<?php

/* Copyright 2009 Mo McRoberts.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The names of the author(s) of this software may not be used to endorse
 *    or promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * AUTHORS OF THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


class DBCore
{
	protected $rsClass;

	public function vquery($query, $params)
	{
		if(!is_array($params)) $params = array();
		$sql = preg_replace('/\?/e', "\$this->quote(array_shift(\$params))", $query);
		return $this->execute($sql);
	}

	public function exec($query)
	{
		$params = func_get_args();
		array_shift($params);
		if($this->vquery($query, $params))
		{
			return true;
		}
		return false;
	}

	/* $rs = $inst->query('SELECT * FROM `sometable` WHERE `field` = ? AND `otherfield` = ?', $something, 27); */
	public function query($query)
	{
		$params = func_get_args();
		array_shift($params);
		if(($r =  $this->vquery($query, $params)))
		{
			return new $this->rsClass($this, $r);
		}
		return null;
	}

	public function getRow($query)
	{
		$row = null;
		$params = func_get_args();
		array_shift($params);
		if(($r =  $this->vquery($query, $params)))
		{
			$rs = $this->rsClass($this, $r);
			$row = $rs->next();
			$rs = null;
		}
		return $row;
	}

	protected function reportError($errmsg, $sqlString)
	{
		ini_set('display_errors', 'On');
		trigger_error($errmsg . ' while executing ' . $sqlString, E_USER_ERROR);
	}

	public function insert($table, $kv)
	{
		$keys = array_keys($kv);
		$values = array_values($kv);
		array_walk($keys, array($this, 'quoteObjectRef'));
		array_walk($values, array($this, 'quoteRef'));
		$sql = 'INSERT INTO ' . $this->quoteObject($table) . '(' . implode(',', $keys) . ') VALUES (' . implode(',', $values) . ')';
		return $this->execute($sql);
	}

	public function update($table, $kv, $clause)
	{
		$sql = 'UPDATE ' . $this->quoteObject($table) . ' SET ';
		foreach($kv as $key => $value)
		{
			$sql .= $this->quoteObject($key) . ' = ' . $this->quote($value) . ', ';
		}
		$sql = substr($sql, 0, -2);
		if(is_string($clause) && strlen($clause))
		{
			$sql .= ' WHERE ' . $clause;
		}
		else if(is_array($clause) && count($clause))
		{
			$sql .= ' WHERE ';
			foreach($clause as $key => $value)
			{
				$sql .= $this->quoteObject($key) . ' = ' . $this->quote($value) . ' AND ';
			}
			$sql = substr($sql, 0, -4);
		}
		return $this->execute($sql);
	}

	public function quoteObject($name)
	{
		return '"' . $name . '"';
	}

	public function quoteRef(&$value)
	{
		$value = $this->quote($value);
	}

	public function quoteObjectRef(&$name)
	{
		$name = $this->quoteObject($name);
	}

}

/* while(($row = $rs->next())) { ... } */
class DBDataSet
{
	public $fields = array();
	public $EOF = true;
	public $db;
	protected $resource;

	public function __construct($db, $resource)
	{
		$this->db = $db;
		$this->resource = $resource;
		$this->EOF = false;
	}

	public function next()
	{
		if($this->EOF) return false;
		if(!$this->getRow())
		{
			$this->EOF = true;
			return null;
		}
		return $this->fields;
	}
}

class MySQL extends DBCore
{
	protected $rsClass = 'MySQLSet';
	protected $mysql;

	public function __construct($name = null, $host = null, $user = null, $pass = null)
	{
		if(!($this->mysql = mysql_connect($host, $user, $pass)))
		{
			$this->raiseError(null);
		}
		if(!mysql_select_db($name, $this->mysql))
		{
			$this->raiseError(null);
		}
	}

	public function quoteObject($name)
	{
		return '`' . $name . '`';
	}

	protected function execute($sql)
	{
		$r = mysql_query($sql, $this->mysql);
		if($r === false)
		{
			$this->raiseError($sql);
		}
		return $r;
	}

	protected function raiseError($query)
	{
		return $this->reportError(mysql_error($this->mysql), $query);
	}

	public function quote($string)
	{
		if(is_null($string))
		{
			return 'NULL';
		}
		if(is_bool($string))
		{
			return ($string ? "'Y'" : '"N"');
		}
		return "'" . mysql_real_escape_string($string, $this->mysql) . "'";
	}

	public function getRow($query)
	{
		$row = null;
		$params = func_get_args();
		array_shift($params);
		if(($r =  $this->vquery($query . ' LIMIT 1', $params)))
		{
			$row = mysql_fetch_assoc($r);
		}
		return $row;
	}

	public function insertId()
	{
		return mysql_insert_id($this->mysql);
	}

}

class MySQLSet extends DBDataSet
{
	protected function getRow()
	{
		return ($this->fields = mysql_fetch_assoc($this->resource));
	}
}

global $DB;

$DB = new MySQL(DB_NAME, DB_HOST, DB_USER, DB_PASSWORD);