#include <SDL.h>
#include <glib-object.h>
#include <lauxlib.h>
#include <lua.h>
#include <pango/pangoft2.h>

#include "window.h"
#include "sdl.h"

#define UD_WINDOW "libluiml.window"

struct window {
	SDL_Window *win;
	SDL_Renderer *ren;
	PangoContext *pc;
};

/* window:destroy_window() */
static int destroy_window(lua_State *L)
{
	struct window *w;

	w = luaL_checkudata(L, 1, UD_WINDOW);
	SDL_DestroyWindow(w->win);
	g_object_unref(w->pc);

	release_sdl();

	return 0;
}

#include "window_wait_event.c"

/* window:get_dimensions() -> width, height */
static int get_dimensions(lua_State *L)
{
	struct window *w;
	int width, height;

	w = luaL_checkudata(L, 1, UD_WINDOW);

	SDL_GetWindowSize(w->win, &width, &height);

	lua_pushnumber(L, width);
	lua_pushnumber(L, height);

	return 2;
}

double clamp(double v, double min, double max)
{
	if (v < min) return min;
	if (v > max) return max;
	return v;
}

/* window:draw_rect(x, y, width, height, r, g, b) */
static int draw_rect(lua_State *L)
{
	struct window *w;
	SDL_Rect r;
	struct {
		Uint8 r, g, b;
	} colour;

	w = luaL_checkudata(L, 1, UD_WINDOW);
	r.x = luaL_checknumber(L, 2);
	r.y = luaL_checknumber(L, 3);
	r.w = luaL_checknumber(L, 4);
	r.h = luaL_checknumber(L, 5);
	colour.r = round(clamp(luaL_checknumber(L, 6), 0, 1) * 255.0);
	colour.g = round(clamp(luaL_checknumber(L, 7), 0, 1) * 255.0);
	colour.b = round(clamp(luaL_checknumber(L, 8), 0, 1) * 255.0);

	SDL_SetRenderDrawColor(w->ren, colour.r, colour.g, colour.b, SDL_ALPHA_OPAQUE);
	SDL_RenderFillRect(w->ren, &r);

	return 0;
}

static int draw_text(lua_State *L)
{
	PangoRectangle extents;
	PangoLayout *layout;
	int width, height;
	struct window *w;
	const char *s;
	SDL_Rect r;
	size_t l;

	w = luaL_checkudata(L, 1, UD_WINDOW);
	r.x = luaL_checknumber(L, 2);
	r.y = luaL_checknumber(L, 3);
	r.w = luaL_checknumber(L, 4);
	r.h = luaL_checknumber(L, 5);
	s = luaL_checklstring(L, 6, &l);

	layout = pango_layout_new(w->pc);
	pango_layout_set_width(layout, r.w * PANGO_SCALE);
	pango_layout_set_height(layout, r.h * PANGO_SCALE);
	pango_layout_set_text(layout, s, l);
	pango_layout_get_extents(layout, NULL, &extents);
	width = PANGO_PIXELS(extents.width);
	height = PANGO_PIXELS(extents.height);

	return 0;
}

static int show(lua_State *L)
{
	struct window *w;

	w = luaL_checkudata(L, 1, UD_WINDOW);

	SDL_RenderPresent(w->ren);

	return 0;
}

/* create_window(title) -> window */
int create_window(lua_State *L)
{
	static const struct luaL_Reg window_metatable[] = {
		{"__gc", destroy_window},
		{"wait_event", wait_event},
		{"get_dimensions", get_dimensions},
		{"draw_rect", draw_rect},
		{"draw_text", draw_text},
		{"show", show},
		{NULL, NULL},
	};
	PangoFontMap *fontmap;
	const char *title, *failed;
	struct window *w;

	if (luaL_newmetatable(L, UD_WINDOW)) {
		lua_pushstring(L, "__index");
		lua_pushvalue(L, -2);
		lua_settable(L, -3);
		luaL_register(L, NULL, window_metatable);
		lua_pop(L, 1);
	}

	title = luaL_checkstring(L, 1);

	acquire_sdl();

	w = lua_newuserdata(L, sizeof *w);
	w->win = SDL_CreateWindow(title,
				  SDL_WINDOWPOS_UNDEFINED,
				  SDL_WINDOWPOS_UNDEFINED,
				  640, 480, SDL_WINDOW_RESIZABLE);

	if (w->win == NULL) {
		failed = "SDL_CreateWindow";
		goto fail_win;
	}

	w->ren = SDL_CreateRenderer(w->win, 0, SDL_RENDERER_PRESENTVSYNC);

	if (w->ren == NULL) {
		failed = "SDL_CreateRenderer";
		goto fail_ren;
	}


	fontmap = pango_ft2_font_map_new();
	w->pc = pango_font_map_create_context(fontmap);
	g_object_unref(fontmap);

	luaL_getmetatable(L, UD_WINDOW);
	lua_setmetatable(L, -2);

	return 1;

fail_ren: SDL_DestroyWindow(w->win);
fail_win: release_sdl();
	  return sdl_error(L, failed);
}