/*
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 engine

import (
	"encoding/csv"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/url"
	"os"
	"path"
	"path/filepath"
	"strings"

	"github.com/cgrates/cgrates/config"
	"github.com/cgrates/cgrates/utils"
	"golang.org/x/net/context"
	"golang.org/x/oauth2"
	"golang.org/x/oauth2/google"
	"google.golang.org/api/sheets/v4"
)

// CSVStorage the basic csv storage
type CSVStorage struct {
	sep       rune
	generator func() csvReaderCloser
	// file names
	resProfilesFn        []string
	statsFn              []string
	thresholdsFn         []string
	filterFn             []string
	routeProfilesFn      []string
	attributeProfilesFn  []string
	chargerProfilesFn    []string
	dispatcherProfilesFn []string
	dispatcherHostsFn    []string
	rateProfilesFn       []string
	actionProfilesFn     []string
	accountsFn           []string
}

// NewCSVStorage creates a CSV storege that takes the data from the paths specified
func NewCSVStorage(sep rune,
	resProfilesFn, statsFn, thresholdsFn, filterFn, routeProfilesFn,
	attributeProfilesFn, chargerProfilesFn, dispatcherProfilesFn, dispatcherHostsFn,
	rateProfilesFn, actionProfilesFn, accountsFn []string) *CSVStorage {
	return &CSVStorage{
		sep:                  sep,
		generator:            NewCsvFile,
		resProfilesFn:        resProfilesFn,
		statsFn:              statsFn,
		thresholdsFn:         thresholdsFn,
		filterFn:             filterFn,
		routeProfilesFn:      routeProfilesFn,
		attributeProfilesFn:  attributeProfilesFn,
		chargerProfilesFn:    chargerProfilesFn,
		dispatcherProfilesFn: dispatcherProfilesFn,
		dispatcherHostsFn:    dispatcherHostsFn,
		rateProfilesFn:       rateProfilesFn,
		actionProfilesFn:     actionProfilesFn,
		accountsFn:           accountsFn,
	}
}

// NewFileCSVStorage returns a csv storage that uses all files from the folder
func NewFileCSVStorage(sep rune, dataPath string) *CSVStorage {
	allFoldersPath, err := getAllFolders(dataPath)
	if err != nil {
		log.Fatal(err)
	}
	resourcesPaths := appendName(allFoldersPath, utils.ResourcesCsv)
	statsPaths := appendName(allFoldersPath, utils.StatsCsv)
	thresholdsPaths := appendName(allFoldersPath, utils.ThresholdsCsv)
	filtersPaths := appendName(allFoldersPath, utils.FiltersCsv)
	routesPaths := appendName(allFoldersPath, utils.RoutesCsv)
	attributesPaths := appendName(allFoldersPath, utils.AttributesCsv)
	chargersPaths := appendName(allFoldersPath, utils.ChargersCsv)
	dispatcherprofilesPaths := appendName(allFoldersPath, utils.DispatcherProfilesCsv)
	dispatcherhostsPaths := appendName(allFoldersPath, utils.DispatcherHostsCsv)
	rateProfilesFn := appendName(allFoldersPath, utils.RateProfilesCsv)
	actionProfilesFn := appendName(allFoldersPath, utils.ActionProfilesCsv)
	accountsFn := appendName(allFoldersPath, utils.AccountsCsv)
	return NewCSVStorage(sep,
		resourcesPaths,
		statsPaths,
		thresholdsPaths,
		filtersPaths,
		routesPaths,
		attributesPaths,
		chargersPaths,
		dispatcherprofilesPaths,
		dispatcherhostsPaths,
		rateProfilesFn,
		actionProfilesFn,
		accountsFn,
	)
}

