroutine(DeferredCoroutine);
                DeferredCoroutine = null;
            }
            DeferredCoroutine = StartCoroutine(ChooseTrackDeferredCoroutine());
        }

        // Public API to rotate tracks, throttled
        public void ChooseTrack()
        {
            ChooseTrackDeferred();
        }

        // Once host has set a track via RPC, it is considered modded, and expected to always set tracks, so never reset this flag back to false.
        bool HostIsModded = false;

        // Playing with modded host automatically disables vanilla compatability mode
        public bool VanillaCompatMode => IsServer ? Config.VanillaCompatMode : !HostIsModded;

        IEnumerator ChooseTrackDeferredCoroutine()
        {
            yield return new WaitForEndOfFrame();
            DeferredCoroutine = null;

            Plugin.Log.LogDebug($"ChooseTrack: Config.VanillaCompatMode? {Config.VanillaCompatMode}, IsServer? {IsServer}, HostIsModded? {HostIsModded}");

            if (Config.VanillaCompatMode)
            {
                // In vanilla compat mode no, matter whether you are a host or a client, you should skip networking anyway
                ChooseTrackCompat();
            }
            else if (IsServer)
            {
                ChooseTrackServerRpc();
            }
            else
            {
                // Alternatively, there could be another RPC to inform clients of host's capabilities when joining the lobby.
                // If host sets a track later, it would override the locally-selected one.
                // The only downside of false-positive eager loading is the overhead of loading
                // an extra pair of audio files and keeping them in cache until the end of round.
                const float HostTimeout = 1f;
                yield return new WaitForSeconds(HostTimeout);
                if (!HostIsModded)
                {
                    ChooseTrackCompat();
                }
            }
        }

        [ClientRpc]
        void SetTrackClientRpc(string name)
        {
            Plugin.Log.LogDebug($"SetTrackClientRpc {name}");
            SetTrack(name);
            HostIsModded = true;
        }

        void SetTrack(string? name)
        {
            Plugin.Log.LogInfo($"SetTrack {name ?? "<none>"}");
            if (name != null && Plugin.FindTrackNamed(name) is { } track)
            {
                // By the time it is time to start playing the intro, the clips should be done loading from disk.
                AudioClipsCacheManager.LoadAudioTrack(track);
                CurrentTrack = Config.OverrideCurrentTrack(track);
            }
            else
            {
                CurrentTrack = null;
            }
        }

        [ServerRpc]
        void ChooseTrackServerRpc()
        {
            var selectableTrack = Plugin.ChooseTrack();
            var audioTrack = selectableTrack.SelectTrack(SelectedTrackIndex);
            Plugin.Log.LogInfo($"ChooseTrackServerRpc {selectableTrack.Name} #{SelectedTrackIndex} {audioTrack.Name}");
            SetTrackClientRpc(audioTrack.Name);
            SelectedTrackIndex += 1;
        }

        void ChooseTrackCompat()
        {
            var vanillaPopUpTimer = gameObject.GetComponent<JesterAI>().popUpTimer;
            Plugin.Log.LogInfo($"Vanilla compat mode, choosing track locally for timer {vanillaPopUpTimer}");
            var audioTrack = Plugin.ChooseTrackCompat(vanillaPopUpTimer);
            // it is important to reset any previous track if no new compatible one is found
            SetTrack(audioTrack?.Name);
        }

        // Paused == not playing. Scheduled == playing.
        internal bool IsPlaying
        {
            get
            {
                if (IntroAudioSource == null || LoopAudioSource == null || IntroAudioSource.clip == null || LoopAudioSource.clip == null)
                {
                    return false;
                }
                return IntroAudioSource.isPlaying;
            }
        }

        internal bool IsPaused { get; private set; }

        internal void Play(JesterAI jester)
        {
            if (IntroAudioSource == null || LoopAudioSource == null || CurrentTrack == null || CurrentTrack.LoadedIntro == null || CurrentTrack.LoadedLoop == null)
            {
                return;
            }
            if (IsPlaying || IsPaused)
            {
                return;
            }

