<?php
/*
**	$Id$
**
**	ITools - the Internet Tools Library
**
**	Copyright (C) 1995-2003 by the ITools Authors.
**	This program is free software; you can redistribute it and/or
**	modify it under the terms of either the GNU General Public License
**	or the GNU Lesser General Public License, as published by the Free
**	Software Foundation. See http://www.gnu.org/licenses/ for details.
**
**	dbi.class - UltraFlexible Database Interface 3000
*/

class it_dbi
{
	# Default configuration of dbi class
	var $_defaultconfig = array
	(
		'db' => null,
		'server' => "localhost",
		'server_update' => null,
		'user' => "itools",
		'pw' => "24%^jXC~",
		'safety' => 1,		/* 0= never die, 1=die if query invalid, 2=die also if no results */
		'keyfield' => "ID",
		'createclasses' => false,
		'classprefix' => "",
		'autoincrement' => true,
		'randomid' => false,
		'sqllog' => false,
		'persistent' => false,
	);

	# Key of currently loaded record or null (public readonly)
	var $_key;

	# Array of name => length of table fields
	var $_fields;


/**
 * Constructor: Initialize the DBI interface
 * @param $config array(key => value) of configuration data
 * @param $query Optional initial query to run
 */
function it_dbi($config, $query = null)
{
	# Shortcut: String config means use this table with default values
	if (!is_array($config))
		$config = array('table' => $config);

	# Create current settings
	foreach ($config + $this->_defaultconfig as $key => $value)
	{
		$var = "_$key";
		$this->$var = $value;
	}
	unset($this->_defaultconfig);	/* to shorten print_r() output */

	if (!isset($this->_db))
		if($config['home'] && ($site = it::match( "/www/([^/]+)", $config['home'])))
			$this->_db = strtr( $site, ".-", "__" );
		else
			$this->_db = $GLOBALS['ULTRADB'];

	$dbid = "$this->_db/$this->_server/$this->_user";

	if (!($this->_link = $GLOBALS['it_dbi_link'][$dbid]))
	{
		# Use persistent connections but prevent reuse if only DB differs
		if (!$this->_persistent || $GLOBALS['it_dbi_connected']["$this->_server/$this->_user"]++)
			$this->_link = @mysql_connect($this->_server, $this->_user, $this->_pw, true);
		else
			$this->_link = @mysql_pconnect($this->_server, $this->_user, $this->_pw);

		if (!$this->_link)
		{
			# One retry after a short delay (always non-persistent)
			it::log('sqllog', "it_dbi(): retrying DB link (mysql_connect $this->_server, $this->_db): " . mysql_error());
			sleep(1);
			$this->_link = @mysql_connect($this->_server, $this->_user, $this->_pw, true);
		}

		if (!$this->_link)
			$this->_fatal("it_dbi(): can't create DB link (mysql_connect $this->_server, $this->_db): " . mysql_error());

		if (!(@mysql_select_db($this->_db, $this->_link)))
			$this->_fatal("it_dbi(): can't select database \"$this->_db\": " . mysql_error($this->_link));

		$GLOBALS['it_dbi_link'][$dbid] = $this->_link;
	}

	if ($this->_createclasses)
	{
		if (!($tables = mysql_list_tables($this->_db, $this->_link)))
			$this->_fatal("it_dbi(): can't list on tables \"$this->_db\": " . mysql_error($this->_link));

		$defaults = '';
		foreach($config as $key => $value)
			if ($key != 'createclasses')
				$defaults .= "'$key' => '".strtr($value, array('\'' => '\\\'', '$' => '\\$'))."', ";

		for ($i = 0; $i < mysql_num_rows($tables); $i++)
		{
			$table = mysql_tablename($tables, $i);
			$classname = "$this->_classprefix$table";

			$result = mysql_list_fields($this->_db, $table, $this->_link);

			for ($fields=array(), $j=0; $j < mysql_num_fields($result); $j++)
			{
				$fields[mysql_field_name($result, $j)] = mysql_field_len($result, $j);
				$flags = mysql_field_flags($result, $j);

				if (strstr($flags, "primary_key"))
				{
					$keyfield = mysql_field_name($result, $j);
					$autoincrement = (bool)strstr($flags, "auto_increment");
					$randomid = (mysql_field_type($result, $j) == "string");
				}
			}

			$fields = var_export($fields, true);

			if ($this->_createclasses && (substr($classname, 0, 4) != 'PMA_') && !class_exists($classname))
			{
				debug("it_dbi: creating class $classname", 5);
				eval("
					class $classname extends it_dbi
					{
						function $classname(\$query = null, \$config = array())
						{
							\$config += array($defaults'table' => '$table', 'keyfield' => '$keyfield', 'autoincrement' => '$autoincrement', 'randomid' => '$randomid');
							\$this->_fields = $fields;
							\$this->it_dbi(\$config, \$query);
						}
					}
				");
			}
		}
	}

	if (isset($query))
		if (is_array($query))
			$this->select($query);
		else
			$this->read($query);
}


