#include <gint/display.h>
#include <gint/keyboard.h>
#include "engine.h"

#define CELL_X(x) (-2 + 10 * (x))
#define CELL_Y(y) (-3 + 10 * (y))

//---
//  Rendering
//---

static void engine_draw_player(struct player const *player)
{
	extern bopti_image_t img_spritesheet;

	dsubimage(CELL_X(player->x) - 1, CELL_Y(player->y) - 5,
		&img_spritesheet, player->dir * 12, 0, 12, 16, DIMAGE_NONE);
}

void engine_draw(struct game const *game)
{
	dclear(C_WHITE);

	for(int p = 0; game->players[p]; p++)
	{
		engine_draw_player(game->players[p]);
	}
}

//---
//  Physics
//---

/* Check whether a cell of the map is walkable */
static int map_walkable(struct map const *map, int x, int y)
{
	/* TODO: Read the map's data array */
	return (x >= 1) && (y >= 1) && (x < map->w - 1) && (y < map->h - 1);
}

int engine_move(struct game *game, struct player *player, int dir)
{
	int dx = (dir == DIR_RIGHT) - (dir == DIR_LEFT);
	int dy = (dir == DIR_DOWN)  - (dir == DIR_UP);

	/* Always update the direction */
	player->dir = dir;

	/* Only move the player if the destination is walkable */
	if(!map_walkable(game->map, player->x + dx, player->y + dy)) return 0;

	player->x += dx;
	player->y += dy;

	return 1;
}