/*
Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
Copyright (C) ITsysCOM GmbH

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 config

import (
	"fmt"
	"regexp"
	"strings"

	"github.com/cgrates/cgrates/utils"
)

var (
	spltRgxp  = regexp.MustCompile(`:s\/`)
	rulesRgxp = regexp.MustCompile(`(?:(.*[^\\])\/(.*[^\\])*\/){1,}`)
)

func NewRSRParsers(parsersRules string, allFiltersMatch bool, rsrSeparator string) (prsrs RSRParsers, err error) {
	if parsersRules == "" {
		return
	}
	if count := strings.Count(parsersRules, "`"); count%2 != 0 { // check if we have matching `
		return nil, fmt.Errorf("Unclosed unspilit syntax")
	} else if count != 0 {
		var splitedRule []string
		for idx := strings.IndexByte(parsersRules, '`'); idx != -1; idx = strings.IndexByte(parsersRules, '`') {
			insideARulePrefix := !strings.HasSuffix(parsersRules[:idx], utils.INFIELD_SEP) // if doesn't have ; we need to concatenate it with last rule
			if insideARulePrefix {
				splitedRule = append(splitedRule, strings.Split(parsersRules[:idx], utils.INFIELD_SEP)...)
			} else {
				splitedRule = append(splitedRule, strings.Split(parsersRules[:idx-1], utils.INFIELD_SEP)...)
			}
			parsersRules = parsersRules[idx+1:]
			idx = strings.IndexByte(parsersRules, '`')
			if insideARulePrefix {
				splitedRule[len(splitedRule)-1] += parsersRules[:idx]
			} else {
				splitedRule = append(splitedRule, parsersRules[:idx])
			}
			parsersRules = parsersRules[idx+1:]
			count -= 2 // the number of ` remaining
			if len(parsersRules) == 0 {
				continue
			}
			insideARuleSufix := !strings.HasPrefix(parsersRules, utils.INFIELD_SEP) // if doesn't have ; we need to concatenate it with last rule
			if insideARuleSufix {
				idx = strings.IndexByte(parsersRules, ';')
				if idx == -1 {
					idx = len(parsersRules)
					splitedRule[len(splitedRule)-1] += parsersRules[:idx]
					break
				}
				splitedRule[len(splitedRule)-1] += parsersRules[:idx]
			} else {
				idx = 0
			}
			parsersRules = parsersRules[idx+1:]
			if len(parsersRules) == 0 {
				break
			}
			if count == 0 { // no more ` so add the rest
				splitedRule = append(splitedRule, strings.Split(parsersRules, utils.INFIELD_SEP)...)
				break
			}
		}
		return NewRSRParsersFromSlice(splitedRule, allFiltersMatch)
	}
	return NewRSRParsersFromSlice(strings.Split(parsersRules, rsrSeparator), allFiltersMatch)
}

func NewRSRParsersFromSlice(parsersRules []string, allFiltersMatch bool) (prsrs RSRParsers, err error) {
	prsrs = make(RSRParsers, len(parsersRules))
	for i, rlStr := range parsersRules {
		if rsrPrsr, err := NewRSRParser(rlStr, allFiltersMatch); err != nil {
			return nil, err
		} else if rsrPrsr == nil {
			return nil, fmt.Errorf("emtpy RSRParser in rule: <%s>", rlStr)
		} else {
			prsrs[i] = rsrPrsr
		}
	}
	return
}

func NewRSRParsersMustCompile(parsersRules string, allFiltersMatch bool, rsrSeparator string) (prsrs RSRParsers) {
	var err error
	if prsrs, err = NewRSRParsers(parsersRules, allFiltersMatch, rsrSeparator); err != nil {
		panic(fmt.Sprintf("rule: <%s>, error: %s", parsersRules, err.Error()))
	}
	return
}

// RSRParsers is a set of RSRParser
type RSRParsers []*RSRParser

func (prsrs RSRParsers) GetRule() (out string) {
	for i, prsr := range prsrs {
		if i == 0 {
			out = prsr.Rules
		} else {
			out = out + utils.NestingSep + prsr.Rules
		}
	}
	return
}

func (prsrs RSRParsers) Compile() (err error) {
	for _, prsr := range prsrs {
		if err = prsr.Compile(); err != nil {
			return
		}
	}
	return
}

// ParseValue will parse the value out considering converters and filters
func (prsrs RSRParsers) ParseValue(value interface{}) (out string, err error) {
	for _, prsr := range prsrs {
		if outPrsr, err := prsr.ParseValue(value); err != nil {
			return "", err
		} else {
			out += outPrsr
		}
	}
	return
}

func (prsrs RSRParsers) ParseDataProvider(dP utils.DataProvider, separator string) (out string, err error) {
	for _, prsr := range prsrs {
		if outPrsr, err := prsr.ParseDataProvider(dP, separator); err != nil {
			return "", err
		} else {
			out += outPrsr
		}
	}
	return
}

func (prsrs RSRParsers) ParseDataProviderWithInterfaces(dP utils.DataProvider, separator string) (out string, err error) {
	for _, prsr := range prsrs {
		if outPrsr, err := prsr.ParseDataProviderWithInterfaces(dP, separator); err != nil {
			return "", err
		} else {
			out += outPrsr
		}
	}
	return
}

