<?php
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

// snippet-start:[cloudfront.php.updatedistribution.complete]
// snippet-start:[cloudfront.php.updatedistribution.import]
require 'vendor/autoload.php';

use Aws\CloudFront\CloudFrontClient;
use Aws\Exception\AwsException;

// snippet-end:[cloudfront.php.updatedistribution.import]

/* ////////////////////////////////////////////////////////////////////////////
 * Purpose: Updates information about an Amazon CloudFront distribution.
 *
 * Prerequisites: An existing CloudFront distribution.
 *
 * Inputs:
 * - $cloudFrontClient: An initialized CloudFront client.
 * - $distributionId: The ID of the distribution to update information about.
 * - $distributionConfig: A collection of settings for the distribution.
 *   This value comes from the companion getDistributionConfig function.
 * - $eTag: The ETag header value for the distribution. This value comes from
 *   the companion getDistributionETag function.
 *
 * Returns: Information about the updated distribution; otherwise,
 * the error message.
 * ///////////////////////////////////////////////////////////////////////// */

// snippet-start:[cloudfront.php.updatedistribution.main]
function updateDistribution(
    $cloudFrontClient,
    $distributionId,
    $distributionConfig,
    $eTag
) {
    try {
        $result = $cloudFrontClient->updateDistribution([
            'DistributionConfig' => $distributionConfig,
            'Id' => $distributionId,
            'IfMatch' => $eTag
        ]);

        return 'The distribution with the following effective URI has ' .
            'been updated: ' . $result['@metadata']['effectiveUri'];
    } catch (AwsException $e) {
        return 'Error: ' . $e->getAwsErrorMessage();
    }
}

function getDistributionConfig($cloudFrontClient, $distributionId)
{
    try {
        $result = $cloudFrontClient->getDistribution([
            'Id' => $distributionId,
        ]);

        if (isset($result['Distribution']['DistributionConfig'])) {
            return [
                'DistributionConfig' => $result['Distribution']['DistributionConfig'],
                'effectiveUri' => $result['@metadata']['effectiveUri']
            ];
        } else {
            return [
                'Error' => 'Error: Cannot find distribution configuration details.',
                'effectiveUri' => $result['@metadata']['effectiveUri']
            ];
        }
    } catch (AwsException $e) {
        return [
            'Error' => 'Error: ' . $e->getAwsErrorMessage()
        ];
    }
}

function getDistributionETag($cloudFrontClient, $distributionId)
{
    try {
        $result = $cloudFrontClient->getDistribution([
            'Id' => $distributionId,
        ]);

        if (isset($result['ETag'])) {
            return [
                'ETag' => $result['ETag'],
                'effectiveUri' => $result['@metadata']['effectiveUri']
            ];
        } else {
            return [
                'Error' => 'Error: Cannot find distribution ETag header value.',
                'effectiveUri' => $result['@metadata']['effectiveUri']
            ];
        }
    } catch (AwsException $e) {
        return [
            'Error' => 'Error: ' . $e->getAwsErrorMessage()
        ];
    }
}

function updateADistribution()
{
    // $distributionId = 'E1BTGP2EXAMPLE';
    $distributionId = 'E1X3BKQ569KEMH';

    $cloudFrontClient = new CloudFrontClient([
        'profile' => 'default',
        'version' => '2018-06-18',
        'region' => 'us-east-1'
    ]);

    // To change a distribution, you must first get the distribution's
    // ETag header value.
    $eTag = getDistributionETag($cloudFrontClient, $distributionId);

    if (array_key_exists('Error', $eTag)) {
        exit($eTag['Error']);
    }

    // To change a distribution, you must also first get information about
    // the distribution's current configuration. Then you must use that
    // information to build a new configuration.
    $currentConfig = getDistributionConfig($cloudFrontClient, $distributionId);

    if (array_key_exists('Error', $currentConfig)) {
        exit($currentConfig['Error']);
    }

    // To change a distribution's configuration, you can set the
    // distribution's related configuration value as part of a change request,
    // for example:
    // 'Enabled' => true
    // Some configuration values are required to be specified as part of a change
    // request, even if you don't plan to change their values. For ones you
    // don't want to change but are required to be specified, you can just reuse
    // their current values, as follows.
    $distributionConfig = [
        'CallerReference' => $currentConfig['DistributionConfig']["CallerReference"],
        'Comment' => $currentConfig['DistributionConfig']["Comment"],
        'DefaultCacheBehavior' => $currentConfig['DistributionConfig']["DefaultCacheBehavior"],
        'DefaultRootObject' => $currentConfig['DistributionConfig']["DefaultRootObject"],
        'Enabled' => $currentConfig['DistributionConfig']["Enabled"],
        'Origins' => $currentConfig['DistributionConfig']["Origins"],
        'Aliases' => $currentConfig['DistributionConfig']["Aliases"],
        'CustomErrorResponses' => $currentConfig['DistributionConfig']["CustomErrorResponses"],
        'HttpVersion' => $currentConfig['DistributionConfig']["HttpVersion"],
        'CacheBehaviors' => $currentConfig['DistributionConfig']["CacheBehaviors"],
        'Logging' => $currentConfig['DistributionConfig']["Logging"],
        'PriceClass' => $currentConfig['DistributionConfig']["PriceClass"],
        'Restrictions' => $currentConfig['DistributionConfig']["Restrictions"],
        'ViewerCertificate' => $currentConfig['DistributionConfig']["ViewerCertificate"],
        'WebACLId' => $currentConfig['DistributionConfig']["WebACLId"]
    ];

    echo updateDistribution(
        $cloudFrontClient,
        $distributionId,
        $distributionConfig,
        $eTag['ETag']
    );
}

// Uncomment the following line to run this code in an AWS account.
// updateADistribution();
// snippet-end:[cloudfront.php.updatedistribution.main]
// snippet-end:[cloudfront.php.updatedistribution.complete]
// snippet-sourceauthor:[pccornel (AWS)]