<?php
/**
 * Copyright 2018 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.
 */
// [START docs_quickstart]
require __DIR__ . '/vendor/autoload.php';

use Google\Client;
use Google\Service\Docs;

/**
 * Returns an authorized API client.
 * @return Client the authorized client object
 */
function getClient()
{
    $client = new Client();
    $client->setApplicationName('Google Docs API PHP Quickstart');
    $client->setScopes('https://www.googleapis.com/auth/documents.readonly	');
    $client->setAuthConfig('credentials.json');
    $client->setAccessType('offline');

    // Load previously authorized credentials from a file.
    $credentialsPath = expandHomeDirectory('token.json');
    if (file_exists($credentialsPath)) {
        $accessToken = json_decode(file_get_contents($credentialsPath), true);
    } else {
        // Request authorization from the user.
        $authUrl = $client->createAuthUrl();
        printf("Open the following link in your browser:\n%s\n", $authUrl);
        print 'Enter verification code: ';
        $authCode = trim(fgets(STDIN));

        // Exchange authorization code for an access token.
        $accessToken = $client->fetchAccessTokenWithAuthCode($authCode);

        // Store the credentials to disk.
        if (!file_exists(dirname($credentialsPath))) {
            mkdir(dirname($credentialsPath), 0700, true);
        }
        file_put_contents($credentialsPath, json_encode($accessToken));
        printf("Credentials saved to %s\n", $credentialsPath);
    }
    $client->setAccessToken($accessToken);

    // Refresh the token if it's expired.
    if ($client->isAccessTokenExpired()) {
        $client->fetchAccessTokenWithRefreshToken($client->getRefreshToken());
        file_put_contents($credentialsPath, json_encode($client->getAccessToken()));
    }
    return $client;
}

/**
 * Expands the home directory alias '~' to the full path.
 * @param string $path the path to expand.
 * @return string the expanded path.
 */
function expandHomeDirectory($path)
{
    $homeDirectory = getenv('HOME');
    if (empty($homeDirectory)) {
        $homeDirectory = getenv('HOMEDRIVE') . getenv('HOMEPATH');
    }
    return str_replace('~', realpath($homeDirectory), $path);
}

// Get the API client and construct the service object.
$client = getClient();
$service = new Docs($client);

// Prints the title of the requested doc:
// https://docs.google.com/document/d/195j9eDD3ccgjQRttHhJPymLJUCOUjs-jmwTrekvdjFE/edit
$documentId = '195j9eDD3ccgjQRttHhJPymLJUCOUjs-jmwTrekvdjFE';
$doc = $service->documents->get($documentId);

printf("The document title is: %s\n", $doc->getTitle());
// [END docs_quickstart]