<?php
/**
 * Support for MySQL, MySQLi, MS SQL & PostgreSQL
 *
 * @author Richard Rowe <inbox@richardrowe.net>
 *
 */

/**
 * @todo Improve error handling
 * @todo Some bug fixing / testing in mysqli class
 * @todo Test MS SQL, MySQL & PostgreSQL classes
 */

interface db_base
{
    public function __construct($host = null, $user = null, $pass = null, $dbname = null);
    public function close();
    public function affected_rows();
    public function fetchrow($result = false);
    public function freeresult($result = false);
    public function insert_id();
    public function num_rows($result = false);
    public function query($sql);
    public function escape_string($str);
    public function error($str);
}


class db_mssql implements db_base
{
    public $link;
    public $result;
    public $error;

    public function __construct($host = null, $user = null, $pass = null, $dbname = null)
    {
        /**
         * Open MS SQL server connection
         */
        if (!$this->link = mssql_connect($host, $user, $pass))
	{
            // error!
            trigger_error('Could not connect to the database.', E_USER_ERROR);
	}

        /**
         * Select MS SQL database
         */
	if (!mssql_select_db($dbname, $this->link))
	{
            // error!
            trigger_error('Could not select the database.', E_USER_ERROR);
	}
    }

    /**
     * Close MS SQL Server connection
     */
    public function close()
    {
	if (!mssql_close($this->link))
	{
            // error!
            trigger_error('Could not close the database.', E_USER_ERROR);
	}

	return true;
    }

    /**
     * Returns the number of records affected by the query
     */
    public function affected_rows()
    {
	return $this->link ? mssql_rows_effected($this->link) : false;
    }

    /**
     * Get row as enumerated array
     */
    public function fetchrow($result = false)
    {
	return $result ? mssql_fetch_assoc($result) : mssql_fetch_assoc($this->result);
    }

    /**
     * Free result memory
     */
    public function freeresult($result = false)
    {
        return $result ? mssql_free_result($result) : mssql_free_result($this->result);
    }

    /**
     * Method taken from phpBB.
     */
    public function insert_id()
    {
		if ($result = mssql_query('SELECT SCOPE_IDENTITY()', $this->link))
		{
			if ($row = mssql_fetch_assoc($result))
			{
				mssql_free_result($result);
				return $row['computed'];
			}

			mssql_free_result($result);
        }

		return false;
    }

    /**
     * Gets the number of rows in result
     */
    public function num_rows($result = false)
    {
        return $result ? mssql_num_rows($result) : mssql_num_rows($this->result);
    }

    /**
     * Send MS SQL query
     */
    public function query($sql)
    {
        if (!$this->result = mssql_query($sql, $this->link))
        {
            // error!
            //trigger_error('<strong>Query error:</strong><br />', E_USER_ERROR);
        }

        return $this->result;
    }

    /**
     * Escapes special characters in a string for use in a SQL statement
     *
     * @param string $str The string that is to be escaped.
     * @return string Returns the escaped string.
     */
    public function escape_string($str)
    {
        // Magic Quotes escapes all incoming data to the PHP script.
        if (ini_get('magic_quotes_gpc'))
        {
            // To avoid escaping the string twice, stripslashes
            $str = stripslashes($str);
        }

        return str_replace('\'', '\'\'', $str);
    }

    public function error($str)
    {
        return $this->error = $str;
    }
}


/**
 * @todo public function insert_id()
 */
class db_postgresql implements db_base
{
    public $link;
    public $result;
    public $error;

    public function __construct($host = null, $user = null, $pass = null, $dbname = null)
    {
        if (!$this->link = pg_connect("host = $host, dbname = $dbname, user = $user, password = $pass"))
        {
            // error!
            trigger_error('Could not connect and / or select the database.', E_USER_ERROR);
        }
    }

    /**
     * Closes a PostgreSQL connection
     */
    public function close()
    {
        if (!pg_close($this->link))
        {
            // error!
            trigger_error('Could nto close the database.', E_USER_ERROR);
        }

        return true;
    }

    /**
     * Returns number of affected records (tuples)
     */
    public function affected_rows()
    {
        return $this->link ? pg_affected_rows($this->link) : false;
    }

    /**
     * Fetch a row as an associative array
     */
    public function fetchrow($result = false)
    {
         return $result ? pg_fetch_assoc($result) : pg_fetch_assoc($this->result);
    }

    /**
     * Free result memory
     */
    public function freeresult($result = false)
    {
         return $result ? pg_free_result($result) : pg_free_result($this->result);
    }

    /**
     *
     */
    public function insert_id()
    {
        //return pg_last_oid($this->link);
    }

    /**
     * Returns the number of rows in a result
     */
    public function num_rows($result = false)
    {
        return $result ? pg_num_rows($result) : pg_num_rows($this->result);
    }

    /**
     * Execute a query
     */
    public function query($sql)
    {
        if (!$this->result = pg_query($this->link, $sql))
        {
            // error!
            trigger_error('<strong>Query failed:</strong><br />' . pg_result_error($this->result), E_USER_ERROR);
        }

        return $this->result;
    }

    /**
     * Escape a string for insertion into a text field
     *
     * @param string $str A string containing text to be escaped.
     * @return A string containing the escaped data.
     */
    public function escape_string($str)
    {
        // Magic Quotes escapes all incoming data to the PHP script.
        if (ini_get('magic_quotes_gpc'))
        {
            // To avoid escaping the string twice, stripslashes
            $str = stripslashes($str);
        }

        return pg_escape_string($this->link, $str);
    }

    public function error($str)
    {
        return $this->error = $str;
    }
}


class db_mysql implements db_base
{
    public $link;
    public $result;
    public $error;

    public function __construct($host = null, $user = null, $pass = null, $dbname = null)
    {
        // Open a connection to a MySQL Server
    	if (!$this->link = mysql_connect($host, $user, $pass, true))
    	{
            trigger_error('<strong>Could not connect to the database:</strong><br />' . mysql_error(), E_USER_ERROR);
	}

