<?php
/**
 * A general Stacker
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2011 Core 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 BaseStacker extends BaseFrameworkSystem {
	// Exception codes
	const EXCEPTION_STACKER_ALREADY_INITIALIZED = 0x050;
	const EXCEPTION_STACKER_IS_FULL             = 0x051;
	const EXCEPTION_NO_STACKER_FOUND            = 0x052;
	const EXCEPTION_STACKER_IS_EMPTY            = 0x053;

	/**
	 * An array holding all stacks
	 */
	private $stacks = array();

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

	/**
	 * Initializes given stacker
	 *
	 * @param	$stackerName	Name of the stack
	 * @return	void
	 * @throws	AlreadyInitializedStackerException	If the stack is already initialized
	 */
	public final function initStacker ($stackerName) {
		// Is the stack already initialized?
		if ($this->isStackInitialized($stackerName)) {
			// Then throw the exception
			throw new AlreadyInitializedStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_ALREADY_INITIALIZED);
		} // END - if

		// Initialize the given stack
		$this->stacks[$stackerName] = array(
			'max_size' => $this->getConfigInstance()->getConfigEntry('stacker_' . $stackerName . '_max_size'),
			'entries'  => array()
		);
	}

	/**
	 * Checks wether the given stack is initialized (set in array $stackers)
	 *
	 * @param	$stackerName	Name of the stack
	 * @return	$isInitialized	Wether the stack is initialized
	 */
	public final function isStackInitialized ($stackerName) {
		// Is is there?
		$isInitialized = ((isset($this->stacks[$stackerName])) && (is_array($this->stacks[$stackerName])));

		// Return result
		return $isInitialized;
	}

	/**
	 * Checks wether the given stack is full
	 *
	 * @param	$stackerName	Name of the stack
	 * @return	$isFull			Wether the stack is full
	 * @throws	NoStackerException	If given stack is missing
	 */
	protected final function isStackFull ($stackerName) {
		// Is the stack not yet initialized?
		if (!$this->isStackInitialized($stackerName)) {
			// Throw an exception
			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
		} // END - if

		// So, is the stack full?
		$isFull = (($this->getStackCount($stackerName)) == $this->getConfigInstance()->getConfigEntry('stacker_' . $stackerName . '_max_size'));

		// Return result
		return $isFull;
	}

	/**
	 * Checks wether the given stack is empty
	 *
	 * @param	$stackerName	Name of the stack
	 * @return	$isEmpty			Wether the stack is empty
	 * @throws	NoStackerException	If given stack is missing
	 */
	public final function isStackEmpty ($stackerName) {
		// Is the stack not yet initialized?
		if (!$this->isStackInitialized($stackerName)) {
			// Throw an exception
			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
		} // END - if

		// So, is the stack full?
		$isFull = (($this->getStackCount($stackerName)) == 0);

		// Return result
		return $isFull;
	}

	/**
	 * Getter for size of given stack (array count)
	 *
	 * @param	$stackerName	Name of the stack
	 * @return	$count			Size of stack (array count)
	 * @throws	NoStackerException	If given stack is missing
	 */
	protected final function getStackCount ($stackerName) {
		// Is the stack not yet initialized?
		if (!$this->isStackInitialized($stackerName)) {
			// Throw an exception
			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
		} // END - if

		// Now, count the array of entries
		$count = count($this->stacks[$stackerName]['entries']);

		// Return result
		return $count;
	}

	/**
	 * Adds a value to given stack
	 *
	 * @param	$stackerName	Name of the stack
	 * @param	$value			Value to add to this stacker
	 * @return	void
	 * @throws	FullStackerException	Thrown if the stack is full
	 */
	protected final function addValue ($stackerName, $value) {
		// Is the stack not yet initialized or full?
		if (!$this->isStackInitialized($stackerName)) {
			// Then do it here
			$this->initStacker($stackerName);
		} elseif ($this->isStackFull($stackerName)) {
			// Stacker is full
			throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
		}

		// Now add the value to the stack
		array_push($this->stacks[$stackerName]['entries'], $value);
	}

	/**
	 * Get last value from named stacker
	 *
	 * @param	$stackerName	Name of the stack
	 * @return	$value			Value of last added value
	 * @throws	NoStackerException	If the named stacker was not found
	 * @throws	EmptyStackerException	If the named stacker is empty
	 */
	protected final function getLastValue ($stackerName) {
		// Is the stack not yet initialized or full?
		if (!$this->isStackInitialized($stackerName)) {
			// Throw an exception
			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
		} elseif ($this->isStackEmpty($stackerName)) {
			//Throw an exception
			throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
		}

		// Now get the last value
		$value = $this->stacks[$stackerName]['entries'][$this->getStackCount($stackerName) - 1];

		// Return it
		return $value;
	}

	/**
	 * Get first value from named stacker
	 *
	 * @param	$stackerName	Name of the stack
	 * @return	$value			Value of last added value
	 * @throws	NoStackerException	If the named stacker was not found
	 * @throws	EmptyStackerException	If the named stacker is empty
	 */
	protected final function getFirstValue ($stackerName) {
		// Is the stack not yet initialized or full?
		if (!$this->isStackInitialized($stackerName)) {
			// Throw an exception
			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
		} elseif ($this->isStackEmpty($stackerName)) {
			//Throw an exception
			throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
		}

		// Now get the last value
		$value = $this->stacks[$stackerName]['entries'][0];

		// Return it
		return $value;
	}

	/**
	 * "Pops" last entry from stack
	 *
	 * @param	$stackerName	Name of the stack
	 * @return	void
	 * @throws	NoStackerException	If the named stacker was not found
	 * @throws	EmptyStackerException	If the named stacker is empty
	 */
	protected final function popLast ($stackerName) {
		// Is the stack not yet initialized or full?
		if (!$this->isStackInitialized($stackerName)) {
			// Throw an exception
			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
		} elseif ($this->isStackEmpty($stackerName)) {
			//Throw an exception
			throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
		}

		// Now, remove the last entry, we don't care about the return value here, see elseif() block above
		array_pop($this->stacks[$stackerName]['entries']);
	}

	/**
	 * "Pops" first entry from stack
	 *
	 * @param	$stackerName	Name of the stack
	 * @return	void
	 * @throws	NoStackerException	If the named stacker was not found
	 * @throws	EmptyStackerException	If the named stacker is empty
	 */
	protected final function popFirst ($stackerName) {
		// Is the stack not yet initialized or full?
		if (!$this->isStackInitialized($stackerName)) {
			// Throw an exception
			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
		} elseif ($this->isStackEmpty($stackerName)) {
			//Throw an exception
			throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
		}

		// Now, remove the last entry, we don't care about the return value here, see elseif() block above
		array_shift($this->stacks[$stackerName]['entries']);
	}
}

// [EOF]
?>