<?php

class Database
{

//
// MySQLi Object
// @var mysqli
//
private $hMySQLi;

//
// Debugging mode
// @var boolean
//
private $debug;

//
// MySQLi Result object
// @var MySQLi::Result
//
private $hResult;

//
// MySQLi Statement object
// @var MySQLi::STMT
//
private $hStmt;

//
// Parameters for prepared statements
// @var array
//
private $params;

//
// Table prefix
// @var string
//
private $pref;

//
// Bound assoc columns
// @var boolean
//
private $bound;

    //
    // Database constructor
    // -----------------------------------------------------
    // @param   boolean Debugging
    //
    public function __construct($debug = false)
    {
        $this->debug = $debug;
    }

    //
    // Connect to mysql database
    // -----------------------------------------------------
    // @param   string  Hostname
    // @param   string  Username
    // @param   string  Password
    // @param   integer Port
    // @param   boolean Persistente connection
    //
    public function connect($host = '127.0.0.1', $user = 'root', $pass = '', $port = 3306,
        $pref = '', $pconn = false)
    {
        $this->pref = $pref;

        if($pconn)
            $host = 'p:'.$host; // Use persistent connection so prefix host with "p:"
        $this->hMySQLi = @new mysqli($host, $user, $pass, '', $port);
        if(!$this->hMySQLi->connect_error)
            return true;

        $this->debug();
        return false;
    }

    //
    // Closes database connection an deletes mysqli object
    // -----------------------------------------------------
    //
    public function disconnect()
    {
        @$this->hMySQLi->close();
        $this->hMySQLi  = null;
        unset($this->hMySQLi);
    }

    //
    // Returns error and errno if an error occurs
    // -----------------------------------------------------
    // @param   array   error[0] and errno[1]
    // @return  mixed   Error or false on no error
    //
    public function error()
    {
        // Returns errors occurs on establish connection to mysqld
        if($this->hMySQLi->connect_error)
        {
            return array($this->hMySQLi->connect_error, $this->hMySQLi->connect_errno, 'connect');
        }

        // Returns errors occurs on mysql usage
        if($this->hMySQLi->error)
        {
            return array($this->hMySQLi->error, $this->hMySQLi->errno, 'core');
        }

        // Returns errors occurs while executing stmt's
        if(is_object($this->hStmt) && $this->hStmt->error)
        {
            return array($this->hStmt->error, $this->hStmt->errno, 'stmt');
        }

        return false;
    }

    //
    // Selects specified default database for querys
    // -----------------------------------------------------
    // @param   string  Database name
    // @return  boolean Database selection state
    //
    public function dbname($dbName)
    {
        $retVal = @$this->hMySQLi->select_db($dbName);
        $this->debug();

        return $retVal;
    }

    //
    // Executes a query on the mysql server
    // -----------------------------------------------------
    // @param   mixed   Query-String or null on prepared statement
    // @param   mixed   Prepared statement parameter
    // @return  boolean True on success, false on fail
    //
    public function query($query = null, &$args = null)
    {
        if(($query == null) && is_object($this->hStmt))
        {
            // Build parameter array for bind_result
            if(is_array($args))
            {
                $params[0]  = '';
                $count      = count($args);
                for($i=0; $i<$count; $i++)
                {
                    $params[0]  .= $args[$i][0];
                    $params[]   = &$args[$i][1];
                }
                call_user_func_array(array($this->hStmt, 'bind_param'), $params);
            }
            // Execute prepared statement
            $this->hResult  = $this->hStmt->execute();
        } else
        {   // Execute simple statement
            $this->resetStmt();
            $query  = preg_replace("/::/", $this->pref, $query, 1);
            $this->hResult  = $this->hMySQLi->query($query);
        }

        if($this->hResult)
            return true;

