<?php

namespace DeliciousBrains\WP_Offload_Media\Providers\Storage;

use AS3CF_Error;
use DeliciousBrains\WP_Offload_Media\Aws3\Aws\CommandPool;
use DeliciousBrains\WP_Offload_Media\Aws3\Aws\ResultInterface;
use DeliciousBrains\WP_Offload_Media\Aws3\Aws\S3\Exception\S3Exception;
use DeliciousBrains\WP_Offload_Media\Aws3\Aws\S3\S3Client;
use DeliciousBrains\WP_Offload_Media\Aws3\Aws\Sdk;
use DeliciousBrains\WP_Offload_Media\Providers\Storage\Streams\AWS_S3_Stream_Wrapper;
use Exception;
use WP_Error;

class AWS_Provider extends Storage_Provider {

	/**
	 * @var Sdk
	 */
	private $aws_client;

	/**
	 * @var S3Client
	 */
	private $s3_client;

	/**
	 * @var string
	 */
	protected static $provider_name = 'Amazon Web Services';

	/**
	 * @var string
	 */
	protected static $provider_short_name = 'AWS';

	/**
	 * Used in filters and settings.
	 *
	 * @var string
	 */
	protected static $provider_key_name = 'aws';

	/**
	 * @var string
	 */
	protected static $service_name = 'Simple Storage Solution';

	/**
	 * @var string
	 */
	protected static $service_short_name = 'S3';

	/**
	 * Used in filters and settings.
	 *
	 * @var string
	 */
	protected static $service_key_name = 's3';

	/**
	 * Optional override of "Provider Name" + "Service Name" for friendly name for service.
	 *
	 * @var string
	 */
	protected static $provider_service_name = 'Amazon S3';

	/**
	 * The slug for the service's quick start guide doc.
	 *
	 * @var string
	 */
	protected static $provider_service_quick_start_slug = 'amazon-s3-quick-start-guide';

	/**
	 * @var array
	 */
	protected static $access_key_id_constants = array(
		'AS3CF_AWS_ACCESS_KEY_ID',
		'DBI_AWS_ACCESS_KEY_ID',
		'AWS_ACCESS_KEY_ID',
	);

	/**
	 * @var array
	 */
	protected static $secret_access_key_constants = array(
		'AS3CF_AWS_SECRET_ACCESS_KEY',
		'DBI_AWS_SECRET_ACCESS_KEY',
		'AWS_SECRET_ACCESS_KEY',
	);

	/**
	 * @var array
	 */
	protected static $use_server_roles_constants = array(
		'AS3CF_AWS_USE_EC2_IAM_ROLE',
		'DBI_AWS_USE_EC2_IAM_ROLE',
		'AWS_USE_EC2_IAM_ROLE',
	);

	/**
	 * @var bool
	 */
	protected static $block_public_access_supported = true;

	/**
	 * @var bool
	 */
	protected static $object_ownership_supported = true;

	/**
	 * @var array
	 */
	protected static $regions = array(
		'us-east-1'      => 'US East (N. Virginia)',
		'us-east-2'      => 'US East (Ohio)',
		'us-west-1'      => 'US West (N. California)',
		'us-west-2'      => 'US West (Oregon)',
		'ca-central-1'   => 'Canada (Central)',
		'ca-west-1'      => 'Canada West (Calgary)',
		'af-south-1'     => 'Africa (Cape Town)',
		'ap-east-1'      => 'Asia Pacific (Hong Kong)',
		'ap-south-1'     => 'Asia Pacific (Mumbai)',
		'ap-south-2'     => 'Asia Pacific (Hyderabad)',
		'ap-northeast-1' => 'Asia Pacific (Tokyo)',
		'ap-northeast-2' => 'Asia Pacific (Seoul)',
		'ap-northeast-3' => 'Asia Pacific (Osaka)',
		'ap-southeast-1' => 'Asia Pacific (Singapore)',
		'ap-southeast-2' => 'Asia Pacific (Sydney)',
		'ap-southeast-3' => 'Asia Pacific (Jakarta)',
		'ap-southeast-4' => 'Asia Pacific (Melbourne)',
		'ap-southeast-5' => 'Asia Pacific (Malaysia)',
		'ap-southeast-7' => 'Asia Pacific (Thailand)',
		'cn-north-1'     => 'China (Beijing)',
		'cn-northwest-1' => 'China (Ningxia)',
		'eu-central-1'   => 'EU (Frankfurt)',
		'eu-central-2'   => 'EU (Zurich)',
		'eu-west-1'      => 'EU (Ireland)',
		'eu-west-2'      => 'EU (London)',
		'eu-west-3'      => 'EU (Paris)',
		'eu-south-1'     => 'EU (Milan)',
		'eu-south-2'     => 'EU (Spain)',
		'eu-north-1'     => 'EU (Stockholm)',
		'il-central-1'   => 'Israel (Tel Aviv)',
		'me-south-1'     => 'Middle East (Bahrain)',
		'me-central-1'   => 'Middle East (UAE)',
		'mx-central-1'   => 'Mexico (Central)',
		'sa-east-1'      => 'South America (São Paulo)',
	);

