<?php
// Own namespace
namespace Org\Mxchange\CoreFramework\Database\Frontend;

// Import framework stuff
use Org\Mxchange\CoreFramework\Bootstrap\FrameworkBootstrap;
use Org\Mxchange\CoreFramework\Criteria\Criteria;
use Org\Mxchange\CoreFramework\Criteria\Storing\StoreableCriteria;
use Org\Mxchange\CoreFramework\Database\Backend\BaseDatabaseBackend;
use Org\Mxchange\CoreFramework\Factory\Object\ObjectFactory;
use Org\Mxchange\CoreFramework\Object\BaseFrameworkSystem;
use Org\Mxchange\CoreFramework\Result\Database\BaseDatabaseResult;
use Org\Mxchange\CoreFramework\Traits\Cache\CacheableTrait;

/**
 * A generic database frontend
 *
 * @author		Roland Haeder <webmaster@shipsimu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2021 Core 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 BaseDatabaseFrontend extends BaseFrameworkSystem {
	// Load traits
	use CacheableTrait;

	/**
	 * Current table name to use
	 */
	private $tableName = 'unknown';

	/**
	 * "Cached" value 'database_cache_enabled' from configuration
	 */
	private $databaseCacheEnabled = false;
	/**
	 * Protected constructor
	 *
	 * @param	$className	Name of the class
	 * @return	void
	 */
	protected function __construct (string $className) {
		// Call parent constructor
		parent::__construct($className);

		// Initialize the cache instance
		$this->initCacheInstance();
	}

	/**
	 * Initializes the cache instance with a new object
	 *
	 * @return	void
	 */
	private final function initCacheInstance () {
		// Set "cache" attributes
		$this->databaseCacheEnabled = FrameworkBootstrap::getConfigurationInstance()->getConfigEntry('database_cache_enabled');

		// Is the cache enabled?
		if ($this->databaseCacheEnabled === true) {
			// Set the new instance
			$this->setCacheInstance(ObjectFactory::createObjectByConfiguredName('cache_class'));
		}
	}

	/**
	 * Setter for table name
	 *
	 * @param	$tableName	Name of table name to set
	 * @return	void
	 */
	protected final function setTableName (string $tableName) {
		$this->tableName = $tableName;
	}

	/**
	 * Getter for table name
	 *
	 * @return	$tableName	Name of table name to set
	 */
	protected final function getTableName () {
		return $this->tableName;
	}

	/**
	 * Gets a cache key from Criteria instance
	 *
	 * @param	$criteriaInstance	An instance of a Criteria class
	 * @param	$onlyKeys			Only use these keys for a cache key
	 * @return	$cacheKey			A cache key suitable for lookup/storage purposes
	 */
	protected function getCacheKeyByCriteria (Criteria $criteriaInstance, array $onlyKeys = []) {
		// Generate it
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FRAMEWORK-SYSTEM: criteriaInstance=' . $criteriaInstance->__toString() . ',onlyKeys()=' . count($onlyKeys) . ' - CALLED!');
		$cacheKey = sprintf('%s@%s',
			$this->__toString(),
			$criteriaInstance->getCacheKey($onlyKeys)
		);

		// And return it
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FRAMEWORK-SYSTEM: cacheKey=' . $cacheKey . ' - EXIT!');
		return $cacheKey;
	}

	/**
	 * 'Inserts' a data set instance into a local file database folder
	 *
	 * @param	$dataSetInstance	A storeable data set
	 * @param	$onlyKeys			Only use these keys for a cache key
	 * @return	void
	 */
	protected function queryInsertDataSet (StoreableCriteria $dataSetInstance, array $onlyKeys = []) {
		// Default cache key is NULL
		//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: dataSetInstance=%s,onlyKeys()=%d - CALLED!', $dataSetInstance->__toString(), count($onlyKeys)));
		$cacheKey = NULL;

