use conquer_once::spin::OnceCell;
use crossbeam_queue::ArrayQueue;
use futures_util::stream::{Stream, StreamExt};
use core::{pin::Pin, task::{Context, Poll}};
use pc_keyboard::{layouts, DecodedKey, HandleControl, Keyboard, ScancodeSet1};
use crate::print;

static SCANCODE_QUEUE: OnceCell<ArrayQueue<u8>> = OnceCell::uninit();

pub struct ScancodeStream;

impl ScancodeStream {
    pub fn new() -> Self {
        SCANCODE_QUEUE.try_init_once(|| ArrayQueue::new(100))
            .expect("ScancodeStream::new should only be called once");
        ScancodeStream
    }

    pub async fn print_keypresses(mut self) {
        let mut keyboard = Keyboard::new(layouts::Us104Key, ScancodeSet1, HandleControl::Ignore);

        while let Some(scancode) = self.next().await {
            if let Ok(Some(key_event)) = keyboard.add_byte(scancode) {
                if let Some(key) = keyboard.process_keyevent(key_event) {
                    match key {
                        DecodedKey::Unicode(character) => print!("{}", character),
                        DecodedKey::RawKey(key) => print!("{:?}", key),
                    }
                }
            }
        }
    }
}

impl Stream for ScancodeStream {
    type Item = u8;

    fn poll_next(self: Pin<&mut Self>, context: &mut Context) -> Poll<Option<u8>> {
        let queue = SCANCODE_QUEUE
            .try_get()
            .expect("scancode queue not initialized");
        match queue.pop() {
            Ok(scancode) => Poll::Ready(Some(scancode)),
            Err(crossbeam_queue::PopError) => Poll::Pending,
        }
    }
}