#include <emulator.h>

int emulator_initialise(Emulator* emulator)
{
    const uint8_t font[] =
    {
        0xF0, 0x90, 0x90, 0x90, 0xF0, // 0
        0x20, 0x60, 0x20, 0x20, 0x70, // 1
        0xF0, 0x10, 0xF0, 0x80, 0xF0, // 2
        0xF0, 0x10, 0xF0, 0x10, 0xF0, // 3
        0x90, 0x90, 0xF0, 0x10, 0x10, // 4
        0xF0, 0x80, 0xF0, 0x10, 0xF0, // 5
        0xF0, 0x80, 0xF0, 0x90, 0xF0, // 6
        0xF0, 0x10, 0x20, 0x40, 0x40, // 7
        0xF0, 0x90, 0xF0, 0x90, 0xF0, // 8
        0xF0, 0x90, 0xF0, 0x10, 0xF0, // 9
        0xF0, 0x90, 0xF0, 0x90, 0x90, // A
        0xE0, 0x90, 0xE0, 0x90, 0xE0, // B
        0xF0, 0x80, 0x80, 0x80, 0xF0, // C
        0xE0, 0x90, 0x90, 0x90, 0xE0, // D
        0xF0, 0x80, 0xF0, 0x80, 0xF0, // E
        0xF0, 0x80, 0xF0, 0x80, 0x80  // F
    };

    //zero out the memory
    memset(emulator, 0, sizeof(Emulator));

    memcpy(emulator->memory + FONT_LOAD_LOCATION, font, sizeof(font));
    emulator->is_on = 1;

    return 0;
}

int emulator_load_rom(Emulator* emulator, char* rom_name)
{
    printf("load rom!: %s\n", rom_name);
    FILE* rom = fopen(rom_name, "r");
    if(rom == NULL)
    {
        perror("no rom file!\n");
        return 1;
    }

    struct stat st;
    fstat(fileno(rom), &st);

     //rom loaded after 0x200 into memory
    int bytes_read = fread(emulator->memory + GAME_LOAD_LOCATION, 1, st.st_size, rom);
    if(bytes_read != st.st_size)
    {
        perror("doesnt cuadrar\n");
        return 2;
    }

    emulator->pc = GAME_LOAD_LOCATION;

    return 0;
}

int emulator_tick(Emulator* emulator)
{
    return 0;
}