package cart

type nrom struct {
	prg       []uint8
	chr       []uint8
	chrIsRAM  bool
	prgRAM    [8 * 1024]uint8
	mirroring Mirroring
}

func newNROM(c *Cartridge) *nrom {
	return &nrom{
		prg:       c.PRG,
		chr:       c.CHR,
		chrIsRAM:  c.CHRIsRAM,
		mirroring: c.Mirroring,
	}
}

func (m *nrom) CPURead(addr uint16) uint8 {
	switch {
	case addr >= 0x8000:
		return m.prg[int(addr-0x8000)%len(m.prg)]
	case addr >= 0x6000:
		return m.prgRAM[addr-0x6000]
	default:
		return 0
	}
}

func (m *nrom) CPUWrite(addr uint16, v uint8) {
	if addr >= 0x6000 && addr < 0x8000 {
		m.prgRAM[addr-0x6000] = v
	}
}

func (m *nrom) PPURead(addr uint16) uint8 {
	return m.chr[int(addr)%len(m.chr)]
}

func (m *nrom) PPUWrite(addr uint16, v uint8) {
	if m.chrIsRAM {
		m.chr[int(addr)%len(m.chr)] = v
	}
}

func (m *nrom) Mirroring() Mirroring { return m.mirroring }