extern crate ctrlc;
use clichess::RecvPositionError;
use clichess::UserRole;
use serde_json::json;
use shakmaty::fen::Fen;
use shakmaty::{Chess, Color, Outcome, Position, Setup};
use std::io;
use std::os::unix::net::UnixStream;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::mpsc::{channel, Receiver, TryRecvError};
use std::sync::{Arc, Mutex};
use std::thread;
use std::time;

struct Client {
    player: clichess::Player,
    side: Color,
    running: Arc<AtomicBool>,
    input_buffer: Arc<Mutex<String>>,
    server_message_recv: Receiver<String>,
}

fn main() {
    let running = setupctrlc();
    let username = std::env::args().nth(1).expect("no name given");
    let public_key = std::env::args().nth(2).expect("no public key given");
    //send username and public key to server
    let mut stream = match UnixStream::connect("/tmp/clichess.socket") {
        Ok(sock) => sock,
        Err(_) => {
            println!("clichess daemon is not running.");
            return;
        }
    };
    let username_pubkey_json = json!({
        "username": username,
        "pubkey": public_key,
    });
    clichess::write_to_stream(&mut stream, username_pubkey_json.to_string()).unwrap();
    let input_buffer = setup_input_buffer();
    //start a thread to listen to server messages
    let server_message_recv = setup_server_message_recv(&stream).unwrap();

    let mut client = Client {
        player: clichess::Player {
            role: UserRole::Spectator,
            username: username,
            public_key: public_key,
        },
        side: Color::White,
        running: running.clone(),
        input_buffer: input_buffer.clone(),
        server_message_recv,
    };

    match prompt_user_for_role(&client, &mut stream) {
        Some(role) => client.player.role = role.clone(),
        None => return,
    };
    if client.player.role == UserRole::Spectator {
        println!(
            "Hello, {} !\n\r You're spectating !",
            client.player.username
        )
    } else {
        println!(
            "Hello, {} !\n\r You're playing with the {} pieces",
            client.player.username,
            client.player.role.to_string()
        );
    }
    let mut current_position = fetch_initial_chess_position(&client);
    loop {
        println!(
            "{}",
            clichess::board_representation(&current_position, client.side)
        );
        //check if game is over.
        if current_position.is_game_over() {
            break;
        }
        if clichess::is_player_turn(&client.player, current_position.turn()) {
            //it's the user turn, taking user input
            let input = read_user_input(&client);
            clichess::write_to_stream(&mut stream, String::from(input.trim())).unwrap();
            if input.trim() == "exit" {
                break;
            }
        }
        //update position after playing.
        match get_current_position(&client) {
            Ok(position) => current_position = position,
            Err(RecvPositionError::UserCanceledError) => break,
            Err(RecvPositionError::CommunicationError) => break,
            Err(RecvPositionError::ParsePositionError) => break,
        };
    }
    match current_position.outcome() {
        None => println!("Bye"),
        Some(Outcome::Draw) => println!("Draw game."),
        Some(Outcome::Decisive { winner }) => {
            if winner == Color::White {
                println!("White has won the game.")
            } else {
                println!("Black has won the game.")
            }
        }
    }
}

fn setup_input_buffer() -> Arc<Mutex<String>> {
    let buf = Arc::new(Mutex::new(String::new()));
    let buf2 = buf.clone();

    thread::spawn(move || {
        loop {
            let mut buffer = String::new();
            //wait for user input
            io::stdin().read_line(&mut buffer).unwrap();
            {
                let mut user_input = buf2.lock().unwrap();
                if user_input.is_empty() {
                    *user_input = buffer;
                } else {
                    println!("It's not your turn !");
                }
            }
        }
    });
    buf
}

fn setupctrlc() -> Arc<AtomicBool> {
    let running = Arc::new(AtomicBool::new(true));
    let r = running.clone();
    ctrlc::set_handler(move || {
        r.store(false, Ordering::SeqCst);
    })
    .expect("Error setting Ctrl-C handler");
    running
}

fn setup_server_message_recv(stream: &UnixStream) -> io::Result<Receiver<String>> {
    let buf = Arc::new(Mutex::new(String::new()));
    let (sender, receiver) = channel();
    let thread_stream = stream.try_clone()?;

