<?php defined('SYSPATH') OR die('No direct access to this file is allowed.');
/**
 * Database class, specific to MySQL 4.1 or higher.
 * 
 * This database class uses the PHP 5.1+ PDO class for everything.
 * 
 * @package Noostr
 * @subpackage Classes
 */

class Database {
	private $autocommit = true;	// autocommit status
	private $commitcount;		// counts queries within transaction
	private $database;		// database password to use
	private $db;			// database connection
	private $host;			// location of the database
	private $lastdata;		// the last data array
	private $lastquery;		// the last query run
	private $password;		// password to the database
	private $user;			// username to the database
	public $count;			// counts queries
	public $datalist = array();	// recording of query data passed
	public $numrows;		// number of rows from last query
	public $querylist = array();	// recording of queries passed
	public $resultlist = array();	// recording of query results

/**
 * Constructor for the class. Lazy loading is implemented so the connection to
 * the database isn't actually made until the first query is executed. All we
 * do here is store the params in private variables until needed.
 *
 * @param string $host Host address of database server.
 * @param string $user Username for database server.
 * @param string $password Password for user on database server.
 * @param string $database Name of the database to use for this instance.
 */
	public function __construct($host, $user, $password, $database) {
		$this->host = $host;
		$this->user = $user;
		$this->password = $password;
		$this->database = $database;
	}

/**
 * Calls the {@link disconnect()} method.
 */
	public function __destruct() {
		$this->disconnect();
	}

/**
 * Connect to the database using the private params from the {@link __construct()} method.
 * We set the query counter and transaction queue counter to 0.
 */
	private function connect() {
		$this->db = null;
		try {
			$this->db = new PDO('mysql:host='.$this->host.';dbname='.$this->database.'', $this->user, $this->password, array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));
		} catch(PDOException $e) {
			echo "Database error!!!<br />";
			switch ($e->getCode()) {
				case 1045:
					// Cannot connect to database
					die('Cannot connect to database!');
					break;
			}
			exit();
		}
		$this->commitcount = 0;
		$this->count = 0;
	}

/**
 * Disconnects from the database after doing a rollback, if needed.
 */
	public function disconnect() {
		if (isset($this->db)) {
			$this->rollback();
			write_log();
			$this->db = null;
		}
	}

/**
 * Sets the database's "autocommit" feature on or off. Currently not used except
 * to enable transaction queue counting.
 * 
 * @param bool $enabled Is the autocommit function enabled?
 */
	public function autocommit($enabled) {
		$this->autocommit = $enabled;
	}

/**
 * Begins a transaction if {@link autocommit()} is disabled.
 */
	public function begin() {
		if (!$this->autocommit) {
			if (!$this->db) {
				$this->connect();
			}
			$this->db->beginTransaction();
		}
	}

/**
 * Commits a transaction if {@link autocommit()} is disabled.
 */
	public function commit() {
		if (!$this->autocommit && $this->autocommit > 0) {
			$this->db->commit();
			$this->commitcount = 0;
		}
	}

 /**
  * Rolls back a transaction if {@link autocommit()} is disabled.
  */
	public function rollback() {
		if (!$this->autocommit && $this->commitcount > 0) {
			$this->db->rollBack();
			$this->commitcount = 0;
		}
	}

/**
 * Runs a query against the database, and returns the result (if any) or FALSE
 * if the query fails. Placeholders and prepared statements should be used
 * wherever possible to avoid SQL injection attacks.
 *
 * @param string $query Query string to run, with or without placeholders.
 * @param array|string $data The data to use instead of the placeholders.
 * @param int $start Starting row of returned data.
 * @param int $rows Number of rows to return.
 * @return array|bool Array of results if query is good, FALSE otherwise.
 */
	public function query($query, $data = null, $start = null, $rows = null) {
		$return = null;
		$result = null;
		$db = null;
		$dberror = null;
		if (!is_array($data)) {
			$data = array($data);
		}
		$this->numrows = 0;
		if (isset($start) && isset($rows)) {
			$query .= ' limit '.$start.', '.$rows;
		}
		if (!$this->autocommit && $this->commitcount == 0) {
			$this->commitcount++;
			$this->begin();
		}
		// Check if this query/data has already been run.
		$querycheck = array_keys($this->querylist, $query);
		if (count($querycheck) > 0) {
			for ($i = 0, $c = count($querycheck); $i < $c; $i++) {
				if ($this->datalist[$querycheck[$i]] == json_encode($data)) {
					// Found a match! Return the cached data.
					$return = json_decode($this->resultlist[$querycheck[$i]], true);
				}
			}
		}
		$this->querylist[] = $query;
		$this->datalist[] = json_encode($data);
		//echo '<em>'.$query.'</em><br />';
		if (is_null($return)) {
			if (!$this->db) {
				$this->connect();
			}
			if ($query != $this->lastquery || json_encode($data) != $this->lastdata) {
				$db = $this->db->prepare($query.';');
				$this->lastquery = $query;
			}
			$this->lastdata = json_encode($data);
			$db->execute(array_values($data));
			$dberror = $db->errorInfo();
			if ($dberror[0] == '42S02') {
				// Table not found!
				if (!defined('INSTALL')) {
					locate(HTTP.URL.PORT.'/install/', true);
				}
			}
			$result = $db->fetchAll(PDO::FETCH_ASSOC);
			$this->count++;
			if (!$this->autocommit && $this->commitcount > 0) {
				$this->commitcount++;
			}
			//print_r($result);
			if (!is_bool($result)) {
				$this->numrows = count($result);
				$return = $result;
			}
			if (strtolower(substr($query, 0, 6)) == 'insert') {
				$return = $this->db->lastInsertId();
			}
			$this->resultlist[] = json_encode($return);
		}
		return $return;
	}
}