use std::io::{self, Write as _};
use std::net::SocketAddr;
use std::sync::{Arc, Mutex};
use std::thread;

use clap::Parser;
use crossterm::event::{Event, KeyCode, KeyEventKind};
use crossterm::terminal::{disable_raw_mode, enable_raw_mode};
use crossterm::event;
use device_state::{DeviceState, WriteType, apply_wheel_delta};
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use tokio::net::TcpStream;
use tokio::sync::mpsc;
use tokio::time::{Duration, interval};

const DEVICE_ID: &str = "esp32-1";
const DEFAULT_HOST: &str = "84.238.32.253";
const DEFAULT_PORT: u16 = 7070;
const WHEEL_PRECISION: i32 = 32;
const WHEEL_STEP: i32 = 1;

#[derive(Parser, Debug)]
#[command(author, version, about)]
struct Args {
    #[arg(long, default_value = DEFAULT_HOST)]
    host: String,
    #[arg(long, default_value_t = DEFAULT_PORT)]
    port: u16,
}

enum InputEvent {
    Button(u8),
    WheelDelta(i32),
    Quit,
}

#[tokio::main]
async fn main() -> io::Result<()> {
    let args = Args::parse();
    let addr: SocketAddr = format!("{}:{}", args.host, args.port).parse().unwrap();

    let state = Arc::new(Mutex::new(DeviceState::new()));
    let (input_tx, mut input_rx) = mpsc::channel::<InputEvent>(64);

    spawn_input_thread(input_tx.clone());
    tokio::spawn(ui_task(state.clone()));

    let mut buf = [0u8; 1024];

    loop {
        let stream = match TcpStream::connect(addr).await {
            Ok(stream) => stream,
            Err(err) => {
                eprintln!("connect error: {err}");
                tokio::time::sleep(Duration::from_secs(1)).await;
                continue;
            }
        };
        let (mut read, mut write) = stream.into_split();

        let device_id = device_state::serialize_write(&WriteType::DeviceId(DEVICE_ID)).unwrap();
        if write.write_all(device_id.as_bytes()).await.is_err() {
            tokio::time::sleep(Duration::from_secs(1)).await;
            continue;
        }

        loop {
            tokio::select! {
                maybe_event = input_rx.recv() => {
                    match maybe_event {
                        Some(InputEvent::Quit) | None => {
                            let _ = disable_raw_mode();
                            return Ok(());
                        }
                        Some(InputEvent::Button(id)) => {
                            let value = state.lock().unwrap().response_value(id);
                            let data = WriteType::QuizResponse(value);
                            let buffer = device_state::serialize_write(&data).unwrap();
                            if write.write_all(buffer.as_bytes()).await.is_err() {
                                break;
                            }
                        }
                        Some(InputEvent::WheelDelta(diff)) => {
                            let mut state = state.lock().unwrap();
                            let wheel = state.wheel();
                            if wheel.max != wheel.min {
                                let mut value = wheel.value;
                                let mut accumulated = wheel.accumulated;
                                apply_wheel_delta(
                                    &mut value,
                                    wheel.min,
                                    wheel.max,
                                    &mut accumulated,
                                    diff,
                                    WHEEL_PRECISION,
                                );
                                let wheel = state.wheel_mut();
                                wheel.value = value;
                                wheel.accumulated = accumulated;
                            }
                        }
                    }
                }
                read_res = read.read(&mut buf) => {
                    let len = match read_res {
                        Ok(0) => break,
                        Ok(len) => len,
                        Err(_) => break,
                    };
                    let Ok(text) = core::str::from_utf8(&buf[..len]) else {
                        continue;
                    };
                    if let Some(last) = text.lines().last() {
                        let Ok(data) = device_state::parse_proxy_output(last) else {
                            continue;
                        };
                        let mut state = state.lock().unwrap();
                        state.apply_proxy_output(data);
                    }
                }
            }
        }

        tokio::time::sleep(Duration::from_millis(500)).await;
    }
}

fn spawn_input_thread(tx: mpsc::Sender<InputEvent>) {
    let _ = thread::Builder::new()
        .name("sim-input".to_string())
        .spawn(move || input_thread(tx));
}

fn input_thread(tx: mpsc::Sender<InputEvent>) {
    let _ = enable_raw_mode();
    let mut stdout = io::stdout();
    let _ = crossterm::execute!(stdout, crossterm::cursor::MoveTo(0, 0));

    loop {
        if let Ok(Event::Key(key)) = event::read() {
            if key.kind == KeyEventKind::Release {
                continue;
            }
            let event = match key.code {
                KeyCode::Char('1') => Some(InputEvent::Button(1)),
                KeyCode::Char('2') => Some(InputEvent::Button(2)),
                KeyCode::Char('3') => Some(InputEvent::Button(3)),
                KeyCode::Char('4') => Some(InputEvent::Button(4)),
                KeyCode::Left => Some(InputEvent::WheelDelta(-WHEEL_STEP)),
                KeyCode::Right => Some(InputEvent::WheelDelta(WHEEL_STEP)),
                KeyCode::Char('a') => Some(InputEvent::WheelDelta(-WHEEL_STEP)),
                KeyCode::Char('d') => Some(InputEvent::WheelDelta(WHEEL_STEP)),
                KeyCode::Char('q') => Some(InputEvent::Quit),
                _ => None,
            };

            if let Some(event) = event {
                let quit = matches!(event, InputEvent::Quit);
                if tx.blocking_send(event).is_err() {
                    break;
                }
                if quit {
                    break;
                }
            }
        }
    }

    let _ = disable_raw_mode();
}

async fn ui_task(state: Arc<Mutex<DeviceState>>) {
    let mut ticker = interval(Duration::from_millis(50));
    loop {
        ticker.tick().await;
        let (line1, line2) = {
            let mut state = state.lock().unwrap();
            state.tick();
            match state.render_lines() {
                Some((line1, line2)) => (line1, line2),
                None => continue,
            }
        };

        let mut stdout = io::stdout();
        let _ = crossterm::execute!(stdout, crossterm::cursor::MoveTo(0, 0));
        let _ = writeln!(stdout, "{:<16}", line1.as_str());
        let _ = writeln!(stdout, "{:<16}", line2.as_str());
        let _ = writeln!(stdout, "[1-4]=buttons  <-/->=wheel a/d  q=quit");
        let _ = stdout.flush();
    }
}