#ifndef RENDERER_H
#define RENDERER_H

struct sys_window;
struct sprite_scope;

#define RENDERER_TEXTURE_MAX_WIDTH 16384
#define RENDERER_TEXTURE_MAX_HEIGHT 16384

typedef u32 vidx;

struct renderer_cmd_buffer;

struct renderer_texture {
    u64 handle;
};

/* ========================== *
 * Shaders
 * ========================== */

enum shader_kind {
    SHADER_NONE,
    SHADER_TRIANGLE,
    SHADER_GRID,

    NUM_SHADERS
};

struct renderer_cmd_parameters {
    enum shader_kind kind;
    union {
        struct {
            struct renderer_texture texture;  /* Overrides sprite if set */
            struct sprite_tag sprite;
        } texture_params;
    };
};

PACK(struct triangle_shader_vertex {
    struct v2 pos;
    struct v2 uv;
    u32 color;
});

PACK(struct grid_shader_vertex {
    struct v2 pos;
    u32 color_bg;
    u32 color_line;
    u32 color_x;
    u32 color_y;
    f32 line_thickness;
    f32 line_spacing;
    struct v2 offset;
});

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

struct renderer_startup_receipt { i32 _; };
struct renderer_startup_receipt renderer_startup(struct sys_window *window);

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

enum renderer_texture_format {
    RENDERER_TEXTURE_FORMAT_NONE,

    RENDERER_TEXTURE_FORMAT_R8G8B8A8_UNORM,

    NUM_RENDERER_TEXTURE_FORMATS
};

#define RENDERER_TEXTURE_FLAG_NONE      (0)
#define RENDERER_TEXTURE_FLAG_TARGET    (1<<0)

struct renderer_texture renderer_texture_alloc(enum renderer_texture_format format, u32 flags, struct v2i32 size, void *initial_data);
void renderer_texture_release(struct renderer_texture t);

void renderer_texture_clear(struct renderer_texture target_texture, u32 clear_color);
void renderer_texture_render(struct renderer_texture texture, struct renderer_cmd_buffer *cmdbuff, struct xform view, struct rect viewport, struct sprite_scope *sprite_scope);
struct v2i32 renderer_texture_get_size(struct renderer_texture texture);

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

 /* Returns a texture linking to the internal backbuffer. Lifetime is managed by renderer. */
struct renderer_texture renderer_backbuffer_recreate(struct v2i32 size);

void renderer_backbuffer_present(i32 vsync);

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

struct renderer_cmd_buffer *renderer_cmd_buffer_alloc(void);

void renderer_cmd_buffer_release(struct renderer_cmd_buffer *cmdbuff);

/* Pushes array of vertices based on `vertices_count` & `indices_count`.
 * Sets `vertices_out` and `indices_out` to start of the pushed arrays, to be filled out by the caller.
 * Returns the index of the first vertex. Each inserted index should be incremented by this.
 *
 * NOTE: This should be preceded by an `ensure_cmd` call to ensure that the correct vertex types
 * are being pushed.
 */
u32 renderer_cmd_buffer_push_vertices(struct renderer_cmd_buffer *cmdbuff, u8 **vertices_out, vidx **indices_out, u32 vertices_count, u32 indices_count);

/* Checks the currently active draw command. Ensures a new command is created
 * if it doesn't match the expected parameters (otherwise the existing command
 * can be re-used for batching). */
void renderer_cmd_buffer_ensure_cmd(struct renderer_cmd_buffer *cmdbuff, struct renderer_cmd_parameters *params);

void renderer_cmd_buffer_send_to_gpu(struct renderer_cmd_buffer *cmdbuff);


#endif