<?php
class Kram_Sql_Mysql extends Kram_Object implements IKram_Sql_Module
{
    private $hostname;
    private $username;
    private $password;
    private $database;
    private $charset;
    /** @var resource, last query resource */
    private $result;

    /** @var array $connect_resource, all resources  */
    static private $connect_resource = array();

    /**
     * Set conf
     * @param string $hostname
     * @param string $username
     * @param string $password
     * @param string $database
     * @param string $charset
     * @return Kram_Sql_Mysql
     */
    function Kram_Sql_Mysql($hostname, $username, $password, $database, $charset)
    {
        $this->hostname = $hostname;
        $this->username = $username;
        $this->password = $password;
        $this->database = $database;
        $this->charset  = $charset;
    }

    public function query($pattern, $args = array())
    {
        $query = $this->executePattern($pattern, $args);
        $result = mysql_query($query, $this->getResourceConnection());
        if ($result === false)
        {
            throw new Kram_Exception("Query cannot be execute: $query. Error: " .
            mysql_error($this->getResourceConnection()));
        }

        $this->result = $result;
        return $this->result;
    }

    public function insert($arr, $table = null)
    {
        $keys = array();
        $values = array();

        if (is_array($arr) && count($arr) > 0)
        {
            foreach ($arr as $column => $value)
            {
                $keys[] = $column;
                $values[] = $this->safeData($value);
            }
        }

        $pattern = "INSERT INTO $table (" . implode(',', $keys) . ") VALUES (" . implode(',', $values) . ")";
        $this->query($pattern);

        return $this->isError();
    }

    public function delete($table = null, $where = null, $args = array())
    {
        $pattern = "DELETE FROM $table ";
        if ($where !== null)
        {
            $where = $this->executePattern($where, $args);
            $pattern .= "WHERE $where";
        }

        $this->query($pattern);

        return $this->isError();
    }

    public function update($data, $table = null, $where = null, $args = array())
    {
        $pattern = null;
        $set = null;

        if (is_array($data) && count($data) > 0)
        {
            $i = 0;
            foreach ($data as $column => $value)
            {
                $set .= "$column = " . $this->safeData($value);
                if ($i < count($data)-1)
                {
                    $set .= ",";
                }
                $i++;
            }
        }

        $where = $this->executePattern($where, $args);
        $pattern = "UPDATE $table SET $set WHERE $where";
        $this->query($pattern);

        return $this->isError();
    }

    public function fetchAll($res = null)
    {
        $arr = false;

        if ($res === null)
        {
            $res = $this->result;
        }

        if ($this->numRows($res) > 0)
        {
            $arr = array();
            $i = 0;
            while ($row = mysql_fetch_array($res))
            {
                foreach ($row as $column => $value)
                {
                    if (!is_numeric($column))
                    {
                        $arr[$i][$column] = $this->changeType($value);
                    }
                }
                $i++;
            }
        }

        return $arr;
    }

    public function fetchRow($row = 0, $col = null, $res = null)
    {
        if ($res === null)
        {
            $res = $this->result;
        }

        $data = $this->changeType(mysql_result($res, $row, $col));

        return $data;
    }

    public function numRows($res = null)
    {
        if ($res === null)
        {
            $res = $this->result;
        }
        return mysql_num_rows($res);
    }

    public function affectedNumRows()
    {
        return mysql_affected_rows($this->getResourceConnection());
    }

    public function insertID()
    {
        return mysql_insert_id($this->getResourceConnection());
    }

    /**
     * is connected to MySQL DB
     * @return boolean
     */
    private function isConnect()
    {
        if (!isset(self::$connect_resource[$this->getAlias()]))
        {
            return false;
        }

        return true;
    }

    /**
     * Connect to SQL server
     * @return void
     */
    private function connect()
    {
        $conn = mysql_connect($this->hostname,
                              $this->username,
                              $this->password);
        if (!is_resource($conn))
        {
            throw new Kram_Exception("Connection to SQL server not be a success.");
        }
        else if (!mysql_select_db($this->database, $conn))
        {
            throw new Kram_Exception("Database does not exist.");
        }
        else
        {
            self::$connect_resource[$this->getAlias()] = $conn;
            $this->query("SET NAMES $this->charset");
        }
    }

    /**
     * Get alias by setted hostname and database name
     * @return string
     */
    private function getAlias()
    {
        return $this->hostname . ':' . $this->database;
    }

    /**
     * Get actual resource connection
     * @return resource
     */
    private function getResourceConnection()
    {
        if (!$this->isConnect())
        {
            $this->connect();
        }

        return self::$connect_resource[$this->getAlias()];
    }

    /**
     * Safe data for MySQL
     * @param string|int $mixed
     * @return safe string
     */
    private function safeData($mixed)
    {
        if (is_numeric($mixed))
        {
            return intval($mixed);
        }

        return "'" . mysql_real_escape_string($mixed, $this->getResourceConnection()) . "'";
    }

    private function executePattern($pattern, $args = array())
    {
        $union = key($args);
        $newPattern = null;

        if (strlen($pattern) > 0 && strpos($pattern, '?') !== false && is_array($args) && count($args) > 0)
        {
            for ($i = 0; $i < strlen($pattern); $i++)
            {

                if ($pattern[$i] == '?')
                {
                    $newPattern .= $this->safeData($args[$union]);
                    $union++;
                }
                else
                {
                    $newPattern .= $pattern[$i];
                }
            }
        }
        else
        {
            $newPattern = $pattern;
        }
        return $newPattern;
    }

    private function isError()
    {
        if ($this->affectedNumRows() <= 0)
        {
            return false;
        }

        return true;
    }

    private function changeType($mixed)
    {
        if (is_numeric($mixed))
        {
            $mixed = (int) $mixed;
        }
        return $mixed;
    }
}