<?php
/**
 * SabreDAV DAV client
 *
 * This client wraps around Curl to provide a convenient API to a WebDAV
 * server.
 *
 * NOTE: This class is experimental, it's api will likely change in the future.
 *
 * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
 * @author    Evert Pot (http://evertpot.com/)
 * @license   http://code.google.com/p/sabredav/wiki/License Modified BSD License
 *
 * Modified by Akeeba Ltd for use in Akeeba Backup in accordance with the aforementioned
 * license of the original source code. Original source code can be found at https://github.com/fruux/sabre-dav.
 */

namespace Akeeba\Engine\Postproc\Connector;

// Protection against direct access
defined('AKEEBAENGINE') or die();

use Akeeba\Engine\Postproc\Connector\Davclient\Xml;
use Psr\Log\LogLevel;
use Akeeba\Engine\Factory;

class Davclient
{

	/**
	 * The propertyMap is a key-value array.
	 *
	 * If you use the propertyMap, any {DAV:}multistatus responses with the
	 * proeprties listed in this array, will automatically be mapped to a
	 * respective class.
	 *
	 * The {DAV:}resourcetype property is automatically added. This maps to
	 * Sabre\DAV\Property\ResourceType
	 *
	 * @var array
	 */
	public $propertyMap = array();

	protected $headers = '';
	protected $baseUri;
	protected $userName;
	protected $password;
	protected $proxy;
	protected $trustedCertificates;

	/**
	 * Basic authentication
	 */
	const AUTH_BASIC = 1;

	/**
	 * Digest authentication
	 */
	const AUTH_DIGEST = 2;

	/**
	 * The authentication type we're using.
	 *
	 * This is a bitmask of AUTH_BASIC and AUTH_DIGEST.
	 *
	 * If DIGEST is used, the client makes 1 extra request per request, to get
	 * the authentication tokens.
	 *
	 * @var int
	 */
	protected $authType;

	/**
	 * Indicates if SSL verification is enabled or not.
	 *
	 * @var boolean
	 */
	protected $verifyPeer;

	/**
	 * Constructor
	 *
	 * Settings are provided through the 'settings' argument. The following
	 * settings are supported:
	 *
	 *   * baseUri
	 *   * userName (optional)
	 *   * password (optional)
	 *   * proxy (optional)
	 *
	 * @param array $settings
	 *
	 * @throws \InvalidArgumentException
	 */
	public function __construct(array $settings)
	{

		if (!isset($settings['baseUri']))
		{
			throw new \InvalidArgumentException('A baseUri must be provided');
		}

		$validSettings = array(
			'baseUri',
			'userName',
			'password',
			'proxy',
		);

		foreach ($validSettings as $validSetting)
		{
			if (isset($settings[$validSetting]))
			{
				$this->$validSetting = $settings[$validSetting];
			}
		}

		if (isset($settings['authType']))
		{
			$this->authType = $settings['authType'];
		}
		else
		{
			$this->authType = self::AUTH_BASIC | self::AUTH_DIGEST;
		}

		// We just need this class to unserialize a node collection. However in our case we really don't need it
		// since we are just checking if exists or not, we don't have to iterate on it, so we can use a (very)
		// simplified method just to avoid PHP warnings
		$this->propertyMap['{DAV:}resourcetype'] = '\\Akeeba\\Engine\\Postproc\\Connector\\Davclient\\Xml';
	}

	/**
	 * Add trusted root certificates to the webdav client.
	 *
	 * The parameter certificates should be a absolute path to a file
	 * which contains all trusted certificates
	 *
	 * @param string $certificates
	 */
	public function addTrustedCertificates($certificates)
	{
		$this->trustedCertificates = $certificates;
	}

	/**
	 * Enables/disables SSL peer verification
	 *
	 * @param boolean $value
	 */
	public function setVerifyPeer($value)
	{
		$this->verifyPeer = $value;
	}

	/**
	 * Does a PROPFIND request
	 *
	 * The list of requested properties must be specified as an array, in clark
	 * notation.
	 *
	 * The returned array will contain a list of filenames as keys, and
	 * properties as values.
	 *
	 * The properties array will contain the list of properties. Only properties
	 * that are actually returned from the server (without error) will be
	 * returned, anything else is discarded.
	 *
	 * Depth should be either 0 or 1. A depth of 1 will cause a request to be
	 * made to the server to also return all child resources.
	 *
	 * @param string $url
	 * @param array  $properties
	 * @param int    $depth
	 *
	 * @return array
	 */
	public function propFind($url, array $properties, $depth = 0)
	{