// NewStringCSVStorage creates a csv storage from strings
func NewStringCSVStorage(sep rune,
	resProfilesFn, statsFn, thresholdsFn, filterFn, routeProfilesFn,
	attributeProfilesFn, chargerProfilesFn, dispatcherProfilesFn, dispatcherHostsFn,
	rateProfilesFn, actionProfilesFn, accountsFn string) *CSVStorage {
	c := NewCSVStorage(sep,
		[]string{resProfilesFn}, []string{statsFn}, []string{thresholdsFn}, []string{filterFn},
		[]string{routeProfilesFn}, []string{attributeProfilesFn}, []string{chargerProfilesFn},
		[]string{dispatcherProfilesFn}, []string{dispatcherHostsFn}, []string{rateProfilesFn},
		[]string{actionProfilesFn}, []string{accountsFn})
	c.generator = NewCsvString
	return c
}

// NewGoogleCSVStorage creates a csv storege from google sheets
func NewGoogleCSVStorage(sep rune, spreadsheetID string) (*CSVStorage, error) {
	sht, err := newSheet()
	if err != nil {
		return nil, err
	}
	sheetNames, err := getSpreatsheetTabs(spreadsheetID, sht)
	if err != nil {
		return nil, err
	}
	getIfExist := func(name string) []string {
		if sheetNames.Has(name) {
			return []string{name}
		}
		return []string{}
	}
	c := NewCSVStorage(sep,
		getIfExist(utils.Resources),
		getIfExist(utils.Stats),
		getIfExist(utils.Thresholds),
		getIfExist(utils.Filters),
		getIfExist(utils.Routes),
		getIfExist(utils.Attributes),
		getIfExist(utils.Chargers),
		getIfExist(utils.DispatcherProfiles),
		getIfExist(utils.DispatcherHosts),
		getIfExist(utils.RateProfiles),
		getIfExist(utils.ActionProfiles),
		getIfExist(utils.AccountsString))
	c.generator = func() csvReaderCloser {
		return &csvGoogle{
			spreadsheetID: spreadsheetID,
			srv:           sht,
		}
	}
	return c, nil
}

// NewURLCSVStorage returns a CSVStorage that can parse URLs
func NewURLCSVStorage(sep rune, dataPath string) *CSVStorage {
	var resourcesPaths []string
	var statsPaths []string
	var thresholdsPaths []string
	var filtersPaths []string
	var routesPaths []string
	var attributesPaths []string
	var chargersPaths []string
	var dispatcherprofilesPaths []string
	var dispatcherhostsPaths []string
	var rateProfilesPaths []string
	var actionProfilesPaths []string
	var accountsPaths []string

	for _, baseURL := range strings.Split(dataPath, utils.InfieldSep) {
		if !strings.HasSuffix(baseURL, utils.CSVSuffix) {
			resourcesPaths = append(resourcesPaths, joinURL(baseURL, utils.ResourcesCsv))
			statsPaths = append(statsPaths, joinURL(baseURL, utils.StatsCsv))
			thresholdsPaths = append(thresholdsPaths, joinURL(baseURL, utils.ThresholdsCsv))
			filtersPaths = append(filtersPaths, joinURL(baseURL, utils.FiltersCsv))
			routesPaths = append(routesPaths, joinURL(baseURL, utils.RoutesCsv))
			attributesPaths = append(attributesPaths, joinURL(baseURL, utils.AttributesCsv))
			chargersPaths = append(chargersPaths, joinURL(baseURL, utils.ChargersCsv))
			dispatcherprofilesPaths = append(dispatcherprofilesPaths, joinURL(baseURL, utils.DispatcherProfilesCsv))
			dispatcherhostsPaths = append(dispatcherhostsPaths, joinURL(baseURL, utils.DispatcherHostsCsv))
			rateProfilesPaths = append(rateProfilesPaths, joinURL(baseURL, utils.RateProfilesCsv))
			actionProfilesPaths = append(actionProfilesPaths, joinURL(baseURL, utils.ActionProfilesCsv))
			accountsPaths = append(accountsPaths, joinURL(baseURL, utils.AccountsCsv))
			continue
		}
		switch {
		case strings.HasSuffix(baseURL, utils.ResourcesCsv):
			resourcesPaths = append(resourcesPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.StatsCsv):
			statsPaths = append(statsPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.ThresholdsCsv):
			thresholdsPaths = append(thresholdsPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.FiltersCsv):
			filtersPaths = append(filtersPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.RoutesCsv):
			routesPaths = append(routesPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.AttributesCsv):
			attributesPaths = append(attributesPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.ChargersCsv):
			chargersPaths = append(chargersPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.DispatcherProfilesCsv):
			dispatcherprofilesPaths = append(dispatcherprofilesPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.DispatcherHostsCsv):
			dispatcherhostsPaths = append(dispatcherhostsPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.RateProfilesCsv):
			rateProfilesPaths = append(rateProfilesPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.ActionProfilesCsv):
			actionProfilesPaths = append(actionProfilesPaths, baseURL)
		case strings.HasSuffix(baseURL, utils.AccountsCsv):
			accountsPaths = append(accountsPaths, baseURL)

