<?php namespace Illuminate\Support;

use Illuminate\Support\Traits\Macroable;

class Arr {

	use Macroable;

	/**
	 * Add an element to an array using "dot" notation if it doesn't exist.
	 *
	 * @param  array   $array
	 * @param  string  $key
	 * @param  mixed   $value
	 * @return array
	 */
	public static function add($array, $key, $value)
	{
		if (is_null(static::get($array, $key)))
		{
			static::set($array, $key, $value);
		}

		return $array;
	}

	/**
	 * Build a new array using a callback.
	 *
	 * @param  array  $array
	 * @param  callable  $callback
	 * @return array
	 */
	public static function build($array, callable $callback)
	{
		$results = [];

		foreach ($array as $key => $value)
		{
			list($innerKey, $innerValue) = call_user_func($callback, $key, $value);

			$results[$innerKey] = $innerValue;
		}

		return $results;
	}

	/**
	 * Collapse an array of arrays into a single array.
	 *
	 * @param  array|\ArrayAccess  $array
	 * @return array
	 */
	public static function collapse($array)
	{
		$results = [];

		foreach ($array as $values)
		{
			if ($values instanceof Collection) $values = $values->all();

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

		return $results;
	}

	/**
	 * Divide an array into two arrays. One with keys and the other with values.
	 *
	 * @param  array  $array
	 * @return array
	 */
	public static function divide($array)
	{
		return [array_keys($array), array_values($array)];
	}

	/**
	 * Flatten a multi-dimensional associative array with dots.
	 *
	 * @param  array   $array
	 * @param  string  $prepend
	 * @return array
	 */
	public static function dot($array, $prepend = '')
	{
		$results = [];

		foreach ($array as $key => $value)
		{
			if (is_array($value))
			{
				$results = array_merge($results, static::dot($value, $prepend.$key.'.'));
			}
			else
			{
				$results[$prepend.$key] = $value;
			}
		}

		return $results;
	}

	/**
	 * Get all of the given array except for a specified array of items.
	 *
	 * @param  array  $array
	 * @param  array|string  $keys
	 * @return array
	 */
	public static function except($array, $keys)
	{
		foreach ((array) $keys as $key)
		{
			static::forget($array, $key);
		}

		return $array;
	}

	/**
	 * Fetch a flattened array of a nested array element.
	 *
	 * @param  array   $array
	 * @param  string  $key
	 * @return array
	 */
	public static function fetch($array, $key)
	{
		foreach (explode('.', $key) as $segment)
		{
			$results = [];

			foreach ($array as $value)
			{
				if (array_key_exists($segment, $value = (array) $value))
				{
					$results[] = $value[$segment];
				}
			}

			$array = array_values($results);
		}

		return array_values($results);
	}

	/**
	 * Return the first element in an array passing a given truth test.
	 *
	 * @param  array  $array
	 * @param  callable  $callback
	 * @param  mixed  $default
	 * @return mixed
	 */
	public static function first($array, callable $callback, $default = null)
	{
		foreach ($array as $key => $value)
		{
			if (call_user_func($callback, $key, $value)) return $value;
		}

		return value($default);
	}

	/**
	 * Return the last element in an array passing a given truth test.
	 *
	 * @param  array  $array
	 * @param  callable  $callback
	 * @param  mixed  $default
	 * @return mixed
	 */
	public static function last($array, callable $callback, $default = null)
	{
		return static::first(array_reverse($array), $callback, $default);
	}

	/**
	 * Flatten a multi-dimensional array into a single level.
	 *
	 * @param  array  $array
	 * @return array
	 */
	public static function flatten($array)
	{
		$return = [];

		array_walk_recursive($array, function($x) use (&$return) { $return[] = $x; });

		return $return;
	}

	/**
	 * Remove one or many array items from a given array using "dot" notation.
	 *
	 * @param  array  $array
	 * @param  array|string  $keys
	 * @return void
	 */
	public static function forget(&$array, $keys)
	{
		$original =& $array;

		foreach ((array) $keys as $key)
		{
			$parts = explode('.', $key);

			while (count($parts) > 1)
			{
				$part = array_shift($parts);

				if (isset($array[$part]) && is_array($array[$part]))
				{
					$array =& $array[$part];
				}
			}

			unset($array[array_shift($parts)]);

