// client/src/input/keyboard.rs

use std::{collections::HashSet, sync::atomic::{AtomicU32, Ordering}};
use evdev::{Device, EventType, InputEvent, KeyCode};
use tokio::sync::broadcast::Sender;
use tracing::{debug, error, warn, trace};

use lesavka_common::lesavka::KeyboardReport;

use super::keymap::{is_modifier, keycode_to_usage};

pub struct KeyboardAggregator {
    dev: Device,
    tx:  Sender<KeyboardReport>,
    dev_mode: bool,
    pressed_keys: HashSet<KeyCode>,
}

/*───────── helpers ───────────────────────────────────────────────────*/
/// Monotonically-increasing ID that can be logged on server & client.
static SEQ: AtomicU32 = AtomicU32::new(0);

impl KeyboardAggregator {
    pub fn new(dev: Device, dev_mode: bool, tx: Sender<KeyboardReport>) -> Self {
        let _ = dev.set_nonblocking(true);
        Self { dev, tx, dev_mode, pressed_keys: HashSet::new(), released: false}
    }

    pub fn process_events(&mut self) {
        // --- first fetch, then log (avoids aliasing borrow) ---
        let events: 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!("read error: {e}"); } return }
        };

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

        for ev in events {
            if ev.event_type() != EventType::KEY { continue }
            let code = KeyCode::new(ev.code());
            match ev.value() {
                1 => { self.pressed_keys.insert(code); } // press
                0 => { self.pressed_keys.remove(&code); } // release
                _ => {}
            }

            let report = self.build_report();
            // Generate a local sequence number for debugging/log-merge only.
            let id = SEQ.fetch_add(1, Ordering::Relaxed);
            if self.dev_mode { debug!(seq = id, ?report, "kbd"); }
            let _ = self.tx.send(KeyboardReport {
                data: report.to_vec()
            });
        }
    }

    fn build_report(&self) -> [u8; 8] {
        let mut out = [0u8; 8];
        let mut mods = 0u8;
        let mut keys = Vec::new();

        for &kc in &self.pressed_keys {
            if let Some(m) = is_modifier(kc) { mods |= m }
            else if let Some(u) = keycode_to_usage(kc) { keys.push(u) }
        }

        out[0] = mods;
        for (i, k) in keys.into_iter().take(6).enumerate() { out[2+i] = k }
        out
    }

    pub fn has_key(&self, kc: KeyCode) -> bool { self.pressed_keys.contains(&kc) }

    pub fn magic_grab(&self) -> bool {
        self.has_key(KeyCode::KEY_LEFTCTRL)
            && self.has_key(KeyCode::KEY_LEFTSHIFT)
            && self.has_key(KeyCode::KEY_G)
    }

    pub fn magic_kill(&self) -> bool {
        self.has_key(KeyCode::KEY_LEFTCTRL)
            && self.has_key(KeyCode::KEY_ESC)
    }
}