use std::marker::PhantomData;
use std::sync::{Arc, Mutex};

pub use crate::processor::memory::mmio::gpu::Colour;
pub use crate::processor::memory::mmio::joypad::{JoypadButtons, JoypadState};
pub use crate::processor::memory::mmio::serial::SerialTarget;
pub use crate::processor::CpuSaveState;
pub use crate::{HEIGHT, WIDTH};
use async_ringbuf::{AsyncHeapConsumer, AsyncHeapProducer, AsyncHeapRb};

pub enum EmulatorMessage {
    Stop,
}

#[derive(Clone, Copy)]
pub enum DownsampleType {
    Linear,
    ZeroOrderHold,
}

pub enum RomFile {
    Path(String),
    Raw(Vec<u8>),
}

pub trait Renderer<Format: From<Colour>> {
    fn prepare(&mut self, width: usize, height: usize);

    fn resize(&mut self, width: usize, height: usize) {
        self.prepare(width, height)
    }

    fn display(&mut self, buffer: &[Format]);

    fn set_title(&mut self, _title: String) {}

    fn latest_joypad_state(&mut self) -> JoypadState;

    fn set_rumble(&mut self, _rumbling: bool) {}
}

pub struct AudioOutput {
    pub sample_rate: f32,
    pub send_rb: AsyncHeapProducer<[f32; 2]>,
    pub downsample_type: DownsampleType,
}

impl AudioOutput {
    pub fn new(
        sample_rate: f32,
        buffers_per_frame: usize,
        downsample_type: DownsampleType,
    ) -> (Self, AsyncHeapConsumer<[f32; 2]>) {
        let rb_len = (sample_rate as usize / 60) / buffers_per_frame;

        let rb = AsyncHeapRb::<[f32; 2]>::new(rb_len);
        let (send_rb, rx) = rb.split();

        (
            Self {
                sample_rate,
                send_rb,
                downsample_type,
            },
            rx,
        )
    }
}

pub trait PocketCamera {
    // resolution - 128x128
    fn get_image(&mut self) -> [u8; 128 * 128];

    fn begin_capture(&mut self);

    fn init(&mut self);
}

pub struct NoCamera {
    buf: [u8; 128 * 128],
}

impl Default for NoCamera {
    fn default() -> Self {
        Self {
            buf: [0; 128 * 128],
        }
    }
}

impl PocketCamera for NoCamera {
    fn get_image(&mut self) -> [u8; 128 * 128] {
        self.buf
    }

    fn begin_capture(&mut self) {
        for v in &mut self.buf {
            *v = rand::random();
        }
    }

    fn init(&mut self) {}
}

pub(crate) type CameraWrapperRef<C> = Arc<Mutex<CameraWrapper<C>>>;

pub(crate) struct CameraWrapper<C>
where
    C: PocketCamera,
{
    pub(crate) inner: C,
    counter: usize,
    next_image: Option<[u8; 128 * 128]>,
}

impl<C> CameraWrapper<C>
where
    C: PocketCamera,
{
    pub(crate) fn new(camera: C) -> Self {
        Self {
            inner: camera,
            counter: 0,
            next_image: None,
        }
    }

    pub(crate) fn is_capturing(&self) -> bool {
        self.counter > 0
    }

    pub(crate) fn tick(&mut self, steps: usize) {
        if self.counter > 0 {
            self.counter = match self.counter.checked_sub(steps) {
                Some(num) => num,
                None => {
                    self.next_image = Some(self.inner.get_image());
                    0
                }
            };
        }
    }

    pub(crate) fn begin_capture(&mut self) {
        self.counter = 32446 * 4;
        self.inner.begin_capture();
    }

    pub(crate) fn get_next(&mut self) -> Option<[u8; 128 * 128]> {
        self.next_image.take()
    }
}

#[non_exhaustive]
pub struct EmulatorOptions<ColourFormat, R>
where
    ColourFormat: From<Colour> + Clone,
    R: Renderer<ColourFormat>,
{
    pub(crate) window: R,
    pub(crate) tile_window: Option<R>,
    pub(crate) rom: RomFile,
    pub(crate) output: AudioOutput,
    pub(crate) save_path: Option<String>,

    pub(crate) no_save: bool,
    pub(crate) bootrom: Option<RomFile>,
    pub(crate) show_bootrom: bool,
    pub(crate) serial_target: SerialTarget,
    pub(crate) cgb_mode: bool,
    spooky: PhantomData<ColourFormat>,
}

impl<ColourFormat, R> EmulatorOptions<ColourFormat, R>
where
    ColourFormat: From<Colour> + Clone,
    R: Renderer<ColourFormat>,
{
    pub fn new(window: R, rom: RomFile, output: AudioOutput) -> Self {
        Self {
            window,
            tile_window: None,
            rom,
            output,
            save_path: None,
            no_save: false,
            bootrom: None,
            show_bootrom: false,
            serial_target: SerialTarget::None,
            cgb_mode: true,
            spooky: PhantomData,
        }
    }

    pub fn with_save_path(mut self, path: Option<String>) -> Self {
        self.save_path = path;
        self
    }

    pub fn force_no_save(mut self) -> Self {
        self.no_save = true;
        self
    }

    pub fn with_no_save(mut self, no_save: bool) -> Self {
        self.no_save = no_save;
        self
    }

    pub fn with_bootrom(mut self, bootrom: Option<RomFile>, show_bootrom: bool) -> Self {
        self.bootrom = bootrom;
        self.show_bootrom = show_bootrom;
        self
    }

    pub fn with_stdout(mut self) -> Self {
        self.serial_target = SerialTarget::Stdout;
        self
    }

    pub fn with_serial_target(mut self, target: SerialTarget) -> Self {
        self.serial_target = target;
        self
    }

    pub fn with_tile_window(mut self, window: Option<R>) -> Self {
        self.tile_window = window;
        self
    }

    pub fn with_cgb_mode(mut self, cgb_mode: bool) -> Self {
        self.cgb_mode = cgb_mode;
        self
    }
}

pub trait EmulatorCoreTrait {
    fn replace_output(&mut self, new: AudioOutput);
    fn cycle_count(&self) -> usize;
    fn pc(&self) -> u16;
    fn print_reg(&self) -> String;
    fn get_memory(&self, address: u16) -> u8;
    fn run(&mut self);
    fn run_stepped(&mut self, step_size: usize);
    fn run_until_buffer_full(&mut self);
}