// client/src/input/mouse.rs

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

use navka_common::navka::MouseReport;

pub struct MouseAggregator {
    dev: Device,
    tx:  Sender<MouseReport>,
    dev_mode: bool,

    buttons: u8,
    last_buttons: u8,
    dx:  i8,
    dy:  i8,
    wheel: i8,
}

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

    #[inline] fn slog(&self, f: impl FnOnce()) { if self.dev_mode { f() } }

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

        if self.dev_mode && !evts.is_empty() {
            debug!("🖱️  {} evts from {}", evts.len(), self.dev.name().unwrap_or("?"));
        }

        for e in evts {
            match e.event_type() {
                EventType::KEY => match e.code() {
                    c if c == KeyCode::BTN_LEFT.0   => self.set_btn(0, e.value()),
                    c if c == KeyCode::BTN_RIGHT.0  => self.set_btn(1, e.value()),
                    c if c == KeyCode::BTN_MIDDLE.0 => self.set_btn(2, e.value()),
                    _ => {}
                },
                EventType::RELATIVE => match e.code() {
                    c if c == RelativeAxisCode::REL_X.0 =>
                        self.dx = self.dx.saturating_add(e.value().clamp(-127,127) as i8),
                    c if c == RelativeAxisCode::REL_Y.0 =>
                        self.dy = self.dy.saturating_add(e.value().clamp(-127,127) as i8),
                    c if c == RelativeAxisCode::REL_WHEEL.0 =>
                        self.wheel = self.wheel.saturating_add(e.value().clamp(-1,1) as i8),
                    _ => {}
                },
                EventType::SYNCHRONIZATION => self.flush(),
                _ => {}
            }
        }
    }

    fn flush(&mut self) {
        if self.dx==0 && self.dy==0 && self.wheel==0 && self.buttons==self.last_buttons {
            return;
        }

        let pkt = [
            self.buttons,
            self.dx.clamp(-127,127) as u8,
            self.dy.clamp(-127,127) as u8,
            self.wheel as u8,
        ];

        if let Err(broadcast::error::SendError(_)) =
            self.tx.send(MouseReport { data: pkt.to_vec() })
        { if self.dev_mode { warn!("❌ no HID receiver (mouse)"); } }
        else if self.dev_mode { debug!("📤 mouse {:?}", pkt) }

        self.dx=0; self.dy=0; self.wheel=0; self.last_buttons=self.buttons;
    }

    #[inline] fn set_btn(&mut self, bit: u8, val: i32) {
        if val!=0 { self.buttons |= 1<<bit } else { self.buttons &= !(1<<bit) }
    }
}