<?php
/**
 * A general DHT class
 *
 * @author		Roland Haeder <webmaster@shipsimu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 Hub 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 BaseDht extends BaseHubSystem {
	/**
	 * Stacker name for "INSERT" node data
	 */
	const STACKER_NAME_INSERT_NODE = 'dht_insert_node';

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

		// Get a stacker instance for this DHT
		$stackerInstance = ObjectFactory::createObjectByConfiguredName('dht_stacker_class');

		// Set it in this class
		$this->setStackerInstance($stackerInstance);

		// Init all stackers
		$this->initStacks();

		/*
		 * Get the state factory and create the initial state, we don't need
		 * the state instance here
		 */
		DhtStateFactory::createDhtStateInstanceByName('init', $this);
	}

	/**
	 * Initializes all stackers
	 *
	 * @return	void
	 */
	private function initStacks () {
		// Initialize all stacker
		$this->getStackerInstance()->initStacks(array(
			self::STACKER_NAME_INSERT_NODE,
		));
	}

	/**
	 * Registers/updates an entry in the DHT with given data from $dhtData
	 * array. Different DHT implemtations may handle this differently as they
	 * may enrich the data with more meta data.
	 *
	 * @param	$dhtData	A valid array with DHT-related data (e.g. node/peer data)
	 * @return	void
	 */
	protected abstract function insertDataIntoDht (array $dhtData);

	/**
	 * Updates/refreshes DHT data (e.g. status).
	 *
	 * @return	void
	 * @todo	Find more to do here
	 */
	public function updateDhtData () {
		// Set some dummy configuration entries, e.g. dht_status
		$this->getConfigInstance()->setConfigEntry('dht_status', $this->getStateInstance()->getStateName());
	}

	/**
	 * Checks whether there are entries in "INSERT" node data stack
	 *
	 * @return	$isPending	Whether there are pending entries
	 */
	public function ifInsertNodeDataPending () {
		// Determine it if it is not empty
		$isPending = ($this->getStackerInstance()->isStackEmpty(self::STACKER_NAME_INSERT_NODE) === FALSE);

		// Return status
		return $isPending;
	}

	/**
	 * Inserts a single entry of node data into the DHT
	 *
	 * @return	void
	 */
	public function insertSingleNodeData () {
		// Get next node data from stack
		$nodeData = $this->getStackerInstance()->popNamed(self::STACKER_NAME_INSERT_NODE);

		// Make sure $nodeData is really an array and has at least one entry
		assert((is_array($nodeData)) && (count($nodeData) > 0));

		// Insert the data
		$this->insertDataIntoDht($nodeData);
	}
}

// [EOF]
?>