//! MJPEG mode: HID over WebSocket — same binary framing as [`super::datachannel`] (`0x01`/`0x02`/`0x03`; layout detailed there).

use axum::{
    extract::{
        ws::{Message, WebSocket, WebSocketUpgrade},
        State,
    },
    response::Response,
};
use futures::{SinkExt, StreamExt};
use std::sync::Arc;
use tracing::{debug, error, info, warn};

use super::datachannel::{parse_hid_message, HidChannelEvent};
use crate::state::AppState;
use crate::utils::LogThrottler;

const RESP_OK: u8 = 0x00;
const RESP_ERR_HID_UNAVAILABLE: u8 = 0x01;
const RESP_ERR_INVALID_MESSAGE: u8 = 0x02;

pub async fn ws_hid_handler(ws: WebSocketUpgrade, State(state): State<Arc<AppState>>) -> Response {
    ws.on_upgrade(move |socket| handle_hid_socket(socket, state))
}

async fn handle_hid_socket(socket: WebSocket, state: Arc<AppState>) {
    let (mut sender, mut receiver) = socket.split();
    let log_throttler = LogThrottler::with_secs(5);

    info!("WebSocket HID connection established (binary protocol)");

    let hid_available = state.hid.is_available().await;
    let initial_response = if hid_available {
        vec![RESP_OK]
    } else {
        vec![RESP_ERR_HID_UNAVAILABLE]
    };

    if sender
        .send(Message::Binary(initial_response.into()))
        .await
        .is_err()
    {
        error!("Failed to send initial HID status");
        return;
    }

    while let Some(msg) = receiver.next().await {
        match msg {
            Ok(Message::Binary(data)) => {
                let hid_available = state.hid.is_available().await;
                if !hid_available {
                    if log_throttler.should_log("hid_unavailable") {
                        warn!("HID controller not available, ignoring message");
                    }
                    let _ = sender
                        .send(Message::Binary(vec![RESP_ERR_HID_UNAVAILABLE].into()))
                        .await;
                    continue;
                }

                if let Err(e) = handle_binary_message(&data, &state).await {
                    if log_throttler.should_log("binary_hid_error") {
                        warn!("Binary HID message error: {}", e);
                    }
                }
            }
            Ok(Message::Text(text)) => {
                if log_throttler.should_log("text_message_rejected") {
                    debug!(
                        "Received text message (not supported): {} bytes",
                        text.len()
                    );
                }
                let _ = sender
                    .send(Message::Binary(vec![RESP_ERR_INVALID_MESSAGE].into()))
                    .await;
            }
            Ok(Message::Ping(data)) => {
                let _ = sender.send(Message::Pong(data)).await;
            }
            Ok(Message::Close(_)) => {
                info!("WebSocket HID connection closed by client");
                break;
            }
            Err(e) => {
                error!("WebSocket error: {}", e);
                break;
            }
            _ => {}
        }
    }

    if let Err(e) = state.hid.reset().await {
        warn!("Failed to reset HID on WebSocket disconnect: {}", e);
    }

    info!("WebSocket HID connection ended");
}

async fn handle_binary_message(data: &[u8], state: &AppState) -> Result<(), String> {
    let event = parse_hid_message(data).ok_or("Invalid binary HID message")?;

    match event {
        HidChannelEvent::Keyboard(kb_event) => {
            state
                .hid
                .send_keyboard(kb_event)
                .await
                .map_err(|e| e.to_string())?;
        }
        HidChannelEvent::Mouse(ms_event) => {
            state
                .hid
                .send_mouse(ms_event)
                .await
                .map_err(|e| e.to_string())?;
        }
        HidChannelEvent::Consumer(consumer_event) => {
            state
                .hid
                .send_consumer(consumer_event)
                .await
                .map_err(|e| e.to_string())?;
        }
    }

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::hid::datachannel::{KB_EVENT_DOWN, MSG_KEYBOARD, MSG_MOUSE, MS_EVENT_MOVE};

    #[test]
    fn test_response_codes() {
        assert_eq!(RESP_OK, 0x00);
        assert_eq!(RESP_ERR_HID_UNAVAILABLE, 0x01);
        assert_eq!(RESP_ERR_INVALID_MESSAGE, 0x02);
    }

    #[test]
    fn test_keyboard_message_format() {
        let data = [MSG_KEYBOARD, KB_EVENT_DOWN, 0x04, 0x01]; // 'A' key with left ctrl
        let event = parse_hid_message(&data);
        assert!(event.is_some());
    }

    #[test]
    fn test_mouse_message_format() {
        let data = [MSG_MOUSE, MS_EVENT_MOVE, 0x0A, 0x00, 0xF6, 0xFF, 0x00]; // x=10, y=-10
        let event = parse_hid_message(&data);
        assert!(event.is_some());
    }
}