<?php
/**
 * A database result class
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009, 2010 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 DatabaseResult extends BaseFrameworkSystem implements SearchableResult, UpdateableResult, SeekableIterator {
	// Exception constants
	const EXCEPTION_INVALID_DATABASE_RESULT = 0x1c0;
	const EXCEPTION_RESULT_UPDATE_FAILED    = 0x1c1;

	/**
	 * Current position in array
	 */
	private $currentPos = -1;

	/**
	 * Current row
	 */
	private $currentRow = null;

	/**
	 * Result array
	 */
	private $resultArray = array();

	/**
	 * Array of out-dated entries
	 */
	private $outDated = array();

	/**
	 * Affected rows
	 */
	private $affectedRows = 0;

	/**
	 * Found value
	 */
	private $foundValue = '';

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

	/**
	 * Creates an instance of this result by a provided result array
	 *
	 * @param	$resultArray		The array holding the result from query
	 * @return	$resultInstance		An instance of this class
	 */
	public final static function createDatabaseResult (array $resultArray) {
		// Get a new instance
		$resultInstance = new DatabaseResult();

		// Set the result array
		$resultInstance->setResultArray($resultArray);

		// Return the instance
		return $resultInstance;
	}

	/**
	 * Setter for result array
	 *
	 * @param	$resultArray	The array holding the result from query
	 * @return	void
	 */
	protected final function setResultArray (array $resultArray) {
		$this->resultArray = $resultArray;
	}

	/**
	 * Updates the current entry by given update criteria
	 *
	 * @param	$updateInstance		An instance of an Updateable criteria
	 * @return	void
	 */
	private function updateCurrentEntryByCriteria (LocalUpdateCriteria $updateInstance) {
		// Get the current entry key
		$entryKey = $this->key();

		// Now get the update criteria array and update all entries
		foreach ($updateInstance->getUpdateCriteria() as $criteriaKey => $criteriaValue) {
			// Update data
			$this->resultArray['rows'][$entryKey][$criteriaKey] = $criteriaValue;

			// Mark it as out-dated
			$this->outDated[$criteriaKey] = 1;
		} // END - foreach
	}

	/**
	 * "Iterator" method next() to advance to the next valid entry. This method
	 * does also check if result is invalid
	 *
	 * @return	$nextValid	Wether the next entry is valid
	 */
	public function next () {
		// Default is not valid
		$nextValid = false;

		// Is the result valid?
		if ($this->valid()) {
			// Next entry found, so count one up and cache it
			$this->currentPos++;
			$this->currentRow = $this->resultArray['rows'][$this->currentPos];
			$nextValid = true;
		} // END - if

		// Return the result
		return $nextValid;
	}

	/**
	 * Seeks for to a specified position
	 *
	 * @param	$index	Index to seek for
	 * @return	void
	 */
	public function seek ($index) {
		// Rewind to beginning
		$this->rewind();

		// Search for the entry
		while ($this->currentPos < $index && ($this->valid())) {
			// Continue on
			$this->next();
		} // END - while
	}

	/**
	 * Gives back the current position or null if not found
	 *
	 * @return	$current	Current element to give back
	 */
	public function current () {
		// Default is not found
		$current = null;

		// Does the current enty exist?
		if (isset($this->resultArray['rows'][$this->currentPos])) {
			// Then get it
			$current = $this->resultArray['rows'][$this->currentPos];
		} // END - if

		// Return the result
		return $current;
	}

	/**
	 * Checks if next() and rewind will give a valid result
	 *
	 * @return	$isValid Wether the next/rewind entry is valid
	 */
	public function valid () {
		// By default nothing is valid
		$isValid = false;

		// Check if 
		if (($this->ifStatusIsOkay()) && (isset($this->resultArray['rows'][($this->currentPos + 1)])) && (isset($this->resultArray['rows'][0]))) {
			// All fine!
			$isValid = true;
		} // END - if

		// Return the result
		return $isValid;
	}

	/**
	 * Determines wether the status of the query was fine (LocalfileDatabase::RESULT_OKAY)
	 *
	 * @return	$ifStatusOkay	Wether the status of the query was okay
	 */
	public function ifStatusIsOkay () {
		return ((isset($this->resultArray['status'])) && ($this->resultArray['status'] === LocalfileDatabase::RESULT_OKAY));
	}

	/**
	 * Gets the current key of iteration
	 *
	 * @return	$currentPos	Key from iterator
	 */
	public function key () {
		return $this->currentPos;
	}

	/**
	 * Rewind to the beginning and clear array $currentRow
	 *
	 * @return	void
	 */
	public function rewind () {
		$this->currentPos = -1;
		$this->currentRow = array();
	}

