<?php
class CU_Collection implements Countable, IteratorAggregate, ArrayAccess
{
	protected $_valueType;
	protected $_collection = array();

	/**
	 * Construct a new typed collection
	 * @param string valueType collection value type
	 */
	public function __construct($valueType)
	{
		$this->_valueType = $valueType;
	}

	/**
	 * Add a value into the collection
	 * @param string $value
	 * @throws InvalidArgumentException when wrong type
	 */
	public function add($value)
	{
		if(!$this->isValidType($value))
			throw new InvalidArgumentException('Trying to add a value of wrong type');

		$this->_collection[] = $value;
	}

	/**
	 * Set index's value
	 * @param integer $index
	 * @param mixed $value
	 * @throws OutOfRangeException
	 * @throws InvalidArgumentException
	 */
	public function set($index, $value)
	{
		if($index >= $this->count())
			throw new OutOfRangeException('Index out of range');

		if(!$this->isValidType($value))
			throw new InvalidArgumentException('Trying to add a value of wrong type');

		$this->_collection[$index] = $value;
	}

	/**
	 * Remove a value from the collection
	 * @param integer $index index to remove
	 * @throws OutOfRangeException if index is out of range
	 */
	public function remove($index)
	{
		if($index >= $this->count())
			throw new OutOfRangeException('Index out of range');

		array_splice($this->_collection, $index, 1);
	}

	/**
	 * Return value at index
	 * @param integer $index
	 * @return mixed
	 * @throws OutOfRangeException
	 */
	public function get($index)
	{
		if($index >= $this->count())
			throw new OutOfRangeException('Index out of range');

		return $this->_collection[$index];
	}

	/**
	 * Determine if index exists
	 * @param integer $index
	 * @return boolean
	 */
	public function exists($index)
	{
		if($index >= $this->count())
			return false;

		return true;
	}
	/**
	 * Return count of items in collection
	 * Implements countable
	 * @return integer
	 */
	public function count()
	{
		return count($this->_collection);
	}

	/**
	 * Determine if this value can be added to this collection
	 * @param string $value
	 * @return boolean
	 */
	public function isValidType($value)
	{
		$baseType = gettype($value);
		if($this->_valueType == $baseType)
			return true;

		if($baseType == 'object')
		{
			$class = get_class($value);

			if($this->_valueType == $class)
				return true;
		}

		return false;
	}

	/**
	 * Return an iterator
	 * Implements IteratorAggregate
	 * @return ArrayIterator
	 */
	public function getIterator()
	{
		return new ArrayIterator($this->_collection);
	}

	/**
	 * Set offset to value
	 * Implements ArrayAccess
	 * @see set
	 * @param integer $offset
	 * @param mixed $value
	 */
	public function offsetSet($offset, $value)
	{
		$this->set($offset, $value);
	}

	/**
	 * Unset offset
	 * Implements ArrayAccess
	 * @see remove
	 * @param integer $offset
	 */
	public function offsetUnset($offset)
	{
		$this->remove($offset);
	}

	/**
	 * get an offset's value
	 * Implements ArrayAccess
	 * @see get
	 * @param integer $offset
	 * @return mixed
	 */
	public function offsetGet($offset)
	{
		return $this->get($offset);
	}

	/**
	 * Determine if offset exists
	 * Implements ArrayAccess
	 * @see exists
	 * @param integer $offset
	 * @return boolean
	 */
	public function offsetExists($offset)
	{
		return $this->exists($offset);
	}
}