		}
	}

	c := NewCSVStorage(sep,
		resourcesPaths,
		statsPaths,
		thresholdsPaths,
		filtersPaths,
		routesPaths,
		attributesPaths,
		chargersPaths,
		dispatcherprofilesPaths,
		dispatcherhostsPaths,
		rateProfilesPaths,
		actionProfilesPaths,
		accountsPaths,
	)
	c.generator = func() csvReaderCloser {
		return &csvURL{}
	}
	return c
}

func joinURL(baseURL, fn string) string {
	u, err := url.Parse(baseURL)
	if err != nil {
		return baseURL + fn
	}
	u.Path = path.Join(u.Path, fn)
	return u.String()
}

func getAllFolders(inPath string) (paths []string, err error) {
	err = filepath.Walk(inPath, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if info.IsDir() {
			paths = append(paths, path)
		}
		return nil
	})
	return
}

func appendName(paths []string, fileName string) (out []string) {
	out = make([]string, len(paths))
	for i, basePath := range paths {
		out[i] = path.Join(basePath, fileName)
	}
	return
}

func (csvs *CSVStorage) proccesData(listType interface{}, fns []string, process func(interface{})) error {
	collumnCount := getColumnCount(listType)
	for _, fileName := range fns {
		csvReader := csvs.generator()
		err := csvReader.Open(fileName, csvs.sep, collumnCount)
		if err != nil {
			// maybe a log to view if failed to open file
			continue // try read the rest
		}
		if err = func() error { // to execute defer corectly
			defer csvReader.Close()
			for record, err := csvReader.Read(); err != io.EOF; record, err = csvReader.Read() {
				if err != nil {
					log.Printf("bad line in %s, %s\n", fileName, err.Error())
					return err
				}
				if item, err := csvLoad(listType, record); err != nil {
					log.Printf("error loading %s: %v", "", err)
					return err
				} else {
					process(item)
				}
			}
			return nil
		}(); err != nil {
			return err
		}
	}
	return nil
}

func (csvs *CSVStorage) GetTPResources(tpid, tenant, id string) ([]*utils.TPResourceProfile, error) {
	var tpResLimits ResourceMdls
	if err := csvs.proccesData(ResourceMdl{}, csvs.resProfilesFn, func(tp interface{}) {
		tpLimit := tp.(ResourceMdl)
		tpLimit.Tpid = tpid
		tpResLimits = append(tpResLimits, &tpLimit)
	}); err != nil {
		return nil, err
	}
	return tpResLimits.AsTPResources(), nil
}

func (csvs *CSVStorage) GetTPStats(tpid, tenant, id string) ([]*utils.TPStatProfile, error) {
	var tpStats StatMdls
	if err := csvs.proccesData(StatMdl{}, csvs.statsFn, func(tp interface{}) {
		tPstats := tp.(StatMdl)
		tPstats.Tpid = tpid
		tpStats = append(tpStats, &tPstats)
	}); err != nil {
		return nil, err
	}
	return tpStats.AsTPStats(), nil
}

