#include <dangerzone/engine.h>

#include "internal/engine_internal.h"
#include "internal/util/error.h"

bool
engine_sdl_init_state(
	engine_sdl_state_t **state,
	uint32_t window_width,
	uint32_t window_height,
	const char window_name[]
) {
 	*state = (engine_sdl_state_t *)
	 	malloc(sizeof(engine_sdl_state_t));

 	if (*state == NULL) {
		eprintf("failed to initialize engine_sdl_state");
		return RCODE_FAILURE;
	}

	(*state)->width = window_width;
	(*state)->height = window_height;
	strncpy(
		(*state)->window_name, window_name,
		WINDOW_NAME_MAX_LENGTH - 1
	);
	(*state)->window_name[WINDOW_NAME_MAX_LENGTH - 1] = '\0';

	return RCODE_SUCCESS;
}

bool
engine_sdl_init_root()
{
	if (!SDL_Init(SDL_INIT_VIDEO)) {
		eprintf("SDL_Init failed! %s\n", SDL_GetError());
		return RCODE_FAILURE;
	} else {
		return RCODE_SUCCESS;
	}
}


bool
engine_sdl_init_window(
	engine_sdl_state_t* state
) {
	state->window = SDL_CreateWindow(
		state->window_name,
		state->width, state->height, 0
	);

	if (state->window == NULL) {
		eprintf("SDL_CreateWindow failed! %s\n", SDL_GetError());
		SDL_Quit();
		return RCODE_FAILURE;
	}

	return RCODE_SUCCESS;
}

bool
engine_sdl_init_renderer(
	engine_sdl_state_t *state
) {
	state->renderer = SDL_CreateRenderer(state->window, NULL);
	if (state->renderer == NULL) {
		eprintf("SDL_CreateRenderer failed! %s\n", SDL_GetError());
		SDL_DestroyWindow(state->window);
		SDL_Quit();
		return RCODE_FAILURE;
	}

	// enable VSync
	if (!SDL_SetRenderVSync(state->renderer, 1)) {
	    eprintf("SDL_SetRenderVSync failed: %s\n", SDL_GetError());
	}

	return RCODE_SUCCESS;
}

bool
engine_sdl_init_texture(
	engine_sdl_state_t *state
) {
	state->texture = SDL_CreateTexture(
		state->renderer, SDL_PIXELFORMAT_XRGB8888,
		SDL_TEXTUREACCESS_STREAMING, 
		state->width, state->height
	);
	if (state->texture == NULL) {
		eprintf("SDL_CreateTexture failed! %s\n", SDL_GetError());
		SDL_DestroyWindow(state->window);
		SDL_DestroyRenderer(state->renderer);
		SDL_Quit();
		return RCODE_FAILURE;
	}

	return RCODE_SUCCESS;
}

engine_sdl_state_t*
engine_sdl_init(
	uint32_t window_width,
	uint32_t window_height,
	const char window_name[]
) {
	engine_sdl_state_t *state;

	if (!engine_sdl_init_state(
			&state,
			window_width,
			window_height,
			window_name
		) || 
		!engine_sdl_init_root() || 
		!engine_sdl_init_window(state) ||
		!engine_sdl_init_renderer(state) ||
		!engine_sdl_init_texture(state)
	) {
		return NULL;
	}

	return state;
}

/**
 * only call intentinally, not when engine_sdl_init fails
 * -> it cleans up after itself already
 */
void 
engine_sdl_destroy(
	engine_sdl_state_t *state
) {
	SDL_DestroyTexture(state->texture);
	SDL_DestroyRenderer(state->renderer);
	SDL_DestroyWindow(state->window);
	SDL_Quit();
	free(state);
}

bool
engine_init(
	uint32_t window_width,
	uint32_t window_height,
	const char window_name[],
	void (*engine_poll_events)(void),
	void (*engine_update_framebuffer)(void)
) {
	internal_state = (engine_internal_state_t *)
		malloc(sizeof(engine_internal_state_t));
	if (internal_state == NULL) {
		return RCODE_FAILURE;
	}

	game_state = (game_state_t *)
		malloc(sizeof(game_state_t));
	if (game_state == NULL) {
		free(internal_state);
		return RCODE_FAILURE;
	}

	game_state->framebuffer = (uint32_t *)
		malloc(sizeof(uint32_t) * window_width * window_height);
	if (game_state->framebuffer == NULL) {
		free(internal_state);
		free(game_state);
		return RCODE_FAILURE;
	}

	internal_state->engine_poll_events
		= engine_poll_events;

	internal_state->engine_update_framebuffer
		= engine_update_framebuffer;

	internal_state->sdl_state = engine_sdl_init(
		window_width,
		window_height,
		window_name
	);
	if (internal_state->sdl_state == NULL) {
		free(internal_state);
		free(game_state->framebuffer);
		free(game_state);
		return RCODE_FAILURE;
	}

	game_state->is_running = true;
	game_state->framebuffer_dirty = true;
	game_state->dirty_rect = (SDL_Rect) {
	    .x = 0,
	    .y = 0,
	    .w = game_state->width,
	    .h = game_state->height
	};
	game_state->width = internal_state->sdl_state->width;
	game_state->height = internal_state->sdl_state->height;

	return RCODE_SUCCESS;
}