<?php
/**
 * A UploadedList URL source class for crawlers
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2014 Crawler Developer Team
 * @license		GNU GPL 3.0 or any newer version
 * @link		http://www.ship-simu.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
class CrawlerUploadedListUrlSource extends BaseUrlSource implements UrlSource, Registerable {
	/**
	 * "Cached" CSV path
	 */
	private $csvFilePath = '';

	/**
	 * Last CSV file instance
	 */
	private $lastCsvFileInstance = NULL;

	/**
	 * Stack for pushing data from this clas to another
	 */
	private $stackSourceInstance = NULL;

	/**
	 * Stack name for a CSV file
	 */
	const STACK_NAME_CSV_FILE = 'csv_file';

	/**
	 * "Imported" CSV files
	 */
	private $csvFileImported = array();

	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);

		// "Cache" CSV path for faster usage
		$this->csvFilePath = $this->getConfigInstance()->getConfigEntry('base_path') . '/' . $this->getConfigInstance()->getConfigEntry('crawler_csv_file_path');

		// Initialize directory instance
		$directoryInstance = ObjectFactory::createObjectByConfiguredName('directory_class', array($this->csvFilePath));

		// Set it here
		$this->setDirectoryInstance($directoryInstance);

		// Init stack instance
		$this->stackSourceInstance = ObjectFactory::createObjectByConfiguredName('crawler_uploaded_list_url_source_stack_class');

		// Init stack
		$this->getStackSourceInstance()->initStack(self::STACK_NAME_CSV_FILE);
	}

	/**
	 * Checks whether a CSV file is found in configured path
	 *
	 * @return	$isFound	Whether a CSV file is found
	 */
	private function isCsvFileFound () {
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('CRAWLER-SOURCE [' . __METHOD__ . ':' . __LINE__ . ']: CALLED!');

		// Is it valid?
		if (!$this->getDirectoryInstance()->getDirectoryIteratorInstance()->valid()) {
			// Rewind to start
			$this->getDirectoryInstance()->getDirectoryIteratorInstance()->rewind();
		} // END - if

		// Read next entry
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('CRAWLER-SOURCE [' . __METHOD__ . ':' . __LINE__ . ']: this->csvFileImported=' . print_r($this->csvFileImported, TRUE));
		$directoryEntry = $this->getDirectoryInstance()->readDirectoryExcept(array_merge(array('.htaccess', '.', '..'), $this->csvFileImported));

		// Debug message
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('SOURCE[' . __METHOD__ . ':' . __LINE__ . '] directoryEntry(' . strlen($directoryEntry) . ')=' . $directoryEntry);

		// Is it empty or wrong file extension?
		if ((empty($directoryEntry)) || (substr($directoryEntry, -4, 4) != '.csv')) {
			// Skip further processing
			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('SOURCE[' . __METHOD__ . ':' . __LINE__ . '] directoryEntry(' . strlen($directoryEntry) . ')=' . $directoryEntry . ' - SKIPPED!');
			return FALSE;
		} // END - if

		// Initialize CSV file instance
		$this->lastCsvFileInstance = ObjectFactory::createObjectByConfiguredName('csv_file_class', array($this->csvFilePath . '/' . $directoryEntry));

		// Found an entry
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('CRAWLER-SOURCE [' . __METHOD__ . ':' . __LINE__ . ']: EXIT!');
		return TRUE;
	}

	/**
	 * Creates an instance of this class
	 *
	 * @return	$sourceInstance		An instance of a Source class
	 */
	public final static function createCrawlerUploadedListUrlSource () {
		// Get new instance
		$sourceInstance = new CrawlerUploadedListUrlSource();

		// Init source
		$sourceInstance->initSource('crawler', 'uploaded_list');

		// Return the prepared instance
		return $sourceInstance;
	}

	/**
	 * Initializes the import of the CSV file which is being processed by other task
	 *
	 * @return	void
	 * @throws	NullPointerException	If lastCsvFileInstance is not set
	 */
	private function importCsvFile () {
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('CRAWLER-SOURCE [' . __METHOD__ . ':' . __LINE__ . ']: CALLED!');

		// Is the instance set?
		if (is_null($this->lastCsvFileInstance)) {
			// This should not happen
			throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
		} // END - if

		// Stack this file
		$this->getStackSourceInstance()->pushNamed(self::STACK_NAME_CSV_FILE, $this->lastCsvFileInstance);

		// ... and mark it as "imported"
		array_push($this->csvFileImported, basename($this->lastCsvFileInstance->getFileName()));

		// ... and finally NULL it (to save some RAM)
		$this->lastCsvFileInstance = NULL;

		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('CRAWLER-SOURCE [' . __METHOD__ . ':' . __LINE__ . ']: EXIT!');
	}

	/**
	 * Getter for stackSourceInstance variable
	 *
	 * @return	$stackSourceInstance	An instance of an additional stack
	 */
	public final function getStackSourceInstance () {
		return $this->stackSourceInstance;
	}

	/**
	 * Processes entries in the stack.
	 *
	 * @return	void
	 * @todo	~10% done
	 */
	public function processStack () {
		// Does the stack have some entries left?
		if (!$this->isUrlStackEmpty()) {
			/*
			 * Handle next entry. This method will be called very often, so need
			 * to process more than one entry at a time.
			 */
			$this->processNextEntry();
		} elseif ($this->isCsvFileFound()) {
			/*
			 * A file containing an URL list is found. Please note the format is
			 * CSV-like as you may wish to provide meta data such as crawl
			 * depth, handling of 3rd-party URLs and such.
			 */
			$this->importCsvFile();
		}

		$this->partialStub('Please implement this method.');
	}
}

// [EOF]
?>