use std::fmt;

use iced::{
    Point, Size,
    advanced::graphics::geometry::Renderer,
    widget::canvas::{Fill, Frame},
};

use crate::{
    hex_view::Memory,
    mem::{Mapper, MemoryMap, Segment},
};

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct Color {
    pub r: u8,
    pub g: u8,
    pub b: u8,
}

impl Into<Fill> for Color {
    fn into(self) -> Fill {
        iced::Color::from_rgb8(self.r, self.g, self.b).into()
    }
}

impl fmt::Display for Color {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "#{:02X}{:02X}{:02X}", self.r, self.g, self.b)
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct RenderBuffer<const W: usize, const H: usize> {
    buffer: Box<[Color]>,
}

impl<const W: usize, const H: usize> RenderBuffer<W, H> {
    pub fn empty() -> Self {
        Self {
            buffer: vec![Color { r: 0, g: 0, b: 0 }; W * H].into_boxed_slice(),
        }
    }

    pub fn write(&mut self, line: usize, pixel: usize, color: Color) {
        assert!(line < H && pixel < W);
        self.buffer[line * W + pixel] = color;
    }
    pub fn read(&self, line: usize, pixel: usize) -> Color {
        assert!(line < H && pixel < W);
        self.buffer[line * W + pixel]
    }

    pub fn clone_from(&mut self, other: &Self) {
        self.buffer.copy_from_slice(&other.buffer);
    }

    pub fn assert_eq(&self, other: &Self) {
        // if self.buffer != other.buffer {
        for y in 0..H {
            for x in 0..W {
                if self.read(y, x) != other.read(y, x) {
                    panic!(
                        "Rendered Buffers do not match\n    Mismatch at ({x}, {y})\n    Left:  {}\n    Right: {}",
                        self.read(y, x),
                        other.read(y, x)
                    );
                }
            }
        }
        // }
    }
}

pub(crate) enum PPUMMRegisters {
    Palette,
}

pub struct OAM {
    mem: Vec<u8>,
    addr: u8,
}

enum BackgroundState {
    NameTableBytePre,
    NameTableByte,
    AttrTableBytePre,
    AttrTableByte,
    PatternTableTileLowPre,
    PatternTableTileLow,
    PatternTableTileHighPre,
    PatternTableTileHigh,
}

pub struct Background {
    /// Current vram address, 15 bits
    pub v: u16,
    /// Temp vram address, 15 bits
    pub t: u16,
    /// Fine X control, 3 bits
    pub x: u8,
    /// Whether this is the first or second write to PPUSCROLL
    /// When false, writes to x
    pub w: bool,

    /// When true, v is incremented by 32 after each read
    pub vram_column: bool,
    pub second_pattern: bool,

    state: BackgroundState,

    pub cur_nametable: u8,
    pub cur_attr: u8,
    pub next_attr: u8,
    pub next_attr_2: u8,
    pub cur_high: u8,
    pub cur_low: u8,
    pub cur_shift_high: u32,
    pub cur_shift_low: u32,
}

pub struct Mask {
    pub grayscale: bool,
    pub background_on_left_edge: bool,
    pub sprites_on_left_edge: bool,
    pub enable_background: bool,
    pub enable_sprites: bool,
    pub em_red: bool,
    pub em_green: bool,
    pub em_blue: bool,
}

