<?php

/**

 * Case-insensitive dictionary, suitable for HTTP headers

 *

 * @package Requests\Utilities

 */

namespace WpOrg\Requests\Utility;

use ArrayAccess;

use ArrayIterator;

use IteratorAggregate;

use ReturnTypeWillChange;

use WpOrg\Requests\Exception;

/**

 * Case-insensitive dictionary, suitable for HTTP headers

 *

 * @package Requests\Utilities

 */

class CaseInsensitiveDictionary implements ArrayAccess, IteratorAggregate {

	/**

	 * Actual item data

	 *

	 * @var array

	 */

	protected $data = [];

	/**

	 * Creates a case insensitive dictionary.

	 *

	 * @param array $data Dictionary/map to convert to case-insensitive

	 */

	public function __construct(array $data = []) {

		foreach ($data as $offset => $value) {

			$this->offsetSet($offset, $value);

		}

	}

	/**

	 * Check if the given item exists

	 *

	 * @param string $offset Item key

	 * @return boolean Does the item exist?

	 */

	#[ReturnTypeWillChange]

	public function offsetExists($offset) {

		if (is_string($offset)) {

			$offset = strtolower($offset);

		}

		return isset($this->data[$offset]);

	}

	/**

	 * Get the value for the item

	 *

	 * @param string $offset Item key

	 * @return string|null Item value (null if the item key doesn't exist)

	 */

	#[ReturnTypeWillChange]

	public function offsetGet($offset) {

		if (is_string($offset)) {

			$offset = strtolower($offset);

		}

		if (!isset($this->data[$offset])) {

			return null;

		}

		return $this->data[$offset];

	}

	/**

	 * Set the given item

	 *

	 * @param string $offset Item name

	 * @param string $value Item value

	 *

	 * @throws \WpOrg\Requests\Exception On attempting to use dictionary as list (`invalidset`)

	 */

	#[ReturnTypeWillChange]

	public function offsetSet($offset, $value) {

		if ($offset === null) {

			throw new Exception('Object is a dictionary, not a list', 'invalidset');

		}

		if (is_string($offset)) {

			$offset = strtolower($offset);

		}

		$this->data[$offset] = $value;

	}

	/**

	 * Unset the given header

	 *

	 * @param string $offset The key for the item to unset.

	 */

	#[ReturnTypeWillChange]

	public function offsetUnset($offset) {

		if (is_string($offset)) {

			$offset = strtolower($offset);

		}

		unset($this->data[$offset]);

	}

	/**

	 * Get an iterator for the data

	 *

	 * @return \ArrayIterator

	 */

	#[ReturnTypeWillChange]

	public function getIterator() {

		return new ArrayIterator($this->data);

	}

	/**

	 * Get the headers as an array

	 *

	 * @return array Header data

	 */

	public function getAll() {

		return $this->data;

	}

}