/**
 * Performs a n^2 check of all collision objects to see if any could be in contact
 *
 * @class BasicBroadphase
 * @constructor
 */
Goblin.BasicBroadphase = function() {
	/**
	 * Holds all of the collision objects that the broadphase is responsible for
	 *
	 * @property bodies
	 * @type {Array}
	 */
	this.bodies = [];

	/**
	 * Array of all (current) collision pairs between the broadphase's bodies
	 *
	 * @property collision_pairs
	 * @type {Array}
	 */
	this.collision_pairs = [];
};

/**
 * Adds a body to the broadphase for contact checking
 *
 * @method addBody
 * @param body {MassPoint|RigidBody} body to add to the broadphase contact checking
 */
Goblin.BasicBroadphase.prototype.addBody = function( body ) {
	this.bodies.push( body );
};

/**
 * Removes a body from the broadphase contact checking
 *
 * @method removeBody
 * @param body {MassPoint|RigidBody} body to remove from the broadphase contact checking
 */
Goblin.BasicBroadphase.prototype.removeBody = function( body ) {
	var i,
		body_count = this.bodies.length;

	for ( i = 0; i < body_count; i++ ) {
		if ( this.bodies[i] === body ) {
			this.bodies.splice( i, 1 );
			break;
		}
	}
};

/**
 * Checks all collision objects to find any which are possibly in contact
 *  resulting contact pairs are held in the object's `collision_pairs` property
 *
 * @method predictContactPairs
 */
Goblin.BasicBroadphase.prototype.predictContactPairs = function() {
	var i, j,
		object_a, object_b,
		bodies_count = this.bodies.length;

	// Clear any old contact pairs
	this.collision_pairs.length = 0;

	// Loop over all collision objects and check for overlapping boundary spheres
	for ( i = 0; i < bodies_count; i++ ) {
		object_a = this.bodies[i];

		for ( j = 0; j < bodies_count; j++ ) {
			if ( i <= j ) {
				// if i < j then we have already performed this check
				// if i === j then the two objects are the same and can't be in contact
				continue;
			}

			object_b = this.bodies[j];

			if ( object_a.mass === Infinity && object_b.mass === Infinity ) {
				// Two static objects aren't considered to be in contact
				continue;
			}

            if ( object_a.aabb.intersects( object_b.aabb ) )
            {
				this.collision_pairs.push([ object_a, object_b ]);
			}
		}
	}
};

/**
 * Checks if a ray segment intersects with objects in the world
 *
 * @method rayIntersect
 * @property start {vec3} start point of the segment
 * @property end {vec3{ end point of the segment
 * @return {Array<RayIntersection>} an unsorted array of intersections
 */
Goblin.BasicBroadphase.prototype.rayIntersect = function( start, end ) {
	var bodies_count = this.bodies.length,
		i, body,
		intersections = [];
	for ( i = 0; i < bodies_count; i++ ) {
		body = this.bodies[i];
		if ( body.aabb.testRayIntersect( start, end ) ) {
			body.rayIntersect( start, end, intersections );
		}
	}

	return intersections;
};