#include "entity.h"
#include "game.h"
#include "map.h"
#include "cfg.h"

bool
entity_collide(Entity *this, Game *g, int ox, int oy)
{
	(void)g;
	const int x0 = this->pos[0] - this->width / 2 + ox;
	const int y0 = this->pos[1] - this->height / 2 + oy;
	const int x1 = x0 + this->width - 1;
	const int y1 = y0 + this->height - 1;
	return (map_get_px(x0, y0) == 1 || map_get_px(x0, y1) == 1 ||
	        map_get_px(x1, y0) == 1 || map_get_px(x1, y1) == 1);
}

void
entity_move(Entity *this, Game *g)
{
	if (entity_collide(this, g, 0, 0)) {
		this->vel[0] = 0.0;
		this->vel[1] = 0.0;
		this->rem[0] = 0.0;
		this->rem[1] = 0.0;
		return;
	}
	for (int a = 0; a < 2; a++) {
		const double sum = this->vel[a] + this->rem[a];
		int spd = (int)sum;
		this->rem[a] = sum - spd;
		const int sign = (spd > 0) - (spd < 0);
		if (sign == 0)
			continue;
		while (spd != 0) {
			this->pos[a] += sign;
			if (entity_collide(this, g, 0, 0)) {
				this->pos[a] -= sign;
				this->rem[a] = 0.0;
				this->vel[a] = 0.0;
				break;
			}
			spd -= sign;
		}
	}
}