<?php
/**
 * A general hub cruncher class
 *
 * @author		Roland Haeder <webmaster@shipsimu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2011 - 2012 Cruncher Developer Team
 * @license		GNU GPL 3.0 or any newer version
 * @link		http://www.shipsimu.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/>.
 */
abstract class BaseHubCruncher extends BaseHubSystem implements Updateable {
	/**
	 * Version information
	 */
	private $version = 'x.x';

	/**
	 * By default no cruncher is active
	 */
	private $isActive = FALSE;

	/**
	 * All buffer queue instances (a FIFO)
	 */
	private $bufferInstance = NULL;

	/**
	 * Stacker name for incoming queue
	 */
	const STACKER_NAME_IN_QUEUE = 'in_queue';

	/**
	 * Stacker name for outcoming queue
	 */
	const STACKER_NAME_OUT_QUEUE = 'out_queue';

	/**
	 * Protected constructor
	 *
	 * @param	$className	Name of the class
	 * @return	void
	 */
	protected function __construct ($className) {
		// Call parent constructor
		parent::__construct($className);

		// Init this cruncher
		$this->initCruncher();
	}

	/**
	 * Initialize the cruncher generically
	 *
	 * @return	void
	 */
	private function initCruncher () {
		// Init the state
		CruncherStateFactory::createCruncherStateInstanceByName('init', $this);
	}

	/**
	 * Getter for version
	 *
	 * @return	$version	Version number of this cruncher
	 */
	protected final function getVersion () {
		return $this->version;
	}

	/**
	 * Setter for version
	 *
	 * @param	$version	Version number of this cruncher
	 * @return	void
	 */
	protected final function setVersion ($version) {
		$this->version = (string) $version;
	}

	/**
	 * Checks whether the in-buffer queue is filled by comparing it's current
	 * amount of entries against a threshold.
	 *
	 * @return	$isFilled	Whether the in-buffer is filled
	 */
	protected function isInBufferQueueFilled () {
		// Determine it
		$isFilled = ($this->bufferInstance->getStackCount(self::STACKER_NAME_IN_QUEUE) > $this->getConfigInstance()->getConfigEntry('cruncher_in_buffer_min_threshold'));

		// And return the result
		return $isFilled;
	}

	/**
	 * This method fills the in-buffer with (a) test unit(s) which are mainly
	 * used for development of the crunching part. They must be enabled in
	 * configuration, or else your cruncher runs out of WUs and waits for more
	 * to show up.
	 *
	 * In this method we already know that the in-buffer is going depleted so
	 * we don't need to double-check it here.
	 *
	 * @return	void
	 */
	abstract protected function fillInBufferQueueWithTestUnits ();

	/**
	 * This method fills the in-buffer with (real) WUs which will be crunched
	 * and the result be sent back to the key producer instance.
	 *
	 * @return	void
	 */
	abstract protected function fillInBufferQueueWithWorkUnits ();

	/**
	 * Enables/disables the cruncher (just sets a flag)
	 *
	 * @param	$version	Version number of this cruncher
	 * @return	void
	 */
	public final function enableIsActive ($isActive = TRUE) {
		$this->isActive = (bool) $isActive;
	}

	/**
	 * Determines whether the cruncher is active
	 *
	 * @return	$isActive	Whether the cruncher is active
	 */
	public final function isActive () {
		return $this->isActive;
	}

	/**
	 * Initializes all buffer queues (mostly in/out). This method is demanded
	 * by the CruncherHelper interface.
	 *
	 * @return	void
	 */
	public function initBufferQueues () {
		/*
		 * Initialize both buffer queues, we can use the FIFO class here
		 * directly and encapsulate its method calls with protected methods.
		 */
		$this->bufferInstance = ObjectFactory::createObjectByConfiguredName('cruncher_buffer_stacker_class');

		// Initialize common stackers, like in/out
		$this->bufferInstance->initStacks(array(
			self::STACKER_NAME_IN_QUEUE,
			self::STACKER_NAME_OUT_QUEUE
		));

		// Output debug message
		self::createDebugInstance(__CLASS__)->debugOutput('CRUNCHER: All buffers are now initialized.');
	}

	/**
	 * This method determines if the in-buffer is going to depleted and if so,
	 * it fetches more WUs from the network. If no WU can be fetched from the
	 * network and if enabled, a random test WU is being generated.
	 *
	 * This method is demanded from the CruncherHelper interface.
	 *
	 * @return	void
	 */
	public function doFetchWorkUnits () {
		// Simply check if we have enough WUs left in the in-buffer queue (a FIFO)
		if (!$this->isInBufferQueueFilled()) {
			// The in-buffer queue needs filling, so head out and get some work
			$this->fillInBufferQueueWithWorkUnits();

			// Is the buffer still not filled and are test-packages allowed?
			if ((!$this->isInBufferQueueFilled()) && ($this->getConfigInstance()->getConfigEntry('cruncher_test_units_enabled') == 'Y')) {
				// Then fill the in-buffer with (one) test-unit(s)
				$this->fillInBufferQueueWithTestUnits();
			} // END - if
		} // END - if
	}

	/**
	 * Updates a given field with new value
	 *
	 * @param	$fieldName		Field to update
	 * @param	$fieldValue		New value to store
	 * @return	void
	 * @throws	DatabaseUpdateSupportException	If this class does not support database updates
	 * @todo	Try to make this method more generic so we can move it in BaseFrameworkSystem
	 */
	public function updateDatabaseField ($fieldName, $fieldValue) {
		// Unfinished
		$this->partialStub('Unfinished!');
		return;
	}
}

// [EOF]
?>