const COLORS: &'static [Color; 0b100_0000] = &[
    Color {
        r: 0x66,
        g: 0x66,
        b: 0x66,
    }, // 00
    Color {
        r: 0x00,
        g: 0x2A,
        b: 0x88,
    }, // 01
    Color {
        r: 0x14,
        g: 0x12,
        b: 0xA7,
    }, // 02
    Color {
        r: 0x3B,
        g: 0x00,
        b: 0xA4,
    }, // 03
    Color {
        r: 0x5C,
        g: 0x00,
        b: 0x7E,
    }, // 04
    Color {
        r: 0x6E,
        g: 0x00,
        b: 0x40,
    }, // 05
    Color {
        r: 0x6C,
        g: 0x06,
        b: 0x00,
    }, // 06
    Color {
        r: 0x56,
        g: 0x1D,
        b: 0x00,
    }, // 07
    Color {
        r: 0x33,
        g: 0x35,
        b: 0x00,
    }, // 08
    Color {
        r: 0x0B,
        g: 0x48,
        b: 0x00,
    }, // 09
    Color {
        r: 0x00,
        g: 0x52,
        b: 0x00,
    }, // 0A
    Color {
        r: 0x00,
        g: 0x4F,
        b: 0x08,
    }, // 0B
    Color {
        r: 0x00,
        g: 0x40,
        b: 0x4D,
    }, // 0C
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 0D
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 0E
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 0F
    Color {
        r: 0xAD,
        g: 0xAD,
        b: 0xAD,
    }, // 10
    Color {
        r: 0x15,
        g: 0x5F,
        b: 0xD9,
    }, // 11
    Color {
        r: 0x42,
        g: 0x40,
        b: 0xFF,
    }, // 12
    Color {
        r: 0x75,
        g: 0x27,
        b: 0xFE,
    }, // 13
    Color {
        r: 0xA0,
        g: 0x1A,
        b: 0xCC,
    }, // 14
    Color {
        r: 0xB7,
        g: 0x1E,
        b: 0x7B,
    }, // 15
    Color {
        r: 0xB5,
        g: 0x31,
        b: 0x20,
    }, // 16
    Color {
        r: 0x99,
        g: 0x4E,
        b: 0x00,
    }, // 17
    Color {
        r: 0x6B,
        g: 0x6D,
        b: 0x00,
    }, // 18
    Color {
        r: 0x38,
        g: 0x87,
        b: 0x00,
    }, // 19
    Color {
        r: 0x0C,
        g: 0x93,
        b: 0x00,
    }, // 1A
    Color {
        r: 0x00,
        g: 0x8F,
        b: 0x32,
    }, // 1B
    Color {
        r: 0x00,
        g: 0x7C,
        b: 0x8D,
    }, // 1C
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 1D
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 1E
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 1F
    Color {
        r: 0xFF,
        g: 0xFE,
        b: 0xFF,
    }, // 20
    Color {
        r: 0x64,
        g: 0xB0,
        b: 0xFF,
    }, // 21
    Color {
        r: 0x92,
        g: 0x90,
        b: 0xFF,
    }, // 22
    Color {
        r: 0xC6,
        g: 0x76,
        b: 0xFF,
    }, // 23
    Color {
        r: 0xF3,
        g: 0x6A,
        b: 0xFF,
    }, // 24
    Color {
        r: 0xFE,
        g: 0x6E,
        b: 0xCC,
    }, // 25
    Color {
        r: 0xFE,
        g: 0x81,
        b: 0x70,
    }, // 26
    Color {
        r: 0xEA,
        g: 0x9E,
        b: 0x22,
    }, // 27
    Color {
        r: 0xBC,
        g: 0xBE,
        b: 0x00,
    }, // 28
    Color {
        r: 0x88,
        g: 0xD8,
        b: 0x00,
    }, // 29
    Color {
        r: 0x5C,
        g: 0xE4,
        b: 0x30,
    }, // 2A
    Color {
        r: 0x45,
        g: 0xE0,
        b: 0x82,
    }, // 2B
    Color {
        r: 0x48,
        g: 0xCD,
        b: 0xDE,
    }, // 2C
    Color {
        r: 0x4F,
        g: 0x4F,
        b: 0x4F,
    }, // 2D
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 2E
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 2F
    Color {
        r: 0xFF,
        g: 0xFE,
        b: 0xFF,
    }, // 30
    Color {
        r: 0xC0,
        g: 0xDF,
        b: 0xFF,
    }, // 31
    Color {
        r: 0xD3,
        g: 0xD2,
        b: 0xFF,
    }, // 32
    Color {
        r: 0xE8,
        g: 0xC8,
        b: 0xFF,
    }, // 33
    Color {
        r: 0xFB,
        g: 0xC2,
        b: 0xFF,
    }, // 34
    Color {
        r: 0xFE,
        g: 0xC4,
        b: 0xEA,
    }, // 35
    Color {
        r: 0xFE,
        g: 0xCC,
        b: 0xC5,
    }, // 36
    Color {
        r: 0xF7,
        g: 0xD8,
        b: 0xA5,
    }, // 37
    Color {
        r: 0xE4,
        g: 0xE5,
        b: 0x94,
    }, // 38
    Color {
        r: 0xCF,
        g: 0xEF,
        b: 0x96,
    }, // 39
    Color {
        r: 0xBD,
        g: 0xF4,
        b: 0xAB,
    }, // 3A
    Color {
        r: 0xB3,
        g: 0xF3,
        b: 0xCC,
    }, // 3B
    Color {
        r: 0xB5,
        g: 0xEB,
        b: 0xF2,
    }, // 3C
    Color {
        r: 0xB8,
        g: 0xB8,
        b: 0xB8,
    }, // 3D
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 3E
    Color {
        r: 0x00,
        g: 0x00,
        b: 0x00,
    }, // 3F
];

