use alloc::collections::{btree_set::BTreeSet, vec_deque::VecDeque};
use pc_keyboard::{KeyCode, KeyEvent, KeyState};
use spin::Mutex;

use crate::events::{Event, EVENTMAN};
static mut KEYS_PRESSED: Mutex<BTreeSet<KeyCode>> = Mutex::new(BTreeSet::new());
static mut KEY_BUF: VecDeque<KeyEvent> = VecDeque::new();
const KEY_BUF_MAX_LEN: usize = 32;

pub(super) unsafe fn init() {
    EVENTMAN.lock().add_listener(crate::events::Event::Ps2KeyEvent(None), |e| {
        let Event::Ps2KeyEvent(ke) = e else {panic!()};
        if let Some(ke) = ke {
            if KEY_BUF.len() > KEY_BUF_MAX_LEN {
                KEY_BUF.pop_front();
            }
            KEY_BUF.push_back(ke.clone());
        }

        Ok(())
   }) 
}

// TODO: It is possible for `KEY_BUF` to get overfilled and lose data and make keys stuck.
// Possibly run this every now an again somehow
unsafe fn process_events() {
    while !KEY_BUF.is_empty() {
        if let Some(ke) = KEY_BUF.pop_front() {
            match ke.state {
                KeyState::Down => {
                    KEYS_PRESSED.lock().insert(ke.code);
                }
                KeyState::Up => {
                    KEYS_PRESSED.lock().remove(&ke.code);
                }
                _ => ()
            }
        }
    }
}

pub fn is_key_down(key: KeyCode) -> bool {
    unsafe {
        process_events();
        return KEYS_PRESSED.lock().contains(&key);
    }
}