#include "chip8.h"
#include "memory.h"
#include "cpu.h"
#include "input.h"
#include "libft.h"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <SDL2/SDL.h>

int chip8_load_rom(t_chip8 *emu, const char *path)
{
    FILE *fp = fopen(path, "rb");
    if (fp == NULL)
    {
        return 1;
    }

    if (memory_load_rom(&emu->memory, fp) == 1)
    {
        fclose(fp);
        return (1);
    }

    fclose(fp);
    return (0);
}

void chip8_init(t_chip8 *emu)
{
    ft_memset(emu->keyboard.keyboard, 0, sizeof(emu->keyboard.keyboard));

    memory_init(&emu->memory);
    memory_load_fontset(&emu->memory);

    memset(emu->v, 0, sizeof(emu->v));
    memset(emu->stack, 0, sizeof(emu->stack));

    emu->i = 0;
    emu->pc = 0x200;

    emu->delay_timer = 0;
    emu->sound_timer = 0;

    emu->sp = 0;

    if (graphics_init(&emu->display) != 0)
    {
        printf("Failed to initialize graphics!\n");
        exit(1);
    }

    if (graphics_display_ready() != 1)
    {
        printf("Graphics display failed to initialize properly!\n");
        exit(1);
    }

    emu->running = 1;
}

void chip8_run(t_chip8 *emu)
{
    uint32_t frame_start, frame_end, frame_duration;
    SDL_Event event;

    while (emu->running)
    {
        frame_start = SDL_GetTicks();

        while (SDL_PollEvent(&event))
        {
            if (event.type == SDL_QUIT)
            {
                emu->running = 0;
                break;
            }
            if (event.type == SDL_KEYDOWN || event.type == SDL_KEYUP)
            {
                input_update(&event, emu->keyboard.keyboard);
            }
        }

        if (emu->keyboard.waiting_for_key)
        {
            uint8_t key = get_pressed_key(emu);
            if (key != 0xFF)
            {
                emu->v[emu->keyboard.key_register] = key;
                emu->keyboard.waiting_for_key = 0;
            }
        }
        else
        {
            for (int i = 0; i < 10; i++)
            {
                uint16_t opcode = cpu_fetch(emu);
                t_instruction instruction = cpu_decode(opcode);
                cpu_execute(emu, instruction);
            }
        }

        if (emu->delay_timer > 0)
            emu->delay_timer--;
        if (emu->sound_timer > 0)
            emu->sound_timer--;

        graphics_render(emu);

        frame_end = SDL_GetTicks();
        frame_duration = frame_end - frame_start;

        if (frame_duration < FRAME_TIME_MS)
        {
            SDL_Delay(FRAME_TIME_MS - frame_duration);
        }
    }
}