<?php namespace Illuminate\Support;



use Closure;

use Countable;

use ArrayAccess;

use ArrayIterator;

use CachingIterator;

use IteratorAggregate;

use Illuminate\Support\Contracts\JsonableInterface;

use Illuminate\Support\Contracts\ArrayableInterface;



class Collection implements ArrayAccess, ArrayableInterface, Countable, IteratorAggregate, JsonableInterface {



	/**

	 * The items contained in the collection.

	 *

	 * @var array

	 */

	protected $items = array();



	/**

	 * Create a new collection.

	 *

	 * @param  array  $items

	 * @return void

	 */

	public function __construct(array $items = array())

	{

		$this->items = $items;

	}



	/**

	 * Create a new collection instance if the value isn't one already.

	 *

	 * @param  mixed  $items

	 * @return \Illuminate\Support\Collection

	 */

	public static function make($items)

	{

		if (is_null($items)) return new static;



		if ($items instanceof Collection) return $items;



		return new static(is_array($items) ? $items : array($items));

	}



	/**

	 * Get all of the items in the collection.

	 *

	 * @return array

	 */

	public function all()

	{

		return $this->items;

	}



	/**

	 * Collapse the collection items into a single array.

	 *

	 * @return \Illuminate\Support\Collection

	 */

	public function collapse()

	{

		$results = array();



		foreach ($this->items as $values)

		{

			$results = array_merge($results, $values);

		}



		return new static($results);

	}



	/**

	 * Diff the collection with the given items.

	 *

	 * @param  \Illuminate\Support\Collection|\Illuminate\Support\Contracts\ArrayableInterface|array  $items

	 * @return \Illuminate\Support\Collection

	 */

	public function diff($items)

	{

		return new static(array_diff($this->items, $this->getArrayableItems($items)));

	}



	/**

	 * Execute a callback over each item.

	 *

	 * @param  Closure  $callback

	 * @return \Illuminate\Support\Collection

	 */

	public function each(Closure $callback)

	{

		array_map($callback, $this->items);



		return $this;

	}



	/**

	 * Fetch a nested element of the collection.

	 *

	 * @param  string  $key

	 * @return \Illuminate\Support\Collection

	 */

	public function fetch($key)

	{

		return new static(array_fetch($this->items, $key));

	}



	/**

	 * Run a filter over each of the items.

	 *

	 * @param  Closure  $callback

	 * @return \Illuminate\Support\Collection

	 */

	public function filter(Closure $callback)

	{

		return new static(array_filter($this->items, $callback));

	}



	/**

	 * Get the first item from the collection.

	 *

	 * @param  \Closure   $callback

	 * @param  mixed      $default

	 * @return mixed|null

	 */

	public function first(Closure $callback = null, $default = null)

	{

		if (is_null($callback))

		{

			return count($this->items) > 0 ? reset($this->items) : null;

		}

		else

		{

			return array_first($this->items, $callback, $default);

		}

	}



	/**

	 * Get a flattened array of the items in the collection.

	 *

	 * @return array

	 */

	public function flatten()

	{

		return new static(array_flatten($this->items));

	}



	/**

	 * Remove an item from the collection by key.

	 *

	 * @param  mixed  $key

	 * @return void

	 */

	public function forget($key)

	{

		unset($this->items[$key]);

	}



	/**

	 * Get an item from the collection by key.

	 *

	 * @param  mixed  $key

	 * @param  mixed  $default

	 * @return mixed

	 */

	public function get($key, $default = null)

	{

		if (array_key_exists($key, $this->items))

		{

			return $this->items[$key];

		}



		return value($default);

	}



	/**

	 * Group an associative array by a field or Closure value.

	 *

	 * @param  callable|string  $groupBy

	 * @return \Illuminate\Support\Collection

	 */

	public function groupBy($groupBy)

	{

		$results = array();



		foreach ($this->items as $key => $value)

		{

			$key = is_callable($groupBy) ? $groupBy($value, $key) : data_get($value, $groupBy);



			$results[$key][] = $value;

		}



		return new static($results);

	}



	/**

	 * Determine if an item exists in the collection by key.

	 *

	 * @param  mixed  $key

	 * @return bool

	 */

	public function has($key)

	{

		return array_key_exists($key, $this->items);

	}



	/**

	 * Concatenate values of a given key as a string.

	 *

	 * @param  string  $value

	 * @param  string  $glue

	 * @return string

	 */

	public function implode($value, $glue = null)

	{

		if (is_null($glue)) return implode($this->lists($value));



		return implode($glue, $this->lists($value));

	}



	/**

	 * Intersect the collection with the given items.

	 *

 	 * @param  \Illuminate\Support\Collection|\Illuminate\Support\Contracts\ArrayableInterface|array  $items

	 * @return \Illuminate\Support\Collection

	 */

	public function intersect($items)

	{

		return new static(array_intersect($this->items, $this->getArrayableItems($items)));

	}



	/**

	 * Determine if the collection is empty or not.

