use crate::native_core::{apu::Apu, cpu::CpuBus, mapper::Mapper, ppu::Ppu};

const CPU_RAM_SIZE: usize = 0x0800;
const PPU_DOTS_PER_SCANLINE: u32 = 341;
const PPU_SCANLINES_PER_FRAME: u32 = 262;
const PPU_DOTS_PER_FRAME: u32 = PPU_DOTS_PER_SCANLINE * PPU_SCANLINES_PER_FRAME;
const PPU_VBLANK_START_SCANLINE: u32 = 241;
const PPU_PRERENDER_SCANLINE: u32 = 261;

pub struct NativeBus {
    cpu_ram: [u8; CPU_RAM_SIZE],
    ppu: Ppu,
    apu: Apu,
    cpu_open_bus: u8,
    joypad_state: u8,
    joypad_shift: u8,
    joypad2_state: u8,
    joypad2_shift: u8,
    joypad_strobe: bool,
    nmi_pending: bool,
    suppress_vblank_this_frame: bool,
    ppu_dot: u32,
    odd_frame: bool,
    in_vblank: bool,
    frame_complete: bool,
    cpu_cycles_since_poll: u32,
    mmc3_a12_prev_high: bool,
    mmc3_a12_low_dots: u16,
    mmc3_last_irq_scanline: u32,
    mapper: Box<dyn Mapper + Send>,
}

impl NativeBus {
    pub fn new(mapper: Box<dyn Mapper + Send>) -> Self {
        Self {
            cpu_ram: [0; CPU_RAM_SIZE],
            ppu: Ppu::new(),
            apu: Apu::new(),
            cpu_open_bus: 0,
            joypad_state: 0,
            joypad_shift: 0,
            joypad2_state: 0,
            joypad2_shift: 0,
            joypad_strobe: false,
            nmi_pending: false,
            suppress_vblank_this_frame: false,
            ppu_dot: 0,
            odd_frame: false,
            in_vblank: false,
            frame_complete: false,
            cpu_cycles_since_poll: 0,
            mmc3_a12_prev_high: false,
            mmc3_a12_low_dots: 8,
            mmc3_last_irq_scanline: u32::MAX,
            mapper,
        }
    }

    pub fn apu_registers(&self) -> &[u8; 0x20] {
        self.apu.registers()
    }

    pub fn apu_channel_outputs(&self) -> crate::native_core::apu::ChannelOutputs {
        self.apu.channel_outputs()
    }

    pub fn render_frame(&self, out_rgba: &mut [u8], frame_number: u32, buttons: [bool; 8]) {
        let _ = (frame_number, buttons);
        let src = self.ppu.frame_buffer();
        if out_rgba.len() >= src.len() {
            out_rgba[..src.len()].copy_from_slice(src);
        }
    }

    pub fn begin_frame(&mut self) {
        self.frame_complete = false;
        self.ppu.begin_frame();
    }

    pub fn take_frame_complete(&mut self) -> bool {
        let out = self.frame_complete;
        self.frame_complete = false;
        out
    }

    pub fn clock_cpu(&mut self, cycles: u8) {
        self.clock_cpu_cycles(cycles as u32);
    }

    pub fn take_cpu_cycles_since_poll(&mut self) -> u32 {
        let cycles = self.cpu_cycles_since_poll;
        self.cpu_cycles_since_poll = 0;
        cycles
    }
}

// CpuBus trait implementation (memory map + side effects).
mod cpu_bus_impl;
mod joypad;
// Save-state serialization helpers.
mod state;
mod timing;

#[cfg(test)]
mod tests;