pub struct Palette {
    colors: &'static [Color; 0x40],
    ram: [u8; 0x20],
}

impl Palette {
    pub fn color(&self, idx: u8, palette: u8) -> Color {
        debug_assert!(idx < 0x20, "Palette index out of range");
        self.colors[(self.ram[idx as usize + palette as usize * 4] & 0x3F) as usize]
    }
}

pub struct PPU {
    // registers: PPURegisters,
    pub frame_count: usize,
    nmi_enabled: bool,
    // nmi_waiting: bool,
    pub even: bool,
    pub scanline: usize,
    pub pixel: usize,

    pub mask: Mask,
    pub vblank: bool,

    pub(crate) memory: MemoryMap<PPUMMRegisters>,
    palette: Palette,
    pub background: Background,
    oam: OAM,
    pub render_buffer: RenderBuffer<256, 240>,
    pub dbg_int: bool,
    pub cycle: usize,
}

bitfield::bitfield! {
    pub struct PPUStatus(u8);
    impl Debug;
    vblank, set_vblank: 7;
    sprite0, set_sprite0: 6;
    sprite_overflow, set_sprite_overflow: 5;
}

impl std::fmt::Debug for PPU {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "PPU: f {}, s {}, p {}",
            self.frame_count, self.scanline, self.pixel
        )
    }
}

impl PPU {
    pub fn with_chr_rom(rom: &[u8], mapper: Mapper) -> Self {
        Self {
            cycle: 25,
            dbg_int: false,

            mask: Mask {
                grayscale: false,
                background_on_left_edge: false,
                sprites_on_left_edge: false,
                enable_background: false,
                enable_sprites: false,
                em_red: false,
                em_green: false,
                em_blue: false,
            },
            palette: Palette {
                colors: COLORS,
                ram: [
                    0x09, 0x01, 0x00, 0x01, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C,
                    0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
                    0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
                ],
            },
            vblank: false,
            frame_count: 0,
            nmi_enabled: false,
            // nmi_waiting: false,
            even: false,
            scanline: 0,
            pixel: 25,
            render_buffer: RenderBuffer::empty(),
            memory: mapper.ppu_map(rom),
            background: Background {
                v: 0,
                t: 0,
                x: 0,
                w: false,
                vram_column: false,
                second_pattern: false,
                state: BackgroundState::NameTableBytePre,
                cur_high: 0,
                cur_low: 0,
                cur_shift_high: 0,
                cur_shift_low: 0,
                cur_nametable: 0,
                cur_attr: 0,
                next_attr: 0,
                next_attr_2: 0,
            },
            oam: OAM {
                mem: vec![0u8; 256],
                addr: 0,
            },
        }
    }
    pub fn reset(&mut self) {
        *self = Self {
            memory: std::mem::replace(&mut self.memory, MemoryMap::new(vec![])),
            ..Self::with_chr_rom(&[], Mapper::from_flags(0))
        };
    }

    pub fn rendering_enabled(&self) -> bool {
        self.mask.enable_background || self.mask.enable_sprites
    }

