<?php

namespace Aws\S3;

use Aws\CacheInterface;
use Aws\LruArrayCache;
use Aws\Result;
use Aws\S3\Exception\S3Exception;
use Exception;
use GuzzleHttp\Psr7;
use GuzzleHttp\Psr7\CachingStream;
use GuzzleHttp\Psr7\Stream;
use Iterator;
use Psr\Http\Message\StreamInterface;
use RuntimeException;
use function Aws\flatmap;

/**
 * Amazon S3 stream wrapper to use "s3://<bucket>/<key>" files with PHP
 * streams, supporting "r", "w", "a", "x".
 *
 * # Opening "r" (read only) streams:
 *
 * Read only streams are truly streaming by default and will not allow you to
 * seek. This is because data read from the stream is not kept in memory or on
 * the local filesystem. You can force a "r" stream to be seekable by setting
 * the "seekable" stream context option true. This will allow true streaming of
 * data from Amazon S3, but will maintain a buffer of previously read bytes in
 * a 'php://temp' stream to allow seeking to previously read bytes from the
 * stream.
 *
 * You may pass any GetObject parameters as 's3' stream context options. These
 * options will affect how the data is downloaded from Amazon S3.
 *
 * # Opening "w" and "x" (write only) streams:
 *
 * Because Amazon S3 requires a Content-Length header, write only streams will
 * maintain a 'php://temp' stream to buffer data written to the stream until
 * the stream is flushed (usually by closing the stream with fclose).
 *
 * You may pass any PutObject parameters as 's3' stream context options. These
 * options will affect how the data is uploaded to Amazon S3.
 *
 * When opening an "x" stream, the file must exist on Amazon S3 for the stream
 * to open successfully.
 *
 * # Opening "a" (write only append) streams:
 *
 * Similar to "w" streams, opening append streams requires that the data be
 * buffered in a "php://temp" stream. Append streams will attempt to download
 * the contents of an object in Amazon S3, seek to the end of the object, then
 * allow you to append to the contents of the object. The data will then be
 * uploaded using a PutObject operation when the stream is flushed (usually
 * with fclose).
 *
 * You may pass any GetObject and/or PutObject parameters as 's3' stream
 * context options. These options will affect how the data is downloaded and
 * uploaded from Amazon S3.
 *
 * Stream context options:
 *
 * - "seekable": Set to true to create a seekable "r" (read only) stream by
 *   using a php://temp stream buffer
 * - For "unlink" only: Any option that can be passed to the DeleteObject
 *   operation
 */
class StreamWrapper {
	/** @var resource|null Stream context (this is set by PHP) */
	public $context;

	/** @var StreamInterface Underlying stream resource */
	private $body;

	/** @var int Size of the body that is opened */
	private $size;

	/** @var array Hash of opened stream parameters */
	private $params = [];

	/** @var string Mode in which the stream was opened */
	private $mode;

	/** @var Iterator Iterator used with opendir() related calls */
	private $objectIterator;

	/** @var string The bucket that was opened when opendir() was called */
	private $openedBucket;

	/** @var string The prefix of the bucket that was opened with opendir() */
	private $openedBucketPrefix;

	/** @var string Opened bucket path */
	private $openedPath;

	/** @var CacheInterface Cache for object and dir lookups */
	private $cache;

	/** @var string The opened protocol (e.g., "s3") */
	private $protocol = 's3';

	/** @var bool Keeps track of whether stream has been flushed since opening */
	private $isFlushed = false;

	/**
	 * Register the 's3://' stream wrapper
	 *
	 * @param S3ClientInterface $client Client to use with the stream wrapper
	 * @param string $protocol Protocol to register as.
	 * @param CacheInterface $cache Default cache for the protocol.
	 */
	public static function register(
		S3ClientInterface $client,
		$protocol = 's3',
		CacheInterface $cache = null
	) {
		if ( in_array( $protocol, stream_get_wrappers() ) ) {
			stream_wrapper_unregister( $protocol );
		}

		// Set the client passed in as the default stream context client
		stream_wrapper_register( $protocol, get_called_class(), STREAM_IS_URL );
		$default                        = stream_context_get_options( stream_context_get_default() );
		$default[ $protocol ]['client'] = $client;

		if ( $cache ) {
			$default[ $protocol ]['cache'] = $cache;
		} elseif ( ! isset( $default[ $protocol ]['cache'] ) ) {
			// Set a default cache adapter.
			$default[ $protocol ]['cache'] = new LruArrayCache();
		}

		stream_context_set_default( $default );
	}

	public function stream_close() {
		if ( $this->body->getSize() === 0 && ! ( $this->isFlushed ) ) {
			$this->stream_flush();
		}
		$this->body = $this->cache = null;
	}

	public function stream_flush() {
		$this->isFlushed = true;
		if ( $this->mode == 'r' ) {
			return false;
		}

		if ( $this->body->isSeekable() ) {
			$this->body->seek( 0 );
		}
		$params         = $this->getOptions( true );
		$params['Body'] = $this->body;

		// Attempt to guess the ContentType of the upload based on the
		// file extension of the key
		if ( ! isset( $params['ContentType'] ) &&
		     ( $type = Psr7\mimetype_from_filename( $params['Key'] ) )
		) {
			$params['ContentType'] = $type;
		}

		$this->clearCacheKey( "s3://{$params['Bucket']}/{$params['Key']}" );

		return $this->boolCall( function () use ( $params ) {
			return (bool) $this->getClient()->putObject( $params );
		} );
	}

	/**
	 * Get the stream context options available to the current stream
	 *
	 * @param bool $removeContextData Set to true to remove contextual kvp's
	 *                                like 'client' from the result.
	 *
	 * @return array
	 */
	private function getOptions( $removeContextData = false ) {
		// Context is not set when doing things like stat
		if ( $this->context === null ) {
			$options = [];
		} else {
			$options = stream_context_get_options( $this->context );
			$options = isset( $options[ $this->protocol ] )
				? $options[ $this->protocol ]
				: [];
		}

		$default = stream_context_get_options( stream_context_get_default() );
		$default = isset( $default[ $this->protocol ] )
			? $default[ $this->protocol ]
			: [];
		$result  = $this->params + $options + $default;

		if ( $removeContextData ) {
			unset( $result['client'], $result['seekable'], $result['cache'] );
		}

		return $result;
	}

	/**
	 * Clears a specific stat cache value from the stat cache and LRU cache.
	 *
	 * @param string $key S3 path (s3://bucket/key).
	 */
	private function clearCacheKey( $key ) {
		clearstatcache( true, $key );
		$this->getCacheStorage()->remove( $key );
	}

	/**
	 * @return LruArrayCache
	 */
	private function getCacheStorage() {
		if ( ! $this->cache ) {
			$this->cache = $this->getOption( 'cache' ) ?: new LruArrayCache();
		}

		return $this->cache;
	}

	/**
	 * Get a specific stream context option
	 *
	 * @param string $name Name of the option to retrieve
	 *
	 * @return mixed|null
	 */
	private function getOption( $name ) {
		$options = $this->getOptions();

		return isset( $options[ $name ] ) ? $options[ $name ] : null;
	}

	/**
	 * Invokes a callable and triggers an error if an exception occurs while
	 * calling the function.
	 *
	 * @param callable $fn
	 * @param int $flags
	 *
	 * @return bool
	 */
	private function boolCall( callable $fn, $flags = null ) {
		try {
			return $fn();
		} catch ( Exception $e ) {
			return $this->triggerError( $e->getMessage(), $flags );
		}
	}

	/**
	 * Trigger one or more errors
	 *
	 * @param string|array $errors Errors to trigger
	 * @param mixed $flags If set to STREAM_URL_STAT_QUIET, then no
	 *                             error or exception occurs
	 *
	 * @return bool Returns false
	 * @throws RuntimeException if throw_errors is true
	 */
	private function triggerError( $errors, $flags = null ) {
		// This is triggered with things like file_exists()
		if ( $flags & STREAM_URL_STAT_QUIET ) {
			return $flags & STREAM_URL_STAT_LINK
				// This is triggered for things like is_link()
				? $this->formatUrlStat( false )
				: false;
		}

		// This is triggered when doing things like lstat() or stat()
		trigger_error( implode( "\n", (array) $errors ), E_USER_WARNING );

		return false;
	}

	/**
	 * Prepare a url_stat result array
	 *
	 * @param string|array $result Data to add
	 *
	 * @return array Returns the modified url_stat result
	 */
	private function formatUrlStat( $result = null ) {
		$stat = $this->getStatTemplate();
		switch ( gettype( $result ) ) {
			case 'NULL':
			case 'string':
				// Directory with 0777 access - see "man 2 stat".
				$stat['mode'] = $stat[2] = 0040777;
				break;
			case 'array':
				// Regular file with 0777 access - see "man 2 stat".
				$stat['mode'] = $stat[2] = 0100777;
				// Pluck the content-length if available.
				if ( isset( $result['ContentLength'] ) ) {
					$stat['size'] = $stat[7] = $result['ContentLength'];
				} elseif ( isset( $result['Size'] ) ) {
					$stat['size'] = $stat[7] = $result['Size'];
				}
				if ( isset( $result['LastModified'] ) ) {
					// ListObjects or HeadObject result
					$stat['mtime'] = $stat[9] = $stat['ctime'] = $stat[10]
						= strtotime( $result['LastModified'] );
				}
		}

		return $stat;
	}

	/**
	 * Gets a URL stat template with default values
	 *
	 * @return array
	 */
	private function getStatTemplate() {
		return [
			0         => 0,
			'dev'     => 0,
			1         => 0,
			'ino'     => 0,
			2         => 0,
			'mode'    => 0,
			3         => 0,
			'nlink'   => 0,
			4         => 0,
			'uid'     => 0,
			5         => 0,
			'gid'     => 0,
			6         => - 1,
			'rdev'    => - 1,
			7         => 0,
			'size'    => 0,
			8         => 0,
			'atime'   => 0,
			9         => 0,
			'mtime'   => 0,
			10        => 0,
			'ctime'   => 0,
			11        => - 1,
			'blksize' => - 1,
			12        => - 1,
			'blocks'  => - 1,
		];
	}

	/**
	 * Gets the client from the stream context
	 *
	 * @return S3ClientInterface
	 * @throws RuntimeException if no client has been configured
	 */
	private function getClient() {
		if ( ! $client = $this->getOption( 'client' ) ) {
			throw new RuntimeException( 'No client in stream context' );
		}

		return $client;
	}

	public function stream_open( $path, $mode, $options, &$opened_path ) {
		$this->initProtocol( $path );
		$this->isFlushed = false;
		$this->params    = $this->getBucketKey( $path );
		$this->mode      = rtrim( $mode, 'bt' );

		if ( $errors = $this->validate( $path, $this->mode ) ) {
			return $this->triggerError( $errors );
		}

		return $this->boolCall( function () use ( $path ) {
			switch ( $this->mode ) {
				case 'r':
					return $this->openReadStream( $path );
				case 'a':
					return $this->openAppendStream( $path );
				default:
					return $this->openWriteStream( $path );
			}
		} );
	}

	/**
	 * Parse the protocol out of the given path.
	 *
	 * @param $path
	 */
	private function initProtocol( $path ) {
		$parts          = explode( '://', $path, 2 );
		$this->protocol = $parts[0] ?: 's3';
	}

	private function getBucketKey( $path ) {
		// Remove the protocol
		$parts = explode( '://', $path );
		// Get the bucket, key
		$parts = explode( '/', $parts[1], 2 );

		return [
			'Bucket' => $parts[0],
			'Key'    => isset( $parts[1] ) ? $parts[1] : null
		];
	}

	/**
	 * Validates the provided stream arguments for fopen and returns an array
	 * of errors.
	 */
	private function validate( $path, $mode ) {
		$errors = [];

		if ( ! $this->getOption( 'Key' ) ) {
			$errors[] = 'Cannot open a bucket. You must specify a path in the '
			            . 'form of s3://bucket/key';
		}

		if ( ! in_array( $mode, [ 'r', 'w', 'a', 'x' ] ) ) {
			$errors[] = "Mode not supported: {$mode}. "
			            . "Use one 'r', 'w', 'a', or 'x'.";
		}

		// When using mode "x" validate if the file exists before attempting
		// to read
		if ( $mode == 'x' &&
		     $this->getClient()->doesObjectExist(
			     $this->getOption( 'Bucket' ),
			     $this->getOption( 'Key' ),
			     $this->getOptions( true )
		     )
		) {
			$errors[] = "{$path} already exists on Amazon S3";
		}

		return $errors;
	}

	private function openReadStream() {
		$client                     = $this->getClient();
		$command                    = $client->getCommand( 'GetObject', $this->getOptions( true ) );
		$command['@http']['stream'] = true;
		$result                     = $client->execute( $command );
		$this->size                 = $result['ContentLength'];
		$this->body                 = $result['Body'];

		// Wrap the body in a caching entity body if seeking is allowed
		if ( $this->getOption( 'seekable' ) && ! $this->body->isSeekable() ) {
			$this->body = new CachingStream( $this->body );
		}

		return true;
	}

	private function openAppendStream() {
		try {
			// Get the body of the object and seek to the end of the stream
			$client     = $this->getClient();
			$this->body = $client->getObject( $this->getOptions( true ) )['Body'];
			$this->body->seek( 0, SEEK_END );

			return true;
		} catch ( S3Exception $e ) {
			// The object does not exist, so use a simple write stream
			return $this->openWriteStream();
		}
	}

	private function openWriteStream() {
		$this->body = new Stream( fopen( 'php://temp', 'r+' ) );

		return true;
	}

	public function stream_eof() {
		return $this->body->eof();
	}

	public function stream_read( $count ) {
		return $this->body->read( $count );
	}

	public function stream_seek( $offset, $whence = SEEK_SET ) {
		return ! $this->body->isSeekable()
			? false
			: $this->boolCall( function () use ( $offset, $whence ) {
				$this->body->seek( $offset, $whence );

				return true;
			} );
	}

	public function stream_tell() {
		return $this->boolCall( function () {
			return $this->body->tell();
		} );
	}

	public function stream_write( $data ) {
		return $this->body->write( $data );
	}

	public function stream_stat() {
		$stat    = $this->getStatTemplate();
		$stat[7] = $stat['size'] = $this->getSize();
		$stat[2] = $stat['mode'] = $this->mode;

		return $stat;
	}

	/**
	 * Returns the size of the opened object body.
	 *
	 * @return int|null
	 */
	private function getSize() {
		$size = $this->body->getSize();

		return $size !== null ? $size : $this->size;
	}

	/**
	 * Provides information for is_dir, is_file, filesize, etc. Works on
	 * buckets, keys, and prefixes.
	 * @link http://www.php.net/manual/en/streamwrapper.url-stat.php
	 */
	public function url_stat( $path, $flags ) {
		$this->initProtocol( $path );

		// Some paths come through as S3:// for some reason.
		$split = explode( '://', $path );
		$path  = strtolower( $split[0] ) . '://' . $split[1];

		// Check if this path is in the url_stat cache
		if ( $value = $this->getCacheStorage()->get( $path ) ) {
			return $value;
		}

		$stat = $this->createStat( $path, $flags );

		if ( is_array( $stat ) ) {
			$this->getCacheStorage()->set( $path, $stat );
		}

		return $stat;
	}

	private function createStat( $path, $flags ) {
		$this->initProtocol( $path );
		$parts = $this->withPath( $path );

		if ( ! $parts['Key'] ) {
			return $this->statDirectory( $parts, $path, $flags );
		}

		return $this->boolCall( function () use ( $parts, $path ) {
			try {
				$result = $this->getClient()->headObject( $parts );
				if ( substr( $parts['Key'], - 1, 1 ) == '/' &&
				     $result['ContentLength'] == 0
				) {
					// Return as if it is a bucket to account for console
					// bucket objects (e.g., zero-byte object "foo/")
					return $this->formatUrlStat( $path );
				}

				// Attempt to stat and cache regular object
				return $this->formatUrlStat( $result->toArray() );
			} catch ( S3Exception $e ) {
				// Maybe this isn't an actual key, but a prefix. Do a prefix
				// listing of objects to determine.
				$result = $this->getClient()->listObjects( [
					'Bucket'  => $parts['Bucket'],
					'Prefix'  => rtrim( $parts['Key'], '/' ) . '/',
					'MaxKeys' => 1
				] );
				if ( ! $result['Contents'] && ! $result['CommonPrefixes'] ) {
					throw new Exception( "File or directory not found: $path" );
				}

				return $this->formatUrlStat( $path );
			}
		}, $flags );
	}

	/**
	 * Get the bucket and key from the passed path (e.g. s3://bucket/key)
	 *
	 * @param string $path Path passed to the stream wrapper
	 *
	 * @return array Hash of 'Bucket', 'Key', and custom params from the context
	 */
	private function withPath( $path ) {
		$params = $this->getOptions( true );

		return $this->getBucketKey( $path ) + $params;
	}

	private function statDirectory( $parts, $path, $flags ) {
		// Stat "directories": buckets, or "s3://"
		if ( ! $parts['Bucket'] ||
		     $this->getClient()->doesBucketExist( $parts['Bucket'] )
		) {
			return $this->formatUrlStat( $path );
		}

		return $this->triggerError( "File or directory not found: $path", $flags );
	}

	/**
	 * Support for mkdir().
	 *
	 * @param string $path Directory which should be created.
	 * @param int $mode Permissions. 700-range permissions map to
	 *                        ACL_PUBLIC. 600-range permissions map to
	 *                        ACL_AUTH_READ. All other permissions map to
	 *                        ACL_PRIVATE. Expects octal form.
	 * @param int $options A bitwise mask of values, such as
	 *                        STREAM_MKDIR_RECURSIVE.
	 *
	 * @return bool
	 * @link http://www.php.net/manual/en/streamwrapper.mkdir.php
	 */
	public function mkdir( $path, $mode, $options ) {
		$this->initProtocol( $path );
		$params = $this->withPath( $path );
		$this->clearCacheKey( $path );
		if ( ! $params['Bucket'] ) {
			return false;
		}

		if ( ! isset( $params['ACL'] ) ) {
			$params['ACL'] = $this->determineAcl( $mode );
		}

		return empty( $params['Key'] )
			? $this->createBucket( $path, $params )
			: $this->createSubfolder( $path, $params );
	}

	/**
	 * Determine the most appropriate ACL based on a file mode.
	 *
	 * @param int $mode File mode
	 *
	 * @return string
	 */
	private function determineAcl( $mode ) {
		switch ( substr( decoct( $mode ), 0, 1 ) ) {
			case '7':
				return 'public-read';
			case '6':
				return 'authenticated-read';
			default:
				return 'private';
		}
	}

	/**
	 * Creates a bucket for the given parameters.
	 *
	 * @param string $path Stream wrapper path
	 * @param array $params A result of StreamWrapper::withPath()
	 *
	 * @return bool Returns true on success or false on failure
	 */
	private function createBucket( $path, array $params ) {
		if ( $this->getClient()->doesBucketExist( $params['Bucket'] ) ) {
			return $this->triggerError( "Bucket already exists: {$path}" );
		}

		return $this->boolCall( function () use ( $params, $path ) {
			$this->getClient()->createBucket( $params );
			$this->clearCacheKey( $path );

			return true;
		} );
	}

	/**
	 * Creates a pseudo-folder by creating an empty "/" suffixed key
	 *
	 * @param string $path Stream wrapper path
	 * @param array $params A result of StreamWrapper::withPath()
	 *
	 * @return bool
	 */
	private function createSubfolder( $path, array $params ) {
		// Ensure the path ends in "/" and the body is empty.
		$params['Key']  = rtrim( $params['Key'], '/' ) . '/';
		$params['Body'] = '';

		// Fail if this pseudo directory key already exists
		if ( $this->getClient()->doesObjectExist(
			$params['Bucket'],
			$params['Key'] )
		) {
			return $this->triggerError( "Subfolder already exists: {$path}" );
		}

		return $this->boolCall( function () use ( $params, $path ) {
			$this->getClient()->putObject( $params );
			$this->clearCacheKey( $path );

			return true;
		} );
	}

	public function rmdir( $path, $options ) {
		$this->initProtocol( $path );
		$this->clearCacheKey( $path );
		$params = $this->withPath( $path );
		$client = $this->getClient();

		if ( ! $params['Bucket'] ) {
			return $this->triggerError( 'You must specify a bucket' );
		}

		return $this->boolCall( function () use ( $params, $path, $client ) {
			if ( ! $params['Key'] ) {
				$client->deleteBucket( [ 'Bucket' => $params['Bucket'] ] );

				return true;
			}

			return $this->deleteSubfolder( $path, $params );
		} );
	}

	/**
	 * Deletes a nested subfolder if it is empty.
	 *
	 * @param string $path Path that is being deleted (e.g., 's3://a/b/c')
	 * @param array $params A result of StreamWrapper::withPath()
	 *
	 * @return bool
	 */
	private function deleteSubfolder( $path, $params ) {
		// Use a key that adds a trailing slash if needed.
		$prefix = rtrim( $params['Key'], '/' ) . '/';
		$result = $this->getClient()->listObjects( [
			'Bucket'  => $params['Bucket'],
			'Prefix'  => $prefix,
			'MaxKeys' => 1
		] );

		// Check if the bucket contains keys other than the placeholder
		if ( $contents = $result['Contents'] ) {
			return ( count( $contents ) > 1 || $contents[0]['Key'] != $prefix )
				? $this->triggerError( 'Subfolder is not empty' )
				: $this->unlink( rtrim( $path, '/' ) . '/' );
		}

		return $result['CommonPrefixes']
			? $this->triggerError( 'Subfolder contains nested folders' )
			: true;
	}

	public function unlink( $path ) {
		$this->initProtocol( $path );

		return $this->boolCall( function () use ( $path ) {
			$this->clearCacheKey( $path );
			$this->getClient()->deleteObject( $this->withPath( $path ) );

			return true;
		} );
	}

	/**
	 * Close the directory listing handles
	 *
	 * @return bool true on success
	 */
	public function dir_closedir() {
		$this->objectIterator = null;
		gc_collect_cycles();

		return true;
	}

	/**
	 * This method is called in response to rewinddir()
	 *
	 * @return boolean true on success
	 */
	public function dir_rewinddir() {
		return $this->boolCall( function () {
			$this->objectIterator = null;
			$this->dir_opendir( $this->openedPath, null );

			return true;
		} );
	}

	/**
	 * Support for opendir().
	 *
	 * The opendir() method of the Amazon S3 stream wrapper supports a stream
	 * context option of "listFilter". listFilter must be a callable that
	 * accepts an associative array of object data and returns true if the
	 * object should be yielded when iterating the keys in a bucket.
	 *
	 * @param string $path The path to the directory
	 *                        (e.g. "s3://dir[</prefix>]")
	 * @param string $options Unused option variable
	 *
	 * @return bool true on success
	 * @see http://www.php.net/manual/en/function.opendir.php
	 */
	public function dir_opendir( $path, $options ) {
		$this->initProtocol( $path );
		$this->openedPath = $path;
		$params           = $this->withPath( $path );
		$delimiter        = $this->getOption( 'delimiter' );
		/** @var callable $filterFn */
		$filterFn           = $this->getOption( 'listFilter' );
		$op                 = [ 'Bucket' => $params['Bucket'] ];
		$this->openedBucket = $params['Bucket'];

		if ( $delimiter === null ) {
			$delimiter = '/';
		}

		if ( $delimiter ) {
			$op['Delimiter'] = $delimiter;
		}

		if ( $params['Key'] ) {
			$params['Key'] = rtrim( $params['Key'], $delimiter ) . $delimiter;
			$op['Prefix']  = $params['Key'];
		}

		$this->openedBucketPrefix = $params['Key'];

		// Filter our "/" keys added by the console as directories, and ensure
		// that if a filter function is provided that it passes the filter.
		$this->objectIterator = flatmap(
			$this->getClient()->getPaginator( 'ListObjects', $op ),
			function ( Result $result ) use ( $filterFn ) {
				$contentsAndPrefixes = $result->search( '[Contents[], CommonPrefixes[]][]' );

				// Filter out dir place holder keys and use the filter fn.
				return array_filter(
					$contentsAndPrefixes,
					function ( $key ) use ( $filterFn ) {
						return ( ! $filterFn || call_user_func( $filterFn, $key ) )
						       && ( ! isset( $key['Key'] ) || substr( $key['Key'], - 1, 1 ) !== '/' );
					}
				);
			}
		);

		return true;
	}

	/**
	 * This method is called in response to readdir()
	 *
	 * @return string Should return a string representing the next filename, or
	 *                false if there is no next file.
	 * @link http://www.php.net/manual/en/function.readdir.php
	 */
	public function dir_readdir() {
		// Skip empty result keys
		if ( ! $this->objectIterator->valid() ) {
			return false;
		}

		// First we need to create a cache key. This key is the full path to
		// then object in s3: protocol://bucket/key.
		// Next we need to create a result value. The result value is the
		// current value of the iterator without the opened bucket prefix to
		// emulate how readdir() works on directories.
		// The cache key and result value will depend on if this is a prefix
		// or a key.
		$cur = $this->objectIterator->current();
		if ( isset( $cur['Prefix'] ) ) {
			// Include "directories". Be sure to strip a trailing "/"
			// on prefixes.
			$result = rtrim( $cur['Prefix'], '/' );
			$key    = $this->formatKey( $result );
			$stat   = $this->formatUrlStat( $key );
		} else {
			$result = $cur['Key'];
			$key    = $this->formatKey( $cur['Key'] );
			$stat   = $this->formatUrlStat( $cur );
		}

		// Cache the object data for quick url_stat lookups used with
		// RecursiveDirectoryIterator.
		$this->getCacheStorage()->set( $key, $stat );
		$this->objectIterator->next();

		// Remove the prefix from the result to emulate other stream wrappers.
		return $this->openedBucketPrefix
			? substr( $result, strlen( $this->openedBucketPrefix ) )
			: $result;
	}

	private function formatKey( $key ) {
		$protocol = explode( '://', $this->openedPath )[0];

		return "{$protocol}://{$this->openedBucket}/{$key}";
	}

	/**
	 * Called in response to rename() to rename a file or directory. Currently
	 * only supports renaming objects.
	 *
	 * @param string $path_from the path to the file to rename
	 * @param string $path_to the new path to the file
	 *
	 * @return bool true if file was successfully renamed
	 * @link http://www.php.net/manual/en/function.rename.php
	 */
	public function rename( $path_from, $path_to ) {
		// PHP will not allow rename across wrapper types, so we can safely
		// assume $path_from and $path_to have the same protocol
		$this->initProtocol( $path_from );
		$partsFrom = $this->withPath( $path_from );
		$partsTo   = $this->withPath( $path_to );
		$this->clearCacheKey( $path_from );
		$this->clearCacheKey( $path_to );

		if ( ! $partsFrom['Key'] || ! $partsTo['Key'] ) {
			return $this->triggerError( 'The Amazon S3 stream wrapper only '
			                            . 'supports copying objects' );
		}

		return $this->boolCall( function () use ( $partsFrom, $partsTo ) {
			$options = $this->getOptions( true );
			// Copy the object and allow overriding default parameters if
			// desired, but by default copy metadata
			$this->getClient()->copy(
				$partsFrom['Bucket'],
				$partsFrom['Key'],
				$partsTo['Bucket'],
				$partsTo['Key'],
				isset( $options['acl'] ) ? $options['acl'] : 'private',
				$options
			);
			// Delete the original object
			$this->getClient()->deleteObject( [
				                                  'Bucket' => $partsFrom['Bucket'],
				                                  'Key'    => $partsFrom['Key']
			                                  ] + $options );

			return true;
		} );
	}

	public function stream_cast( $cast_as ) {
		return false;
	}
}
