use std::collections::{HashMap, VecDeque};

use crsn::asm::data::literal::Value;
use crsn::asm::instr::Cond;
use crsn::module::{CrsnExtension, EvalRes, OpTrait};
use crsn::runtime::fault::Fault;
use crsn::runtime::run_thread::{state::RunState, ThreadInfo};

use crate::defs::ScreenOp;
use minifb::{Window, WindowOptions, ScaleMode};
use parking_lot::Mutex;
use std::sync::Arc;

#[derive(Debug, Default)]
struct Backend {
    width: usize,
    height: usize,
    buffer: Vec<u32>,
    window: Option<Window>,
}

// Hack for Window
unsafe impl std::marker::Send for Backend { }

impl OpTrait for ScreenOp {
    fn execute(&self, info: &ThreadInfo, state: &mut RunState) -> Result<EvalRes, Fault> {
        let eres = EvalRes::default();
        match self {
            ScreenOp::ScreenInit { width, height } => {
                let w = state.read(*width)?;
                let h = state.read(*height)?;
                init(state, w, h)?;
            }
            ScreenOp::SetPixel { x, y, color } => {
                let x = state.read(*x)?;
                let y = state.read(*y)?;
                let color = state.read(*color)?;

                let backend : &mut Backend = state.ext_mut();
                match &mut backend.window {
                    Some(w) => {
                        let index = y * backend.width as u64 + x;
                        if index as usize > backend.buffer.len() {
                            warn!("Screen set pixel out of bounds");
                            state.set_flag(Cond::Invalid, true);
                        } else {
                            backend.buffer[index as usize] = color as u32;

                            w
                                .update_with_buffer(&backend.buffer, backend.width, backend.height)
                                .expect("Update screen"); // TODO fault
                        }
                    }
                    None => {
                        state.set_flag(Cond::Invalid, true);
                    }
                }
            }
        }

        Ok(eres)
    }
    //
}

fn init(state: &mut RunState, width: Value, height: Value) -> Result<(), Fault> {
    let mut window = Window::new(
        "Croissant",
        width as usize,
        height as usize,
        WindowOptions {
            resize: true,
            scale_mode: ScaleMode::AspectRatioStretch,
            ..WindowOptions::default()
        },
    ).expect("Unable to create window"); // TODO fault


    let backend : &mut Backend = state.ext_mut();

    if backend.window.is_some() {
        return Err(Fault::NotAllowed("Screen already initialized".into()));
    }

    backend.width = width as usize;
    backend.height = height as usize;
    backend.buffer = vec![0; (width * height) as usize];

    // window.limit_update_rate(Some(std::time::Duration::from_micros(16600)));
    window.limit_update_rate(None);

    window
        .update_with_buffer(&backend.buffer, backend.width, backend.height)
        .expect("Update screen"); // TODO fault

    backend.window = Some(window);

    Ok(())
}