func (csvs *CSVStorage) GetTPThresholds(tpid, tenant, id string) ([]*utils.TPThresholdProfile, error) {
	var tpThreshold ThresholdMdls
	if err := csvs.proccesData(ThresholdMdl{}, csvs.thresholdsFn, func(tp interface{}) {
		tHresholdCfg := tp.(ThresholdMdl)
		tHresholdCfg.Tpid = tpid
		tpThreshold = append(tpThreshold, &tHresholdCfg)
	}); err != nil {
		return nil, err
	}
	return tpThreshold.AsTPThreshold(), nil
}

func (csvs *CSVStorage) GetTPFilters(tpid, tenant, id string) ([]*utils.TPFilterProfile, error) {
	var tpFilter FilterMdls
	if err := csvs.proccesData(FilterMdl{}, csvs.filterFn, func(tp interface{}) {
		fIlterCfg := tp.(FilterMdl)
		fIlterCfg.Tpid = tpid
		tpFilter = append(tpFilter, &fIlterCfg)
	}); err != nil {
		return nil, err
	}
	return tpFilter.AsTPFilter(), nil
}

func (csvs *CSVStorage) GetTPRoutes(tpid, tenant, id string) ([]*utils.TPRouteProfile, error) {
	var tpRoutes RouteMdls
	if err := csvs.proccesData(RouteMdl{}, csvs.routeProfilesFn, func(tp interface{}) {
		suppProfile := tp.(RouteMdl)
		suppProfile.Tpid = tpid
		tpRoutes = append(tpRoutes, &suppProfile)
	}); err != nil {
		return nil, err
	}
	return tpRoutes.AsTPRouteProfile(), nil
}

func (csvs *CSVStorage) GetTPAttributes(tpid, tenant, id string) ([]*utils.TPAttributeProfile, error) {
	var tpAls AttributeMdls
	if err := csvs.proccesData(AttributeMdl{}, csvs.attributeProfilesFn, func(tp interface{}) {
		attributeProfile := tp.(AttributeMdl)
		attributeProfile.Tpid = tpid
		tpAls = append(tpAls, &attributeProfile)
	}); err != nil {
		return nil, err
	}
	return tpAls.AsTPAttributes(), nil
}

func (csvs *CSVStorage) GetTPChargers(tpid, tenant, id string) ([]*utils.TPChargerProfile, error) {
	var tpCPPs ChargerMdls
	if err := csvs.proccesData(ChargerMdl{}, csvs.chargerProfilesFn, func(tp interface{}) {
		cpp := tp.(ChargerMdl)
		cpp.Tpid = tpid
		tpCPPs = append(tpCPPs, &cpp)
	}); err != nil {
		return nil, err
	}
	return tpCPPs.AsTPChargers(), nil
}

func (csvs *CSVStorage) GetTPDispatcherProfiles(tpid, tenant, id string) ([]*utils.TPDispatcherProfile, error) {
	var tpDPPs DispatcherProfileMdls
	if err := csvs.proccesData(DispatcherProfileMdl{}, csvs.dispatcherProfilesFn, func(tp interface{}) {
		dpp := tp.(DispatcherProfileMdl)
		dpp.Tpid = tpid
		tpDPPs = append(tpDPPs, &dpp)
	}); err != nil {
		return nil, err
	}
	return tpDPPs.AsTPDispatcherProfiles(), nil
}

func (csvs *CSVStorage) GetTPDispatcherHosts(tpid, tenant, id string) ([]*utils.TPDispatcherHost, error) {
	var tpDDHs DispatcherHostMdls
	if err := csvs.proccesData(DispatcherHostMdl{}, csvs.dispatcherHostsFn, func(tp interface{}) {
		dpp := tp.(DispatcherHostMdl)
		dpp.Tpid = tpid
		tpDDHs = append(tpDDHs, &dpp)
	}); err != nil {
		return nil, err
	}
	return tpDDHs.AsTPDispatcherHosts(), nil
}