		$body = '<?xml version="1.0"?>' . "\n";
		$body .= '<d:propfind xmlns:d="DAV:">' . "\n";
		$body .= '  <d:prop>' . "\n";

		foreach ($properties as $property)
		{
			list($namespace, $elementName) = Xml::parseClarkNotation($property);

			if ($namespace === 'DAV:')
			{
				$body .= '    <d:' . $elementName . ' />' . "\n";
			}
			else
			{
				$body .= "    <x:" . $elementName . " xmlns:x=\"" . $namespace . "\"/>\n";
			}
		}

		$body .= '  </d:prop>' . "\n";
		$body .= '</d:propfind>';

		$response = $this->request('PROPFIND', $url, $body, array(
			'Depth'        => $depth,
			'Content-Type' => 'application/xml'
		));

		$result = $this->parseMultiStatus($response['body']);

		// If depth was 0, we only return the top item
		if ($depth === 0)
		{
			reset($result);
			$result = current($result);

			return isset($result[200]) ? $result[200] : array();
		}

		$newResult = array();

		foreach ($result as $href => $statusList)
		{
			$newResult[$href] = isset($statusList[200]) ? $statusList[200] : array();
		}

		return $newResult;
	}

	/**
	 * Updates a list of properties on the server
	 *
	 * The list of properties must have clark-notation properties for the keys,
	 * and the actual (string) value for the value. If the value is null, an
	 * attempt is made to delete the property.
	 *
	 * @todo Must be building the request using the DOM, and does not yet
	 *       support complex properties.
	 *
	 * @param string $url
	 * @param array  $properties
	 *
	 * @return void
	 */
	public function propPatch($url, array $properties)
	{
		$body = '<?xml version="1.0"?>' . "\n";
		$body .= '<d:propertyupdate xmlns:d="DAV:">' . "\n";

		foreach ($properties as $propName => $propValue)
		{
			list($namespace, $elementName) = Xml::parseClarkNotation($propName);

			if ($propValue === null)
			{
				$body .= "<d:remove><d:prop>\n";

				if ($namespace === 'DAV:')
				{
					$body .= '    <d:' . $elementName . ' />' . "\n";
				}
				else
				{
					$body .= "    <x:" . $elementName . " xmlns:x=\"" . $namespace . "\"/>\n";
				}

				$body .= "</d:prop></d:remove>\n";
			}
			else
			{
				$body .= "<d:set><d:prop>\n";

				if ($namespace === 'DAV:')
				{
					$body .= '    <d:' . $elementName . '>';
				}
				else
				{
					$body .= "    <x:" . $elementName . " xmlns:x=\"" . $namespace . "\">";
				}

				// I know
				$body .= htmlspecialchars($propValue, ENT_NOQUOTES, 'UTF-8');

				if ($namespace === 'DAV:')
				{
					$body .= '</d:' . $elementName . '>' . "\n";
				}
				else
				{
					$body .= "</x:" . $elementName . ">\n";
				}

				$body .= "</d:prop></d:set>\n";
			}
		}

		$body .= '</d:propertyupdate>';

		$this->request('PROPPATCH', $url, $body, array(
			'Content-Type' => 'application/xml'
		));
	}

	/**
	 * Performs an HTTP options request
	 *
	 * This method returns all the features from the 'DAV:' header as an array.
	 * If there was no DAV header, or no contents this method will return an
	 * empty array.
	 *
	 * @return array
	 */
	public function options()
	{
		$result = $this->request('OPTIONS');

		if (!isset($result['headers']['dav']))
		{
			return array();
		}

		$features = explode(',', $result['headers']['dav']);

		foreach ($features as &$v)
		{
			$v = trim($v);
		}

		return $features;
	}

	/**
	 * Performs an actual HTTP request, and returns the result.
	 *
	 * If the specified url is relative, it will be expanded based on the base
	 * url.
	 *
	 * The returned array contains 3 keys:
	 *   * body - the response body
	 *   * httpCode - a HTTP code (200, 404, etc)
	 *   * headers - a list of response http headers. The header names have
	 *     been lowercased.
	 *
	 * @param string $method
	 * @param string $url
	 * @param string $body
	 * @param array  $headers
	 *
	 * @throws \Exception
	 *
	 * @return array
	 */
	public function request($method, $url = '', $body = null, $headers = array())
	{
		$this->headers = '';

		Factory::getLog()->log(LogLevel::DEBUG, "Remote relative WebDav URL: " . $url);

		$url = $this->getAbsoluteUrl($url);

		Factory::getLog()->log(LogLevel::DEBUG, "Absolute WebDav URL: " . $url);

