/*
Rating system designed to be used in VoIP Carriers World
Copyright (C) 2013 ITsysCOM

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>
*/

package utils

import (
	"errors"
	"regexp"
)

// Regexp Search/Replace, used for example for field formatting
type ReSearchReplace struct {
	SearchRegexp    *regexp.Regexp
	ReplaceTemplate string
}

func (self *ReSearchReplace) Process(source string) string {
	res := []byte{}
	match := self.SearchRegexp.FindStringSubmatchIndex(source)
	res = self.SearchRegexp.ExpandString(res, self.ReplaceTemplate, source, match)
	return string(res)
}

// Used to parse extra fields definition
func ParseSearchReplaceFromFieldRule(fieldRule string) (string, *ReSearchReplace, error) {
	// String rule expected in the form ~hdr_name:s/match_rule/replace_rule/
	getRuleRgxp := regexp.MustCompile(`~(\w+):s\/(.+[^\\])\/(.+[^\\])\/`) // Make sure the separator / is not escaped in the rule
	allMatches := getRuleRgxp.FindStringSubmatch(fieldRule)
	if len(allMatches) != 4 { // Second and third groups are of interest to us
		return "", nil, errors.New("Invalid Search&Replace field rule.")
	}
	fieldName := allMatches[1]
	searchRegexp, err := regexp.Compile(allMatches[2])
	if err != nil {
		return fieldName, nil, err
	}
	return fieldName, &ReSearchReplace{searchRegexp, allMatches[3]}, nil
}