func (csvs *CSVStorage) GetTPRateProfiles(tpid, tenant, id string) ([]*utils.TPRateProfile, error) {
	var tpDPPs RateProfileMdls
	if err := csvs.proccesData(RateProfileMdl{}, csvs.rateProfilesFn, func(tp interface{}) {
		dpp := tp.(RateProfileMdl)
		dpp.Tpid = tpid
		tpDPPs = append(tpDPPs, &dpp)
	}); err != nil {
		return nil, err
	}
	return tpDPPs.AsTPRateProfile(), nil
}

func (csvs *CSVStorage) GetTPActionProfiles(tpid, tenant, id string) ([]*utils.TPActionProfile, error) {
	var tpDPPs ActionProfileMdls
	if err := csvs.proccesData(ActionProfileMdl{}, csvs.actionProfilesFn, func(tp interface{}) {
		dpp := tp.(ActionProfileMdl)
		dpp.Tpid = tpid
		tpDPPs = append(tpDPPs, &dpp)
	}); err != nil {
		return nil, err
	}
	return tpDPPs.AsTPActionProfile(), nil
}

func (csvs *CSVStorage) GetTPAccounts(tpid, tenant, id string) ([]*utils.TPAccount, error) {
	var tpDPPs AccountMdls
	if err := csvs.proccesData(AccountMdl{}, csvs.accountsFn, func(tp interface{}) {
		dpp := tp.(AccountMdl)
		dpp.Tpid = tpid
		tpDPPs = append(tpDPPs, &dpp)
	}); err != nil {
		return nil, err
	}
	return tpDPPs.AsTPAccount()
}

func (csvs *CSVStorage) GetTpIds(colName string) ([]string, error) {
	return nil, utils.ErrNotImplemented
}

func (csvs *CSVStorage) GetTpTableIds(tpid, table string,
	distinct []string, filters map[string]string, p *utils.PaginatorWithSearch) ([]string, error) {
	return nil, utils.ErrNotImplemented
}

type csvReaderCloser interface {
	Open(data string, sep rune, nrFields int) (err error)
	Read() (record []string, err error)
	Close()
}

func NewCsvFile() csvReaderCloser {
	return &csvFile{}
}

type csvFile struct {
	csvReader *csv.Reader
	fp        *os.File
}

func (c *csvFile) Open(fn string, sep rune, nrFields int) (err error) {
	c.fp, err = os.Open(fn)
	if err != nil {
		return
	}
	c.csvReader = csv.NewReader(c.fp)
	c.csvReader.Comma = sep
	c.csvReader.Comment = utils.CommentChar
	c.csvReader.FieldsPerRecord = nrFields
	c.csvReader.TrailingComma = true
	return
}

func (c *csvFile) Read() (record []string, err error) {
	return c.csvReader.Read()
}

func (c *csvFile) Close() {
	if c.fp != nil {
		c.fp.Close()
	}
}

func NewCsvString() csvReaderCloser {
	return &csvString{}
}

type csvString struct {
	csvReader *csv.Reader
}

func (c *csvString) Open(data string, sep rune, nrFields int) (err error) {
	c.csvReader = csv.NewReader(strings.NewReader(data))
	c.csvReader.Comma = sep
	c.csvReader.Comment = utils.CommentChar
	c.csvReader.FieldsPerRecord = nrFields
	c.csvReader.TrailingComma = true
	return
}

func (c *csvString) Read() (record []string, err error) {
	return c.csvReader.Read()
}