		$curlSettings = array(
			CURLOPT_RETURNTRANSFER => true,
			// I can't get the headers in the response, since it would corrupt my downloads
			CURLOPT_HEADER         => false,
			CURLOPT_HEADERFUNCTION => array($this, 'storeHeaders'),
			CURLOPT_POSTFIELDS     => $body,
			// Automatically follow redirects
			CURLOPT_FOLLOWLOCATION => true,
			CURLOPT_MAXREDIRS      => 5,
		);

		if ($this->verifyPeer !== null)
		{
			$curlSettings[CURLOPT_SSL_VERIFYPEER] = $this->verifyPeer;
		}

		if ($this->trustedCertificates)
		{
			$curlSettings[CURLOPT_CAINFO] = $this->trustedCertificates;
		}

		switch ($method)
		{
			case 'HEAD' :

				// do not read body with HEAD requests (this is necessary because cURL does not ignore the body with HEAD
				// requests when the Content-Length header is given - which in turn is perfectly valid according to HTTP
				// specs...) cURL does unfortunately return an error in this case ("transfer closed transfer closed with
				// ... bytes remaining to read") this can be circumvented by explicitly telling cURL to ignore the
				// response body
				$curlSettings[CURLOPT_NOBODY] = true;
				$curlSettings[CURLOPT_CUSTOMREQUEST] = 'HEAD';
				break;
			case 'GET':
				$curlSettings[CURLOPT_CUSTOMREQUEST] = 'GET';

				if (is_resource($body))
				{
					$curlSettings[CURLOPT_FILE] = $body;

					unset($curlSettings[CURLOPT_POSTFIELDS]);
				}

				break;
			CASE 'PUT':
				// ATTENTION!!! If you want to upload a file, you have to directly supply the file content inside the request body.
				// This is necessary because if we hit a redirect, cURL will screw up since he can't automatically rewind
				// a file pointer resource, but he can do that with a string.
				$curlSettings[CURLOPT_CUSTOMREQUEST] = $method;
				break;
			default:
				$curlSettings[CURLOPT_CUSTOMREQUEST] = $method;
				break;
		}

		// Adding HTTP headers
		$nHeaders = array();

		foreach ($headers as $key => $value)
		{
			$nHeaders[] = $key . ': ' . $value;
		}

		$curlSettings[CURLOPT_HTTPHEADER] = $nHeaders;

		if ($this->proxy)
		{
			$curlSettings[CURLOPT_PROXY] = $this->proxy;
		}

		if ($this->userName && $this->authType)
		{
			$curlType = 0;

			if ($this->authType & self::AUTH_BASIC)
			{
				$curlType |= CURLAUTH_BASIC;
			}

			if ($this->authType & self::AUTH_DIGEST)
			{
				$curlType |= CURLAUTH_DIGEST;
			}

			$curlSettings[CURLOPT_HTTPAUTH] = $curlType;
			$curlSettings[CURLOPT_USERPWD] = $this->userName . ':' . $this->password;
		}

		list($response, $curlInfo, $curlErrNo, $curlError) = $this->curlRequest($url, $curlSettings);

		$this->parseHeaders();

		$response = array(
			'body'       => $response,
			'statusCode' => $curlInfo['http_code'],
			'headers'    => $this->headers
		);

		if ($curlErrNo)
		{
			throw new \Exception('[CURL] Error while making request: ' . $curlError . ' (error code: ' . $curlErrNo . ')');
		}

		if ($response['statusCode'] >= 400)
		{
			switch ($response['statusCode'])
			{
				case 400 :
					throw new \Exception('Bad request', 400);
				case 401 :
					throw new \Exception('Not authenticated', 401);
				case 402 :
					throw new \Exception('Payment required', 402);
				case 403 :
					throw new \Exception('Forbidden', 403);
				case 404:
					throw new \Exception('Resource not found.', 404);
				case 405 :
					throw new \Exception('Method not allowed', 405);
				case 409 :
					throw new \Exception('Conflict', 409);
				case 412 :
					throw new \Exception('Precondition failed', 412);
				case 413 :
					throw new \Exception('Request Entity Too Large', 413);
				case 416 :
					throw new \Exception('Requested Range Not Satisfiable', 416);
				case 500 :
					throw new \Exception('Internal server error', 500);
				case 501 :
					throw new \Exception('Not Implemented', 501);
				case 507 :
					throw new \Exception('Insufficient storage', 507);
				default:
					throw new \Exception('HTTP error response. (errorcode ' . $response['statusCode'] . ')');
			}
		}