        $this->debug();
        return false;
    }

    //
    // Fetch result as assoc array
    // -----------------------------------------------------
    // @return  mixed   Assoc-Array or FALSE
    //
    public function fetch()
    {
        if(is_object($this->hStmt))
        {
            // Bind columns as references for assoc result
            if($this->bound === false)
            {
                $fields     = array();
                $meta       = $this->hStmt->result_metadata();
                $columns    = $meta->fetch_fields();
                foreach($columns as $column)
                {
                    $fields[]   = &$this->bound[$column->name];
                }
                call_user_func_array(array($this->hStmt, 'bind_result'), $fields);
            }

            // Fillout assoc result
            if($this->hStmt->fetch())
                return $this->bound;
        } elseif($this->hResult)
            return $this->hResult->fetch_assoc();

        return false;
    }

    //
    // Fetch all rows into one array
    // -----------------------------------------------------
    // @return  mixed   Assoc-Array or FALSE
    //
    public function fetchAll()
    {
        $result = array();
        while($result[] = $this->fetch()) {}
        if(count($result))
            return $result;

        return array();
    }

    //
    // Prepares query for execution
    // -----------------------------------------------------
    // @param   string  Query
    // @return  boolean Prepare state
    //
    public function prepare($query)
    {
        $query = preg_replace("/::/", $this->pref, $query, 1);

        $this->resetStmt();
        if($this->hStmt = $this->hMySQLi->prepare($query))
            return true;

        $this->debug();
        return false;
    }

    //
    // Starts transaction if database engine
    // supports it (like InnoDB, NOT MyISAM)
    // -----------------------------------------------------
    //
    public function transaction()
    {
        $this->resetStmt();
        // Disable autocommit so transactions are not commited automatically (Transaction begin)
        $this->hMySQLi->autocommit(false);

        $this->debug();
    }

    //
    // Rollbacks active transaction
    // -----------------------------------------------------
    //
    public function rollback()
    {
        $this->hMySQLi->rollback();
        // Re-Enable autocommit (Transaction end)
        $this->hMySQLi->autocommit(true);

        $this->debug();
    }

    //
    // Commits active transaction
    // -----------------------------------------------------
    //
    public function commit()
    {
        $this->hMySQLi->commit();
        // Re-Enable autocommit (Transaction end)
        $this->hMySQLi->autocommit(true);

        $this->debug();
    }

    //
    // Frees result and stmt objects used memory
    // -----------------------------------------------------
    //
    public function setPrefix($prefix)
    {
        $this->pref = $prefix;
    }

    //
    // Frees result and stmt objects used memory
    // -----------------------------------------------------
    //
    private function resetStmt($null = true)
    {
        if(is_object($this->hStmt))
        {
            // Reset statement-obj if initialized
            @$this->hStmt->free_result();
            @$this->hStmt->close();
            if($null)
                $this->hStmt    = null;
        } elseif(is_object($this->hResult))
        {
            // Reset result-obj
            @$this->hResult->free();
            @$this->hResult->close();
            if($null)
                $this->hStmt    = null;
        }
        $this->bound    = false;
    }

    //
    // Gets the number of rows in a result
    // -----------------------------------------------------
    // @return  integer Result rows
    //
    public function count()
    {
        if(is_object($this->hResult))
            return $this->hResult->num_rows;

        if(is_object($this->hStmt))
            return $this->hStmt->num_rows;
    }

    //
    // Gets the number of affected rows in a
    // previous MySQL operation
    // -----------------------------------------------------
    // @return  integer Affected rows
    //
    public function affected()
    {

    }

    //
    // Debugging function displays error messages if an error
    // occurs
    // -----------------------------------------------------
    //
    private function debug()
    {
        if($this->debug)
        {
            $error = $this->error();
            if($error)
            {
                echo "\nMySQLi - Debugging Mode ({$error[2]}):\n----------------------------------\n";
                echo "Error: {$error[0]}\nErrno: {$error[1]}\n\n";
            }
        }
    }

}

?>