#pragma once

#include <stddef.h>
#include <stdint.h>

#define rom_offset(member) (0x100 + offsetof(struct rom_header, member))
#define rom_offset_end(member) (0x100 + offsetof(struct rom_header, member) + sizeof(((struct rom_header *)0)->member))

enum rom_cgb {
    ROM_CGB_SUPPORTED = 0x80,
    ROM_CGB_ONLY = 0xC0
};

enum rom_sgb {
    ROM_SGB_NO = 0x00,
    ROM_SGB_SUPPORTED = 0x03
};

enum rom_type {
    ROM_TYPE_ROM_ONLY = 0x00,

    ROM_TYPE_MBC1 = 0x01,
    ROM_TYPE_MBC1_RAM = 0x2,
    ROM_TYPE_MBC1_RAM_BATTERY = 0x03,

    // UNUSED = 0x04

    ROM_TYPE_MBC2 = 0x05,
    ROM_TYPE_MBC2_BATTERY = 0x06,

    // UNUSED = 0x07

    ROM_TYPE_ROM_RAM = 0x08,
    ROM_TYPE_ROM_RAM_BATTERY = 0x09,

    // UNUSED = 0x0A

    ROM_TYPE_MMM01 = 0x0B,
    ROM_TYPE_MMM01_RAM = 0x0C,
    ROM_TYPE_MMM01_RAM_BATTERY = 0x0D,

    // UNUSED = 0x0E

    ROM_TYPE_MBC3_TIMER_BATTERY = 0x0F,
    ROM_TYPE_MBC3_TIMER_RAM_BATTERY = 0x10,
    ROM_TYPE_MBC3 = 0x11,
    ROM_TYPE_MBC3_RAM = 0x12,
    ROM_TYPE_MBC3_RAM_BATTERY = 0x13,

    // UNUSED = 0x14

    // Doesn't exist, but included for "completeness".
    ROM_TYPE_MBC4 = 0x15,
    ROM_TYPE_MBC4_RAM = 0x16,
    ROM_TYPE_MBC4_RAM_BATTERY = 0x17,

    // UNUSED = 0x18

    ROM_TYPE_MBC5 = 0x19,
    ROM_TYPE_MBC5_RAM = 0x1A,
    ROM_TYPE_MBC5_RAM_BATTERY = 0x1B,
    ROM_TYPE_MBC5_RUMBLE = 0x1C,
    ROM_TYPE_MBC5_RUMBLE_RAM = 0x1D,
    ROM_TYPE_MBC5_RUMBLE_RAM_BATTERY = 0x1E,

    // UNUSED = 0x1F

    ROM_TYPE_MBC6_RAM_BATTERY = 0x20,

    // UNUSED = 0x21

    ROM_TYPE_MBC7_ACCEL_RAM_BATTERY = 0x22,

    // UNUSED ...

    ROM_TYPE_POCKET_CAMERA = 0xFC,
    ROM_TYPE_BANDAI_TAMA5 = 0xFD,
    ROM_TYPE_HUC3 = 0xFE,
    ROM_TYPE_HUC1_RAM_BATTERY = 0xFF
};

enum rom_region {
    ROM_REGION_JAPANESE = 0x00,
    ROM_REGION_INTERNATIONAL = 0x01
};

// http://gbdev.gg8.se/files/docs/mirrors/pandocs.html#thecartridgeheader
// https://raw.githubusercontent.com/AntonioND/giibiiadvance/master/docs/TCAGBD.pdf (page 51)
struct rom_header {
    uint8_t entry[4];
    uint8_t logo[0x30];
    uint8_t title[0xB];
    uint8_t manufacturer[4];
    uint8_t cgb_flag;
    uint8_t licensee[2];
    uint8_t sgb_flag;
    uint8_t type;
    uint8_t rom_size;  // 0x8000 << x
    uint8_t ram_size;  // MBC2 uses 0, but has a size of 512 * 4 bytes
    uint8_t region;
    uint8_t old_licensee;  // If 0x33, use the new licensee
    uint8_t version;
    uint8_t header_checksum;
    uint8_t global_checksum[2];  // Big endian
} __attribute__((packed));

extern uint8_t rom_logo[];