            IntroAudioSource.clip = CurrentTrack.LoadedIntro;
            LoopAudioSource.clip = CurrentTrack.LoadedLoop;
            BeatTimeState = new BeatTimeState(CurrentTrack);

            if (!VanillaCompatMode)
            {
                // In non-vanilla-compat mode, override the popup timer (which is shorter than the Intro audio clip)
                jester.popUpTimer = CurrentTrack.WindUpTimer;
            }

            float IntroAudioSourceTime;
            if (Config.ShouldSkipWindingPhase && !VanillaCompatMode)
            {
                const float rewind = 5f;
                jester.popUpTimer = rewind;
                IntroAudioSourceTime = CurrentTrack.WindUpTimer - rewind;
            }
            else
            {
                // reset if previously skipped winding by assigning different starting time.
                IntroAudioSourceTime = 0f;
            }
            // Reading .time back only changes after Play(), hence a standalone variable for reliability
            IntroAudioSource.time = IntroAudioSourceTime;

            double dspTime = AudioSettings.dspTime;
            double loopStartDspTime = dspTime + IntroAudioSource.clip.length - IntroAudioSourceTime;
            Plugin.Log.LogDebug($"Play: dspTime={dspTime:N4}, intro.time={IntroAudioSourceTime:N4}/{IntroAudioSource.clip.length:N4}, scheduled loop={loopStartDspTime:N4}");

            IntroAudioSource.Play();
            LoopAudioSource.PlayScheduled(loopStartDspTime);
        }

        internal void Pause()
        {
            if (IntroAudioSource == null || LoopAudioSource == null || IntroAudioSource.clip == null || LoopAudioSource.clip == null)
            {
                return;
            }
            if (!IsPlaying || IsPaused)
            {
                return;
            }
            IsPaused = true;

            double dspTime = AudioSettings.dspTime;
            Plugin.Log.LogDebug($"Pause: dspTime={dspTime:N4}, intro.time={IntroAudioSource.time:N4}/{IntroAudioSource.clip.length:N4}, loop.time={LoopAudioSource.time:N4}/{LoopAudioSource.clip.length:N4}");

            IntroAudioSource.Pause();
            LoopAudioSource.Stop();
        }

        internal void UnPause()
        {
            if (IntroAudioSource == null || LoopAudioSource == null || IntroAudioSource.clip == null || LoopAudioSource.clip == null)
            {
                return;
            }
            if (!IsPaused)
            {
                return;
            }
            IsPaused = false;

            double dspTime = AudioSettings.dspTime;
            double loopStartDspTime = dspTime + IntroAudioSource.clip.length - IntroAudioSource.time;
            Plugin.Log.LogDebug($"UnPause: dspTime={dspTime:N4}, intro.time={IntroAudioSource.time:N4}/{IntroAudioSource.clip.length:N4}, scheduled Loop={loopStartDspTime:N4}");

            IntroAudioSource.UnPause();
            LoopAudioSource.PlayScheduled(loopStartDspTime);
        }

        internal void Stop()
        {
            PoweredLightsBehaviour.Instance.ResetLightColor();
            DiscoBallManager.Disable();
            ScreenFiltersManager.Clear();

            double dspTime = AudioSettings.dspTime;
            if (IntroAudioSource != null && LoopAudioSource != null && IntroAudioSource.clip != null && LoopAudioSource.clip != null)
            {
                Plugin.Log.LogDebug($"Stop: dspTime={dspTime:N4}, intro.time={IntroAudioSource.time:N4}/{IntroAudioSource.clip.length:N4}, loop.time={LoopAudioSource.time:N4}/{LoopAudioSource.clip.length:N4}");
            }
            else
            {
                Plugin.Log.LogDebug($"Stop: dspTime={dspTime:N4}");
            }

            if (IntroAudioSource != null)
            {
                IntroAudioSource.Stop();
                IntroAudioSource.clip = null;
            }
            if (LoopAudioSource != null)
            {
                LoopAudioSource.Stop();
                LoopAudioSource.clip = null;
            }
            BeatTimeState = null;
            IsPaused = false;

