<?php
class DBInterface {
    /************************************************************************************
    *   Author: Bill Nalesnik
    *   Date: 7/2/2008
    *   This class will handle database interactions
    ************************************************************************************/

    var $dbuser = 'dbuser';     // default database user name
    var $dbpass = 'dbpass';     // default database password
    var $dbhost = 'dbhost';     // default database host
    var $dbname = 'nrfadmin_NRF';       // default database to connect to

    var $dbport = 'dbport';

    /***
     * Properties
     */
    var $link;  // link to the database to use anywhere it is needed
    var $result;    // resultset of queries that return one
    var $sql;   // the actual sql of the query to be run
    var $last_id;   // If an 'INSERT' query is run, this contains the id of the last inserted row
    var $rows;  // The number of rows affected or returned by a query

    /***
     * This is the constructor function that will allow this to work in PHP 4 and 5
     * @return void
     */
    function DBInterface() {
        //destructor
        register_shutdown_function(array(&$this, '__destruct'));

        //constructor
        $argcv = func_get_args();
        call_user_func_array(array(&$this, '__construct'), $argcv);
    }

    /***
     * Constructor - initiates a connection to the database if desired
     * @return void
     * @param $db Object[optional] Name of the database to connect to
     * @param $cn Object[optional] Boolean to determine if a connection should be made
     */
    function __construct($db = '', $cn = true) {
        $this->dbname = ($db == '' ? $this->dbname : $db);

        if ($cn === true) {
            $this->db_connect();
        }
    }

    /***
     * Actually connect to a database
     * @return boolean true on success, false on failure
     * @param $db Object name of database to connect to
     */
    function db_connect() {
        // In order to minimize the performance bottlenecks, we are going to open a
        //  persistent connection
        $this->link = @mysql_connect($this->dbhost, $this->dbuser, $this->dbpass, true);

        if ($this->link) {
            mysql_select_db($this->dbname, $this->link);
            return true;
        }
        else {
            return false;
        }
    }

    /***
     * Run a mysql query.  If a result is obtained, then the number of rows is updated
     * @return Boolean true if successful false on falure
     */
    function db_query() {
        $this->result = @mysql_query($this->sql, $this->link);

        if ($this->result) {
            $this->rows = mysql_numrows($this->result);
            return true;
        }
        else {
            return false;
        }
    }

    /***
     * Runs a mysql action query (INSERT, DELETE, UPDATE...).
     *  If the query is an insert query, this function will also
     *  populate the last_id property with the id number of the last
     *  inserted record.  The rows property of the class is also updated
     * @param extra[optional] Boolean determines if the extra operations are done
     * @return Boolean true if query runs successfully false on falure
     */
    function db_action_query($extra=true) {
        $a = strpos(strtoupper($this->sql), "INSERT");

        mysql_query($this->sql, $this->link);

        if ($extra) {
            $this->rows = mysql_affected_rows($this->link);

            if ($a !== false) {
                $this->last_id = mysql_insert_id($this->link);
            }
        }

        return ($this->rows !== -1 ? true : false);
    }

    /***
     * Wrapper function for mysql_fetch_assoc
     * @return Returns an associative array that corresponds to the
     *          fetched row and moves the internal data pointer ahead.
     */
    function get_row() {
        return mysql_fetch_assoc($this->result);
    }

    /***
     * Moves the data pointer of a resultset back to the beginning.
     * @return boolean true on success, false on failure
     */
    function rewind() {
        return mysql_data_seek($this->link, 0);
    }

    /***
     * Cleanup function which closes the database connection and unsets
     * the resultset variable
     * @return void
     */
    function db_close() {
        @mysql_free_result($this->result);
        @mysql_close($this->link);
    }

    function __destruct() {
        $this->db_close();
    }
}
?>