<?php defined('IN_CMS') or die('No direct access allowed.');

class Db {

	private static $driver = 'mysql';
	private static $hostname, $username, $password, $database;
	private static $driver_options = array();

	private static $dbh = null;
	private static $debug = false;
	private static $affected_rows = 0;
	private static $profile = array();

	public static function connect() {
		// config
		$params = Config::get('database');

		// set default mysql port number
		if(empty($params['port'])) {
			$params['port'] = 3306;
		}

		// set default collation
		if(empty($params['collation'])) {
			$params['collation'] = 'utf8_bin';
		}

		// set debug mode
		static::$debug = Config::get('debug', false);
		
		// build dns string
		$dsn = 'mysql:dbname=' . $params['name'] . ';host=' . $params['host'] . ';port=' . $params['port'];

		// mysql driver options
		$options = array(PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\' COLLATE ' . $params['collation']);

		// try connection
		static::$dbh = new PDO($dsn, $params['username'], $params['password'], $options);
		
		// set error handling to exceptions
		static::$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

		return true;
	}

	public static function close() {
		static::$dbh = null;
	}

	private static function profiling($statement, $binds, $start) {
		static::$profile[] = array(
			'sql' => $statement->queryString,
			'binds' => $binds,
			'time' => round(microtime(true) - $start, 4),
			'rows' => $statement->rowCount()
		);
	}

	public static function profile() {
		return static::$profile;
	}

	/*
	 * Querying
	 */
	public static function query($sql, $binds = array()) {
		// make sure we have a connection
		if(is_null(static::$dbh)) {
			static::connect();
		}
	
		// check binds
		if(!is_array($binds)) {
			$binds = array($binds);
		}

		// profile in debug mode
		if(static::$debug) {
			$start = microtime(true);
		}

		// prepare
		$sth = static::$dbh->prepare($sql);

		// bind params
		$reflector = new ReflectionMethod('PDOStatement', 'bindValue');

		foreach($binds as $index => $value) {
			$key = is_int($index) ? $index + 1 : $index;
			$type = is_bool($value) ? PDO::PARAM_BOOL : (is_int($value) ? PDO::PARAM_INT : PDO::PARAM_STR);
			$reflector->invokeArgs($sth, array($key, $value, $type));
		}

		// get results
		$sth->execute();

		// profile in debug mode
		if(static::$debug) {
			static::profiling($sth, $binds, $start);
		}

		// update affected rows
		static::$affected_rows = $sth->rowCount();

		// return statement
		return $sth;
	}

	/*
	 * Simple query, returns TRUE or FALSE
	 */
	public static function exec($sql, $binds = array()) {
		// make sure we have a connection
		if(is_null(static::$dbh)) {
			static::connect();
		}

		// check binds
		if(!is_array($binds)) {
			$binds = array($binds);
		}

		// profile in debug mode
		if(static::$debug) {
			$start = microtime(true);
		}

		// prepare
		$sth = static::$dbh->prepare($sql);

		// bind params
		$reflector = new ReflectionMethod('PDOStatement', 'bindValue');

		foreach($binds as $index => $value) {
			$key = is_int($index) ? $index + 1 : $index;
			$type = is_bool($value) ? PDO::PARAM_BOOL : (is_int($value) ? PDO::PARAM_INT : PDO::PARAM_STR);
			$reflector->invokeArgs($sth, array($key, $value, $type));
		}

		// get results
		$result = $sth->execute();

		// profile in debug mode
		if(static::$debug) {
			static::profiling($sth, $binds, $start);
		}

		// update affected rows
		static::$affected_rows = $sth->rowCount();

		// return result
		return $result;
	}
	
	/*
	 * Shortcuts
	 */
	public static function update($table, $columns = array(), $condition = array()) {
		$updates = array();
		$args = array();

		foreach($columns as $key => $value) {
			$updates[] = '`' . $key . '` = ?';
			$args[] = $value;
		}
		
		$sql = "update `" . $table . "` set " . implode(', ', $updates);
		
		if(count($condition)) {
			$where = array();

			foreach($condition as $key => $value) {
				$where[] = '`' . $key . '` = ?';
				$args[] = $value;
			}

			$sql .= " where " . implode(' and ', $where);
		}	
		
		return Db::exec($sql, $args);
	}

	public static function insert($table, $row = array()) {
		$keys = array();
		$values = array();
		$args = array();
		
		foreach($row as $key => $value) {
			$keys[] = '`' . $key . '`';
			$values[] = '?';
			$args[] = $value;
		}
		
		$sql = "insert into `" . $table . "` (" . implode(', ', $keys) . ") values (" . implode(', ', $values) . ")";	

		return Db::exec($sql, $args);
	}

	public static function delete($table, $condition = array()) {
		$sql = "delete from `" . $table . "`";
		
		if(count($condition)) {
			$where = array();

			foreach($condition as $key => $value) {
				$where[] = '`' . $key . '` = ?';
				$args[] = $value;
			}

			$sql .= " where " . implode(' and ', $where);
		}	
		
		return Db::exec($sql, $args);
	}

	public static function row($sql, $binds = array(), $fetch_style = PDO::FETCH_OBJ) {
		// get statement
		$stm = static::query($sql, $binds);

		// return data
		return $stm->fetch($fetch_style);
	}

	public static function results($sql, $binds = array(), $fetch_style = PDO::FETCH_OBJ) {
		// get statement
		$stm = static::query($sql, $binds);

		// return data array
		return $stm->fetchAll($fetch_style);
	}

	public static function column($sql, $binds = array(), $column_number = 0) {
		// get statement
		$stm = static::query($sql, $binds);

		// return data
		return $stm->fetchColumn($column_number);
	}

	public static function pairs($sql, $binds = array()) {
		// get result set
		$results = static::results($sql, $binds, PDO::FETCH_NUM);

		if(is_array($results) === false) {
			return false;
		}

		// pair them up
		$pairs = array();

		foreach($results as $row) {
			foreach(array_chunk($row, 2) as $pair) {
				if(count($pair) != 2) {
					continue;
				}

				list($key, $value) = $pair;
				$pairs[$key] = $value;
			}
		}

		// return pairs
		return $pairs;
	}

	public static function insert_id() {
		return static::$dbh->lastInsertId();
	}

	public static function affected_rows() {
		return static::$affected_rows;
	}

}