            // Just in case if players have spawned multiple Jesters,
            // Don't reset Config.CurrentTrack to null,
            // so that the latest chosen track remains set.
            CurrentTrack = null;
        }

        public void OverrideDeathScreenGameOverText()
        {
            if (CurrentTrack == null)
            {
                // Playing as a client with a host who doesn't have the mod
                return;
            }
            StartCoroutine(DeathScreenGameOverTextManager.SetTextAndClear(CurrentTrack.GameOverText));
        }
    }

    [HarmonyPatch(typeof(JesterAI))]
    static class JesterPatch
    {
        [HarmonyPatch(nameof(JesterAI.SetJesterInitialValues))]
        [HarmonyPostfix]
        static void SetJesterInitialValuesPostfix(JesterAI __instance)
        {
            // music will be fully stopped & reset later in the Update, so it won't trip over CurrentTrack null checks at the beginning
            var behaviour = __instance.GetComponent<MuzikaGromcheJesterNetworkBehaviour>();
            behaviour.Pause();
#if DEBUG
            // Almost instant follow timer
            __instance.beginCrankingTimer = 1f + Plugin.CompatModeAllowLongerTrack;
#endif
        }

        class State
        {
            public int currentBehaviourStateIndex;
            public int previousState;
            public float stunNormalizedTimer;
        }

        [HarmonyPatch(nameof(JesterAI.Update))]
        [HarmonyPrefix]
        static void JesterUpdatePrefix(JesterAI __instance, out State __state)
        {
            __state = new State
            {
                currentBehaviourStateIndex = __instance.currentBehaviourStateIndex,
                previousState = __instance.previousState,
                stunNormalizedTimer = __instance.stunNormalizedTimer,
            };
        }

#if DEBUG
        // avoid spamming console with errors each frame
        public static DedupManualLogSource DedupLog = null!;
#endif

        [HarmonyPatch(nameof(JesterAI.Update))]
        [HarmonyPostfix]
        static void JesterUpdatePostfix(JesterAI __instance, State __state)
        {
            var behaviour = __instance.GetComponent<MuzikaGromcheJesterNetworkBehaviour>();
            var introAudioSource = behaviour.IntroAudioSource;
            var loopAudioSource = behaviour.LoopAudioSource;

            if (behaviour.CurrentTrack == null || behaviour.CurrentTrack.LoadedIntro == null || behaviour.CurrentTrack.LoadedLoop == null)
            {
#if DEBUG
                if (behaviour.CurrentTrack == null)
                {                    
                    DedupLog.LogWarning("CurrentTrack is not set!");
                }
                else if (AudioClipsCacheManager.AllDone)
                {
                    DedupLog.LogWarning("Failed to load audio clips, no in-flight requests running");
                }
                else
                {
                    DedupLog.LogWarning("Waiting for audio clips to load");
                }
#endif
                return;
            }
#if DEBUG
            DedupLog.Clear();
#endif
            var vanillaCompatMode = behaviour.VanillaCompatMode;

            // This switch statement resembles the one from JesterAI.Update
            switch (__state.currentBehaviourStateIndex)
            {
                case 0:
                    // Only ever consider playing audio in case 0 (roaming/following state) in vanilla-compat mode
                    if (vanillaCompatMode)
                    {
                        // The intro has to be actually longer than the wind-up timer.
                        // The timer was never overridden in vanilla compat mode,
                        // AND vanilla only decreases it in case 1 (winding state),
                        // so these calculations are numerically stable.
                        var extraAudioDuration = behaviour.CurrentTrack.WindUpTimer - __instance.popUpTimer;
                        if (extraAudioDuration > 0f)
                        {
                            // The cranking timer, however, is everdecreasing in this state.
                            // Wait for this timer to become smaller than the extra audio length.
                            if (__instance.beginCrankingTimer < extraAudioDuration)
                            {
                                // The audio could already be playing (since last Update)
                                behaviour.Play(__instance);
                                if (__instance.stunNormalizedTimer > 0f)
                                {
                                    behaviour.Pause();
                                }
                                else
                                {
                                    behaviour.UnPause();
                                }
                            }
                        }
                    }
                    break;
                case 1:
                    // Always stop vanilla audio popGoesTheWeaselTheme, we use custom audio sources anyway.
                    // Base method only starts it in the case 1 branch, no need to stop it elsewhere.
                    __instance.farAudio.Stop();