	/**
	 * @var string
	 */
	protected static $default_region = 'us-east-1';

	/**
	 * @var string
	 */
	protected $default_domain = 'amazonaws.com';

	/**
	 * @var string
	 */
	protected $console_url = 'https://console.aws.amazon.com/s3/buckets/';

	/**
	 * @var string
	 */
	protected $console_url_prefix_param = '/';

	const API_VERSION       = '2006-03-01';
	const SIGNATURE_VERSION = 'v4';

	const PUBLIC_ACL  = 'public-read';
	const PRIVATE_ACL = 'private';

	/**
	 * Keeps track of Block Public Access state for buckets to save hitting API.
	 *
	 * @var array
	 */
	private $blocked_buckets = array();

	/**
	 * Keeps track of Object Ownership Enforced state for buckets to save hitting API.
	 *
	 * @var array
	 */
	private $enforced_ownership_buckets = array();

	/**
	 * AWS_Provider constructor.
	 *
	 * @param \AS3CF_Plugin_Base $as3cf
	 */
	public function __construct( \AS3CF_Plugin_Base $as3cf ) {
		parent::__construct( $as3cf );

		// Autoloader.
		require_once $as3cf->get_plugin_sdks_dir_path() . '/Aws3/aws-autoloader.php';

		if ( ! function_exists( 'idn_to_ascii' ) && ! defined( 'IDNA_DEFAULT' ) ) {
			define( 'IDNA_DEFAULT', 0 );
		}

		add_filter(
			'as3cf_get_unsigned_url_can_access_private_file_desc_aws',
			array( $this, 'get_unsigned_url_can_access_private_file_desc' )
		);
	}

	/**
	 * Optionally modify the description for the "Can access private file" warning from the delivery provider
	 * validation if OOE is enabled on the current bucket.
	 *
	 * @handles as3cf_get_unsigned_url_can_access_private_file_desc_aws
	 *
	 * @param string $message
	 *
	 * @return string
	 */
	public function get_unsigned_url_can_access_private_file_desc( $message ): string {
		$bucket = $this->as3cf->get_setting( 'bucket' );
		$region = $this->as3cf->get_setting( 'region' );

		// Return default message if no bucket is defined.
		if ( empty( $bucket ) ) {
			return $message;
		}

		// Ensure we have a valid client.
		$this->get_client( array( 'region' => $region ) );

		// Return default message if OOE not enabled.
		if ( ! $this->object_ownership_enforced( $bucket ) ) {
			return $message;
		}

		return sprintf(
			__(
				'Delivery provider is connected, but private media is currently exposed through unsigned URLs. Because Object Ownership is enforced on the bucket, access can only be controlled by editing the Amazon S3 bucket policy or by using a CDN that supports private media. <a href="%1$s" target="_blank">Read more</a>',
				'amazon-s3-and-cloudfront'
			),
			static::get_provider_service_quick_start_url() . '#object-ownership'
		);
	}

	/**
	 * Run a command over a batch of items, returning any failures.
	 *
	 * @param string $command
	 * @param array  $items
	 *
	 * @return array Failures with elements Key and Message
	 *
	 * NOTE: Only really useful for commands that take 'Key' as one of their args.
	 */
	private function batch_command( $command, array $items ) {
		$failures = array();

		$commands = array_map( function ( $item ) use ( $command ) {
			return $this->s3_client->getCommand( $command, $item );
		}, $items );

