<?php

	/**************************
	*      DatabaseDriver     *
	*        08-04-2016       *
	***************************
	* Designed & Developed by *
	*      xdrm-brackets      *
	***************************
	*    https://xdrm.io/     *
	**************************/

	namespace database\core;
	use database\core\PDOWrapper\PDOWrapper;
	use \error\core\Error;
	use \error\core\Err;


	class DatabaseDriver{

		/* STATIC ATTRIBUTES */
		private static function conf() : array{
			// YOUR CONFIGURATION BEHIND
			$path = __CONFIG__.'/database-driver.json';

			/* (1) Checks the file */
			if( !is_file($path) )
				return [];

			/* (2) Checks json */
			$parsed = json_decode( file_get_contents($path), true );

			if( !is_array($parsed) )
				return [];

			/* (3) Returns configuration */
			return $parsed;
		}

		/** @var DatabaseDriver[]  */
		private static $instance = []; // Database driver instance list

		/** @var Error  */
		public $error;

		/* ATTRIBUTES */
		private $host;
		private $dbname;
		private $username;
		private $password;
		private $pdo;


		/** CONSTRUCTOR OF A DATABASE DRIVER
		*
		* @param	String		$host 							Database Server's host
		* @param	String		$dbname 						Database name
		* @param	String		$username 						Database username
		* @param	String		$password 							Database password
		* @param 	bool		$debug
		*
		*/
		private function __construct(String $host, String $dbname, String $username, String $password, bool $debug = false){
			/* (2) Stores configuration */
			$this->host     = $host;
			$this->dbname   = $dbname;
			$this->username = $username;
			$this->password = $password;

			try{

				$this->pdo = new PDOWrapper('mysql:host='.$this->host.';dbname='.$this->dbname.';charset=utf8', $this->username, $this->password, [
					\PDO::ATTR_DEFAULT_FETCH_MODE => \PDO::FETCH_ASSOC,
					\PDO::ATTR_TIMEOUT            => 5,
					\PDO::ERRMODE_EXCEPTION		  => true
				]);

				$this->pdo->setAttribute(\PDO::ATTR_STRINGIFY_FETCHES, false);
				$this->pdo->setAttribute(\PDO::ATTR_EMULATE_PREPARES, false);

				if($debug){
					$this->pdo->enableDebug();
				}

				// On signale que tout s'est bien passe
				$this->error = new Error(Err::Success);

			}catch(\Exception $e){
				// On signale qu'il y a une erreur
				$this->error = new Error(Err::PDOConnection);
			}
		}


		/************************************************
		****       Multiton Management (static)      ****
		************************************************/

		/** ADDS A NEW CONNECTION
		*
		* @param	String		$label 					[optional] Database Label
		*
		* @return 	boolean								If added successfully
		*
		*/
		private static function add(String $label='default') : bool{
			$conf = self::conf();

			/* [1] Default values
			=========================================================*/

			/* (1) If label and no path */
			if( $label !== 'default' && !isset($conf[$label]) )
				return false;


			/* [3] Instanciates the driver
			=========================================================*/
			try{

				/* (1) If local -> instanciates with local configuration */
				// if( !checkdnsrr($_SERVER['SERVER_NAME'], 'NS') )
				if(!isset($conf[$label]['local']['debug'])){
					$conf[$label]['local']['debug'] = false;
				}

				if(isset($_SESSION['CurrentDatabase']) && is_string($_SESSION['CurrentDatabase'])){
					$conf[$label]['local']['dbname'] = $_SESSION['CurrentDatabase'];
				}else{
					$_SESSION["CurrentDatabase"] = $conf[$label]['local']['dbname'];
				}

				self::$instance[$label] = new DatabaseDriver($conf[$label]['local']['host'], $conf[$label]['local']['dbname'], $conf[$label]['local']['user'], $conf[$label]['local']['password'],$conf[$label]['local']['debug']);


				return true ;

			}catch(\Exception $e){

				/* (3) If fails */
				return false;

			}

		}


		/** GET A DATABASE DRIVER INSTANCE
		*
		* @param	String		$label 							[optional] Driver's label
		* @throws 	\Exception
		* @return 	DatabaseDriver 								Multiton
		*
		*/
		public static function get(String $label='default') : DatabaseDriver{
			$conf = self::conf();

			/* [1] Checks arguments
			=========================================================*/

			/* (1) If no label, or unknown label */
			if( !isset(self::$instance[$label]) ){

				/* (2.1) Try to add the configuration if exists */
				if( isset($conf[$label]) ){
					self::add($label);
					return self::get($label);
				}


				throw new \Exception('Database @label is incorrect.');
			}


			/* [2] Returns instance
			=========================================================*/
			return self::$instance[$label];
		}


		/** retourne la connection statique
		 * @param String|null $label
		 * @throws \Exception
		 * @return \PDO
		 */
		public static function getPDO(?String $label=null) : \PDO{
			if(is_string($label)){
				$instance = self::get($label);
			}else{
				$instance = self::get();
			}

			return $instance->pdo;
		}

		/**
		 * @return \PDO
		 */
		public function pdo(){
			return $this->pdo;
		}


		/**
		 * @return array
		 */
		public function getConfig(){
			return [
				'host' => $this->host,
				'dbname' => $this->dbname,
				'username' => $this->username,
				'password' => $this->password
			];
		}

		/**
		 * enable request stacking
		 */
		public function enableStacking(){
			$this->pdo->enableStacking();
		}

		/**
		 * send all the stacked request and flush the stack
		 */
		public function flushStack(){
			$this->pdo->executeStack();
		}

		/** get all debug data
		 * @return array
		 */
		public function getDebug() : array{
			return $this->pdo->getDebug();
		}

		/**
		 * @return bool
		 */
		public function isDebugEnabled() : bool {
			return $this->pdo->isDebugEnabled();
		}


	}
?>