                    if (__state.previousState != 1 && !vanillaCompatMode)
                    {
                        // In non-vanilla-compat mode, start playing immediately upon entering case 1 (winding state)
                        behaviour.Play(__instance);
                    }
                    else if (vanillaCompatMode)
                    {
                        // In vanilla-compat mode, the intro has to actually be no longer than the wind-up timer to be started here in case 1 (winding state).
                        // The Jester's pop-up timer, however, is everdecreasing in this state.
                        // Wait for this timer to become smaller than the audio length.
                        var introDuration = behaviour.CurrentTrack.WindUpTimer;
                        if (__instance.popUpTimer <= introDuration)
                        {
                            behaviour.Play(__instance);
                        }
                    }
                    if (__instance.stunNormalizedTimer > 0f)
                    {
                        behaviour.Pause();
                    }
                    else
                    {
                        behaviour.UnPause();
                    }
                    break;
                case 2:
                    if (__state.previousState != 2)
                    {
                        // creatureVoice plays screamingSFX, and it should be prevented from playing.
                        // Base method only starts it in the case 2 && previousState != 2 branch, no need to stop it elsewhere.
                        __instance.creatureVoice.Stop();
                    }
                    break;
            }

            // transition away from state 2 ("poppedOut"), normally to state 0
            if (__state.previousState == 2 && __instance.previousState != 2)
            {
                behaviour.Stop();
                // Rotate track groups
                behaviour.ChooseTrack();
            }

            // Manage the timeline: switch color of the lights according to the current playback/beat position.
            else if ((__instance.previousState == 1 || __instance.previousState == 2) && behaviour.BeatTimeState is { } beatTimeState)
            {
                var events = beatTimeState.Update(introAudioSource, loopAudioSource);
                var localPlayerCanHearMusic = Plugin.LocalPlayerCanHearMusic(__instance);
                foreach (var ev in events)
                {
                    switch (ev)
                    {
                        case WindUpZeroBeatEvent:
                            DiscoBallManager.Enable();
                            break;

                        case SetLightsColorEvent e:
                            PoweredLightsBehaviour.Instance.SetLightColor(e);
                            break;

                        case FlickerLightsEvent:
                            RoundManager.Instance.FlickerLights(true);
                            break;

                        case LyricsEvent e when localPlayerCanHearMusic:
                            Plugin.DisplayLyrics(e.Text);
                            break;

                        case DrunkEvent e when localPlayerCanHearMusic:
                            ScreenFiltersManager.Drunkness = e.Drunkness;
                            break;

                        case CondensationEvent e when localPlayerCanHearMusic:
                            ScreenFiltersManager.HelmetCondensationDrops = e.Condensation;
                            break;
                    }
                }
            }
        }

        [HarmonyPatch(nameof(JesterAI.killPlayerAnimation))]
        [HarmonyPrefix]
        static void JesterKillPlayerAnimationPrefix(JesterAI __instance, int playerId)
        {
            // Note on cast to int: base game already downcasts ulong to int anyway
            if (playerId == (int)GameNetworkManager.Instance.localPlayerController.playerClientId)
            {
                var behaviour = __instance.GetComponent<MuzikaGromcheJesterNetworkBehaviour>();
                behaviour.OverrideDeathScreenGameOverText();
            }
        }
    }
}