		$results = CommandPool::batch( $this->s3_client, $commands );

		if ( ! empty( $results ) ) {
			foreach ( $results as $result ) {
				/* @var S3Exception $result */
				if ( is_a( $result, 'DeliciousBrains\WP_Offload_Media\Aws3\Aws\S3\Exception\S3Exception' ) ) {
					$failed_command = $result->getCommand()->toArray();
					$failures[]     = array(
						'Key'     => $failed_command['Key'],
						'Message' => $result->getAwsErrorMessage(),
					);
				}
			}
		}

		return $failures;
	}

	/**
	 * Prepare the bucket error.
	 *
	 * @param WP_Error $object
	 * @param bool     $single Are we dealing with a single bucket?
	 *
	 * @return string
	 */
	public function prepare_bucket_error( WP_Error $object, bool $single = true ): string {
		if ( false !== strpos( $object->get_error_message(), 'InvalidAccessKeyId' ) ) {
			return sprintf(
				__( 'Media cannot be offloaded due to an invalid Access Key ID. <a href="%1$s">Update access keys</a>', 'amazon-s3-and-cloudfront' ),
				'#/storage/provider'
			);
		}

		if ( false !== strpos( $object->get_error_message(), 'SignatureDoesNotMatch' ) ) {
			return sprintf(
				__( 'Media cannot be offloaded due to an invalid Secret Access Key. <a href="%1$s">Update access keys</a>', 'amazon-s3-and-cloudfront' ),
				'#/storage/provider'
			);
		}

		if (
			false !== strpos( $object->get_error_message(), 'CreateBucket' ) &&
			false !== strpos( $object->get_error_message(), 'BucketAlreadyOwnedByYou' )
		) {
			return __( 'The bucket name already exists in your account. To confirm you\'d like to use it, please select "Use Existing Bucket". Alternatively, enter a different bucket name.', 'amazon-s3-and-cloudfront' );
		}

		if (
			false !== strpos( $object->get_error_message(), 'CreateBucket' ) &&
			false !== strpos( $object->get_error_message(), 'BucketAlreadyExists' )
		) {
			return __( 'The bucket name already exists in another account. Please enter a different bucket name.', 'amazon-s3-and-cloudfront' );
		}

		if (
			false !== strpos( $object->get_error_message(), 'GetBucketLocation' ) &&
			false !== strpos( $object->get_error_message(), 'NoSuchBucket' )
		) {
			return sprintf(
				__( 'Media cannot be offloaded because a bucket with the configured name does not exist. <a href="%1$s">Enter a different bucket</a>', 'amazon-s3-and-cloudfront' ),
				'#/storage/bucket'
			);
		}

		if (
			false !== strpos( $object->get_error_message(), 'GetBucketLocation' ) &&
			false !== strpos( $object->get_error_message(), 'InvalidBucketName' )
		) {
			return sprintf(
				__( 'Media cannot be offloaded because the bucket name is not valid. <a href="%1$s">Enter a different bucket name</a>.', 'amazon-s3-and-cloudfront' ),
				'#/storage/bucket'
			);
		}

		// Fallback to generic error parsing.
		return parent::prepare_bucket_error( $object, $single );
	}

	/**
	 * Returns default args array for the client.
	 *
	 * @return array
	 */
	protected function default_client_args() {
		return array(
			'signature_version'              => static::SIGNATURE_VERSION,
			'version'                        => static::API_VERSION,
			'region'                         => static::get_default_region(),
			'csm'                            => ! apply_filters( 'as3cf_disable_aws_csm', true ),
			'use_arn_region'                 => ! apply_filters( 'as3cf_disable_aws_use_arn_region', true ),
			's3_us_east_1_regional_endpoint' => apply_filters( 'as3cf_aws_s3_us_east_1_regional_endpoint', 'legacy' ),
			'endpoint_discovery'             => apply_filters( 'as3cf_disable_aws_endpoint_discovery', true ) ? array( 'enabled' => false ) : array( 'enabled' => true ),
			'sts_regional_endpoints'         => apply_filters( 'as3cf_aws_sts_regional_endpoints', 'legacy' ),
			'use_aws_shared_config_files'    => apply_filters( 'as3cf_aws_use_shared_config_files', false ),
		);
	}

	/**
	 * Process the args before instantiating a new client for the provider's SDK.
	 *
	 * @param array $args
	 *
	 * @return array
	 */
	protected function init_client_args( array $args ) {
		return $args;
	}

	/**
	 * Instantiate a new client for the provider's SDK.
	 *
	 * @param array $args
	 */
	protected function init_client( array $args ) {
		$this->aws_client = new Sdk( $args );
	}

	/**
	 * Process the args before instantiating a new service specific client.
	 *
	 * @param array $args
	 *
	 * @return array
	 */
	protected function init_service_client_args( array $args ) {
		return $args;
	}