    thread::spawn(move || {
        loop {
            //wait for server message
            let buffer =
                clichess::read_line_from_stream(&thread_stream).expect("Error message from server");
            sender.send(buffer).unwrap();
        }
    });
    Ok(receiver)
}

fn read_user_input(client: &Client) -> String {
    //clear input before waiting for a new one
    {
        let mut user_input = client.input_buffer.lock().unwrap();
        user_input.clear();
    }
    let mut input = String::new();
    while client.running.load(Ordering::SeqCst) {
        thread::sleep(time::Duration::from_millis(10));
        {
            let user_input = client.input_buffer.lock().unwrap();
            if user_input.is_empty() {
                continue;
            } else {
                input = user_input.clone();
                break;
            }
        }
    }
    if client.running.load(Ordering::SeqCst) {
        input
    } else {
        String::from("exit")
    }
}

//wait for next position from server, then return the current board.
fn get_current_position(client: &Client) -> Result<Chess, RecvPositionError> {
    let response = fetch_message_from_server(client);
    if response.is_empty() {
        Err(RecvPositionError::UserCanceledError)
    } else {
        Ok(parse_position(&response))
    }
}

fn fetch_message_from_server(client: &Client) -> String {
    let mut response = String::new();
    while client.running.load(Ordering::SeqCst) {
        thread::sleep(time::Duration::from_millis(10));
        {
            let server_response_recv = &client.server_message_recv;
            match server_response_recv.try_recv() {
                Ok(msg) => {
                    response = msg;
                    break;
                }
                Err(TryRecvError::Disconnected) => println!("Error: server disconnected."),
                Err(TryRecvError::Empty) => continue,
            }
        }
    }
    response
}

fn parse_position(string: &str) -> Chess {
    let setup: Fen = string.trim().parse().expect("Invalid message from server.");
    let position: Chess = setup.position().expect("Invalid message from server.");
    position
}

fn prompt_user_for_role(client: &Client, stream: &mut UnixStream) -> Option<UserRole> {
    let mut role = None;
    loop {
        let available_roles = fetch_available_roles(client);
        let mut prompt = String::new();
        if !available_roles.contains(&UserRole::White)
            && !available_roles.contains(&UserRole::Black)
        {
            prompt.push_str("You can only spectate this game. Press enter to start spectating.");
        } else if available_roles.contains(&UserRole::White) {
            prompt = String::from("Do you want to play as White (W)");
            if available_roles.contains(&UserRole::White) {
                prompt.push_str(", Black (B)");
            }
            prompt.push_str(" or Spectate (S)?");
        } else {
            prompt = String::from("Do you want to play as Black (B) or Spectate (S)?");
        }
        println!("{}", prompt);
        //wait for user to give a correct answer.
        let mut input = String::from(read_user_input(client).trim());
        if input.trim() == "exit" {
            clichess::write_to_stream(stream, String::from("exit")).unwrap();
            break;
        }

        if !available_roles.contains(&UserRole::White)
            && !available_roles.contains(&UserRole::Black)
        {
            //we can only spectate
            input = String::from("S");
        }
        match clichess::parse_to_role(&input) {
            Ok(r) => role = Some(r),
            Err(e) => {
                println!("{}", e);
                continue;
            }
        };
        if role.is_some() && !available_roles.contains(&role.expect("role is some")) {
            println!("Sorry, this side is not available.");
            continue;
        }
        //send info to server
        clichess::write_to_stream(stream, String::from(input)).unwrap();
        //get confirmation from server
        let response = fetch_message_from_server(&client);
        if response != "OK" {
            println!(
                "There was an issue with the server. Maybe your choice is not available anymore?"
            );
            clichess::write_to_stream(stream, String::from("ACK")).unwrap();
            continue;
        }
        clichess::write_to_stream(stream, String::from("OK")).unwrap();
        break;
    }
    role
}

fn fetch_initial_chess_position(client: &Client) -> Chess {
    parse_position(&fetch_message_from_server(client))
}

fn fetch_available_roles(client: &Client) -> Vec<UserRole> {
    roles_from_str(&fetch_message_from_server(client)).unwrap()
}

fn roles_from_str(s: &str) -> Result<Vec<UserRole>, String> {
    s.split(',').map(clichess::parse_to_role).collect()
}