		// Is cache enabled?
		if ($this->databaseCacheEnabled === true) {
			// First get a key suitable for our cache and extend it with this class name
			$cacheKey = $this->getCacheKeyByCriteria($dataSetInstance, $onlyKeys);
			//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FRONTEND: Using cache key ' . $cacheKey . ' for purging ...');
		}

		// Does this key exists in cache?
		//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: cacheKey[%s]=%s', gettype($cacheKey), $cacheKey));
		if (($this->databaseCacheEnabled === true) && ($this->getCacheInstance()->offsetExists($cacheKey))) {
			// Purge the cache
			//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: Calling this->cacheInstance->purgeOffset(%s) ...', $cacheKey));
			$this->getCacheInstance()->purgeOffset($cacheKey);
		}

		// Handle it over to the middleware
		FrameworkBootstrap::getDatabaseInstance()->queryInsertDataSet($dataSetInstance);

		// Trace message
		//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FRONTEND: EXIT!');
	}

	/**
	 * 'Updates' a data set instance with a database layer
	 *
	 * @param	$dataSetInstance	A storeable data set
	 * @param	$onlyKeys			Only use these keys for a cache key
	 * @return	void
	 */
	protected function queryUpdateDataSet (StoreableCriteria $dataSetInstance, array $onlyKeys = []) {
		// Init cache key
		$cacheKey = NULL;

		// Is cache enabled?
		if ($this->databaseCacheEnabled === true) {
			// First get a key suitable for our cache and extend it with this class name
			$cacheKey = $this->getCacheKeyByCriteria($dataSetInstance, $onlyKeys);
			//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FRONTEND: Using cache key ' . $cacheKey . ' for purging ...');
		}

		// Does this key exists in cache?
		if (($this->databaseCacheEnabled === true) && ($this->getCacheInstance()->offsetExists($cacheKey))) {
			// Purge the cache
			$this->getCacheInstance()->purgeOffset($cacheKey);
		}

		// Handle it over to the middleware
		FrameworkBootstrap::getDatabaseInstance()->queryUpdateDataSet($dataSetInstance);
	}

	/**
	 * Getter for index key
	 *
	 * @return	$indexKey	Index key
	 */
	public final function getIndexKey () {
		return FrameworkBootstrap::getDatabaseInstance()->getIndexKey();
	}

	/**
	 * Getter for last exception
	 *
	 * @return	$lastException	Last exception or NULL if none occured
	 */
	public final function getLastException () {
		return FrameworkBootstrap::getDatabaseInstance()->getLastException();
	}

	/**
	 * Do a "select" query on the current table with the given search criteria and
	 * store it in cache for later usage
	 *
	 * @param	$criteriaInstance	An instance of a Criteria class
	 * @param	$onlyKeys			Only use these keys for a cache key
	 * @return	$resultInstance		An instance of a database result class
	 */
	public function doSelectByCriteria (Criteria $criteriaInstance, array $onlyKeys = []) {
		// Default cache key if cache is not enabled
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: criteriaInstance=%s,onlyKeys()=%d - CALLED!', $criteriaInstance->__toString(), count($onlyKeys)));
		$cacheKey = NULL;
		$result = [];

		// Is the cache enabled?
		if ($this->databaseCacheEnabled === true) {
			// First get a key suitable for our cache and extend it with this class name
			$cacheKey = $this->getCacheKeyByCriteria($criteriaInstance, $onlyKeys);
		}

		// Does this key exists in cache?
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: cacheKey[%s]=%s', gettype($cacheKey), $cacheKey));
		if (($this->databaseCacheEnabled === true) && ($this->getCacheInstance()->offsetExists($cacheKey, BaseDatabaseResult::RESULT_NAME_ROWS, 1))) {
			// Then use this result
			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: Cache used for cacheKey=%s', $cacheKey));
			$result = $this->getCacheInstance()->offsetGet($cacheKey);
		} else {
			// Now it's time to ask the database layer for this select statement
			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: Quering database, cacheKey=%s ...', $cacheKey));
			$result = FrameworkBootstrap::getDatabaseInstance()->doSelectByTableCriteria($this->getTableName(), $criteriaInstance);