func NewRSRParser(parserRules string, allFiltersMatch bool) (rsrParser *RSRParser, err error) {
	if len(parserRules) == 0 {
		return
	}
	rsrParser = &RSRParser{Rules: parserRules, AllFiltersMatch: allFiltersMatch}
	if strings.HasSuffix(parserRules, utils.FILTER_VAL_END) { // Has filter, populate the var
		fltrStart := strings.Index(parserRules, utils.FILTER_VAL_START)
		if fltrStart < 1 {
			return nil, fmt.Errorf("invalid RSRFilter start rule in string: <%s>", parserRules)
		}
		fltrVal := parserRules[fltrStart+1 : len(parserRules)-1]
		rsrParser.filters, err = utils.ParseRSRFilters(fltrVal, utils.ANDSep)
		if err != nil {
			return nil, fmt.Errorf("Invalid FilterValue in string: %s, err: %s", fltrVal, err.Error())
		}
		parserRules = parserRules[:fltrStart] // Take the filter part out before compiling further
	}
	if idxConverters := strings.Index(parserRules, "{*"); idxConverters != -1 { // converters in the string
		if !strings.HasSuffix(parserRules, "}") {
			return nil,
				fmt.Errorf("invalid converter terminator in rule: <%s>",
					parserRules)
		}
		convertersStr := parserRules[idxConverters+1 : len(parserRules)-1] // strip also {}
		convsSplt := strings.Split(convertersStr, utils.ANDSep)
		rsrParser.converters = make(utils.DataConverters, len(convsSplt))
		for i, convStr := range convsSplt {
			var conv utils.DataConverter
			if conv, err = utils.NewDataConverter(convStr); err != nil {
				return nil,
					fmt.Errorf("invalid converter value in string: <%s>, err: %s",
						convStr, err.Error())
			}
			rsrParser.converters[i] = conv
		}
		parserRules = parserRules[:idxConverters]
	}
	if !strings.HasPrefix(parserRules, utils.DynamicDataPrefix) ||
		len(parserRules) == 1 { // special case when RSR is defined as static attribute
		return
	}
	// dynamic content via attributeNames
	spltRules := spltRgxp.Split(parserRules, -1)
	rsrParser.path = spltRules[0][1:] // in form ~hdr_name
	if len(spltRules) > 1 {
		for _, ruleStr := range spltRules[1:] { // :s/ already removed through split
			allMatches := rulesRgxp.FindStringSubmatch(ruleStr)
			if len(allMatches) != 3 {
				return nil, fmt.Errorf("not enough members in Search&Replace, ruleStr: <%s>, matches: %v, ", ruleStr, allMatches)
			}
			var srRegexp *regexp.Regexp
			if srRegexp, err = regexp.Compile(allMatches[1]); err != nil {
				return nil, fmt.Errorf("invalid Search&Replace subfield rule: <%s>", allMatches[1])
			}
			rsrParser.rsrRules = append(rsrParser.rsrRules, &utils.ReSearchReplace{
				SearchRegexp:    srRegexp,
				ReplaceTemplate: allMatches[2],
			})
		}
	}
	return
}

func NewRSRParserMustCompile(parserRules string, allFiltersMatch bool) (rsrPrsr *RSRParser) {
	var err error
	if rsrPrsr, err = NewRSRParser(parserRules, allFiltersMatch); err != nil {
		panic(fmt.Sprintf("compiling rules: <%s>, error: %s", parserRules, err.Error()))
	}
	return
}

// RSRParser is a parser for data coming from various sources
type RSRParser struct {
	Rules           string // Rules container holding the string rules, public so it can be stored
	AllFiltersMatch bool   // all filters must match policy

	path       string                   // instruct extracting info out of header in event
	rsrRules   []*utils.ReSearchReplace // rules to use when parsing value
	converters utils.DataConverters     // set of converters to apply on output
	filters    utils.RSRFilters         // The value to compare when used as filter
}

// AttrName exports the attribute name of the RSRParser
func (prsr *RSRParser) AttrName() string {
	return prsr.path
}

// Compile parses Rules string and repopulates other fields
func (prsr *RSRParser) Compile() (err error) {
	var newPrsr *RSRParser
	if newPrsr, err = NewRSRParser(prsr.Rules, prsr.AllFiltersMatch); err != nil {
		return
	}
	if newPrsr != nil {
		*prsr = *newPrsr
	}
	return
}

// RegexpMatched will investigate whether we had at least one regexp match through the rules
func (prsr *RSRParser) RegexpMatched() bool {
	for _, rsrule := range prsr.rsrRules {
		if rsrule.Matched {
			return true
		}
	}
	return false
}

// parseValue the field value from a string
func (prsr *RSRParser) parseValue(value string) string {
	if prsr.path == "" { // Enforce parsing of static values
		return prsr.Rules
	}
	for _, rsRule := range prsr.rsrRules {
		value = rsRule.Process(value)
	}
	return value
}

// ParseValue will parse the value out considering converters and filters
func (prsr *RSRParser) ParseValue(value interface{}) (out string, err error) {
	out = prsr.parseValue(utils.IfaceAsString(value))
	if out, err = prsr.converters.ConvertString(out); err != nil {
		return
	}
	if !prsr.filters.Pass(out, prsr.AllFiltersMatch) {
		return "", utils.ErrFilterNotPassingNoCaps
	}
	return
}

func (prsr *RSRParser) ParseDataProvider(dP utils.DataProvider, separator string) (out string, err error) {
	var outStr string
	if prsr.path != "" {
		if outStr, err = dP.FieldAsString(
			strings.Split(prsr.path, separator)); err != nil &&
			(err != utils.ErrNotFound || prsr.filters.FilterRules() != "^$") {
			return
		}
	}
	return prsr.ParseValue(outStr)
}

func (prsr *RSRParser) ParseDataProviderWithInterfaces(dP utils.DataProvider, separator string) (out string, err error) {
	var outIface interface{}
	if prsr.path != "" {
		if outIface, err = dP.FieldAsInterface(
			strings.Split(prsr.path, separator)); err != nil &&
			(err != utils.ErrNotFound || prsr.filters.FilterRules() != "^$") {
			return
		}
	}
	return prsr.ParseValue(outIface)
}