/* 
Written for the Getting Started With Unity ActiveTuts Series by Matt Stuttard (MSFX)
*/

// minimum and maximum spawn delay times
public var minimumSpawnDelayTime:int = 1;
public var maximumSpawnDelayTime:int = 5;

// the pickup prefab, assigned via the Inspector
public var pickupPrefab:GameObject;

// the number of pickups to have
public var numberOfPickups:int = 2;

// the ARRAY of spawnpoints that our pickup will be spawned at
private var spawnPointList:GameObject[];

// array of which spawn points are available
private var spawnIndexAvailableList:Array = [];

// variable to hold the total number of spawn points, saves having to recalculate
private var numberOfSpawnPoints:int;


function Awake()
{
	// retrieve GameObjects tagged as 'SpawnPoint' within the 'PickupSpawnPoints' GameObject which this script is a Component of
	spawnPointList = gameObject.FindGameObjectsWithTag("SpawnPoint");
	
	// retreive number of spawn points
	numberOfSpawnPoints = spawnPointList.length;
	
	// make sure number of pickups doesn't exceed number of spawn points
	if (numberOfPickups > numberOfSpawnPoints) numberOfPickups = numberOfSpawnPoints;
	
	// make all spawn points available by setting each index to true
	for (var i:int = 0;  i < numberOfSpawnPoints; i++) 
	{
		spawnIndexAvailableList[i] = true;
	}
	
	// spawn X amount of pickups according to numberOfPickups
	for (var j:int = 0;  j < numberOfPickups; j++)  
	{
		SpawnPickup();
	}
}

function SpawnPickup()
{
	// generate a random integer to use as the index to select a spawn point from the list
	var randomSpawnIndex:int = Random.Range(0, numberOfSpawnPoints);
	
	// while the selected spawn index is unavailable regenerate another one
	while (!spawnIndexAvailableList[randomSpawnIndex])
	{
		randomSpawnIndex = Random.Range(0, numberOfSpawnPoints);
	}
	
	// retrieve the position and rotation of the pickups spawn point
	var spawnedPickupPosition:Vector3 = spawnPointList[randomSpawnIndex].transform.position;
	var spawnedPickupRotation:Quaternion = spawnPointList[randomSpawnIndex].transform.rotation;
	
	// instantiate (create) the pickup prefab with the above position and rotation
	var spawnedPickup:GameObject = Instantiate(pickupPrefab, spawnedPickupPosition, spawnedPickupRotation);
	
	// set the spawned pickup as a child of the 'PickupSpawnPoints' gameobject that this script is a Component of
	// this is so we can use SendMessageUpwards within scripts attached to the pickupPrefab to call functions within this script
	spawnedPickup.transform.parent = spawnPointList[randomSpawnIndex].transform;
	
	// set the name of the pickup as its index
	spawnedPickup.name = randomSpawnIndex.ToString();
	
	// make the spawn index unavailable to prevent another pickup being spawned in this position
	spawnIndexAvailableList[randomSpawnIndex] = false;
}


function Collected(pickupCollected:GameObject)
{
	// retrieve name of the collected pickup and cast to int
	var index:int = parseInt(pickupCollected.name);
	
	// pickup has been destroyed so make the spawn index available again
	spawnIndexAvailableList[index] = true;
	
	// destroy the pickup
	Destroy(pickupCollected);
	
	// wait for a random amount of seconds between minimumSpawnDelayTime and maximumSpawnDelayTime
	yield WaitForSeconds(Random.Range(minimumSpawnDelayTime, maximumSpawnDelayTime));
	
	// spawn a new pickup
	SpawnPickup();
}
