use super::*;

impl Ppu {
    pub fn save_state(&self, out: &mut Vec<u8>) {
        out.extend_from_slice(&self.vram);
        out.extend_from_slice(&self.palette_ram);
        out.extend_from_slice(&self.oam);
        out.push(self.ctrl);
        out.push(self.mask);
        out.push(self.status);
        out.push(self.oam_addr);
        out.push(u8::from(self.write_latch));
        out.extend_from_slice(&self.vram_addr.to_le_bytes());
        out.extend_from_slice(&self.temp_addr.to_le_bytes());
        out.push(self.fine_x);
        out.push(self.scroll_x);
        out.push(self.scroll_y);
        out.push(self.read_buffer);
        out.push(self.io_latch);
        out.extend_from_slice(&self.bg_shift_pattern_lo.to_le_bytes());
        out.extend_from_slice(&self.bg_shift_pattern_hi.to_le_bytes());
        out.extend_from_slice(&self.bg_shift_attr_lo.to_le_bytes());
        out.extend_from_slice(&self.bg_shift_attr_hi.to_le_bytes());
        out.push(self.next_tile_id);
        out.push(self.next_tile_attr);
        out.push(self.next_tile_lsb);
        out.push(self.next_tile_msb);
        out.push(self.sprite_count);
        out.extend_from_slice(&self.sprite_indices);
        out.push(self.next_sprite_count);
        out.extend_from_slice(&self.next_sprite_indices);
    }

    pub fn load_state(&mut self, data: &[u8]) -> Result<usize, String> {
        let mut cursor = 0usize;
        self.vram.copy_from_slice(sio::take_exact(
            data,
            &mut cursor,
            VRAM_SIZE,
            PPU_STATE_CTX,
        )?);
        self.palette_ram.copy_from_slice(sio::take_exact(
            data,
            &mut cursor,
            PALETTE_SIZE,
            PPU_STATE_CTX,
        )?);
        self.oam
            .copy_from_slice(sio::take_exact(data, &mut cursor, OAM_SIZE, PPU_STATE_CTX)?);
        self.ctrl = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
        self.mask = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
        self.status = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
        self.oam_addr = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
        self.write_latch = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)? != 0;
        self.vram_addr = sio::take_u16(data, &mut cursor, PPU_STATE_CTX)?;
        self.vram_addr &= 0x3FFF;
        self.temp_addr = sio::take_u16(data, &mut cursor, PPU_STATE_CTX)? & 0x3FFF;
        self.fine_x = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
        self.scroll_x = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
        self.scroll_y = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
        self.read_buffer = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
        self.io_latch = if cursor < data.len() {
            sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?
        } else {
            0
        };
        if cursor + 30 <= data.len() {
            self.bg_shift_pattern_lo = sio::take_u16(data, &mut cursor, PPU_STATE_CTX)?;
            self.bg_shift_pattern_hi = sio::take_u16(data, &mut cursor, PPU_STATE_CTX)?;
            self.bg_shift_attr_lo = sio::take_u16(data, &mut cursor, PPU_STATE_CTX)?;
            self.bg_shift_attr_hi = sio::take_u16(data, &mut cursor, PPU_STATE_CTX)?;
            self.next_tile_id = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
            self.next_tile_attr = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
            self.next_tile_lsb = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
            self.next_tile_msb = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
            self.sprite_count = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
            self.sprite_indices.copy_from_slice(sio::take_exact(
                data,
                &mut cursor,
                8,
                PPU_STATE_CTX,
            )?);
            self.next_sprite_count = sio::take_u8(data, &mut cursor, PPU_STATE_CTX)?;
            self.next_sprite_indices.copy_from_slice(sio::take_exact(
                data,
                &mut cursor,
                8,
                PPU_STATE_CTX,
            )?);
        } else {
            self.bg_shift_pattern_lo = 0;
            self.bg_shift_pattern_hi = 0;
            self.bg_shift_attr_lo = 0;
            self.bg_shift_attr_hi = 0;
            self.next_tile_id = 0;
            self.next_tile_attr = 0;
            self.next_tile_lsb = 0;
            self.next_tile_msb = 0;
            self.sprite_count = 0;
            self.sprite_indices = [0; 8];
            self.next_sprite_count = 0;
            self.next_sprite_indices = [0; 8];
        }
        self.scroll_events.clear();
        self.scroll_events.push(self.current_scroll_event(0, 0));
        Ok(cursor)
    }
}