	/**
	 * Instantiate a new service specific client.
	 *
	 * @param array $args
	 *
	 * @return S3Client
	 */
	protected function init_service_client( array $args = array() ) {
		if ( empty( $args['region'] ) || $args['region'] === static::get_default_region() ) {
			$this->s3_client = $this->aws_client->createMultiRegionS3( $args );
		} else {
			$this->s3_client = $this->aws_client->createS3( $args );
		}

		return $this->s3_client;
	}

	/**
	 * Make sure region "slug" fits expected format.
	 *
	 * @param string $region
	 *
	 * @return string
	 */
	public function sanitize_region( $region ) {
		if ( ! is_string( $region ) ) {
			// Don't translate any region errors
			return $region;
		}

		$region = strtolower( $region );

		/**
		 * Translate older bucket locations to newer S3 region names
		 * http://docs.aws.amazon.com/general/latest/gr/rande.html#s3_region
		 */
		switch ( $region ) {
			case 'eu':
				$region = 'eu-west-1';
				break;
		}

		return $region;
	}

	/**
	 * Create bucket.
	 *
	 * @param array $args
	 */
	public function create_bucket( array $args ) {
		if ( ! empty( $args['LocationConstraint'] ) ) {
			$args['CreateBucketConfiguration']['LocationConstraint'] = $args['LocationConstraint'];
			unset( $args['LocationConstraint'] );
		}

		$this->s3_client->createBucket( $args );

		if ( static::block_public_access_supported() ) {
			$this->block_public_access( $args['Bucket'], false );
		}

		if ( static::object_ownership_supported() ) {
			$this->enforce_object_ownership( $args['Bucket'], false );
		}
	}

	/**
	 * Check whether bucket exists.
	 *
	 * @param string $bucket
	 *
	 * @return bool
	 */
	public function does_bucket_exist( $bucket ) {
		return $this->s3_client->doesBucketExist( $bucket );
	}

	/**
	 * Returns region for bucket.
	 *
	 * @param array $args
	 *
	 * @return string
	 */
	public function get_bucket_location( array $args ) {
		$location = $this->s3_client->getBucketLocation( $args );
		$region   = empty( $location['LocationConstraint'] ) ? '' : $location['LocationConstraint'];

		return $region;
	}

	/**
	 * List buckets.
	 *
	 * @param array $args
	 *
	 * @return array
	 */
	public function list_buckets( array $args = array() ) {
		return $this->s3_client->listBuckets( $args )->toArray();
	}

	/**
	 * Check whether key exists in bucket.
	 *
	 * @param string $bucket
	 * @param string $key
	 * @param array  $options
	 *
	 * @return bool
	 */
	public function does_object_exist( $bucket, $key, array $options = array() ) {
		return $this->s3_client->doesObjectExist( $bucket, $key, $options );
	}

	/**
	 * Get public "canned" ACL string.
	 *
	 * @return string
	 */
	public function get_public_acl() {
		return static::PUBLIC_ACL;
	}

	/**
	 * Get private "canned" ACL string.
	 *
	 * @return string
	 */
	public function get_private_acl() {
		return static::PRIVATE_ACL;
	}

	/**
	 * Is public access to the given bucket prohibited?
	 *
	 * @param string $bucket
	 *
	 * @return bool|null
	 *
	 * Note: It's very possible that permissions don't allow the check, in which case default value is returned.
	 */
	public function public_access_blocked( $bucket ) {
		if ( isset( $this->blocked_buckets[ $bucket ] ) ) {
			return $this->blocked_buckets[ $bucket ];
		}

		$blocked = parent::public_access_blocked( $bucket );

		try {
			$result = $this->s3_client->getPublicAccessBlock( array( 'Bucket' => $bucket ) );
		} catch ( Exception $e ) {
			// No policy defined at either bucket or account level, so no blocking happening.
			if ( false !== strpos( $e->getMessage(), 'NoSuchPublicAccessBlockConfiguration' ) ) {
				$blocked = false;
			} else {
				AS3CF_Error::log( 'Could not get Block All Public Access status: ' . $e->getMessage() );

				return $blocked;
			}
		}

		if ( ! empty( $result ) && ! empty( $result['PublicAccessBlockConfiguration'] ) ) {
			$settings = $result['PublicAccessBlockConfiguration'];
			if (
				empty( $settings['BlockPublicAcls'] ) &&
				empty( $settings['BlockPublicPolicy'] ) &&
				empty( $settings['IgnorePublicAcls'] ) &&
				empty( $settings['RestrictPublicBuckets'] ) ) {
				$blocked = false;
			} else {
				$blocked = true;
			}
		}