	/**
	 * Searches for an entry in data result and returns it
	 *
	 * @param	$criteriaInstance	The criteria to look inside the data set
	 * @return	$result				Found result entry
	 * @todo	0% done
	 */
	public function searchEntry (LocalSearchCriteria $criteriaInstance) {
		die(__METHOD__.": Unfinished!");
	}

	/**
	 * Adds an update request to the database result for writing it to the
	 * database layer
	 *
	 * @param	$criteriaInstance	An instance of a updateable criteria
	 * @return	void
	 * @throws	ResultUpdateException	If no result was updated
	 */
	public function add2UpdateQueue (LocalUpdateCriteria $criteriaInstance) {
		// Rewind the pointer
		$this->rewind();

		// Get search criteria
		$searchInstance = $criteriaInstance->getSearchInstance();

		// And start looking for the result
		$foundEntries = 0;
		while (($this->valid()) && ($foundEntries < $searchInstance->getLimit())) {
			// Get next entry
			$this->next();
			$currentEntry = $this->current();

			// Is this entry found?
			if ($searchInstance->ifEntryMatches($currentEntry)) {
				// Update this entry
				$this->updateCurrentEntryByCriteria($criteriaInstance);

				// Count one up
				$foundEntries++;
			} // END - if
		} // END - while

		// If no entry is found/updated throw an exception
		if ($foundEntries == 0) {
			// Throw an exception here
			throw new ResultUpdateException($this, self::EXCEPTION_RESULT_UPDATE_FAILED);
		} // END - if

		// Set affected rows
		$this->setAffectedRows($foundEntries);

		// Set update instance
		$this->setUpdateInstance($criteriaInstance);
	}

	/**
	 * Setter for affected rows
	 *
	 * @param	$rows	Number of affected rows
	 * @return	void
	 */
	public final function setAffectedRows ($rows) {
		$this->affectedRows = $rows;
	}

	/**
	 * Getter for affected rows
	 *
	 * @return	$rows	Number of affected rows
	 */
	public final function getAffectedRows () {
		return $this->affectedRows;
	}

	/**
	 * Getter for found value of previous found() call
	 *
	 * @return	$foundValue		Found value of previous found() call
	 */
	public final function getFoundValue () {
		return $this->foundValue;
	}

	/**
	 * Checks wether we have out-dated entries or not
	 *
	 * @return	$needsUpdate	Wether we have out-dated entries
	 */
	public function ifDataNeedsFlush () {
		$needsUpdate = (count($this->outDated) > 0);
		return $needsUpdate;
	}

	/**
	 * Adds registration elements to a given dataset instance
	 *
	 * @param	$criteriaInstance	An instance of a storeable criteria
	 * @return	void
	 */
	public function addElementsToDataSet (StoreableCriteria $criteriaInstance) {
		// Walk only through out-dated columns
		foreach ($this->outDated as $key => $dummy) {
			// Does this key exist?
			//* DEBUG: */ echo "outDated: {$key}<br />\n";
			if ($this->find($key)) {
				// Then update it
				$criteriaInstance->addCriteria($key, $this->getFoundValue());
			} // END - if
		} // END - foreach
	}

	/**
	 * Find a key inside the result array
	 *
	 * @param	$key	The key we shall find
	 * @return	$found	Wether the key was found or not
	 */
	public function find ($key) {
		// By default nothing is found
		$found = false;

		// Rewind the pointer
		$this->rewind();

		// Walk through all entries
		while ($this->valid()) {
			// Advance to next entry
			$this->next();

			// Get the whole array
			$currentEntry = $this->current();

			// Is the element there?
			if (isset($currentEntry[$key])) {
				// Okay, found!
				$found = true;

				// So "cache" it
				$this->foundValue = $currentEntry[$key];

				// And stop searching
				break;
			} // END - if
		} // END - while

		// Return the result
		return $found;
	}

	/**
	 * Solver for result index value with call-back method
	 *
	 * @param	$databaseColumn		Database column where the index might be found
	 * @param	$wrapperInstance	The wrapper instance to ask for array element
	 * @para	$callBack			Call-back object for setting the index;
	 * 								0=object instance,1=method name
	 * @return	void
4	 * @todo	Find a caching way without modifying the result array
	 */
	public function solveResultIndex ($databaseColumn, BaseDatabaseWrapper $wrapperInstance, array $callBack) {
		// By default nothing is found
		$indexValue = 0;

		// Is the element in result itself found?
		if ($this->find($databaseColumn)) {
			// Use this value
			$indexValue = $this->getFoundValue();
		} elseif ($this->find($wrapperInstance->getIndexKey())) {
			// Use this value
			$indexValue = $this->getFoundValue();
		}

		// Set the index
		call_user_func_array($callBack, array($indexValue));
	}
}

// [EOF]
?>