#include "bullet.h"
#include "components.h"
#include "game_config.h"
#include "sprite.h"
#include "standard.h"
#include "world.h"

Entity new_skull(World* world, int x, int y) {
	CSprite* sprite;
	CPosition* pos;
	CEnemy* enemy;
	CCollider* col;
	Entity e;

	e = new_entity(world);
	add_components(
		world,
		e,
		ctype_position |
		ctype_sprite |
		ctype_enemy |
		ctype_skull |
		ctype_collider
	);
	pos = &world->positions[e];
	sprite = &world->sprites[e];
	enemy = &world->enemies[e];
	col = &world->colliders[e];

	pos->x = x;
	pos->y = y;

	col->x = 2  << fbits;
	col->y = 2  << fbits;
	col->w = 14 << fbits;
	col->h = 14 << fbits;

	init_csprite(sprite, sprite_skull_right);

	enemy->hp = skull_hp;
	enemy->shoot_timer = 0;

	return e;
}

void enemy_system(World* world) {
	/* Skulls. */
	int i;
	unsigned bits;
	CPosition* pos;
	CEnemy* enemy;
	Player* player;
	CPosition* ppos;
	int dpx, dpy, tpx, tpy, d;

	player = &world->player;
	ppos = &world->positions[player->entity];

	for (i = 0; i < world->entity_count; i++) {
		bits = world->bitmask[i];
		if (bits & ctype_enemy) {
			enemy = &world->enemies[i];
			if (enemy->hp <= 0) {
				destroy_entity(world, i);
			}
		}
	}

	for (i = 0; i < world->entity_count; i++) {
		bits = world->bitmask[i];
		if (
			(bits & ctype_position) &&
			(bits & ctype_enemy) &&
			(bits & ctype_skull)
		) {
			pos = &world->positions[i];
			enemy = &world->enemies[i];

			dpx = ((ppos->x - pos->x) >> 4) + 256;
			dpy = ((ppos->y - pos->y) >> 4) + 256;
			tpx = dpx;
			tpy = dpy;
			d = ((dpx * dpx) >> fbits) + ((dpy * dpy) >> fbits);

			if (d < 10 << fbits) {
				dpx = -dpx;
				dpy = -dpy;
				enemy->backpedal = 1;
			} else if (enemy->backpedal) {
				if (d > 30 << fbits) {
					enemy->backpedal = 0;
				} else {
					dpx = -dpx;
					dpy = -dpy;
				}
			}

			dpx = (dpx < 0 ? -1 : 1);
      dpy = (dpy < 0 ? -1 : 1);

			pos->x += dpx * skull_speed;
			pos->y += dpy * skull_speed;

			if (enemy->shoot_timer > skull_shoot_cooldown) {
				vec_nrmise(&tpx, &tpy);

				new_enemy_bullet(
					world,
					pos->x + 2560,
					pos->y + 2560,
					tpx * enemy_bullet_speed,
					tpy * enemy_bullet_speed
				);
				enemy->shoot_timer = 0;
			}

			enemy->shoot_timer++;
		}
	}
}