// client/src/input/mouse.rs

use evdev::{Device, InputEvent, EventType, KeyCode, RelativeAxisCode};
use tokio::sync::broadcast::Sender;
use tracing::{error, debug};

use navka_common::navka::HidReport;
use navka_common::navka::hid_report::Kind;

/// Aggregator for a single mouse device
pub struct MouseAggregator {
    dev: Device,
    tx: Sender<HidReport>,
    buttons: u8,
    dx: i8,
    dy: i8,
    wheel: i8,
}

impl MouseAggregator {
    pub fn new(dev: Device, tx: Sender<HidReport>) -> Self {
        Self {
            dev,
            tx,
            buttons: 0,
            dx: 0,
            dy: 0,
            wheel: 0,
        }
    }

    /// helper to set or clear a mouse button bit
    fn set_btn(&mut self, idx: usize, pressed: bool) {
        if pressed {
            self.buttons |= 1 << idx;
        } else {
            self.buttons &= !(1 << idx);
        }
    }

    pub fn process_events(&mut self) {
        let events_vec: Vec<InputEvent> = match self.dev.fetch_events() {
            Ok(it) => it.collect(),
            Err(e) if e.kind() == std::io::ErrorKind::WouldBlock => {
                return;
            }
            Err(e) => {
                error!("Mouse device read error: {e}");
                return;
            }
        };

        for ev in events_vec {
            self.handle_event(ev);
        }
    }

    fn handle_event(&mut self, ev: InputEvent) {
        match ev.event_type() {
            EventType::RELATIVE => {
                match RelativeAxisCode::new(ev.code()) {
                    RelativeAxisCode::REL_X     => self.dx    = ev.value() as i8,
                    RelativeAxisCode::REL_Y     => self.dy    = ev.value() as i8,
                    RelativeAxisCode::REL_WHEEL => self.wheel = ev.value() as i8,
                    _ => {}
                }
            }
            EventType::KEY => {
                let pressed = ev.value() != 0;
                match ev.code() {
                    c if c == KeyCode::BTN_LEFT.0   => self.set_btn(0, pressed),
                    c if c == KeyCode::BTN_RIGHT.0  => self.set_btn(1, pressed),
                    c if c == KeyCode::BTN_MIDDLE.0 => self.set_btn(2, pressed),
                    _ => {}
                }
            }
            _ => {}
        }

        // whenever we changed something, emit:
        let report = [self.buttons, self.dx as u8, self.dy as u8, self.wheel as u8];
        self.send_report(report);

        // reset deltas so we send *relative* movement
        self.dx = 0;
        self.dy = 0;
        self.wheel = 0;
    }

    fn send_report(&self, report: [u8; 4]) {
        let msg = HidReport {
            kind: Some(hid_report::Kind::MouseReport(report.to_vec())),
        };

        match self.tx.send(msg.clone()) {
            Ok(n) => {
                tracing::trace!("queued → {} receiver(s)", n);
            }
            Err(e) => {
                tracing::warn!("send dropped report ({e}); falling back to send()");
                let _ = self.tx.send(msg);
            }
        }
    }
}