// Syntax: xquery(query_template_text, argument's_1_value, argument's_2_value, ...)
// OR:	 xquery(ADOConnection, query_template_text, argument's_1_value, argument's_2_value, ...)
// (procedure checks the type of the 1st argument and if it's string parses the 1st syntax otherwise the 2nd)
// Special characters for a query template:
// ^@TableName - indicates that the combination ^@ is to be replaced with table prefix
// ^N - numeric parameter (is not to be quoted)
// ^S - string parameter (is to be quoted)
// ^0 - "NULL" or "NOT NULL"

// (c) Kamnev Artjom (Kamnium), Mesilov Maxim (Severus)
// http://life.screenshots.ru

// PRIVATE! this replaces a special chars combination with a specified string
function repl(qtext, pos, withwhat){
	return qtext.substr(0, pos) + withwhat + qtext.substr(pos+2);
}// End of repl

function xquery(){
	// opt_table_prefix - prefix for tables
	// opt_conn - connection object
	var Conn; // there'll be connection object reference

	// getting the list of function's arguments
	var args=new Array();
	args=xquery.arguments;

	// Check what type of syntax to use
	if (typeof(args[0])=='string'){
		qtext=args[0]; // the first argument is always query template text
		curArg=1; // bypassing query text only
		Conn=opt_conn;
	}else{
		qtext=args[1]; // the first argument is always query template text		
		curArg=2; // bypassing connection object reference and query text
		Conn=args[0];
	}
	
	qtext=qtext.replace('^@', opt_table_prefix+'_'); // replacing with table prefixes

	i=0;
	while (i<qtext.length){ // length is always up-to-date, even if special chars are replaced
		if (qtext.charAt(i)=='^'){
			if (curArg>=args.length){
				return false; // too many parameters in the query template!
			}

			switch (qtext.charAt(i+1)){
				case 'N': {
					if (args[curArg]==null){
						return false; // no nulls in the middle of JS arglist!
					}

					if (isNaN(args[curArg])){
						return false; // incorrect parameter, numbers only!
					}

					qtext=repl(qtext, i, args[curArg]);

					break;
				}
				case 'S': {
					if (args[curArg]==null){
						return false; // no nulls in the middle of JS arglist!
					}

					args[curArg]=args[curArg].toString();
					args[curArg]=args[curArg].replace("'", "`");
					args[curArg]=args[curArg].replace('^', '!');

					qtext=repl(qtext, i, "'" + args[curArg] + "'");

					break;
				}
				case '0': {
  					if (args[curArg]==null){
			   			return false; // no nulls in the middle of JS arglist!
					}

					args[curArg]=args[curArg].toString();
					args[curArg]=args[curArg].toUpperCase();

					if ( (args[curArg]!='NULL') && (args[curArg]!='NOT NULL') ){
						return false; // incorrect parameter, "NULL" or "NOT NULL" only!
					}

					qtext=repl(qtext, i, args[curArg]);

					break;
				}
				default: {
					qtext=repl(qtext, i, '  '); // hmm, don't worry!
				}
			}

			curArg++;
		}else{

			i++;

		}
	}
	
	try{
		ResultData=Conn.Execute(qtext);
		return ResultData;
	}catch(foo){
		if (opt_debug_mode){
			print('<P><CODE><B>SQL error:</B>' + "<BR>\r\n");
			
			var dbg_err=new Enumerator(Conn.Errors);
			for (; !dbg_err.atEnd(); dbg_err.moveNext()){
				print('Error #' + dbg_err.item().Number + "<BR>\r\n");
				print('	' + dbg_err.item().Description + "<BR>\r\n");
				print('	Source: ' + dbg_err.item().Source + "<BR>\r\n");
				print('	SQL State: ' + dbg_err.item().SQLState + "<BR>\r\n");
				print('	NativeError: ' + dbg_err.item().NativeError + "<BR>\r\n");	
			}  
			print("<BR>Query string: <BR>\r\n" + qtext + '</CODE></P>');
		}
		return false;
	}

}// End of xquery