    pub fn read_reg(&mut self, offset: u16) -> u8 {
        match offset {
            0 => panic!("ppuctrl is write-only"),
            1 => panic!("ppumask is write-only"),
            2 => {
                let tmp = if self.vblank { 0b1000_0000 } else { 0 };
                self.vblank = false;
                self.background.w = false;
                tmp
            }
            3 => panic!("oamaddr is write-only"),
            4 => self.oam.mem[self.oam.addr as usize],
            5 => panic!("ppuscroll is write-only"),
            6 => panic!("ppuaddr is write-only"),
            7 => {
                // println!("Updating v for ppudata read");
                let val = self
                    .memory
                    .read(self.background.v)
                    .reg_map(|a, off| match a {
                        PPUMMRegisters::Palette => self.palette.ram[off as usize],
                    });
                // if self.background
                self.increment_v();
                val
            }
            // 7 => self.registers.data,
            _ => panic!("No register at {:02X}", offset),
        }
    }
    pub fn write_reg(&mut self, offset: u16, val: u8) {
        match offset {
            0x00 => {
                self.nmi_enabled = val & 0b1000_0000 != 0;
                self.background.t =
                    (self.background.t & 0b0001_1000_0000_0000) | (((val & 0b11) as u16) << 10);
                self.background.vram_column = val & 0b0000_0100 != 0;
                self.background.second_pattern = val & 0b0001_0000 != 0;
                // TODO: other control fields
            }
            0x01 => {
                // self.dbg_int = true;
                self.mask.grayscale = val & 0b0000_0001 != 0;
                self.mask.background_on_left_edge = val & 0b0000_0010 != 0;
                self.mask.sprites_on_left_edge = val & 0b0000_0100 != 0;
                self.mask.enable_background = val & 0b0000_1000 != 0;
                self.mask.enable_sprites = val & 0b0001_0000 != 0;
                self.mask.em_red = val & 0b0010_0000 != 0;
                self.mask.em_green = val & 0b0100_0000 != 0;
                self.mask.em_blue = val & 0b1000_0000 != 0;
                // todo!("Mask: {:02X}", val)
            }
            0x02 => {
                todo!("Unable to write to PPU status")
                // TODO: ppu status
            }
            0x03 => self.oam.addr = val,
            0x04 => {
                self.oam.mem[self.oam.addr as usize] = val;
                self.oam.addr = self.oam.addr.wrapping_add(1);
            }
            0x05 => {
                if self.background.w {
                    // Is y scroll
                    self.background.t = (self.background.t & 0b0000_1100_0001_1111)
                        | (((val as u16) << 2) & 0b0000_0011_1110_0000)
                        | (((val as u16) << 12) & 0b0111_0000_0000_0000);
                    self.background.w = false;
                } else {
                    // Is x scroll
                    self.background.x = val & 0b111; // Lowest three bits
                    self.background.t =
                        (self.background.t & 0b0111_1111_1110_0000) | (val as u16 >> 3);
                    self.background.w = true;
                }
            }
            0x06 => {
                // TODO: ppu addr
                if self.background.w {
                    self.background.v =
                        u16::from_le_bytes([val, self.background.v.to_le_bytes()[1]]);
                    self.background.w = false;
                } else {
                    self.background.v =
                        u16::from_le_bytes([self.background.v.to_le_bytes()[0], val & 0b0011_1111]);
                    self.background.w = true;
                }
                // println!("Updating v for ppuaddr write: to {:04X}", self.background.v);
                // self.dbg_int = true;
                // todo!("PPUADDR write")
            }
            0x07 => {
                // println!("Writing: {:02X}, @{:04X}", val, self.background.v);
                self.memory
                    .write(self.background.v, val, |r, o, v| match r {
                        PPUMMRegisters::Palette => {
                            // println!("Writing {:02X} to {:02X}", v & 0x3F, o);
                            self.palette.ram[o as usize] = v & 0x3F;
                        }
                    });
                self.increment_v();
                // self.background.v += 1; // TODO: implement inc behavior
            }
            _ => panic!("No register at {:02X}", offset),
        }
    }
    /// Apply either row wise or column wise increment
    fn increment_v(&mut self) {
        if self.background.vram_column {
            // if self.background.v
            self.background.v += 32;
        } else {
            self.background.v += 1;
        }
        // self.background.v = self
        //     .background
        //     .v
        //     .wrapping_add(if self.background.vram_column { 32 } else { 1 });
    }
    // pub fn write_oamdma(&mut self, val: u8) {
    //     // TODO: OAM high addr
    // }

