// client/src/input/keyboard.rs

use std::collections::HashSet;
use evdev::{Device, InputEvent, KeyCode, EventType};
use tracing::warn;

use navka_common::navka::HidReport;
use crate::input::keymap::{keycode_to_usage, is_modifier};

/// The aggregator logic for a single keyboard device.
pub struct KeyboardAggregator {
    dev: Device,
    pressed_keys: HashSet<KeyCode>,
}

impl KeyboardAggregator {
    pub fn new(dev: Device) -> Self {
        Self {
            dev,
            pressed_keys: HashSet::new(),
        }
    }

    /// Called frequently (e.g. every ~10ms) to fetch + handle events
    pub fn process_events(&mut self) {
        match self.dev.fetch_events() {
            Ok(events) => {
                for ev in events {
                    self.handle_event(ev);
                }
            }
            Err(e) if e.kind() == std::io::ErrorKind::WouldBlock => {
                // nothing
            }
            Err(e) => {
                tracing::error!("Keyboard device read error: {e}");
            }
        }
    }

    fn handle_event(&mut self, ev: InputEvent) {
        if ev.event_type() == EventType::KEY {
            let code = KeyCode::new(ev.code());
            match ev.value() {
                1 => { self.pressed_keys.insert(code); }
                0 => { self.pressed_keys.remove(&code); }
                2 => { /* repeats, if needed */ }
                _ => {}
            }

            let report = self.build_report();
            // TODO: send this somewhere (e.g. an mpsc::Sender)
            // For now, just log:
            tracing::debug!(?report, "Keyboard HID report");
            // optional: magic chord
            if self.is_magic_chord() {
                warn!("Magic chord pressed => exit aggregator??");
                // Or do something else
            }
        }
    }

    fn build_report(&self) -> [u8; 8] {
        let mut bytes = [0u8; 8];

        let mut normal_keys = Vec::new();
        let mut modifiers = 0u8;

        for &kc in &self.pressed_keys {
            if let Some(m) = is_modifier(kc) {
                modifiers |= m;
            } else if let Some(usage) = keycode_to_usage(kc) {
                normal_keys.push(usage);
            }
        }

        bytes[0] = modifiers;
        for (i, keycode) in normal_keys.into_iter().take(6).enumerate() {
            bytes[2 + i] = keycode;
        }
        bytes
    }

    fn is_magic_chord(&self) -> bool {
        // example logic
        self.pressed_keys.contains(&KeyCode::KEY_LEFTCTRL) &&
        self.pressed_keys.contains(&KeyCode::KEY_ESC)
    }
}