	 *

	 * @return bool

	 */

	public function isEmpty()

	{

		return empty($this->items);

	}



	/**

	* Get the last item from the collection.

	*

	* @return mixed|null

	*/

	public function last()

	{

		return count($this->items) > 0 ? end($this->items) : null;

	}



	/**

	 * Get an array with the values of a given key.

	 *

	 * @param  string  $value

	 * @param  string  $key

	 * @return array

	 */

	public function lists($value, $key = null)

	{

		return array_pluck($this->items, $value, $key);

	}



	/**

	 * Run a map over each of the items.

	 *

	 * @param  Closure  $callback

	 * @return \Illuminate\Support\Collection

	 */

	public function map(Closure $callback)

	{

		return new static(array_map($callback, $this->items, array_keys($this->items)));

	}



	/**

	 * Merge the collection with the given items.

	 *

	 * @param  \Illuminate\Support\Collection|\Illuminate\Support\Contracts\ArrayableInterface|array  $items

	 * @return \Illuminate\Support\Collection

	 */

	public function merge($items)

	{

		return new static(array_merge($this->items, $this->getArrayableItems($items)));

	}



	/**

	 * Get and remove the last item from the collection.

	 *

	 * @return mixed|null

	 */

	public function pop()

	{

		return array_pop($this->items);

	}



	/**

	 * Push an item onto the beginning of the collection.

	 *

	 * @param  mixed  $value

	 * @return void

	 */

	public function prepend($value)

	{

		array_unshift($this->items, $value);

	}



	/**

	 * Push an item onto the end of the collection.

	 *

	 * @param  mixed  $value

	 * @return void

	 */

	public function push($value)

	{

		$this->items[] = $value;

	}



	/**

	 * Put an item in the collection by key.

	 *

	 * @param  mixed  $key

	 * @param  mixed  $value

	 * @return void

	 */

	public function put($key, $value)

	{

		$this->items[$key] = $value;

	}



	/**

	 * Reduce the collection to a single value.

	 *

	 * @param  callable  $callback

	 * @param  mixed  $initial

	 * @return mixed

	 */

	public function reduce($callback, $initial = null)

	{

		return array_reduce($this->items, $callback, $initial);

	}



    /**

     * Get one or more items randomly from the collection.

     *

     * @param  int $amount

     * @return mixed

     */

    public function random($amount = 1)

    {

        $keys = array_rand($this->items, $amount);



        return is_array($keys) ? array_intersect_key($this->items, array_flip($keys)) : $this->items[$keys];

    }



	/**

	 * Reverse items order.

	 *

	 * @return \Illuminate\Support\Collection

	 */

	public function reverse()

	{

		return new static(array_reverse($this->items));

	}



	/**

	 * Get and remove the first item from the collection.

	 *

	 * @return mixed|null

	 */

	public function shift()

	{

		return array_shift($this->items);

	}



	/**

	 * Slice the underlying collection array.

	 *

	 * @param  int   $offset

	 * @param  int   $length

	 * @param  bool  $preserveKeys

	 * @return \Illuminate\Support\Collection

	 */

	public function slice($offset, $length = null, $preserveKeys = false)

	{

		return new static(array_slice($this->items, $offset, $length, $preserveKeys));

	}



	/**

	 * Chunk the underlying collection array.

	 *

	 * @param  int $size

	 * @param  bool  $preserveKeys

	 * @return \Illuminate\Support\Collection

	 */

	public function chunk($size, $preserveKeys = false)

	{

		$chunks = new static;



		foreach (array_chunk($this->items, $size, $preserveKeys) as $chunk)

		{

			$chunks->push(new static($chunk));

		}



		return $chunks;

	}



	/**

	 * Sort through each item with a callback.

	 *

	 * @param  Closure  $callback

	 * @return \Illuminate\Support\Collection

	 */

	public function sort(Closure $callback)

	{

		uasort($this->items, $callback);



		return $this;

	}



	/**

	 * Sort the collection using the given Closure.

	 *

	 * @param  \Closure|string  $callback

	 * @param  int              $options

	 * @param  bool             $descending

	 * @return \Illuminate\Support\Collection

	 */

	public function sortBy($callback, $options = SORT_REGULAR, $descending = false)

	{

		$results = array();



		if (is_string($callback)) $callback =

                          $this->valueRetriever($callback);



		// First we will loop through the items and get the comparator from a callback

		// function which we were given. Then, we will sort the returned values and

		// and grab the corresponding values for the sorted keys from this array.

		foreach ($this->items as $key => $value)

		{

			$results[$key] = $callback($value);

		}



		$descending ? arsort($results, $options)

                    : asort($results, $options);



		// Once we have sorted all of the keys in the array, we will loop through them

		// and grab the corresponding model so we can set the underlying items list

		// to the sorted version. Then we'll just return the collection instance.

		foreach (array_keys($results) as $key)

		{

			$results[$key] = $this->items[$key];

		}



		$this->items = $results;



		return $this;

	}



	/**

	 * Sort the collection in descending order using the given Closure.