    pub fn run_one_clock_cycle(&mut self) -> bool {
        self.cycle += 1;
        self.pixel += 1;
        if self.scanline == 261
            && (self.pixel == 341 || (self.pixel == 340 && self.even && self.rendering_enabled()))
        {
            self.scanline = 0;
            self.pixel = 0;
            self.even = !self.even;
        }
        if self.pixel == 341 {
            self.pixel = 0;
            self.scanline += 1;
        }
        if self.mask.enable_background || self.mask.enable_sprites {
            if self.scanline < 240 || self.scanline == 261 {
                if self.pixel == 257 {
                    self.background.v = (self.background.v & 0b0111_1011_1110_0000)
                        | (self.background.t & 0b0000_0100_0001_1111);
                }
                if self.pixel >= 280 && self.pixel <= 304 && self.scanline == 261 {
                    self.background.v = (self.background.v & 0b0000_0100_0001_1111)
                        | (self.background.t & 0b0111_1011_1110_0000);
                }
                if self.pixel > 280 && self.pixel < 320 {
                    self.background.cur_shift_high <<= 1;
                    self.background.cur_shift_low <<= 1;
                }
                // TODO
                if self.pixel == 0 {
                    // self.dbg_int = true;
                    // idle cycle
                } else if self.pixel < 257 || self.pixel > 320 {
                    // self.dbg_int = true;
                    const POS: u32 = 1 << 15;
                    // Determine background color
                    let a = self.background.cur_shift_high & POS;
                    let b = self.background.cur_shift_low & POS;
                    let val = (a >> 14) | (b >> 15);
                    debug_assert!(val < 4);

                    let h_off = ((self.pixel - 1) / 16) % 2;
                    let v_off = (self.scanline / 16) % 2;
                    let off = v_off * 4 + h_off * 2;
                    let palette = (self.background.cur_attr >> off) & 0x3;

                    if self.scanline < 240 && self.pixel < 257 {
                        // Write to screen
                        self.render_buffer.write(
                            self.scanline,
                            self.pixel - 1,
                            self.palette
                                .color(val as u8, if val != 0 { palette } else { 0 }), // self.palette.colors[val as usize],
                        ); // TODO: this should come from shift registers
                    }
                    if self.pixel < 337 {
                        self.background.cur_shift_high <<= 1;
                        self.background.cur_shift_low <<= 1;
                    }

