#ifndef GPU_H
#define GPU_H

#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "ic.h"

#define PSX_GPU_BEGIN 0x1f801810
#define PSX_GPU_SIZE  0x8
#define PSX_GPU_END   0x1f801814

#define PSX_GPU_FB_WIDTH 1024
#define PSX_GPU_FB_HEIGHT 512

// Use this when updating your texture
#define PSX_GPU_FB_STRIDE 2048

// 0x100000 * 2
#define PSX_GPU_VRAM_SIZE (0x200000)

#define PSX_GPU_CLOCK_NTSC 53693175 // 53.693175 MHz
#define PSX_GPU_CLOCK_FREQ_NTSC 53.693175f // 53.693175 MHz
#define PSX_GPU_CLOCK_FREQ_PAL 53.203425f // 53.203425 MHz
#define PSX_GPU_CYCLES_PER_SCANLINE_NTSC 3413.0f
#define PSX_GPU_CYCLES_PER_SCANLINE_PAL 3406.0f
#define PSX_GPU_SCANS_PER_FRAME_NTSC 263
#define PSX_GPU_SCANS_PER_FRAME_PAL 314

enum {
    GPU_EVENT_DMODE,
    GPU_EVENT_VBLANK,
    GPU_EVENT_VBLANK_END,
    GPU_EVENT_HBLANK,
    GPU_EVENT_HBLANK_END,
    GPU_EVENT_VBLANK_TIMER
};

enum {
    GPU_STATE_RECV_CMD,
    GPU_STATE_RECV_ARGS,
    GPU_STATE_RECV_DATA
};

struct psx_gpu_t;

typedef struct psx_gpu_t psx_gpu_t;

typedef void (*psx_gpu_cmd_t)(psx_gpu_t*);
typedef void (*psx_gpu_event_callback_t)(psx_gpu_t*);

enum {
    RS_VARIABLE,
    RS_1X1,
    RS_8X8,
    RS_16X16
};

enum {
    RA_RAW      = 0x01,
    RA_TRANSP   = 0x02,
    RA_TEXTURED = 0x04
};

enum {
    PA_RAW      = 0x01,
    PA_TRANSP   = 0x02,
    PA_TEXTURED = 0x04,
    PA_QUAD     = 0x08,
    PA_SHADED   = 0x10
};

typedef struct {
    int16_t x, y;
    uint32_t c;
    uint8_t tx, ty;
} vertex_t;

typedef struct {
    uint8_t attrib;
    vertex_t v[4];
    uint16_t clut, texp;
} poly_data_t;

#ifdef USE_HARDWARE
typedef void (*psx_gpu_render_triangle_t)(psx_gpu_t*, vertex_t, vertex_t, vertex_t, poly_data_t, int);
#endif

typedef struct {
    uint8_t attrib;
    vertex_t v0;
    uint16_t clut;
    uint16_t width, height;
} rect_data_t;

#ifdef USE_HARDWARE
typedef struct {
    psx_gpu_render_triangle_t render_triangle;
} psx_gpu_renderer_t;
#endif

struct psx_gpu_t {
    uint32_t bus_delay;
    uint32_t io_base, io_size;

    void* udata[4];

    uint16_t* vram;
    uint16_t* empty;
    int display_enable;

    // State data
    uint32_t buf[16];
    uint32_t recv_data;
    int buf_index;
    int cmd_args_remaining;
    int cmd_data_remaining;
    int line_done;
    vertex_t prev_line_vertex;

    // Command counters
    uint32_t color;
    uint32_t xpos, ypos;
    uint32_t xsiz, ysiz;
    uint32_t tsiz;
    uint32_t addr;
    uint32_t xcnt, ycnt;
    vertex_t v0, v1, v2, v3;
    uint32_t pal, texp;
    uint32_t c0_xcnt, c0_ycnt;
    uint32_t c0_addr;
    int c0_xsiz, c0_ysiz;
    int c0_tsiz;
    int gp1_10h_req;

    // GPU state
    uint32_t state;

    uint32_t display_mode;
    uint32_t gpuread;
    uint32_t gpustat;

    // Drawing area
    uint32_t draw_x1, draw_y1;
    uint32_t draw_x2, draw_y2;

    // Drawing offset
    int32_t off_x, off_y;

    // Texture Window
    uint32_t texw_mx, texw_my;
    uint32_t texw_ox, texw_oy;

    // CLUT offset
    uint32_t clut_x, clut_y;

    // Texture page
    uint32_t texp_x, texp_y;
    uint32_t texp_d;

    // Display area
    uint32_t disp_x, disp_y;
    uint32_t disp_x1, disp_x2;
    uint32_t disp_y1, disp_y2;

    // Timing and IRQs
    float cycles;
    int line;

    psx_ic_t* ic;

    psx_gpu_event_callback_t event_cb_table[8];
#ifdef USE_HARDWARE
    psx_gpu_renderer_t renderer;
#endif
};

static inline int psx_gpu_is_pal_mode(const psx_gpu_t* gpu) {
    return gpu && ((gpu->display_mode & 0x8) != 0);
}

static inline float psx_gpu_clock_frequency(const psx_gpu_t* gpu) {
    return psx_gpu_is_pal_mode(gpu) ? PSX_GPU_CLOCK_FREQ_PAL : PSX_GPU_CLOCK_FREQ_NTSC;
}

static inline float psx_gpu_frame_rate(const psx_gpu_t* gpu) {
    const float clock_hz = psx_gpu_clock_frequency(gpu) * 1000000.0f;
    const float cycles_per_scanline = psx_gpu_is_pal_mode(gpu)
        ? PSX_GPU_CYCLES_PER_SCANLINE_PAL
        : PSX_GPU_CYCLES_PER_SCANLINE_NTSC;
    const int scans_per_frame = psx_gpu_is_pal_mode(gpu)
        ? PSX_GPU_SCANS_PER_FRAME_PAL
        : PSX_GPU_SCANS_PER_FRAME_NTSC;

    return clock_hz / (cycles_per_scanline * (float)scans_per_frame);
}

psx_gpu_t* psx_gpu_create(void);
void psx_gpu_init(psx_gpu_t*, psx_ic_t*);
uint32_t psx_gpu_read32(psx_gpu_t*, uint32_t);
uint16_t psx_gpu_read16(psx_gpu_t*, uint32_t);
uint8_t psx_gpu_read8(psx_gpu_t*, uint32_t);
void psx_gpu_write32(psx_gpu_t*, uint32_t, uint32_t);
void psx_gpu_write16(psx_gpu_t*, uint32_t, uint16_t);
void psx_gpu_write8(psx_gpu_t*, uint32_t, uint8_t);
void psx_gpu_destroy(psx_gpu_t*);
void psx_gpu_set_udata(psx_gpu_t*, int, void*);
void psx_gpu_set_event_callback(psx_gpu_t*, int, psx_gpu_event_callback_t);
void* psx_gpu_get_display_buffer(psx_gpu_t*);
void psx_gpu_update(psx_gpu_t*, int);
void gpu_render_triangle(psx_gpu_t*, vertex_t, vertex_t, vertex_t, poly_data_t, int);
uint16_t gpu_fetch_texel(psx_gpu_t*, uint16_t, uint16_t, uint32_t, uint32_t, uint16_t, uint16_t, int);

#endif