<?php

/**
 * Case-insensitive dictionary, suitable for HTTP headers
 *
 * @package Requests
 * @subpackage Utilities
 */

/**
 * Case-insensitive dictionary, suitable for HTTP headers
 *
 * @package Requests
 * @subpackage Utilities
 */
class Requests_Utility_CaseInsensitiveDictionary implements ArrayAccess, IteratorAggregate
{
    /**
     * Actual item data
     *
     * @var array
     */
    protected $data = array();

    /**
     * Creates a case insensitive dictionary.
     *
     * @param array $data Dictionary/map to convert to case-insensitive
     */
    public function __construct(array $data = array())
    {
        foreach ($data as $key => $value) {
            $this->offsetSet($key, $value);
        }
    }

    /**
     * Check if the given item exists
     *
     * @param string $key Item key
     * @return boolean Does the item exist?
     */
    public function offsetExists(mixed $key): bool
    {
        $key = strtolower($key);
        return isset($this->data[$key]);
    }

    /**
     * Get the value for the item
     *
     * @param string $key Item key
     * @return string Item value
     */
    public function offsetGet(mixed $key): bool
    {
        $key = strtolower($key);
        if (!isset($this->data[$key])) {
            return null;
        }

        return $this->data[$key];
    }

    /**
     * Set the given item
     *
     * @throws Requests_Exception On attempting to use dictionary as list (`invalidset`)
     *
     * @param string $key Item name
     * @param string $value Item value
     */
    public function offsetSet(mixed $key, mixed $value): void
    {
        if ($key === null) {
            throw new Requests_Exception('Object is a dictionary, not a list', 'invalidset');
        }

        $key = strtolower($key);
        $this->data[$key] = $value;
    }

    /**
     * Unset the given header
     *
     * @param string $key
     */
    public function offsetUnset(mixed $key): void
    {
        unset($this->data[strtolower($key)]);
    }

    /**
     * Get an iterator for the data
     *
     * @return ArrayIterator
     */
    public function getIterator(): \Traversable
    {
        return new ArrayIterator($this->data);
    }

    /**
     * Get the headers as an array
     *
     * @return array Header data
     */
    public function getAll()
    {
        return $this->data;
    }
}