                    if self.scanline < 240 || self.scanline == 261 {
                        if self.pixel <= 260 || self.pixel >= 321 {
                            if self.pixel % 8 == 2 {
                                // Name table fetch
                                // let addr = 0x2000 + self.pixel / 8 + self.scanline / 8;
                                let addr = 0x2000 | (self.background.v & 0x0FFF);
                                // println!("Cur: {:04X}, comp: {:04X}", addr, addr_2);
                                let val = self.memory.read(addr).reg_map(|_, _| 0);
                                self.background.cur_nametable = val;
                            } else if self.pixel % 8 == 4 {
                                // Attr table fetch
                                // let addr = 0x23C0 + self.pixel / 16 + self.scanline / 16;
                                let addr = 0x23C0
                                    | (self.background.v & 0x0C00)
                                    | ((self.background.v >> 4) & 0x38)
                                    | ((self.background.v >> 2) & 0x07);
                                // println!("Cur: {:04X}, comp: {:04X}", addr, addr_2);
                                // assert_eq!(addr, addr_2);
                                let val = self.memory.read(addr).reg_map(|_, _| 0); // TODO: handle reg reads
                                self.background.next_attr_2 = val;
                            } else if self.pixel % 8 == 6 {
                                // BG pattern low
                                let addr = self.background.cur_nametable as u16 * 16
                                    + ((self.background.v & 0x7000) >> 12)
                                    // + (self.scanline % 8) as u16
                                    + if self.background.second_pattern {
                                        0x1000
                                    } else {
                                        0
                                    };
                                let val = self.memory.read(addr).reg_map(|_, _| 0);
                                self.background.cur_low = val;
                            } else if self.pixel % 8 == 0 && self.pixel > 0 {
                                let addr = self.background.cur_nametable as u16 * 16
                                    + 8
                                    + ((self.background.v & 0x7000) >> 12)
                                    // (self.scanline % 8) as u16
                                    + if self.background.second_pattern {
                                        0x1000
                                    } else {
                                        0
                                    };
                                let val = self.memory.read(addr).reg_map(|_, _| todo!());
                                self.background.cur_high = val;
                                self.background.cur_shift_low |= self.background.cur_low as u32;
                                self.background.cur_shift_high |= self.background.cur_high as u32;
                                self.background.cur_attr = self.background.next_attr;
                                self.background.next_attr = self.background.next_attr_2;
                                // Inc horizontal
                                if self.background.v & 0x1F == 31 {
                                    self.background.v = (self.background.v & !0x1F) ^ 0x400;
                                } else {
                                    self.background.v += 1;
                                }
                                // Inc vertical
                                if self.pixel == 256 {
                                    //  && self.scanline % 4 == 0
                                    if self.background.v & 0x7000 != 0x7000 {
                                        self.background.v += 0x1000;
                                    } else {
                                        self.background.v &= !0x7000;
                                        let mut y = (self.background.v & 0x03E0) >> 5;
                                        if y == 29 {
                                            y = 0;
                                            self.background.v ^= 0x0800
                                        } else if y == 31 {
                                            y = 0;
                                        } else {
                                            y += 1;
                                        }
                                        self.background.v =
                                            (self.background.v & !0x03E0) | (y << 5);
                                    }
                                }
                            }
                        }
                    }
                } else {
                    // TODO: Sprite fetches
                }
            }
        }
        if self.scanline == 261 && self.pixel == 1 {
            self.vblank = false;
            // TODO: clear sprite 0 & sprite overflow
        }
        if self.scanline == 241 && self.pixel == 1 {
            self.vblank = true;
            // self.nmi_waiting = self.nmi_enabled;
            self.frame_count += 1;
            self.background.state = BackgroundState::NameTableBytePre;
            return true;
        }
        return false;
    }

    pub fn nmi_on_vblank(&self) -> bool {
        self.nmi_enabled
    }
    pub fn peek_nmi(&self) -> bool {
        self.vblank && self.nmi_enabled
    }
    pub fn nmi_waiting(&mut self) -> bool {
        self.vblank && self.nmi_enabled
        // if self.nmi_waiting {
        //     self.nmi_waiting = false;
        //     return true;
        // } else {
        //     return false;
        // }
    }
    pub fn peek_irq(&self) -> bool {
        false
    }
    pub fn irq_waiting(&mut self) -> bool {
        false
    }