		$this->blocked_buckets[ $bucket ] = $blocked;

		return $blocked;
	}

	/**
	 * Update the block public access setting for the given bucket.
	 *
	 * @param string $bucket
	 * @param bool   $block
	 */
	public function block_public_access( string $bucket, bool $block ) {
		if ( empty( $bucket ) ) {
			return;
		}

		$setting = array(
			'Bucket'                         => $bucket,
			'PublicAccessBlockConfiguration' => array(
				'BlockPublicAcls'       => $block,
				'BlockPublicPolicy'     => $block,
				'IgnorePublicAcls'      => $block,
				'RestrictPublicBuckets' => $block,
			),
		);

		$this->s3_client->putPublicAccessBlock( $setting );

		unset( $this->blocked_buckets[ $bucket ] );
	}

	/**
	 * Is object ownership enforced (and therefore ACLs disabled)?
	 *
	 * @param string $bucket
	 *
	 * @return bool|null
	 *
	 * Note: It's very possible that permissions don't allow the check, in which case default value is returned.
	 */
	public function object_ownership_enforced( string $bucket ): ?bool {
		if ( isset( $this->enforced_ownership_buckets[ $bucket ] ) ) {
			return $this->enforced_ownership_buckets[ $bucket ];
		}

		$enforced = parent::object_ownership_enforced( $bucket );

		try {
			$result             = $this->s3_client->getBucketOwnershipControls( array( 'Bucket' => $bucket ) );
			$ownership_controls = $result->get( 'OwnershipControls' );
		} catch ( Exception $e ) {
			// No policy defined at either bucket or account level, so no object ownership enforcement happening.
			if ( false !== strpos( $e->getMessage(), 'OwnershipControlsNotFoundError' ) ) {
				$enforced = false;
			} else {
				AS3CF_Error::log( 'Could not get Object Ownership status: ' . $e->getMessage() );

				return $enforced;
			}
		}

		if ( ! empty( $ownership_controls ) && ! empty( $ownership_controls['Rules'][0]['ObjectOwnership'] ) ) {
			if ( 'BucketOwnerEnforced' === $ownership_controls['Rules'][0]['ObjectOwnership'] ) {
				$enforced = true;
			} else {
				$enforced = false;
			}
		}

		$this->enforced_ownership_buckets[ $bucket ] = $enforced;

		return $enforced;
	}

	/**
	 * Update the object ownership enforced setting for the given bucket.
	 *
	 * @param string $bucket
	 * @param bool   $enforce
	 */
	public function enforce_object_ownership( string $bucket, bool $enforce ) {
		if ( empty( $bucket ) ) {
			return;
		}

		$ownership = $enforce ? 'BucketOwnerEnforced' : 'BucketOwnerPreferred';

		$setting = array(
			'Bucket'            => $bucket,
			'OwnershipControls' => array(
				'Rules' => array(
					array(
						'ObjectOwnership' => $ownership,
					),
				),
			),
		);

		$this->s3_client->putBucketOwnershipControls( $setting );

		unset( $this->enforced_ownership_buckets[ $bucket ] );
	}

	/**
	 * Download object, destination specified in args.
	 *
	 * @see https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-s3-2006-03-01.html#getobject
	 *
	 * @param array $args
	 */
	public function get_object( array $args ) {
		$this->s3_client->getObject( $args );
	}

	/**
	 * Get object's URL.
	 *
	 * @param string $bucket
	 * @param string $key
	 * @param int    $timestamp
	 * @param array  $args
	 *
	 * @return string
	 */
	public function get_object_url( $bucket, $key, $timestamp, array $args = array() ) {
		$command_args = array( 'Bucket' => $bucket, 'Key' => $key );

		if ( ! empty( $args ) ) {
			$command_args = array_merge( $command_args, $args );
		}

		$command = $this->s3_client->getCommand( 'GetObject', $command_args );

		if ( empty( $timestamp ) || ! is_int( $timestamp ) || $timestamp < 0 ) {
			return (string) \DeliciousBrains\WP_Offload_Media\Aws3\Aws\serialize( $command )->getUri();
		} else {
			return (string) $this->s3_client->createPresignedRequest( $command, $timestamp )->getUri();
		}
	}

	/**
	 * List objects.
	 *
	 * @param array $args
	 *
	 * @return array
	 */
	public function list_objects( array $args = array() ) {
		return $this->s3_client->listObjects( $args )->toArray();
	}

