<?php

/*
 * Copyright 2015 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
namespace VendorDuplicator\Google\Auth\Credentials;

/**
 * Authenticates requests using IAM credentials.
 */
class IAMCredentials
{
    const SELECTOR_KEY = 'x-goog-iam-authority-selector';
    const TOKEN_KEY = 'x-goog-iam-authorization-token';
    /**
     * @var string
     */
    private $selector;
    /**
     * @var string
     */
    private $token;
    /**
     * @param $selector string the IAM selector
     * @param $token string the IAM token
     */
    public function __construct($selector, $token)
    {
        if (!\is_string($selector)) {
            throw new \InvalidArgumentException('selector must be a string');
        }
        if (!\is_string($token)) {
            throw new \InvalidArgumentException('token must be a string');
        }
        $this->selector = $selector;
        $this->token = $token;
    }
    /**
     * export a callback function which updates runtime metadata.
     *
     * @return array updateMetadata function
     */
    public function getUpdateMetadataFunc()
    {
        return array($this, 'updateMetadata');
    }
    /**
     * Updates metadata with the appropriate header metadata.
     *
     * @param array $metadata metadata hashmap
     * @param string $unusedAuthUri optional auth uri
     * @param callable $httpHandler callback which delivers psr7 request
     *        Note: this param is unused here, only included here for
     *        consistency with other credentials class
     *
     * @return array updated metadata hashmap
     */
    public function updateMetadata($metadata, $unusedAuthUri = null, callable $httpHandler = null)
    {
        $metadata_copy = $metadata;
        $metadata_copy[self::SELECTOR_KEY] = $this->selector;
        $metadata_copy[self::TOKEN_KEY] = $this->token;
        return $metadata_copy;
    }
}