    pub fn render_name_table<R: Renderer>(&self, frame: &mut Frame<R>) {
        for y in 0..60 {
            for x in 0..64 {
                let row = y % 30;
                let col = x % 32;
                let off = 0x2000 + 0x400 * (y / 30 * 2 + x / 32);
                let name = self.memory.peek((off + col + row * 32) as u16).unwrap() as u16 * 16
                    + if self.background.second_pattern {
                        0x1000
                    } else {
                        0
                    };
                let attr = self
                    .memory
                    .peek((col / 4 + row / 4 * 8 + 0x3C0 + off) as u16)
                    .unwrap();
                // attr << (((col & 1) << 1) | ((row & 1) << 0)) * 2
                // let h_off = ((self.pixel - 1) / 16) % 2;
                // let v_off = (self.scanline / 16) % 2;
                // let off = v_off * 4 + h_off * 2;
                let palette = (attr >> (((col & 1) << 1) | ((row & 1) << 2))) & 0x3;
                for y_off in 0..8 {
                    let low = self.memory.peek(name + y_off).unwrap();
                    let high = self.memory.peek(name + y_off + 8).unwrap();
                    for bit in 0..8 {
                        frame.fill_rectangle(
                            Point::new(
                                x as f32 * 8. + 8. - bit as f32,
                                y as f32 * 8. + y_off as f32,
                            ),
                            Size::new(1., 1.),
                            match (low & (1 << bit) != 0, high & (1 << bit) != 0) {
                                (false, false) => self.palette.color(0, 0),
                                (true, false) => self.palette.color(1, palette),
                                (false, true) => self.palette.color(2, palette),
                                (true, true) => self.palette.color(3, palette),
                                // (false, false) => Color { r: 0, g: 0, b: 0 },
                                // (true, false) => Color {
                                //     r: 64,
                                //     g: 64,
                                //     b: 64,
                                // },
                                // (false, true) => Color {
                                //     r: 128,
                                //     g: 128,
                                //     b: 128,
                                // },
                                // (true, true) => Color {
                                //     r: 255,
                                //     g: 255,
                                //     b: 255,
                                // },
                            },
                        );
                    }
                }
                // for
                // let pat = self.memory.peek();
            }
        }
    }
    pub fn name_cursor_info(&self, cursor: Point) -> Option<String> {
        let x = (cursor.x / 8.) as usize;
        let y = (cursor.y / 8.) as usize;
        if x < 64 && y < 60 {
            let row = y % 30;
            let col = x % 32;
            let off = 0x2000 + 0x400 * (y / 30 * 2 + x / 32);
            let name = self.memory.peek((off + col + row * 32) as u16).unwrap() as usize;
            let attr = self
                .memory
                .peek((col / 4 + row / 4 * 8 + 0x3C0 + off) as u16)
                .unwrap();
            Some(format!(
                "Row, Column: {}, {}
X, Y: {}, {}
Tilemap address: ${:04X}

Tile Index: ${:02X}
Tile Address (PPU): ${:04X}
Tile Address (CHR): ${:04X}

Palette Index {}
Palette Address ${:04X}

Attribute Address ${:04X}
Attribute data: ${:02X}
",
                row,
                col,
                col * 8,
                row * 8,
                off + col + row * 32,
                name,
                name * 16
                    + if self.background.second_pattern {
                        0x1000
                    } else {
                        0
                    },
                name * 16
                    + if self.background.second_pattern {
                        0x1000
                    } else {
                        0
                    },
                (attr >> (((col & 1) << 1) | ((row & 1) << 2))) & 0x3,
                ((attr >> (((col & 1) << 1) | ((row & 1) << 2))) & 0x3) as usize * 4 + 0x3F00,
                col / 4 + row / 4 * 8 + 0x3C0 + off,
                attr,
            ))
        } else {
            None
        }
    }

    pub fn render_pattern_tables<R: Renderer>(&self, frame: &mut Frame<R>) {
        for y in 0..16 {
            for x in 0..16 {
                let name = (y * 16 + x) * 16;
                for y_off in 0..8 {
                    let low = self.memory.peek(name + y_off).unwrap();
                    let high = self.memory.peek(name + y_off + 8).unwrap();
                    for bit in 0..8 {
                        frame.fill_rectangle(
                            Point::new(
                                x as f32 * 8. + 8. - bit as f32,
                                y as f32 * 8. + y_off as f32,
                            ),
                            Size::new(1., 1.),
                            match (low & (1 << bit) != 0, high & (1 << bit) != 0) {
                                (false, false) => Color { r: 0, g: 0, b: 0 },
                                (true, false) => Color {
                                    r: 64,
                                    g: 64,
                                    b: 64,
                                },
                                (false, true) => Color {
                                    r: 128,
                                    g: 128,
                                    b: 128,
                                },
                                (true, true) => Color {
                                    r: 255,
                                    g: 255,
                                    b: 255,
                                },
                            },
                        );
                    }
                }
            }
        }