	 *

	 * @param  \Closure|string  $callback

	 * @param  int              $options

	 * @return \Illuminate\Support\Collection

	 */

	public function sortByDesc($callback, $options = SORT_REGULAR)

	{

		return $this->sortBy($callback, $options, true);

	}



	/**

	 * Splice portion of the underlying collection array.

	 *

	 * @param  int    $offset

	 * @param  int    $length

	 * @param  mixed  $replacement

	 * @return \Illuminate\Support\Collection

	 */

	public function splice($offset, $length = 0, $replacement = array())

	{

		return new static(array_splice($this->items, $offset, $length, $replacement));

	}



	/**

	 * Get the sum of the given values.

	 *

	 * @param  \Closure  $callback

	 * @param  string  $callback

	 * @return mixed

	 */

	public function sum($callback)

	{

		if (is_string($callback))

		{

			$callback = $this->valueRetriever($callback);

		}



		return $this->reduce(function($result, $item) use ($callback)

		{

			return $result += $callback($item);



		}, 0);

	}



	/**

	 * Take the first or last {$limit} items.

	 *

	 * @param  int  $limit

	 * @return \Illuminate\Support\Collection

	 */

	public function take($limit = null)

	{

		if ($limit < 0) return $this->slice($limit, abs($limit));



		return $this->slice(0, $limit);

	}



	/**

	 * Transform each item in the collection using a callback.

	 *

	 * @param  Closure  $callback

	 * @return \Illuminate\Support\Collection

	 */

	public function transform(Closure $callback)

	{

		$this->items = array_map($callback, $this->items);



		return $this;

	}



	/**

	 * Return only unique items from the collection array.

	 *

	 * @return \Illuminate\Support\Collection

	 */

	public function unique()

	{

		return new static(array_unique($this->items));

	}



	/**

	 * Reset the keys on the underlying array.

	 *

	 * @return \Illuminate\Support\Collection

	 */

	public function values()

	{

		$this->items = array_values($this->items);



		return $this;

	}



	/**

	 * Get a value retrieving callback.

	 *

	 * @param  string  $value

	 * @return \Closure

	 */

	protected function valueRetriever($value)

	{

		return function($item) use ($value)

		{

			return is_object($item) ? $item->{$value} : array_get($item, $value);

		};

	}



	/**

	 * Get the collection of items as a plain array.

	 *

	 * @return array

	 */

	public function toArray()

	{

		return array_map(function($value)

		{

			return $value instanceof ArrayableInterface ? $value->toArray() : $value;



		}, $this->items);

	}



	/**

	 * Get the collection of items as JSON.

	 *

	 * @param  int  $options

	 * @return string

	 */

	public function toJson($options = 0)

	{

		return json_encode($this->toArray(), $options);

	}



	/**

	 * Get an iterator for the items.

	 *

	 * @return ArrayIterator

	 */

	public function getIterator()

	{

		return new ArrayIterator($this->items);

	}



	/**

	 * Get a CachingIterator instance.

	 *

	 * @return \CachingIterator

	 */

	public function getCachingIterator($flags = CachingIterator::CALL_TOSTRING)

	{

		return new CachingIterator($this->getIterator(), $flags);

	}



	/**

	 * Count the number of items in the collection.

	 *

	 * @return int

	 */

	public function count()

	{

		return count($this->items);

	}



	/**

	 * Determine if an item exists at an offset.

	 *

	 * @param  mixed  $key

	 * @return bool

	 */

	public function offsetExists($key)

	{

		return array_key_exists($key, $this->items);

	}



	/**

	 * Get an item at a given offset.

	 *

	 * @param  mixed  $key

	 * @return mixed

	 */

	public function offsetGet($key)

	{

		return $this->items[$key];

	}



	/**

	 * Set the item at a given offset.

	 *

	 * @param  mixed  $key

	 * @param  mixed  $value

	 * @return void

	 */

	public function offsetSet($key, $value)

	{

		if (is_null($key))

		{

			$this->items[] = $value;

		}

		else

		{

			$this->items[$key] = $value;

		}

	}



	/**

	 * Unset the item at a given offset.

	 *

	 * @param  string  $key

	 * @return void

	 */

	public function offsetUnset($key)

	{

		unset($this->items[$key]);

	}



	/**

	 * Convert the collection to its string representation.

	 *

	 * @return string

	 */

	public function __toString()

	{

		return $this->toJson();

	}



	/**

	 * Results array of items from Collection or ArrayableInterface.

	 *

  	 * @param  \Illuminate\Support\Collection|\Illuminate\Support\Contracts\ArrayableInterface|array  $items

	 * @return array

	 */

	private function getArrayableItems($items)

	{

		if ($items instanceof Collection)

		{

			$items = $items->all();

		}

		elseif ($items instanceof ArrayableInterface)

		{

			$items = $items->toArray();

		}



		return $items;

	}



}