	/**
	 * Update the ACL for an object.
	 *
	 * @param array $args
	 */
	public function update_object_acl( array $args ) {
		$this->s3_client->putObjectAcl( $args );
	}

	/**
	 * Update the ACL for multiple objects.
	 *
	 * @param array $items
	 *
	 * @return array Failures with elements Key and Message
	 */
	public function update_object_acls( array $items ) {
		return $this->batch_command( 'PutObjectAcl', $items );
	}

	/**
	 * Upload file to bucket.
	 *
	 * @param array $args
	 */
	public function upload_object( array $args ) {
		$this->s3_client->putObject( $args );
	}

	/**
	 * Delete object from bucket.
	 *
	 * @param array $args
	 */
	public function delete_object( array $args ) {
		$this->s3_client->deleteObject( $args );
	}

	/**
	 * Delete multiple objects from bucket.
	 *
	 * @param array $args
	 */
	public function delete_objects( array $args ) {
		if ( ! isset( $args['Delete'] ) && isset( $args['Objects'] ) ) {
			$args['Delete']['Objects'] = $args['Objects'];
			unset( $args['Objects'] );
		}

		$this->s3_client->deleteObjects( $args );
	}

	/**
	 * Returns arrays of found keys for given bucket and prefix locations, retaining given array's integer based index.
	 *
	 * @param array $locations Array with attachment ID as key and Bucket and Prefix in an associative array as values.
	 *
	 * @return array
	 */
	public function list_keys( array $locations ) {
		$keys = array();

		$commands = array_map( function ( $location ) {
			return $this->s3_client->getCommand( 'ListObjects', $location );
		}, $locations );

		$results = CommandPool::batch( $this->s3_client, $commands, array( 'preserve_iterator_keys' => true ) );

		/** @var ResultInterface $result */
		foreach ( $results as $attachment_id => $result ) {
			if ( is_a( $result, 'DeliciousBrains\WP_Offload_Media\Aws3\Aws\ResultInterface' ) ) {
				$found_keys = $result->search( 'Contents[].Key' );

				if ( ! empty( $found_keys ) ) {
					$keys[ $attachment_id ] = $found_keys;
				}
			} elseif ( is_a( $result, 'DeliciousBrains\WP_Offload_Media\Aws3\Aws\S3\Exception\S3Exception' ) ) {
				/** @var S3Exception $result */
				AS3CF_Error::log( __FUNCTION__ . ' - ' . $result->getAwsErrorMessage() . ' - Attachment ID: ' . $attachment_id );
			} else {
				AS3CF_Error::log( __FUNCTION__ . ' - Unrecognised class returned from CommandPool::batch - Attachment ID: ' . $attachment_id );
			}
		}

		return $keys;
	}

	/**
	 * Copies objects into current bucket from another bucket hosted with provider.
	 *
	 * @param array $items
	 *
	 * @return array Failures with elements Key and Message
	 */
	public function copy_objects( array $items ) {
		return $this->batch_command( 'CopyObject', $items );
	}

	/**
	 * Generate the stream wrapper protocol
	 *
	 * @param string $region
	 *
	 * @return string
	 */
	protected function get_stream_wrapper_protocol( $region ) {
		$protocol = 's3';
		$protocol .= str_replace( '-', '', $region );

		return $protocol;
	}

	/**
	 * Register a stream wrapper for specific region.
	 *
	 * @param string $region
	 *
	 * @return bool
	 */
	public function register_stream_wrapper( $region ) {
		$protocol = $this->get_stream_wrapper_protocol( $region );

		// Register the region specific S3 stream wrapper to be used by plugins
		AWS_S3_Stream_Wrapper::register( $this->s3_client, $protocol );

		return true;
	}

	/**
	 * Check that a bucket and key can be written to.
	 *
	 * @param string $bucket
	 * @param string $key
	 * @param string $file_contents
	 *
	 * @return bool|string Error message on unexpected exception
	 */
	public function can_write( $bucket, $key, $file_contents ) {
		try {
			// Attempt to create the test file.
			$this->upload_object(
				static::filter_object_meta(
					array(
						'Bucket' => $bucket,
						'Key'    => $key,
						'Body'   => $file_contents,
					)
				)
			);

