#include "cairo_bindings.h"
#include "texture.h"

int honey_cairo_mt_ref = LUA_NOREF;

static const cairo_user_data_key_t TEXTURE_KEY;

int honey_setup_cairo(lua_State* L)
{
    honey_lua_create_table
        (L, 2,
         HONEY_TABLE, "__index", 1,
         HONEY_FUNCTION, "getTexture", honey_cairo_get_texture,

         HONEY_FUNCTION, "__gc", honey_cairo_destroy);
    honey_cairo_mt_ref = luaL_ref(L, LUA_REGISTRYINDEX);

    lua_pushcfunction(L, honey_cairo_new);
    lua_setfield(L, -2, "cairo");
}

/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */

struct texture_ref {
    int id;
    lua_State* L;
};

static void destroy_texture_ref(void* data)
{
    struct texture_ref* ref = data;
    luaL_unref(ref->L, LUA_REGISTRYINDEX, ref->id);
    free(ref);
}

int honey_cairo_new(lua_State* L)
{
    int choice = honey_lua_parse_arguments(L, 2, 0, 1, HONEY_TABLE, NULL);

    lua_pushcfunction(L, honey_lua_texture_new);
    if (choice == 0)
	honey_lua_pcall(L, 0, 1);
    else {
	lua_pushvalue(L, 1);
	honey_lua_pcall(L, 1, 1);
    }

    /* configure texture swizzling ARGB -> RGBA */
    honey_texture* texture = lua_touserdata(L, -1);
    glBindTexture(GL_TEXTURE_2D, texture->id);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_R, GL_GREEN);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_G, GL_BLUE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_B, GL_ALPHA);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_A, GL_RED);

    /* setup texture reference */
    struct texture_ref* ref = malloc(sizeof(struct texture_ref));
    if (ref == NULL)
	honey_lua_throw_error
	    (L, "failed to allocate memory for texture handle!");
    
    ref->id = luaL_ref(L, LUA_REGISTRYINDEX);

    /* create cairo surface */
    cairo_surface_t** surface = lua_newuserdata(L, sizeof(cairo_surface_t*));
    *surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
					  texture->params.width,
					  texture->params.height);
    
    cairo_status_t status = cairo_surface_status(*surface);
    if (status != CAIRO_STATUS_SUCCESS)
        honey_lua_throw_error
            (L, "libcairo error: %s", cairo_status_to_string(status));

    /* bind texture ref to surface userdata */
    status = cairo_surface_set_user_data(*surface,
					 &TEXTURE_KEY,
					 ref,
					 destroy_texture_ref);
    if (status != CAIRO_STATUS_SUCCESS)
        honey_lua_throw_error
            (L, "libcairo error: %s", cairo_status_to_string(status));

    lua_rawgeti(L, LUA_REGISTRYINDEX, honey_cairo_mt_ref);
    lua_setmetatable(L, -2);

    return 1;
}

/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */

int honey_cairo_update_texture(lua_State* L)
{
    cairo_surface_t** surface;
    honey_lua_parse_arguments(L, 1, 1, HONEY_USERDATA, &surface);

    struct texture_ref *ref = cairo_surface_get_user_data(*surface, &TEXTURE_KEY);
    lua_rawgeti(L, LUA_REGISTRYINDEX, ref->id);
    honey_texture* texture = lua_touserdata(L, -1);
    lua_pop(L, 1);

    glBindTexture(GL_TEXTURE_2D, texture->id);
    unsigned char* image_data = cairo_image_surface_get_data(*surface);
    glTexSubImage2D(GL_TEXTURE_2D,
		    0, 0, 0,
		    texture->params.width,
		    texture->params.height,
		    GL_RGBA,
		    GL_UNSIGNED_BYTE,
		    image_data);
    return 0;
}

/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */

int honey_cairo_get_texture(lua_State* L)
{
    cairo_surface_t** surface;
    honey_lua_parse_arguments(L, 1, 1, HONEY_USERDATA, &surface);

    struct texture_ref *ref = cairo_surface_get_user_data(*surface, &TEXTURE_KEY);
    lua_rawgeti(L, LUA_REGISTRYINDEX, ref->id);
    return 1;
}

/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */

int honey_cairo_destroy(lua_State* L)
{
    cairo_surface_t** surface;
    honey_lua_parse_arguments(L, 1, 1, HONEY_USERDATA, &surface);

    cairo_surface_destroy(*surface);

    return 0;
}

/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */