<?php
/**
 * Akeeba Engine
 *
 * @package   akeebaengine
 * @copyright Copyright (c)2006-2022 Nicholas K. Dionysopoulos / Akeeba Ltd
 * @license   GNU General Public License version 3, or later
 */

namespace Akeeba\Engine\Util\Transfer;

defined('AKEEBAENGINE') || die();

use Akeeba\Engine\Postproc\ProxyAware;
use RuntimeException;

/**
 * FTP transfer object, using cURL as the transport backend
 */
class FtpCurl extends Ftp implements TransferInterface
{
	use ProxyAware;

	/**
	 * Timeout for transferring data to the FTP server, default: 10 minutes
	 *
	 * @var  integer
	 */
	protected $timeout = 600;

	/**
	 * Should I ignore the IP returned by the server during Passive mode transfers?
	 *
	 * @var   bool
	 *
	 * @see   http://www.elitehosts.com/blog/php-ftp-passive-ftp-server-behind-nat-nightmare/
	 */
	private $skipPassiveIP = true;

	/**
	 * Should we enable verbose output to STDOUT? Useful for debugging.
	 *
	 * @var   bool
	 */
	private $verbose = false;

	/**
	 * Public constructor
	 *
	 * @param   array  $options  Configuration options
	 *
	 * @throws  RuntimeException
	 */
	public function __construct(array $options)
	{
		parent::__construct($options);

		if (isset($options['passive_fix']))
		{
			$this->skipPassiveIP = $options['passive_fix'] ? true : false;
		}

		if (isset($options['verbose']))
		{
			$this->verbose = $options['verbose'] ? true : false;
		}
	}

	/**
	 * Save all parameters on serialization except the connection resource
	 *
	 * @return  array
	 */
	public function __sleep()
	{
		return [
			'host',
			'port',
			'username',
			'password',
			'directory',
			'ssl',
			'passive',
			'timeout',
			'skipPassiveIP',
			'verbose',
		];
	}

	/**
	 * Test the connection to the FTP server and whether the initial directory is correct. This is done by attempting to
	 * list the contents of the initial directory. The listing is not parsed (we don't really care!) and we do NOT check
	 * if we can upload files to that remote folder.
	 *
	 * @throws  RuntimeException
	 */
	public function connect()
	{
		$ch = $this->getCurlHandle($this->directory . '/');
		curl_setopt($ch, CURLOPT_HEADER, 1);
		curl_setopt($ch, CURLOPT_NOBODY, 1);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

		curl_exec($ch);

		$errNo = curl_errno($ch);
		$error = curl_error($ch);
		curl_close($ch);

		if ($errNo)
		{
			throw new RuntimeException("cURL Error $errNo connecting to remote FTP server: $error", 500);
		}
	}

	/**
	 * Write the contents into the file
	 *
	 * @param   string  $fileName  The full path to the file
	 * @param   string  $contents  The contents to write to the file
	 *
	 * @return  boolean  True on success
	 */
	public function write($fileName, $contents)
	{
		// Make sure the buffer:// wrapper is loaded
		class_exists('\\Akeeba\\Engine\\Util\\Buffer', true);

		$handle = fopen('buffer://akeeba_engine_transfer_ftp_curl', 'r+');
		fwrite($handle, $contents);

		// Note: don't manually close the file pointer, it's closed automatically by uploadFromHandle
		try
		{
			$this->uploadFromHandle($fileName, $handle);
		}
		catch (RuntimeException $e)
		{
			return false;
		}

		return true;
	}

	/**
	 * Uploads a local file to the remote storage
	 *
	 * @param   string  $localFilename   The full path to the local file
	 * @param   string  $remoteFilename  The full path to the remote file
	 * @param   bool    $useExceptions   Throw an exception instead of returning "false" on connection error.
	 *
	 * @return  boolean  True on success
	 */
	public function upload($localFilename, $remoteFilename, $useExceptions = true)
	{
		$fp = @fopen($localFilename, 'r');

		if ($fp === false)
		{
			throw new RuntimeException("Unreadable local file $localFilename");
		}

		// Note: don't manually close the file pointer, it's closed automatically by uploadFromHandle
		try
		{
			$this->uploadFromHandle($remoteFilename, $fp);
		}
		catch (RuntimeException $e)
		{
			if ($useExceptions)
			{
				throw $e;
			}

			return false;
		}

		return true;
	}

	/**
	 * Read the contents of a remote file into a string
	 *
	 * @param   string  $fileName  The full path to the remote file
	 *
	 * @return  string  The contents of the remote file
	 */
	public function read($fileName)
	{
		try
		{
			return $this->downloadToString($fileName);
		}
		catch (RuntimeException $e)
		{
			throw new RuntimeException("Can not download remote file $fileName", 500, $e);
		}
	}

	/**
	 * Download a remote file into a local file
	 *
	 * @param   string  $remoteFilename  The remote file path to download from
	 * @param   string  $localFilename   The local file path to download to
	 * @param   bool    $useExceptions   Throw an exception instead of returning "false" on connection error.
	 *
	 * @return  boolean  True on success
	 */
	public function download($remoteFilename, $localFilename, $useExceptions = true)
	{
		$fp = @fopen($localFilename, 'w');

		if ($fp === false)
		{
			if ($useExceptions)
			{
				throw new RuntimeException(sprintf('Download from FTP failed. Can not open local file %s for writing.', $localFilename));
			}

			return false;
		}

		// Note: don't manually close the file pointer, it's closed automatically by downloadToHandle
		try
		{
			$this->downloadToHandle($remoteFilename, $fp);
		}
		catch (RuntimeException $e)
		{
			if ($useExceptions)
			{
				throw $e;
			}

			return false;
		}

		return true;
	}

	/**
	 * Delete a file (remove it from the disk)
	 *
	 * @param   string  $fileName  The full path to the file
	 *
	 * @return  boolean  True on success
	 */
	public function delete($fileName)
	{
		$commands = [
			'DELE ' . $this->getPath($fileName),
		];

		try
		{
			$this->executeServerCommands($commands);
		}
		catch (RuntimeException $e)
		{
			return false;
		}

		return true;
	}

	/**
	 * Create a copy of the file. Actually, we have to read it in memory and upload it again.
	 *
	 * @param   string  $from  The full path of the file to copy from
	 * @param   string  $to    The full path of the file that will hold the copy
	 *
	 * @return  boolean  True on success
	 */
	public function copy($from, $to)
	{
		// Make sure the buffer:// wrapper is loaded
		class_exists('\\Akeeba\\Engine\\Util\\Buffer', true);

		$handle = fopen('buffer://akeeba_engine_transfer_ftp', 'r+');

		try
		{
			$this->downloadToHandle($from, $handle, false);
			$this->uploadFromHandle($to, $handle);
		}
		catch (RuntimeException $e)
		{
			return false;
		}

		return true;
	}

	/**
	 * Move or rename a file
	 *
	 * @param   string  $from  The full path of the file to move
	 * @param   string  $to    The full path of the target file
	 *
	 * @return  boolean  True on success
	 */
	public function move($from, $to)
	{
		$from = $this->getPath($from);
		$to   = $this->getPath($to);

		$commands = [
			'RNFR /' . $from,
			'RNTO /' . $to,
		];

		try
		{
			$this->executeServerCommands($commands);
		}
		catch (RuntimeException $e)
		{
			return false;
		}

		return true;
	}

	/**
	 * Change the permissions of a file
	 *
	 * @param   string   $fileName     The full path of the file whose permissions will change
	 * @param   integer  $permissions  The new permissions, e.g. 0644 (remember the leading zero in octal numbers!)
	 *
	 * @return  boolean  True on success
	 */
	public function chmod($fileName, $permissions)
	{
		// Make sure permissions are in an octal string representation
		if (!is_string($permissions))
		{
			$permissions = decoct($permissions);
		}

		$commands = [
			'SITE CHMOD ' . $permissions . ' /' . $this->getPath($fileName),
		];

		try
		{
			$this->executeServerCommands($commands);
		}
		catch (RuntimeException $e)
		{
			return false;
		}

		return true;
	}

	/**
	 * Create a directory if it doesn't exist. The operation is implicitly recursive, i.e. it will create all
	 * intermediate directories if they do not already exist.
	 *
	 * @param   string   $dirName      The full path of the directory to create
	 * @param   integer  $permissions  The permissions of the created directory
	 *
	 * @return  boolean  True on success
	 */
	public function mkdir($dirName, $permissions = 0755)
	{
		$targetDir = rtrim($dirName, '/');

		$directories = explode('/', $targetDir);

		$remoteDir = '';

		foreach ($directories as $dir)
		{
			if (!$dir)
			{
				continue;
			}

			$remoteDir .= '/' . $dir;

			// Continue if the folder already exists. Otherwise I'll get a an error even if everything is fine
			if ($this->isDir($remoteDir))
			{
				continue;
			}

			$commands = [
				'MKD ' . $remoteDir,
			];

			try
			{
				$this->executeServerCommands($commands);
			}
			catch (RuntimeException $e)
			{
				return false;
			}
		}

		$this->chmod($dirName, $permissions);

		return true;
	}

	/**
	 * Checks if the given directory exists
	 *
	 * @param   string  $path  The full path of the remote directory to check
	 *
	 * @return  boolean  True if the directory exists
	 */
	public function isDir($path)
	{
		$ch = $this->getCurlHandle($path . '/');
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

		curl_exec($ch);

		$errNo = curl_errno($ch);
		curl_close($ch);

		if ($errNo)
		{
			return false;
		}

		return true;
	}

	/**
	 * Get the current working directory. NOT IMPLEMENTED.
	 *
	 * @return  string
	 */
	public function cwd()
	{
		$commands = [
			'PWD',
		];

		try
		{
			$result = $this->executeServerCommands($commands, '');
		}
		catch (RuntimeException $e)
		{
			return '/';
		}

		return $result;
	}

	/**
	 * Lists the subdirectories inside an FTP directory
	 *
	 * @param   null|string  $dir  The directory to scan. Skip to use the current directory.
	 *
	 * @return  array|bool   A list of folders, or false if we could not get a listing
	 *
	 * @throws  RuntimeException  When the server is incompatible with our FTP folder scanner
	 */
	public function listFolders($dir = null)
	{
		if (empty($dir))
		{
			$dir = $this->directory;
		}

		$dir = rtrim($dir, '/');

		$ch = $this->getCurlHandle($dir . '/');
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

		$list = curl_exec($ch);

		$errNo = curl_errno($ch);
		$error = curl_error($ch);
		curl_close($ch);

		if ($errNo)
		{
			throw new RuntimeException(sprintf("cURL Error $errNo ($error) while listing contents of directory \"%s\" – make sure the folder exists and that you have adequate permissions to it", $dir), 500);
		}

		if (empty($list))
		{
			throw new RuntimeException("Sorry, your FTP server doesn't support our FTP directory browser.");
		}

		$folders = [];

		// Convert the directory listing into an array of lines without *NIX/Windows/Mac line ending characters
		$list = explode("\n", $list);
		$list = array_map('rtrim', $list);

		foreach ($list as $v)
		{
			$vInfo = preg_split("/[\s]+/", $v, 9);

			if ($vInfo[0] !== "total")
			{
				$perms = $vInfo[0];

				if (substr($perms, 0, 1) == 'd')
				{
					$folders[] = $vInfo[8];
				}
			}
		}

		asort($folders);

		return $folders;
	}

	/**
	 * Is the verbose debug option set?
	 *
	 * @return  boolean
	 */
	public function isVerbose()
	{
		return $this->verbose;
	}

	/**
	 * Set the verbose debug option
	 *
	 * @param   boolean  $verbose
	 *
	 * @return  void
	 */
	public function setVerbose($verbose)
	{
		$this->verbose = $verbose;
	}

	/**
	 * Returns the absolute remote path from a path relative to the initial directory configured when creating the
	 * transfer object.
	 *
	 * @param   string  $fileName  The relative path of a file or directory
	 *
	 * @return  string  The absolute path for use by the transfer object
	 */
	public function getPath($fileName)
	{
		$fileName = ltrim(str_replace('\\', '/', $fileName), '/');

		$isInitialDirectory = $fileName === $this->directory;
		$startsWithInitialDirectory = (strpos($fileName, rtrim($this->directory, '/') . '/') === 0)
			|| (strpos($fileName, trim($this->directory, '/') . '/') === 0);

		// Relative file? Add the initial directory
		if (!$isInitialDirectory && !$startsWithInitialDirectory)
		{
			$fileName = '/' . trim($this->directory, '/') .
				(empty($fileName) ? '' : '/') . $fileName;
		}

		return '/' . ltrim($fileName, '/');
	}

	/**
	 * Returns a cURL resource handler for the remote FTP server
	 *
	 * @param   string  $remoteFile  Optional. The remote file / folder on the FTP server you'll be manipulating with cURL.
	 *
	 * @return  resource
	 */
	protected function getCurlHandle($remoteFile = '')
	{
		/**
		 * Get the FTP URI
		 *
		 * VERY IMPORTANT! WE NEED THE DOUBLE SLASH AFTER THE HOST NAME since we are giving an absolute path.
		 * @see https://technicalsanctuary.wordpress.com/2012/11/01/curl-curl-9-server-denied-you-to-change-to-the-given-directory/
		 */
		$ftpUri = 'ftp://' . $this->host . '//';

		$isInitialDirectory = $remoteFile === $this->directory;
		$startsWithInitialDirectory = (strpos($remoteFile, rtrim($this->directory, '/') . '/') === 0)
			|| (strpos($remoteFile, trim($this->directory, '/') . '/') === 0);

		// Relative file? Add the initial directory
		if (!$isInitialDirectory && !$startsWithInitialDirectory)
		{
			$ftpUri .= '/' . trim($this->directory, '/');
		}

		if (!empty($remoteFile) && substr($ftpUri, -2) !== '//')
		{
			$ftpUri .= '/';
		}

		// Add a remote file if necessary. The filename must be URL encoded since we're creating a URI.
		if (!empty($remoteFile))
		{
			$suffix = '';

			if (substr($remoteFile, -7, 6) == ';type=')
			{
				$suffix     = substr($remoteFile, -7);
				$remoteFile = substr($remoteFile, 0, -7);
			}

			$dirname = dirname($remoteFile);

			// Windows messing up dirname('/'). KILL ME.
			if ($dirname == '\\')
			{
				$dirname = '';
			}

			$dirname  = trim($dirname, '/');
			$basename = basename($remoteFile);

			if ((substr($remoteFile, -1) == '/') && !empty($basename))
			{
				$suffix = '/' . $suffix;
			}

			$ftpUri .= '/' . $dirname . (empty($dirname) ? '' : '/') . urlencode($basename) . $suffix;
		}

		// Colons in usernames must be URL escaped
		$username = str_replace(':', '%3A', $this->username);

		$ch = curl_init();

		$this->applyProxySettingsToCurl($ch);

		curl_setopt($ch, CURLOPT_URL, $ftpUri);
		curl_setopt($ch, CURLOPT_USERPWD, $username . ":" . $this->password);
		curl_setopt($ch, CURLOPT_PORT, $this->port);
		curl_setopt($ch, CURLOPT_TIMEOUT, $this->timeout);

		// Should I enable Implict SSL?
		if ($this->ssl)
		{
			curl_setopt($ch, CURLOPT_FTP_SSL, CURLFTPSSL_ALL);
			curl_setopt($ch, CURLOPT_FTPSSLAUTH, CURLFTPAUTH_DEFAULT);

			// Most FTPS servers use self-signed certificates. That's the only way to connect to them :(
			curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
			curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
		}

		// Should I ignore the server-supplied passive mode IP address?
		if ($this->passive && $this->skipPassiveIP)
		{
			curl_setopt($ch, CURLOPT_FTP_SKIP_PASV_IP, 1);
		}

		// Should I enable active mode?
		if (!$this->passive)
		{
			/**
			 * cURL always uses passive mode for FTP transfers. Setting the CURLOPT_FTPPORT flag enables the FTP PORT
			 * command which makes the connection active. Setting it to '-'  lets the library use your system's default
			 * IP address.
			 *
			 * @see https://curl.haxx.se/libcurl/c/CURLOPT_FTPPORT.html
			 */
			curl_setopt($ch, CURLOPT_FTPPORT, '-');
		}

		// Should I enable verbose output? Useful for debugging.
		if ($this->verbose)
		{
			curl_setopt($ch, CURLOPT_VERBOSE, 1);
		}

		// Automatically create missing directories
		curl_setopt($ch, CURLOPT_FTP_CREATE_MISSING_DIRS, 1);

		return $ch;
	}

	/**
	 * Uploads a file using file contents provided through a file handle
	 *
	 * @param   string    $remoteFilename  Remote file to write contents to
	 * @param   resource  $fp              File or stream handler of the source data to upload
	 *
	 * @return  void
	 *
	 * @throws  RuntimeException
	 */
	protected function uploadFromHandle($remoteFilename, $fp)
	{
		// We need the file size. We can do that by getting the file position at EOF
		fseek($fp, 0, SEEK_END);
		$filesize = ftell($fp);
		rewind($fp);

		/**
		 * The ;type=i suffix forces Binary file transfer mode
		 *
		 * @see  https://curl.haxx.se/mail/archive-2008-05/0089.html
		 */
		$ch = $this->getCurlHandle($remoteFilename . ';type=i');
		curl_setopt($ch, CURLOPT_UPLOAD, 1);
		curl_setopt($ch, CURLOPT_INFILE, $fp);
		curl_setopt($ch, CURLOPT_INFILESIZE, $filesize);

		curl_exec($ch);

		$error_no = curl_errno($ch);
		$error    = curl_error($ch);

		curl_close($ch);
		fclose($fp);

		if ($error_no)
		{
			throw new RuntimeException($error, $error_no);
		}
	}

	/**
	 * Downloads a remote file to the provided file handle
	 *
	 * @param   string    $remoteFilename  Filename on the remote server
	 * @param   resource  $fp              File handle where the downloaded content will be written to
	 * @param   bool      $close           Optional. Should I close the file handle when I'm done? (Default: true)
	 *
	 * @return  void
	 *
	 * @throws  RuntimeException
	 */
	protected function downloadToHandle($remoteFilename, $fp, $close = true)
	{
		/**
		 * The ;type=i suffix forces Binary file transfer mode
		 *
		 * @see  https://curl.haxx.se/mail/archive-2008-05/0089.html
		 */
		$ch = $this->getCurlHandle($remoteFilename . ';type=i');

		curl_setopt($ch, CURLOPT_FILE, $fp);

		curl_exec($ch);

		$error_no = curl_errno($ch);
		$error    = curl_error($ch);

		curl_close($ch);

		if ($close)
		{
			fclose($fp);
		}

		if ($error_no)
		{
			throw new RuntimeException($error, $error_no);
		}
	}

	/**
	 * Downloads a remote file and returns it as a string
	 *
	 * @param   string  $remoteFilename  Filename on the remote server
	 *
	 * @return  string
	 *
	 * @throws  RuntimeException
	 */
	protected function downloadToString($remoteFilename)
	{
		/**
		 * The ;type=i suffix forces Binary file transfer mode
		 *
		 * @see  https://curl.haxx.se/mail/archive-2008-05/0089.html
		 */
		$ch = $this->getCurlHandle($remoteFilename . ';type=i');

		curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
		curl_setopt($ch, CURLOPT_HEADER, false);

		$ret = curl_exec($ch);

		$error_no = curl_errno($ch);
		$error    = curl_error($ch);

		curl_close($ch);

		if ($error_no)
		{
			throw new RuntimeException($error, $error_no);
		}

		return $ret;
	}

	/**
	 * Executes arbitrary FTP commands
	 *
	 * @param   string[]     $commands    An array with the FTP commands to be executed
	 * @param   string|null  $remoteFile  The remote file / folder to use in the cURL URI when executing the commands
	 *
	 * @return  string  The output of the executed commands
	 *
	 */
	protected function executeServerCommands(array $commands, ?string $remoteFile = null): string
	{
		$remoteFile = $remoteFile ?? ($this->directory . '/');

		$ch = $this->getCurlHandle($remoteFile);

		curl_setopt($ch, CURLOPT_QUOTE, $commands);
		curl_setopt($ch, CURLOPT_HEADER, 1);
		curl_setopt($ch, CURLOPT_NOBODY, 1);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

		$listing = curl_exec($ch);
		$errNo   = curl_errno($ch);
		$error   = curl_error($ch);
		curl_close($ch);

		if ($errNo)
		{
			throw new RuntimeException($error, $errNo);
		}

		return $listing;
	}
}