import SwiftUI

enum Selector: Hashable {
    case overview
    case room(String)
    case direct(String)
}

struct Room: Identifiable {
    var id: String { name }
    let name: String
}

struct Direct: Identifiable {
    var id: String { name }
    let name: String
}

struct ContentView: View {
    let rooms = ["Core Dev", "Rust", "Ads"].map { Room(name: $0) }
    let directs = ["Jeroen", "Ilnur"].map { Direct(name: $0) }
    @State private var selected: Selector = .overview;
    
    var body: some View {
        NavigationSplitView {
            List(selection: $selected) {
                Text("Overview").tag(Selector.overview)
                Section("Rooms") {
                    ForEach(rooms) { it in
                        Text(it.name).tag(Selector.room(it.id))
                    }
                }
                Section("Directs") {
                    ForEach(directs) { it in
                        Text(it.name).tag(Selector.direct(it.id))
                    }
                }
            }
        } detail: {
            switch selected {
            case .overview:
                Overview()
            case .room(_):
                TopicListView()
            case .direct(_):
                MessageListView()
            }
        }
    }
}

struct Overview: View {
    var body: some View {
        Text("welcome")
    }
}

struct MessageListView: View {
    @State var newMessage: String = ""
    @ObservedObject var viewModel: TopicViewModel = TopicViewModel(messages: [
        Message(author: "Jeroen", body: "Hello everyone!"),
        Message(author: "Jeroen", body: "Hoe gaat het?"),
        Message(author: "Ilnur", body: "Normalno"),
        Message(author: "Jeroen", body: "Zbs!"),
    ])
    
    var body: some View {
        ScrollView {
            Text("Start of the conversation")
            VStack(alignment: .leading) {
                ForEach(viewModel.messages) { it in
                    Divider()
                    MessageBatchView(
                        author: it.author,
                        messages: [it.body]
                    )
                }
            }
        }
        .contentMargins(5)
        .defaultScrollAnchor(.bottom)
        .background(.white)
        HStack {
            TextField(text: $newMessage) {
                Text("New message")
            }.textFieldStyle(.roundedBorder)
            Button(action: {}) {
                Text("Send")
            }
        }.padding(5)
    }
}

struct MessageBatchView: View {
    let author: String
    let messages: [String]

    var body: some View {
        Text("\(author):").bold()
        ForEach(messages, id: \.hash) { it in
            Text(it)
        }
    }
}

struct TopicListView: View {
    @State var topicTitle: String = ""

    var body: some View {
        ScrollView {
            VStack(alignment: .leading) {
                TextField(text: $topicTitle) {
                    Text("A new topic!")
                }
                Divider()
                TopicSlugView(
                    title: "How do I patch KDE3 for FreeBSD?",
                    numberOfReplies: 5,
                    openedWhen: "Opened 5 days ago"
                )
                TopicSlugView(
                    title: "Our coffee machine is broken, pls fix",
                    numberOfReplies: 133,
                    openedWhen: "Opened yesterday"
                )
            }
            .padding(5)
        }
    }
}

struct TopicSlugView: View {
    let title: String
    let numberOfReplies: Int
    let openedWhen: String
    
    var body: some View {
        Button {
            
        } label: {
            VStack(alignment: .leading) {
                Text(title).bold()
                HStack {
                    Text("\(numberOfReplies) replies")
                    Spacer()
                    Text(openedWhen)
                    
                }
            }
        }
    }
}

class TopicViewModel: ObservableObject {
    @Published var messages: [Message]
    
    init(messages: [Message]) {
        self.messages = messages
    }
    
}

struct Message: Identifiable {
    let id: UUID = UUID()
    var author: String
    var body: String
}

#Preview {
    ContentView()
}