			// clean up after each pass
			$array =& $original;
		}
	}

	/**
	 * Get an item from an array using "dot" notation.
	 *
	 * @param  array   $array
	 * @param  string  $key
	 * @param  mixed   $default
	 * @return mixed
	 */
	public static function get($array, $key, $default = null)
	{
		if (is_null($key)) return $array;

		if (isset($array[$key])) return $array[$key];

		foreach (explode('.', $key) as $segment)
		{
			if ( ! is_array($array) || ! array_key_exists($segment, $array))
			{
				return value($default);
			}

			$array = $array[$segment];
		}

		return $array;
	}

	/**
	 * Check if an item exists in an array using "dot" notation.
	 *
	 * @param  array   $array
	 * @param  string  $key
	 * @return bool
	 */
	public static function has($array, $key)
	{
		if (empty($array) || is_null($key)) return false;

		if (array_key_exists($key, $array)) return true;

		foreach (explode('.', $key) as $segment)
		{
			if ( ! is_array($array) || ! array_key_exists($segment, $array))
			{
				return false;
			}

			$array = $array[$segment];
		}

		return true;
	}

	/**
	 * Get a subset of the items from the given array.
	 *
	 * @param  array  $array
	 * @param  array|string  $keys
	 * @return array
	 */
	public static function only($array, $keys)
	{
		return array_intersect_key($array, array_flip((array) $keys));
	}

	/**
	 * Pluck an array of values from an array.
	 *
	 * @param  array   $array
	 * @param  string  $value
	 * @param  string  $key
	 * @return array
	 */
	public static function pluck($array, $value, $key = null)
	{
		$results = [];

		foreach ($array as $item)
		{
			$itemValue = data_get($item, $value);

			// If the key is "null", we will just append the value to the array and keep
			// looping. Otherwise we will key the array using the value of the key we
			// received from the developer. Then we'll return the final array form.
			if (is_null($key))
			{
				$results[] = $itemValue;
			}
			else
			{
				$itemKey = data_get($item, $key);

				$results[$itemKey] = $itemValue;
			}
		}

		return $results;
	}

	/**
	 * Get a value from the array, and remove it.
	 *
	 * @param  array   $array
	 * @param  string  $key
	 * @param  mixed   $default
	 * @return mixed
	 */
	public static function pull(&$array, $key, $default = null)
	{
		$value = static::get($array, $key, $default);

		static::forget($array, $key);

		return $value;
	}

	/**
	 * Set an array item to a given value using "dot" notation.
	 *
	 * If no key is given to the method, the entire array will be replaced.
	 *
	 * @param  array   $array
	 * @param  string  $key
	 * @param  mixed   $value
	 * @return array
	 */
	public static function set(&$array, $key, $value)
	{
		if (is_null($key)) return $array = $value;

		$keys = explode('.', $key);

		while (count($keys) > 1)
		{
			$key = array_shift($keys);

			// If the key doesn't exist at this depth, we will just create an empty array
			// to hold the next value, allowing us to create the arrays to hold final
			// values at the correct depth. Then we'll keep digging into the array.
			if ( ! isset($array[$key]) || ! is_array($array[$key]))
			{
				$array[$key] = [];
			}

			$array =& $array[$key];
		}

		$array[array_shift($keys)] = $value;

		return $array;
	}

	/**
	 * Sort the array using the given callback.
	 *
	 * @param  array  $array
	 * @param  callable  $callback
	 * @return array
	 */
	public static function sort($array, callable $callback)
	{
		return Collection::make($array)->sortBy($callback)->all();
	}

	/**
	 * Filter the array using the given callback.
	 *
	 * @param  array  $array
	 * @param  callable  $callback
	 * @return array
	 */
	public static function where($array, callable $callback)
	{
		$filtered = [];

		foreach ($array as $key => $value)
		{
			if (call_user_func($callback, $key, $value)) $filtered[$key] = $value;
		}

		return $filtered;
	}

}