			// delete it straight away if created
			$this->delete_object( array(
				'Bucket' => $bucket,
				'Key'    => $key,
			) );

			return true;
		} catch ( Exception $e ) {
			// If we encounter an error that isn't access denied, throw that error.
			if ( ! $e instanceof S3Exception || ! in_array( $e->getAwsErrorCode(), array( 'AccessDenied', 'NoSuchBucket' ) ) ) {
				return $e->getMessage();
			}
		}

		return false;
	}

	/**
	 * Get the region specific prefix for raw URL
	 *
	 * @param string   $region
	 * @param null|int $expires
	 *
	 * @return string
	 */
	protected function url_prefix( $region = '', $expires = null ) {
		$prefix = 's3';

		if ( ! empty( $region ) && $this->get_default_region() !== $region ) {
			$prefix .= '.' . $region;
		}

		return $prefix;
	}

	/**
	 * Get the url domain for the files
	 *
	 * @param string $domain Likely prefixed with region
	 * @param string $bucket
	 * @param string $region
	 * @param int    $expires
	 * @param array  $args   Allows you to specify custom URL settings
	 *
	 * @return string
	 */
	protected function url_domain( $domain, $bucket, $region = '', $expires = null, $args = array() ) {
		if ( apply_filters( 'as3cf_' . static::get_provider_key_name() . '_' . static::get_service_key_name() . '_bucket_in_path', false !== strpos( $bucket, '.' ) ) ) {
			// TODO: This mode is going away, kinda, sorta, one day.
			// TODO: When AWS sort out HTTPS for bucket in domain with dots we can remove this format.
			// @see https://aws.amazon.com/blogs/aws/amazon-s3-path-deprecation-plan-the-rest-of-the-story/
			$domain = $domain . '/' . $bucket;
		} else {
			$domain = $bucket . '.' . $domain;
		}

		return $domain;
	}

	/**
	 * Get the suffix param to append to the link to the provider's console.
	 *
	 * @param string $bucket
	 * @param string $prefix
	 * @param string $region
	 *
	 * @return string
	 */
	protected function get_console_url_suffix_param( string $bucket = '', string $prefix = '', string $region = '' ): string {
		return empty( $region ) ? '' : '?region=' . $region;
	}

	/**
	 * Notification strings for when Block All Public Access enabled on storage provider but delivery provider does not support it.
	 *
	 * @return array Keys are heading and message
	 */
	public static function get_block_public_access_warning() {
		global $as3cf;

		$cloudfront_setup_doc = $as3cf::dbrains_url(
			'/wp-offload-media/doc/cloudfront-setup/',
			array( 'utm_campaign' => 'support+docs', 'utm_content' => 'change+bucket+access' )
		);

		$bucket_access_blocked_message = sprintf(
			__( 'If you\'re following our documentation on <a href="%1$s">setting up Amazon CloudFront</a> for delivery, you can ignore this warning and continue.<br> If you\'re not planning on using Amazon CloudFront for delivery, you need to <a href="%2$s">disable Block All Public Access</a>.', 'amazon-s3-and-cloudfront' ),
			$cloudfront_setup_doc,
			'#/storage/security'
		);

		return array(
			'heading' => _x( 'Block All Public Access is Enabled', 'warning heading', 'amazon-s3-and-cloudfront' ),
			'message' => $bucket_access_blocked_message,
		);
	}

	/**
	 * Description for when Block All Public Access is enabled and Delivery Provider does not support it.
	 *
	 * @return string
	 */
	public static function get_block_public_access_enabled_unsupported_desc() {
		global $as3cf;

		$mesg = __( 'Block All Public Access should only been enabled when Amazon CloudFront is configured for delivery.', 'amazon-s3-and-cloudfront' );
		$mesg .= '&nbsp;';
		$mesg .= $as3cf::settings_more_info_link( 'bucket', '', 'change+bucket+access' );

		return $mesg;
	}

	/**
	 * Description for when Block All Public Access is enabled and Delivery Provider does not support it.
	 *
	 * @return string
	 */
	public static function get_block_public_access_enabled_unsupported_setup_desc() {
		global $as3cf;

		$cloudfront_setup_doc = $as3cf::dbrains_url(
			'/wp-offload-media/doc/cloudfront-setup/',
			array( 'utm_campaign' => 'support+docs', 'utm_content' => 'change+bucket+access' )
		);
		$bucket_settings_doc  = $as3cf::dbrains_url(
			'/wp-offload-media/doc/settings/',
			array( 'utm_campaign' => 'support+docs', 'utm_content' => 'change+bucket+access' ),
			'bucket'
		);

		return sprintf(
			__( 'If you\'re following our documentation on <a href="%1$s">setting up Amazon CloudFront</a> for delivery, you can ignore this warning and continue. If you\'re not planning on using Amazon CloudFront for delivery, you need to <a href="%2$s">disable Block All Public Access</a>.', 'amazon-s3-and-cloudfront' ),
			$cloudfront_setup_doc,
			$bucket_settings_doc
		);
	}