        // Select a MySQL database
	if (!mysql_select_db($dbname, $this->link))
	{
            trigger_error('<strong>Could not select the database:</strong><br />' . mysql_error(), E_USER_ERROR);
        }
    }

    /**
    * Close MySQL connection
    */
    public function close()
    {
        if (!mysql_close($this->link))
        {
            // error!
            trigger_error('Could not close the database.', E_USER_ERROR);
        }

        return true;
    }

    /**
    * Get number of affected rows in previous MySQL operation
    */
    public function affected_rows()
    {
        return $this->link ? mysql_affected_rows($this->link) : false;
    }

    /**
    * Fetch a result row as an associative array
    *
    * @param resource $result The result resource that is being evaluated. This result comes from a call to mysql_query().
    */
    public function fetchrow($result = false)
    {
        return $result ? mysql_fetch_assoc($result) : mysql_fetch_assoc($this->result);
    }

    /**
    * Free result memory
    *
    * @param resource $result The result resource that is being evaluated. This result comes from a call to mysql_query().
    */
    public function freeresult($result = false)
    {
        return $result ? mysql_free_result($result) : mysql_free_result($this->result);
    }

    /**
    * Get the ID generated from the previous INSERT operation
    */
    public function insert_id()
    {
        return $this->link ? mysql_insert_id($this->link) : false;
    }

    /**
    * Get number of rows in result
    *
    * @param resource $result The result resource that is being evaluated. This result comes from a call to mysql_query().
    */
    public function num_rows($result = false)
    {
        return $result ? mysql_num_rows($result) : mysql_num_rows($this->result);
    }

    /**
    * Send a MySQL query
    *
    * @param string $sql A SQL query. The query string should not end with a semicolon.
    */
    public function query($sql)
    {
        if (!$this->result = mysql_db_query($sql, $this->link))
        {
            // error!
            trigger_error('<strong>Query error:</strong><br />' . mysql_error($this->link), E_USER_ERROR);
        }

        return $this->result;
    }

    /**
    * Escapes special characters in a string for use in a SQL statement
    *
    * @param string $str The string that is to be escaped.
    * @return string Returns the escaped string, or FALSE on error.
    */
    public function escape_string($str)
    {
        // Magic Quotes escapes all incoming data to the PHP script.
        if (ini_get('magic_quotes_gpc'))
        {
            // To avoid escaping the string twice, stripslashes
            $str = stripslashes($str);
        }

        return mysql_real_escape_string($str, $this->link);
    }

    public function error($str)
    {
        return $this->error = $str;
    }
}


class db_mysqli implements db_base
{
    public $link;
    public $result;
    public $errors;

    public function __construct($host = null, $user = null, $pass = null, $dbname = null)
    {
        if (!$this->link = new mysqli($host, $user, $pass, $dbname))
        {
            // error!
            trigger_error('Could not connect to the database', E_USER_ERROR);
        }
    }

    /**
     * Closes a previously opened database connection
     */
    public function close()
    {
        if (!$this->link->close())
        {
            // error!
            trigger_error('Failed to close database.', E_USER_ERROR);
        }

        return true;
    }

    /**
     * Gets the number of affected rows in a previous MySQL operation
     */
    public function affected_rows()
    {
        return $this->link ? $this->link->affected_rows() : false;
    }


    /**
     * Fetch a result row as an associative array
     *
     * @param $result Returned by $this->query($sql)
     */
    public function fetchrow($result = false)
    {
        return $result ? $result->fetch_assoc() : $this->link->fetch_assoc();
    }

    /**
     * Frees the memory associated with a result
     *
     * @param $result Returned by $this->query($sql)
     */
    public function freeresult($result = false)
    {
        return $result ? $result->free() : $this->result->free();
    }

    /**
     * Returns the auto generated id used in the last query
     */
    public function insert_id()
    {
        return $this->link ? $this->link->insert_id() : false;
    }

    /**
     * Gets the number of rows in a result
     *
     * @param $result Returned by $this->query($sql)
     */
    public function num_rows($result = false)
    {
        //$result->num_rows()
        return $result ? mysqli_num_rows($result) : $this->result->num_rows();
    }

    /**
     * Performs a query on the database
     *
     * @param $sql The query string
     */
    public function query($sql)
    {
        if (!$this->result = $this->link->query($sql))
        {
			// error!
            trigger_error('<strong>Query error:</strong><br />' . mysqli_error($this->link) . '<br />File: ' . __FILE__ . '<br />Line: ' . __LINE__, E_USER_ERROR);
        }

        return $this->result;
    }

    /**
    * Escapes special characters in a string for use in a SQL statement, taking into account the current charset of the connection
    *
    * @param string $str The string to be escaped.
    * @return string Returns an escaped string.
    */
    public function escape_string($str)
    {
        // Magic Quotes escapes all incoming data to the PHP script.
        if (ini_get('magic_quotes_gpc'))
        {
            // To avoid escaping the string twice, we use stripslashes
            $str = stripslashes($str);
        }

        return $this->link->real_escape_string($str);
    }

    public function error($str)
    {
        return $this->error = $str;
    }
}

?>