        for y in 0..16 {
            for x in 0..16 {
                let name = (y * 16 + x) * 16;
                for y_off in 0..8 {
                    let low = self.memory.peek(name + y_off + 0x1000).unwrap();
                    let high = self.memory.peek(name + y_off + 8 + 0x1000).unwrap();
                    for bit in 0..8 {
                        frame.fill_rectangle(
                            Point::new(
                                x as f32 * 8. + 8. - bit as f32,
                                y as f32 * 8. + y_off as f32 + 130.,
                            ),
                            Size::new(1., 1.),
                            match (low & (1 << bit) != 0, high & (1 << bit) != 0) {
                                (false, false) => Color { r: 0, g: 0, b: 0 },
                                (true, false) => Color {
                                    r: 64,
                                    g: 64,
                                    b: 64,
                                },
                                (false, true) => Color {
                                    r: 128,
                                    g: 128,
                                    b: 128,
                                },
                                (true, true) => Color {
                                    r: 255,
                                    g: 255,
                                    b: 255,
                                },
                            },
                        );
                    }
                }
                // for
                // let pat = self.memory.peek();
            }
        }
    }
    pub fn pattern_cursor_info(&self, cursor: Point) -> Option<String> {
        let x = (cursor.x / 8.) as usize;
        let y = (cursor.y / 8.) as usize;
        if x < 16 && y < 32 {
            Some(format!(
                "Tile address (PPU):   {:04X}\nTile address (CHR):    {:04X}\nIndex:    {:02X}",
                (y * 16 + x) * 16,
                (y * 16 + x) * 16,
                ((y % 16) * 16 + x),
            ))
        } else {
            None
        }
    }

    pub fn render_palette<R: Renderer>(&self, frame: &mut Frame<R>) {
        for y in 0..8 {
            for x in 0..4 {
                frame.fill_rectangle(
                    Point::new(x as f32 * 10., y as f32 * 10.),
                    Size::new(10., 10.),
                    self.palette.colors[(self.palette.ram[x + y * 4] & 0x3F) as usize],
                );
            }
        }
    }
    pub fn palette_cursor_info(&self, cursor: Point) -> Option<String> {
        let x = (cursor.x / 10.) as usize;
        let y = (cursor.y / 10.) as usize;
        if x < 4 && y < 8 {
            Some(format!(
                "Index:   {:02X}\nValue:    {:02X}\nColor code:    {}",
                x + y * 4,
                self.palette.ram[x + y * 4] & 0x3F,
                self.palette.colors[(self.palette.ram[x + y * 4] & 0x3F) as usize],
            ))
        } else {
            None
        }
    }

    pub fn mem(&self) -> &impl Memory {
        &self.memory
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn ppu_registers() {
        let mut ppu = PPU::with_chr_rom(&[0u8; 8192], Mapper::from_flags(0));
        assert_eq!(ppu.background.v, 0);
        assert_eq!(ppu.background.t, 0);
        assert_eq!(ppu.background.x, 0);
        assert_eq!(ppu.background.w, false);
        ppu.write_reg(0, 0);
        assert_eq!(ppu.background.v, 0);
        ppu.write_reg(0, 0b11);
        assert_eq!(
            ppu.background.t, 0b0001100_00000000,
            "Actual: {:016b}",
            ppu.background.t
        );
        assert_eq!(ppu.background.w, false);

        ppu.write_reg(5, 0x7D);
        assert_eq!(
            ppu.background.t, 0b0001100_00001111,
            "Actual: {:016b}",
            ppu.background.t
        );
        assert_eq!(ppu.background.x, 0b101);
        assert_eq!(ppu.background.w, true);
        ppu.write_reg(5, 0x5E);
        assert_eq!(
            ppu.background.t, 0b1101101_01101111,
            "Actual: {:016b}",
            ppu.background.t
        );
        assert_eq!(ppu.background.x, 0b101);
        assert_eq!(ppu.background.w, false);

        ppu.write_reg(5, 0x7D);
        assert_eq!(
            ppu.background.t, 0b1101101_01101111,
            "Actual: {:016b}",
            ppu.background.t
        );
        assert_eq!(ppu.background.x, 0b101);
        assert_eq!(ppu.background.w, true);
        ppu.read_reg(2);
        assert_eq!(ppu.background.w, false);
    }
}