	/**
	 * Description for when Block All Public Access is disabled and Delivery Provider does not support it.
	 *
	 * @return string
	 */
	public static function get_block_public_access_disabled_unsupported_desc() {
		global $as3cf;

		$mesg = __( 'Since you\'re not using Amazon CloudFront for delivery, we recommend you keep Block All Public Access disabled unless you have a very good reason to enable it.', 'amazon-s3-and-cloudfront' );
		$mesg .= '&nbsp;';
		$mesg .= $as3cf::settings_more_info_link( 'bucket', '', 'change+bucket+access' );

		return $mesg;
	}

	/**
	 * Notification strings for when Object Ownership enforced on storage provider but delivery provider does not support it.
	 *
	 * @return array Keys are heading and message
	 *
	 * This function should be overridden by providers that do support enforced Object Ownership to give more specific message.
	 */
	public static function get_object_ownership_enforced_warning() {
		global $as3cf;

		$cloudfront_setup_doc = $as3cf::dbrains_url(
			'/wp-offload-media/doc/cloudfront-setup/',
			array( 'utm_campaign' => 'support+docs', 'utm_content' => 'change+bucket+access' )
		);

		$bucket_access_blocked_message = sprintf(
			__( 'If you\'re following our documentation on <a href="%1$s">setting up Amazon CloudFront</a> for delivery, you can ignore this warning and continue.<br>If you\'re not planning on using Amazon CloudFront for delivery, you need to <a href="%2$s">turn off Object Ownership enforcement</a>.', 'amazon-s3-and-cloudfront' ),
			$cloudfront_setup_doc,
			'#/storage/security'
		);

		return array(
			'heading' => _x( 'Object Ownership is Enforced', 'warning heading', 'amazon-s3-and-cloudfront' ),
			'message' => $bucket_access_blocked_message,
		);
	}

	/**
	 * Description for when Object Ownership is enforced and Delivery Provider does not support it.
	 *
	 * @return string
	 */
	public static function get_object_ownership_enforced_unsupported_desc(): string {
		global $as3cf;

		$mesg = __( 'Object Ownership should only been enforced when Amazon CloudFront is configured for delivery.', 'amazon-s3-and-cloudfront' );
		$mesg .= '&nbsp;';
		$mesg .= $as3cf::settings_more_info_link( 'bucket', '', 'change+bucket+access' );

		return $mesg;
	}

	/**
	 * Description for when Object Ownership is enforced during initial setup.
	 *
	 * @return string
	 */
	public static function get_object_ownership_enforced_unsupported_setup_desc(): string {
		global $as3cf;

		$cloudfront_setup_doc = $as3cf::dbrains_url(
			'/wp-offload-media/doc/cloudfront-setup/',
			array( 'utm_campaign' => 'support+docs', 'utm_content' => 'change+bucket+access' )
		);

		$object_ownership_doc = $as3cf::dbrains_url(
			'/wp-offload-media/doc/amazon-s3-bucket-object-ownership/',
			array( 'utm_campaign' => 'support+docs', 'utm_content' => 'change+bucket+access' )
		);

		return sprintf(
			__( 'If you\'re following our documentation on <a href="%1$s">setting up Amazon CloudFront</a> for delivery, you can ignore this warning and continue.<br>If you\'re not planning on using Amazon CloudFront for delivery, you need to edit the bucket\'s Object Ownership setting and <a href="%2$s">enable ACLs</a> or add a <a href="%3$s">Bucket Policy</a>.', 'amazon-s3-and-cloudfront' ),
			$cloudfront_setup_doc,
			$object_ownership_doc . '#acls',
			$object_ownership_doc . '#bucket-policy'
		);
	}

	/**
	 * Description for when Object Ownership is not enforced and Delivery Provider does not support it.
	 *
	 * @return string
	 */
	public static function get_object_ownership_not_enforced_unsupported_desc(): string {
		global $as3cf;

		$mesg = __( 'Since you\'re not using Amazon CloudFront for delivery, we recommend you do not enforce Object Ownership unless you have a very good reason to do so.', 'amazon-s3-and-cloudfront' );
		$mesg .= '&nbsp;';
		$mesg .= $as3cf::settings_more_info_link( 'bucket', '', 'change+bucket+access' );

		return $mesg;
	}
}
