#ifndef GPU_H
#define GPU_H

struct sys_window;

#define GPU_TEXTURE_MAX_WIDTH 16384
#define GPU_TEXTURE_MAX_HEIGHT 16384

/* ========================== *
 * Startup
 * ========================== */

struct gpu_startup_receipt { i32 _; };
struct gpu_startup_receipt gpu_startup(struct sys_window *window);

/* ========================== *
 * Texture
 * ========================== */

enum gpu_texture_format {
    GPU_TEXTURE_FORMAT_NONE,
    GPU_TEXTURE_FORMAT_R8G8B8A8_UNORM,
    GPU_TEXTURE_FORMAT_R8G8B8A8_UNORM_SRGB,

    NUM_GPU_TEXTURE_FORMATS
};

enum gpu_texture_flag {
    GPU_TEXTURE_FLAG_NONE           = (0),
    GPU_TEXTURE_FLAG_TARGETABLE     = (1 << 0)
};

struct gpu_texture {
    u64 handle;
};

struct gpu_texture gpu_texture_alloc(enum gpu_texture_format format, u32 flags, struct v2i32 size, void *initial_data);

void gpu_texture_release(struct gpu_texture t);

void gpu_texture_clear(struct gpu_texture target_texture, u32 clear_color);

struct v2i32 gpu_texture_get_size(struct gpu_texture texture);

/* ========================== *
 * Backbuffer
 * ========================== */

 /* Returns a texture representing the internal backbuffer. Lifetime is managed by gpu layer. */
struct gpu_texture gpu_recreate_backbuffer(struct v2i32 size);

/* Presents the backbuffer to the screen */
void gpu_swap_backbuffer(i32 vsync);

/* ========================== *
 * Cmd buffer
 * ========================== */

struct gpu_indices {
    u16 count;
    u16 *indices;
};

enum gpu_cmd_kind {
    GPU_CMD_KIND_NONE,
    GPU_CMD_KIND_DRAW_MESH,
    GPU_CMD_KIND_DRAW_TEXTURE,
    GPU_CMD_KIND_DRAW_GRID,

    NU
};

struct gpu_cmd_params {
    enum gpu_cmd_kind kind;
    union {
        struct {
            struct v2_array vertices;
            struct gpu_indices indices;
            u32 color;
        } mesh;
        struct {
            struct xform xf;
            struct sprite_tag sprite;
            struct gpu_texture texture;
            struct clip_rect clip;
            u32 tint;
        } texture;
        struct {
            struct xform xf;
            f32 line_thickness;
            f32 line_spacing;
            struct v2 offset;
            u32 bg0_color;
            u32 bg1_color;
            u32 line_color;
            u32 x_color;
            u32 y_color;
        } grid;
    };
};

struct gpu_cmd_store {
    u64 handle;
};

struct gpu_cmd_store gpu_cmd_store_alloc(void);

void gpu_cmd_store_release(struct gpu_cmd_store gpu_cmd_store);

void gpu_push_cmd(struct gpu_cmd_store gpu_cmd_store, struct gpu_cmd_params params);

void gpu_submit_cmds(struct gpu_cmd_store gpu_cmd_store);

void gpu_run_cmds(struct gpu_cmd_store gpu_cmd_store, struct gpu_texture target, struct xform view, struct rect viewport);

#endif