<?php
  /**
   * Copyright (c) 2012 Bart Visscher <bartv@thisnet.nl>
   * This file is licensed under the Affero General Public License version 3 or
   * later.
   * See the COPYING-README file.
   */
  
  
  class OC_FileChunking {
  	protected $info;
  	protected $cache;
  
  	static public function decodeName($name) {
  		preg_match('/(?P<name>.*)-chunking-(?P<transferid>\d+)-(?P<chunkcount>\d+)-(?P<index>\d+)/', $name, $matches);
  		return $matches;
  	}
  
  	public function __construct($info) {
  		$this->info = $info;
  	}
  
  	public function getPrefix() {
  		$name = $this->info['name'];
  		$transferid = $this->info['transferid'];
  
  		return $name.'-chunking-'.$transferid.'-';
  	}
  
  	protected function getCache() {
  		if (!isset($this->cache)) {

  			$this->cache = new \OC\Cache\File();

  		}
  		return $this->cache;
  	}
  
  	/**
  	 * Stores the given $data under the given $key - the number of stored bytes is returned
  	 *
  	 * @param $index
  	 * @param $data
  	 * @return int
  	 */
  	public function store($index, $data) {
  		$cache = $this->getCache();
  		$name = $this->getPrefix().$index;
  		$cache->set($name, $data);
  
  		return $cache->size($name);
  	}
  
  	public function isComplete() {
  		$prefix = $this->getPrefix();
  		$parts = 0;
  		$cache = $this->getCache();
  		for($i=0; $i < $this->info['chunkcount']; $i++) {
  			if ($cache->hasKey($prefix.$i)) {
  				$parts ++;
  			}
  		}
  		return $parts == $this->info['chunkcount'];
  	}

  	/**
  	 * Assembles the chunks into the file specified by the path.
  	 * Chunks are deleted afterwards.
  	 *
  	 * @param string $f target path
  	 *
  	 * @return assembled file size
  	 *
  	 * @throws \OC\InsufficientStorageException when file could not be fully
  	 * assembled due to lack of free space
  	 */

  	public function assemble($f) {
  		$cache = $this->getCache();
  		$prefix = $this->getPrefix();
  		$count = 0;

  		for ($i = 0; $i < $this->info['chunkcount']; $i++) {

  			$chunk = $cache->get($prefix.$i);

  			// remove after reading to directly save space
  			$cache->remove($prefix.$i);

  			$count += fwrite($f, $chunk);
  		}

  		return $count;
  	}
  
  	/**

  	 * Returns the size of the chunks already present
  	 * @return size in bytes
  	 */
  	public function getCurrentSize() {
  		$cache = $this->getCache();
  		$prefix = $this->getPrefix();
  		$total = 0;
  		for ($i = 0; $i < $this->info['chunkcount']; $i++) {
  			$total += $cache->size($prefix.$i);
  		}
  		return $total;
  	}
  
  	/**

  	 * Removes all chunks which belong to this transmission
  	 */
  	public function cleanup() {
  		$cache = $this->getCache();
  		$prefix = $this->getPrefix();
  		for($i=0; $i < $this->info['chunkcount']; $i++) {
  			$cache->remove($prefix.$i);
  		}
  	}
  
  	/**
  	 * Removes one specific chunk
  	 * @param $index
  	 */
  	public function remove($index) {
  		$cache = $this->getCache();
  		$prefix = $this->getPrefix();
  		$cache->remove($prefix.$index);
  	}
  
  	public function signature_split($orgfile, $input) {
  		$info = unpack('n', fread($input, 2));
  		$blocksize = $info[1];
  		$this->info['transferid'] = mt_rand();
  		$count = 0;
  		$needed = array();
  		$cache = $this->getCache();
  		$prefix = $this->getPrefix();
  		while (!feof($orgfile)) {
  			$new_md5 = fread($input, 16);
  			if (feof($input)) {
  				break;
  			}
  			$data = fread($orgfile, $blocksize);
  			$org_md5 = md5($data, true);
  			if ($org_md5 == $new_md5) {
  				$cache->set($prefix.$count, $data);
  			} else {
  				$needed[] = $count;
  			}
  			$count++;
  		}
  		return array(
  			'transferid' => $this->info['transferid'],
  			'needed' => $needed,
  			'count' => $count,
  		);
  	}

  	/**
  	 * Assembles the chunks into the file specified by the path.
  	 * Also triggers the relevant hooks and proxies.
  	 *
  	 * @param string $path target path
  	 *
  	 * @return assembled file size or false if file could not be created
  	 *
  	 * @throws \OC\InsufficientStorageException when file could not be fully
  	 * assembled due to lack of free space
  	 */

  	public function file_assemble($path) {
  		$absolutePath = \OC\Files\Filesystem::normalizePath(\OC\Files\Filesystem::getView()->getAbsolutePath($path));
  		$data = '';
  		// use file_put_contents as method because that best matches what this function does
  		if (OC_FileProxy::runPreProxies('file_put_contents', $absolutePath, $data)
  			&& \OC\Files\Filesystem::isValidPath($path)) {
  			$path = \OC\Files\Filesystem::getView()->getRelativePath($absolutePath);
  			$exists = \OC\Files\Filesystem::file_exists($path);
  			$run = true;
  			if(!$exists) {
  				OC_Hook::emit(
  					\OC\Files\Filesystem::CLASSNAME,
  					\OC\Files\Filesystem::signal_create,
  					array(
  						\OC\Files\Filesystem::signal_param_path => $path,
  						\OC\Files\Filesystem::signal_param_run => &$run
  					)
  				);
  			}
  			OC_Hook::emit(
  				\OC\Files\Filesystem::CLASSNAME,
  				\OC\Files\Filesystem::signal_write,
  				array(
  					\OC\Files\Filesystem::signal_param_path => $path,
  					\OC\Files\Filesystem::signal_param_run => &$run
  				)
  			);
  			if(!$run) {
  				return false;
  			}
  			$target = \OC\Files\Filesystem::fopen($path, 'w');
  			if($target) {
  				$count = $this->assemble($target);
  				fclose($target);
  				if(!$exists) {
  					OC_Hook::emit(
  						\OC\Files\Filesystem::CLASSNAME,
  						\OC\Files\Filesystem::signal_post_create,
  						array( \OC\Files\Filesystem::signal_param_path => $path)
  					);
  				}
  				OC_Hook::emit(
  					\OC\Files\Filesystem::CLASSNAME,
  					\OC\Files\Filesystem::signal_post_write,
  					array( \OC\Files\Filesystem::signal_param_path => $path)
  				);
  				OC_FileProxy::runPostProxies('file_put_contents', $absolutePath, $count);
  				return $count > 0;
  			}else{
  				return false;
  			}
  		}
  	}
  }