			// Cache the result if not null
			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: result[]=%s', gettype($result)));
			if (!is_null($result)) {
				// Is cache enabled?
				if ($this->databaseCacheEnabled === true) {
					// A valid result has returned from the database layer
					//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: Setting cacheKey=%s with result()=%d entries', $cacheKey, count($result)));
					$this->getCacheInstance()->offsetSet($cacheKey, $result);
				}
			} else {
				// This invalid result must be wrapped
				$result = array(
					BaseDatabaseResult::RESULT_NAME_STATUS    => 'invalid',
					BaseDatabaseResult::RESULT_NAME_EXCEPTION => FrameworkBootstrap::getDatabaseInstance()->getLastException()
				);
			}
		}

		// Create an instance of a CachedDatabaseResult class with the given result
		// @TODO Minor: Update above comment to e.g. BaseDatabaseResult
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: result[%s]=%s,result[%s]?=%d,result[%s]?=%d', BaseDatabaseResult::RESULT_NAME_STATUS, $result[BaseDatabaseResult::RESULT_NAME_STATUS], BaseDatabaseResult::RESULT_NAME_ROWS, isset($result[BaseDatabaseResult::RESULT_NAME_ROWS]), BaseDatabaseResult::RESULT_NAME_EXCEPTION, isset($result[BaseDatabaseResult::RESULT_NAME_EXCEPTION])));
		$resultInstance = ObjectFactory::createObjectByConfiguredName('database_result_class', array($result));

		// And return the instance
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FRONTEND: resultInstance=%s - EXIT!', $resultInstance->__toString()));
		return $resultInstance;
	}

	/**
	 * Count the numbers of rows we shall receive
	 *
	 * @param	$criteriaInstance	An instance of a Criteria class
	 * @param	$onlyKeys			Only use these keys for a cache key
	 * @return	$numRows			Numbers of rows of database entries
	 */
	public function doSelectCountByCriteria (Criteria $criteriaInstance, array $onlyKeys = []) {
		// Total numbers is -1 so we can distinglish between failed and valid queries
		$numRows = 0;

		// Get the result from above method
		$resultInstance = $this->doSelectByCriteria($criteriaInstance, $onlyKeys);

		// Was that query fine?
		if ($resultInstance->ifStatusIsOkay()) {
			// Then get the number of rows
			$numRows = $resultInstance->getAffectedRows();

			// Debug message
			//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FRONTEND: numRows=' . $numRows);
		}

		// Return the result
		return $numRows;
	}

	/**
	 * Getter for primary key used in wrapped table
	 *
	 * @return	$primaryKey		Primary key used in wrapped table
	 */
	public final function getPrimaryKeyValue () {
		// Get the table name and a database instance and ask for it
		$primaryKey = FrameworkBootstrap::getDatabaseInstance()->getPrimaryKeyOfTable($this->getTableName());

		// Return value
		return $primaryKey;
	}

	/**
	 * Count rows of this table
	 *
	 * @return	$count	Count of total rows in this table
	 */
	public final function countTotalRows () {
		// Get the table name and a database instance and ask for it
		$count = FrameworkBootstrap::getDatabaseInstance()->countTotalRows($this->getTableName());

		// Return value
		return $count;
	}

	/**
	 * Removes non-public data from given array.
	 *
	 * @param	$data	An array with possible non-public data that needs to be removed.
	 * @return	$data	A cleaned up array with only public data.
	 */
	public function removeNonPublicDataFromArray (array $data) {
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('WRAPPER[' . $this->__toString() . ']: Calling FrameworkBootstrap::getDatabaseInstance()->removeNonPublicDataFromArray(data) ...');
		$data = FrameworkBootstrap::getDatabaseInstance()->removeNonPublicDataFromArray($data);

		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('WRAPPER[' . $this->__toString() . ']: data[]=' . gettype($data));
		return $data;
	}

}