#include "bullets.h"
#include "game.h"

Bullet createBullet(Entity entity, Vector3 direction, Vector3 offset, float damage) {
	Bullet bullet = (Bullet){
		.hit = false,
		.ray = (Ray){
			.position = Vector3Add(entity.position, offset),
			.direction = direction,
		},
		.fromId = entity.id,
		.fromFingerprint = entity.fingerprint,
		.damage = damage
	};

	return bullet;
}

void initBullets(Bullets * bullets) {
	bullets->bullets = NULL;
	bullets->bulletsCount = 0;
}

void freeBullets(Bullets * bullets) {
	if (bullets->bullets != NULL)
		KF_FREE(bullets->bullets);
}

KfError addBullet(Bullets * bullets, Bullet bullet) {
	// Not allocated yet.
	if (bullets->bullets == NULL) {
		bullets->bullets = (Bullet*)KF_CALLOC(1, sizeof(Bullet));

		if (bullets->bullets == NULL) {
			ALLOCATION_ERROR;
			return KFERROR;
		}

		bullets->bulletsCount = 1;
		bullets->bullets[0] = bullet;
		return KFSUCCESS;
	}

	++bullets->bulletsCount;

	// Reallocate.
	bullets->bullets = (Bullet*)KF_REALLOCARRAY(
		bullets->bullets, 
		bullets->bulletsCount,
		sizeof(Bullet)
	);

	if (bullets->bullets == NULL) {
		ALLOCATION_ERROR;
		return KFERROR;
	}
	
	bullets->bullets[bullets->bulletsCount - 1] = bullet;
	return KFSUCCESS;
}

KfError popBackBullets(Bullets * bullets) {
	if (bullets->bullets == NULL)
		return KFSUCCESS;

	// At one.
	if (bullets->bulletsCount == 1) {
		KF_FREE(bullets->bullets);
		bullets->bullets = NULL;
		bullets->bulletsCount = 0;
		return KFSUCCESS;
	}

	--bullets->bulletsCount;

	// Reallocate.
	bullets->bullets = (Bullet*)KF_REALLOCARRAY(
		bullets->bullets, 
		bullets->bulletsCount,
		sizeof(Bullet)
	);

	if (bullets->bullets == NULL) {
		ALLOCATION_ERROR;
		return KFERROR;
	}

	return KFSUCCESS;
}

void updateBullets(Game * game, Bullets * bullets) {
	int i;
	Bullet * last = NULL;

	if (bullets->bullets == NULL)
		return;

	// Update each bullet.
	for (i = 0; i < bullets->bulletsCount; ++i)
		updateBullet(game, &bullets->bullets[i]);

	// Remove end if hit or out of bounds.
	last = &bullets->bullets[bullets->bulletsCount - 1];

	if (last->hit)
		popBackBullets(bullets);
	else if (Vector3Length(last->ray.position) >= GAME_BOUNDS)
		popBackBullets(bullets);
}

void updateBullet(Game * game, Bullet * bullet) {
	int i, j;
	RayCollision collision;
	Ray ray;
	Entity * currentEntity;

	// Already hit.
	if (bullet->hit)
		return;

	// Set direction.
	ray.direction = bullet->ray.direction;

	// Check collision.
	for (i = 0; i < game->world.entitiesCount; ++i) {
		currentEntity = &game->world.entities[i];

		// This was the entity that shot it.
		if (currentEntity->fingerprint == bullet->fromFingerprint)
			continue;
		else if (currentEntity->model == NULL) // Null model indeed.
			continue;

		// Set position relative to entity.
		ray.position = Vector3Subtract(bullet->ray.position, currentEntity->position);

		// Loop through meshes.
		for (j = 0; j < currentEntity->model->meshCount; ++j) {
			collision = GetRayCollisionMesh(
				ray,
				currentEntity->model->meshes[j],
				currentEntity->model->transform
			);

			// Did hit.
			if (!collision.hit)
				continue;

			currentEntity->health -= bullet->damage;
			bullet->hit = true;
			goto afterCollisionCheck;
		}
	}

afterCollisionCheck:

	// Update position.
	bullet->ray.position = Vector3Add(
		bullet->ray.position,
		bullet->ray.direction
	);

	// Debug ray (:
	//DrawRay(bullet->ray, BLUE);
}