/**
 * Internal: construct SQL SET clause of changed values from member vars and tags array.
 * Merge current values into $tags. Modifies caller's array (callers rely on it)!
 */
function _set(&$tags)
{
	# Add member vars to tags, considering unquoted fields
	foreach (get_object_vars($this) as $field => $value)
		# Don't use isset($tags[$field]) (would not handle null values correctly)
		if (isset($this->_fields[$field]) && !array_key_exists('-'.$field, $tags) && !array_key_exists($field, $tags))
				$tags[$field] = $value;

	# Create SQL
	$r = array();
	foreach((array)$tags as $key => $value)
	{
		if (substr($key, 0, 1) == '-')		# Unquoted value (always added)
			$r[] = substr($key, 1)."=$value";
		elseif (!isset($this->_data) || ($value !== $this->_data[$key]))	# Add to SQL if value has changed
			$r[] = "$key=".(isset($value) ? "'".mysql_real_escape_string($value, $this->_link)."'" : 'NULL');
	}

	return $r ? 'SET '.implode(', ', $r) : '';
}


/* Intermal: construct SQL WHERE clause */
function _where($where)
{
	return isset($where) ? ' ' . it_db_table::construct_sql_clause($where) : '';
}


/**
 * Internal: Output class name::error message and terminate execution.
 */
function _fatal($text)
{
	it::fatal(get_class($this).'::'.$text);
	/* NOT REACHED */
}


/**
 * Post-process data after reading a record.
 * This is a stub-function that can be overloaded.
 */
function _read_post_process()
{
}


/**
 * Pre-process data before writing a record.
 * This is a stub-function that can be overloaded.
 * @param $tags Reference to update/create tags, can be modified as needed
 */
function _write_pre_process(&$tags)
{
}


/**
 * Clear record
 */
function clear($pp = true)
{
	foreach ((array)$this->_fields as $key => $value)
		unset($this->$key);
	unset($this->_data);
	unset($this->_key);
	$pp && $this->_read_post_process();
}


/**
 * Semi-internal: send a raw SQL query and return mysql result value
 * @param $query complete SQL query string
 * @return raw MySQL result. May die if query fails and safety is big enough
 */
function query($query)
{
	debug(get_class($this)."::query(\"$query\")", 4);

	$start = gettimeofday();

	if ($this->_server_update && !preg_match('/^(EXPLAIN|SELECT|SHOW) /i', $query))
	{
		if ($this->_link = @mysql_connect($this->_server_update, $this->_user, $this->_pw, true))
		{
			if (!mysql_select_db($this->_db, $this->_link))
				$this->_fatal("Error selecting update database '$this->_db' on host '$this->_server_update'.");

			$this->_server = $this->_server_update;
			unset($this->_server_update);
			#it::log('sqllog', "switched to update server $this->_server");
		}
		else
			$this->_fatal("Error connecting to update database server '$this->_server_update' as user '$this->_user'.");
	}

	if (!($result = mysql_query($query, $this->_link)) && $this->_safety)
	{
		if (($this->_safety < 2) && (mysql_errno($this->_link) == 1062))	/* Duplicate entry */
			return false;

		$error = mysql_errno($this->_link).' ('.mysql_error($this->_link).')';
		$trace = debug_backtrace();
		$res = mysql_fetch_row(mysql_query('select database()', $this->_link));
		$this->_fatal("query(\"$query\") on {$res[0]} failed: $error\nfile {$trace[1]['file']} line {$trace[1]['line']}");
	}


	if ($this->_sqllog || EDC('sqllog'))
	{
		$end = gettimeofday();
		$msec = round(($end['sec'] - $start['sec']) * 1000 + ($end['usec'] - $start['usec']) / 1000);
		it::log('sqllog', "$msec\t$query");
	}

	return $result;
}


/**
 * Read a single record by primary key, not destroying old query result $this->_result
 * @param $id primary key. If null, record is cleared
 * @return True if record could be read, false if not.
 */
function read($id=null)
{
	$mres = $this->_result;
	$result = $this->select(array($this->_keyfield => $id));
	$this->_result = $mres;
	return $result;
}


/**
 * Select a set of records from table and fetch the first one
 * @param $query Optional array of (field => value) or (int => sqlstring) pairs. Defaults to null (select all records)
 *	         Can contain magic field 'SELECT' for things like 'COUNT(*)' or 'DISTINCT foo', defaults to '*'
 *	         Can contain magic field 'JOIN' for things like 'tableA LEFT JOIN tableB ON a=b', defaults to table name
 *	         If magic field 'CALC_FOUND_ROWS' is true, sets member var _found_rows to number of matching rows without LIMIT
 *	         If magic field 'NOFETCH' is true, then the first row is not prefetched (e.g. when directly using _result)
 * @return Number of matching rows, use iterate() to fetch the next record
 * @see it_dbi::iterate(), it_db_table::construct_sql_clause()
 */
function select($query = null)
{
	$result = 0;
	$calc_found_rows = false;