		return $response;
	}

	/**
	 * Callback function used to collect all the headers.
	 * Headers are important since it's the only way to detected
	 * failures, but we can't add them to the response body since this would corrupt downloaded files (and doing a
	 * substr on a potentially 100Mb file is not efficient)
	 *
	 * @param   resource $ch         Pointer to a cURL resource
	 * @param   string   $ch_headers Header
	 *
	 * @return  int         Length of the header
	 */
	protected function storeHeaders($ch, $ch_headers)
	{
		$this->headers .= $ch_headers;

		return strlen($ch_headers);
	}

	/**
	 * Parses the stored headers and updates the internal member with the last one for error detection
	 *
	 * @return void
	 */
	protected function parseHeaders()
	{
		// In the case of 100 Continue, or redirects we'll have multiple lists
		// of headers for each separate HTTP response. We can easily split this
		// because they are separated by \r\n\r\n
		$headerBlob = explode("\r\n\r\n", trim($this->headers, "\r\n"));

		// We only care about the last set of headers
		$headerBlob = $headerBlob[count($headerBlob) - 1];

		// Splitting headers
		$headerBlob = explode("\r\n", $headerBlob);

		$headers = array();
		foreach ($headerBlob as $header)
		{
			$parts = explode(':', $header, 2);

			if (count($parts) == 2)
			{
				$headers[strtolower(trim($parts[0]))] = trim($parts[1]);
			}
		}

		$this->headers = $headers;
	}

	/**
	 * Wrapper for all curl functions.
	 *
	 * The only reason this was split out in a separate method, is so it
	 * becomes easier to unittest.
	 *
	 * @param   string $url
	 * @param   array  $settings
	 *
	 * @return  array
	 */
	protected function curlRequest($url, $settings)
	{

		$curl = curl_init($url);
		curl_setopt_array($curl, $settings);

		return array(
			curl_exec($curl),
			curl_getinfo($curl),
			curl_errno($curl),
			curl_error($curl)
		);
	}

	/**
	 * Returns the full url based on the given url (which may be relative). All
	 * urls are expanded based on the base url as given by the server.
	 *
	 * @param   string $url
	 *
	 * @return  string
	 */
	protected function getAbsoluteUrl($url)
	{
		// If the url starts with http:// or https://, the url is already absolute.
		if (preg_match('/^http(s?):\/\//', $url))
		{
			return $url;
		}

		$parts = parse_url($this->baseUri);

		return $parts['scheme'] . '://' . $parts['host'] . (isset($parts['port']) ? ':' . $parts['port'] : '') . $parts['path'] . '/' . ltrim($url, '/');
	}

	/**
	 * Parses a WebDAV multistatus response body
	 *
	 * This method returns an array with the following structure
	 *
	 * array(
	 *   'url/to/resource' => array(
	 *     '200' => array(
	 *        '{DAV:}property1' => 'value1',
	 *        '{DAV:}property2' => 'value2',
	 *     ),
	 *     '404' => array(
	 *        '{DAV:}property1' => null,
	 *        '{DAV:}property2' => null,
	 *     ),
	 *   )
	 *   'url/to/resource2' => array(
	 *      .. etc ..
	 *   )
	 * )
	 *
	 *
	 * @param   string $body xml body
	 *
	 * @throws  \InvalidArgumentException
	 *
	 * @return  array
	 */
	public function parseMultiStatus($body)
	{

		$body = Xml::convertDAVNamespace($body);

		$responseXML = simplexml_load_string($body, null, LIBXML_NOBLANKS | LIBXML_NOCDATA);

		if ($responseXML === false)
		{
			throw new \InvalidArgumentException('The passed data is not valid XML');
		}

		$responseXML->registerXPathNamespace('d', 'urn:DAV');

		$propResult = array();

		foreach ($responseXML->xpath('d:response') as $response)
		{
			$response->registerXPathNamespace('d', 'urn:DAV');
			$href = $response->xpath('d:href');
			$href = (string)$href[0];

			$properties = array();

			foreach ($response->xpath('d:propstat') as $propStat)
			{

				$propStat->registerXPathNamespace('d', 'urn:DAV');
				$status = $propStat->xpath('d:status');
				list($httpVersion, $statusCode, $message) = explode(' ', (string)$status[0], 3);

				// Only using the propertymap for results with status 200.
				$propertyMap = $statusCode === '200' ? $this->propertyMap : array();

				$properties[$statusCode] = Xml::parseProperties(dom_import_simplexml($propStat), $propertyMap);
			}

			$propResult[$href] = $properties;
		}

		return $propResult;
	}
}
