use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
use tokio::net::tcp::{ReadHalf, WriteHalf};
use tokio::net::TcpStream;

use crate::prelude::*;

struct TestScope<'a> {
    reader: BufReader<ReadHalf<'a>>,
    writer: WriteHalf<'a>,
    buffer: Vec<u8>,
}
impl<'a> TestScope<'a> {
    async fn send(&mut self, str: &(impl AsRef<str> + ?Sized)) -> Result<()> {
        self.writer.write_all(str.as_ref().as_bytes()).await?;
        self.writer.flush().await?;
        Ok(())
    }

    async fn expect(&mut self, str: &(impl AsRef<str> + ?Sized)) -> Result<()> {
        let len = self.reader.read_until(b'\n', &mut self.buffer).await?;
        assert_eq!(std::str::from_utf8(&self.buffer[0..len])?, str.as_ref());
        self.buffer.clear();
        Ok(())
    }
}

async fn init_client(stream: &mut TcpStream) -> Result<TestScope> {
    let (reader, writer) = stream.split();
    let reader = BufReader::new(reader);
    let buffer = vec![];
    Ok(TestScope {
        reader,
        writer,
        buffer,
    })
}

macro_rules! send {
    ($scope: expr, $($arg:tt),*) => {{
        $scope.send(&format!($($arg,)*)).await?;
    }};
}

macro_rules! expect {
    ($scope: expr, $($arg:tt),*) => {{
        $scope.expect(&format!($($arg,)*)).await?;
    }};
}

async fn registration(scope: &mut TestScope<'_>, nickname: &str) -> Result<()> {
    expect!(scope, ":irc.localhost NOTICE * :Welcome to my server!\n");
    send!(scope, "NICK {nickname}\n");
    send!(scope, "USER UserName 0 * :Real Name\n");
    expect!(scope, ":irc.localhost 001 {nickname} :Welcome to Kek Server\n");
    expect!(scope, ":irc.localhost 002 {nickname} :Welcome to Kek Server\n");
    expect!(scope, ":irc.localhost 003 {nickname} :Welcome to Kek Server\n");
    expect!(scope, ":irc.localhost 004 {nickname} irc.localhost kek-0.1.alpha.3 DGMQRSZagiloswz CFILPQbcefgijklmnopqrstvz bkloveqjfI\n");
    expect!(scope, ":irc.localhost 005 {nickname} CHANTYPES=# :are supported by this server\n");
    Ok(())
}

async fn join(scope: &mut TestScope<'_>, nickname: &str) -> Result<()> {
    send!(scope, "JOIN #channol\n");
    expect!(scope, ":{nickname} JOIN #channol\n");
    expect!(scope, ":irc.localhost 332 {nickname} #channol :chan topic lol\n");
    expect!(scope, ":irc.localhost 353 {nickname} = #channol :{nickname}\n");
    expect!(scope, ":irc.localhost 366 {nickname} #channol :End of /NAMES list\n");
    Ok(())
}

#[tokio::test]
async fn test_registration() -> Result<()> {
    let mut stream = TcpStream::connect("127.0.0.1:6667").await?;
    let mut scope = init_client(&mut stream).await?;

    registration(&mut scope, "NickName").await?;
    join(&mut scope, "NickName").await?;
    Ok(())
}

#[tokio::test]
async fn test_two_connections_one_player() -> Result<()> {
    let mut stream1 = TcpStream::connect("127.0.0.1:6667").await?;
    let mut scope1 = init_client(&mut stream1).await?;
    let mut stream2 = TcpStream::connect("127.0.0.1:6667").await?;
    let mut scope2 = init_client(&mut stream2).await?;

    registration(&mut scope1, "NickName").await?;
    registration(&mut scope2, "NickName").await?;
    join(&mut scope1, "NickName").await?;
    join(&mut scope2, "NickName").await?;
    send!(scope1, "PRIVMSG #channol :Chmoki vsem v etam chati!\n");
    expect!(scope2, ":NickName PRIVMSG #channol :Chmoki vsem v etam chati!\n");
    send!(scope2, "PRIVMSG #channol :I tebe privetiki\n");
    expect!(scope1, ":NickName PRIVMSG #channol :I tebe privetiki\n");

    Ok(())
}

#[tokio::test]
async fn test_two_players() -> Result<()> {
    let mut stream1 = TcpStream::connect("127.0.0.1:6667").await?;
    let mut scope1 = init_client(&mut stream1).await?;
    let mut stream2 = TcpStream::connect("127.0.0.1:6667").await?;
    let mut scope2 = init_client(&mut stream2).await?;

    registration(&mut scope1, "NickName1").await?;
    registration(&mut scope2, "NickName2").await?;
    join(&mut scope1, "NickName1").await?;
    join(&mut scope2, "NickName2").await?;
    send!(scope1, "PRIVMSG #channol :Chmoki vsem v etam chati!\n");
    expect!(scope2, ":NickName1 PRIVMSG #channol :Chmoki vsem v etam chati!\n");
    send!(scope2, "PRIVMSG #channol :I tebe privetiki\n");
    expect!(scope1, ":NickName2 PRIVMSG #channol :I tebe privetiki\n");

    Ok(())
}