	$what = '*';
	if (isset($query['SELECT']))
	{
		$what = $query['SELECT'];
		unset($query['SELECT']);
	}

	$join = $this->_table;
	if (isset($query['JOIN']))
	{
		$join = $query['JOIN'];
		unset($query['JOIN']);
	}

	unset($this->_found_rows);
	if (isset($query['CALC_FOUND_ROWS']) && $query['CALC_FOUND_ROWS'])
	{
		$calc_found_rows = true;
		$what = 'SQL_CALC_FOUND_ROWS '.$what;
		unset($query['CALC_FOUND_ROWS']);
	}

	$nofetch = $this->_nofetch = isset($query['NOFETCH']) ? $query['NOFETCH'] : false;
	unset($query['NOFETCH']);

	if ($this->_result = $this->query($sql = "SELECT $what FROM $join " . $this->_where($query)))
		$result = mysql_num_rows($this->_result);

	if ($calc_found_rows)
	{
		list($count) = mysql_fetch_row($this->query('SELECT FOUND_ROWS()'));
		$this->_found_rows = intval($count);
	}

	if (!$this->iterate() && ($this->_safety >= 2))
		$this->_fatal("select(): query produced no results: \"$sql\"");

	$this->_nofetch = !$nofetch;

	return $result;
}


/**
 * Iterate through select()ed records
 * @return true if another record was fetched, false if no more records
 * @see it_dbi::select()
 */
function iterate()
{
	if (!$this->_nofetch)
	{
		$this->clear(false);
		if ($this->_data = mysql_fetch_assoc($this->_result))
		{
			if (!empty($this->_keyfield))
				$this->_key = $this->_data[$this->_keyfield];

			foreach ($this->_data as $key => $value)
				$this->$key = $value;
		}

		$this->_read_post_process();
	}
	else
		$this->_nofetch = false;

	return (bool)$this->_data;
}


/**
 * Insert a record into table. Values are taken from member vars and $tags.
 * After inserting, all values are valid (record is read back).
 * Does not destroy internal state of last select() call
 * @param $tags Additional key => value pairs (these have priority over member vars)
 */
function insert($tags = array(), $command = "INSERT")
{
	/* Pre-processing, $tags is passed by reference and may be modified here */
	$this->_write_pre_process($tags);

	unset($this->_data);		# All new value set
	$set = $this->_set($tags);	# Update $tags (!) and generate SQL

	if ($this->_randomid && !isset($tags[$this->_keyfield]))
	{
		$tags[$this->_keyfield] = md5(uniqid(mt_rand()));
		$set = $this->_set($tags);	# Generate new SQL containing ID
	}

	if ($result = $this->query("$command INTO $this->_table " . $set))
	{
		$id = ($this->_autoincrement && !isset($tags[$this->_keyfield])) ? mysql_insert_id($this->_link) : $tags[$this->_keyfield];
		if (!$this->read($id) && $this->_safety)
			$this->_fatal("insert(): can't read record back (key truncated?), id=\"$id\"");
	}

	return $result;
}


/**
 * Replace a record in a table
 * @param $tags Additional key => value pairs (these have priority over member vars)
 * Does not destroy internal state of last select() call
 * @see it_dbi::insert()
 */
function replace($tags = array())
{
	return $this->insert($tags, "REPLACE");
}


/**
 * Update a record in a table
 * @param $tags Additional key => value pairs (these have priority over member vars)
 * Does not destroy internal state of last select() call
 */
function update($tags = array(), $query = null)
{
	$result = true;

	/* Pre-processing, $tags is passed by reference and may be modified here */
	$this->_write_pre_process($tags);

	if (!$query && !empty($this->_keyfield))
		$query = array($this->_keyfield => $this->_data[$this->_keyfield]);

	if ($set = $this->_set($tags))
		if ($result = $this->query("UPDATE $this->_table " . $set . $this->_where($query)))
			if (isset($this->_key) && $this->read($this->_key))
				$this->_nofetch = false; # So we can do while(iterate()) update();

	return $result;
}


/**
 * Delete a record
 * Does not destroy query result $this->_result
 */
function delete($query = null)
{
	$result = 0;

	if (!$query && $this->_keyfield)
	{
		$query = array($this->_keyfield => $this->_key);
		$this->clear();
	}

	if ($query)
	{
		if ($sres = $this->query(($sql = "DELETE FROM $this->_table " . $this->_where($query))))
			$result = mysql_affected_rows($this->_link);
	}

	return $result;
}

} /* End class it_dbi */

?>