<?php

/**
 * Part of the Collections package.
 *
 * NOTICE OF LICENSE
 *
 * Licensed under the 3-clause BSD License.
 *
 * This source file is subject to the 3-clause BSD License that is
 * bundled with this package in the LICENSE file.
 *
 * @package    Collections
 * @version    1.1.0
 * @author     Cartalyst LLC
 * @license    BSD License (3-clause)
 * @copyright  (c) 2011-2015, Cartalyst LLC
 * @link       http://cartalyst.com
 */

namespace Cartalyst\Collections;

use Closure;
use Countable;
use ArrayAccess;
use ArrayIterator;
use JsonSerializable;
use IteratorAggregate;

class Collection implements ArrayAccess, Countable, IteratorAggregate, JsonSerializable
{
    /**
     * The items contained in the collection.
     *
     * @var array
     */
    protected $items = [];

    /**
     * Constructor.
     *
     * @param  array  $items
     * @return void
     */
    public function __construct(array $items = [])
    {
        $this->items = $items;
    }

    /**
     * Create a new collection instance if the value isn't one already.
     *
     * @param  array  $items
     * @return static
     */
    public static function make(array $items = [])
    {
        return new static($items);
    }

    /**
     * Get all of the items in the collection.
     *
     * @return array
     */
    public function all()
    {
        return $this->items;
    }

    /**
     * Count the number of items in the collection.
     *
     * @return int
     */
    public function count()
    {
        return count($this->items);
    }

    /**
     * Get the first item from the collection.
     *
     * @param  \Closure   $callback
     * @param  mixed      $default
     * @return mixed|null
     */
    public function first(Closure $callback = null, $default = null)
    {
        return count($this->items) > 0 ? reset($this->items) : null;
    }

    /**
     * Remove an item from the collection by key.
     *
     * @param  mixed  $key
     * @return void
     */
    public function forget($key)
    {
        $this->offsetUnset($key);
    }

    /**
     * Get an item from the collection by key.
     *
     * @param  mixed  $key
     * @param  mixed  $default
     * @return mixed
     */
    public function get($key, $default = null)
    {
        if ($this->offsetExists($key)) {
            return $this->items[$key];
        }

        return $default;
    }

    /**
     * Determine if an item exists in the collection by key.
     *
     * @param  mixed  $key
     * @return bool
     */
    public function has($key)
    {
        return $this->offsetExists($key);
    }

    /**
     * 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  $value
     * @return array
     */
    public function lists($value)
    {
        return array_map(function ($item) use ($value) {
            return isset($item[$value]) ? $item[$value] : null;
        }, $this->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 end of the collection.
     *
     * @param  mixed  $value
     * @return void
     */
    public function push($value)
    {
        $this->offsetSet(null, $value);
    }

    /**
     * Pulls an item from the collection.
     *
     * @param  mixed  $key
     * @param  mixed  $default
     * @return mixed
     */
    public function pull($key, $default = null)
    {
        $value = $this->offsetGet($key);

        $this->offsetUnset($key);

        return $value ?: $default;
    }

    /**
     * Put an item in the collection by key.
     *
     * @param  mixed  $key
     * @param  mixed  $value
     * @return void
     */
    public function put($key, $value)
    {
        $this->offsetSet($key, $value);
    }

    /**
     * Get and remove the first item from the collection.
     *
     * @return mixed|null
     */
    public function shift()
    {
        return array_shift($this->items);
    }

    /**
     * Sort through each item with a callback.
     *
     * @param  \Closure  $callback
     * @return $this
     */
    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 $this
     */
    public function sortBy($callback, $options = SORT_REGULAR, $descending = false)
    {
        $results = [];

        if (is_string($callback)) {
            $callback = function ($item) use ($callback) {
                foreach (explode('.', $callback) as $segment) {
                    if (is_array($item)) {
                        if ( ! array_key_exists($segment, $item)) {
                            return null;
                        }
                        $item = $item[$segment];
                    }
                }

                return $item;
            };
        }

        // 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 $this
     */
    public function sortByDesc($callback, $options = SORT_REGULAR)
    {
        return $this->sortBy($callback, $options, true);
    }

    /**
     * Get the sum of the collection items.
     *
     * @param  mixed  $callback
     * @return mixed
     */
    public function sum($callback = null)
    {
        if (is_null($callback)) {
            return array_sum($this->items);
        }

        return array_reduce($this->items, function ($result, $item) use ($callback) {
            if (is_string($callback)) {
                return $result += $item->{$callback}();
            }

            return $result += $callback($item);
        }, 0);
    }

    /**
     * Get the collection of items as a plain array.
     *
     * @return array
     */
    public function toArray()
    {
        return array_map(function ($value) {
            return $value instanceof Arrayable ? $value->toArray() : $value;

        }, $this->items);
    }

    /**
     * Convert the object into something JSON serializable.
     *
     * @return array
     */
    public function jsonSerialize()
    {
        return $this->toArray();
    }

    /**
     * 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);
    }

    /**
     * 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]);
    }

    /**
     * Dynamically retrieve the value of an item.
     *
     * @param  string  $key
     * @return mixed
     */
    public function __get($key)
    {
        return $this->get($key);
    }

    /**
     * Dynamically set the value of an item.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @return void
     */
    public function __set($key, $value)
    {
        $this->items[$key] = $value;
    }

    /**
     * Dynamically check if an item is set.
     *
     * @param  string  $key
     * @return void
     */
    public function __isset($key)
    {
        return isset($this->items[$key]);
    }

    /**
     * Convert the collection to its string representation.
     *
     * @return string
     */
    public function __toString()
    {
        return $this->toJson();
    }

    /**
     * Dynamically unset an item.
     *
     * @param  string  $key
     * @return void
     */
    public function __unset($key)
    {
        unset($this->items[$key]);
    }
}