<?php
/**
 * Generic Collection class
 * 
 * Based on: http://codeutopia.net/code/library/CU/Collection.php
 * 
 * My additions are marked with "--aaron"
 */
class CU_Collection implements Countable, IteratorAggregate, ArrayAccess
{
    protected $_valueType;
    
    // --aaron
    /**
     * Whether or not the members or this collection are of a "basic" type
     * 
     * Basic types are anything that has a matching "is_*" function listed
     * in {@link http://us2.php.net/manual/en/ref.var.php}. Anything else is
     * assumed to be the name of a class or interface.
     *
     * @var boolean
     */
    protected $_isBasicType = false;
    
    // --aaron
    /**
     * The "is_*" function that validates {@link $_valueType}
     *
     * This property is only used if {@link $_isBasicType} == true
     * @var string
     */
    protected $_validateFunc;
    
    protected $_collection = array();

    /**
     * Construct a new typed collection
     * @param string valueType collection value type
     */
    public function __construct($valueType)
    {
        $this->_valueType = $valueType;
        // --aaron
        if(function_exists("is_$valueType")) {
            $this->_isBasicType = true;
            $this->_validateFunc = "is_$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)
    {
        // --aaron
        if($this->_isBasicType) {
            $validateFunc = $this->_validateFunc;
            return $validateFunc($value);
        } else {
            // instanceof works on interfaces as well as classes.
            // It also checks the entire inheritance chain
            return $value instanceof $this->_valueType;
        }
    }

    /**
     * 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);
    }
}