func (c *csvString) Close() { // no need for close
}

// Google

// Retrieve a token, saves the token, then returns the generated client.
func getClient(cfg *oauth2.Config, configPath string) (*http.Client, error) {
	// The file token.json stores the user's access and refresh tokens, and is
	// created automatically when the authorization flow completes for the first
	// time.
	tok := &oauth2.Token{}
	raw, err := getCfgJSONData(config.CgrConfig().LoaderCgrCfg().GapiToken)
	if err != nil {
		tok, err = getTokenFromWeb(cfg)
		if err != nil {
			return nil, err
		}
		path2TokFileb := config.CgrConfig().LoaderCgrCfg().GapiToken
		path2TokFile := string(path2TokFileb[1 : len(path2TokFileb)-1])
		if err := os.MkdirAll(filepath.Dir(path2TokFile), os.FileMode(0777)); err != nil { // create the directory if not exists
			return nil, err
		}
		saveToken(path2TokFile, tok)
	} else if err = json.Unmarshal(raw, tok); err != nil {
		return nil, err
	}
	return cfg.Client(context.Background(), tok), nil
}

// Request a token from the web, then returns the retrieved token.
func getTokenFromWeb(config *oauth2.Config) (*oauth2.Token, error) {
	authURL := config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
	fmt.Printf("Go to the following link in your browser then type the "+
		"authorization code: \n%v\n", authURL)

	var authCode string
	if _, err := fmt.Scan(&authCode); err != nil {
		err = fmt.Errorf("Unable to read authorization code: %v", err)
		return nil, err
	}

	tok, err := config.Exchange(context.TODO(), authCode)
	if err != nil {
		err = fmt.Errorf("Unable to retrieve token from web: %v", err)
	}
	return tok, err
}

// Saves a token to a file path.
func saveToken(path string, token *oauth2.Token) {
	fmt.Printf("Saving credential file to: %s\n", path)
	f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
	if err != nil {
		log.Printf("Unable to cache oauth token: %v\n", err)
		return
	}
	defer f.Close()
	json.NewEncoder(f).Encode(token)
}

func getCfgJSONData(raw json.RawMessage) (data []byte, err error) {
	if len(raw) == 0 {
		return
	}
	if raw[0] == '{' && raw[len(raw)-1] == '}' {
		data = raw
		return
	}
	dataPath := string(raw[1 : len(raw)-1])
	if !strings.HasSuffix(dataPath, utils.JSONSuffix) {
		dataPath = path.Join(dataPath, utils.GoogleCredentialsFileName)
	}
	return os.ReadFile(dataPath)
}

func newSheet() (sht *sheets.Service, err error) { //*google_api
	var cred []byte
	var cfgPathDir string
	if cred, err = getCfgJSONData(config.CgrConfig().LoaderCgrCfg().GapiCredentials); err != nil {
		err = fmt.Errorf("Unable to read client secret file: %v", err)
		return
	}
	// If modifying these scopes, delete your previously saved token.json.
	config, err := google.ConfigFromJSON(cred, "https://www.googleapis.com/auth/spreadsheets.readonly")
	if err != nil {
		err = fmt.Errorf("Unable to parse client secret file to config: %v", err)
		return
	}
	client, err := getClient(config, cfgPathDir)
	if err != nil {
		return nil, err
	}
	sht, err = sheets.New(client)
	if err != nil {
		err = fmt.Errorf("Unable to retrieve Sheets client: %v", err)
	}
	return
}

func getSpreatsheetTabs(spreadsheetID string, srv *sheets.Service) (sheetsName utils.StringSet, err error) {
	sheetsName = make(utils.StringSet)
	sht, err := srv.Spreadsheets.Get(spreadsheetID).Do()
	if err != nil {
		err = fmt.Errorf("Unable get the information about spreadsheet because: %v", err)
		return
	}
	for _, sheet := range sht.Sheets {
		sheetsName.Add(sheet.Properties.Title)
	}
	return
}

type csvGoogle struct {
	spreadsheetID string
	srv           *sheets.Service
	response      *sheets.ValueRange
	indx          int
	nrFields      int
}

func (c *csvGoogle) Open(data string, sep rune, nrFields int) (err error) {
	c.response, err = c.srv.Spreadsheets.Values.Get(c.spreadsheetID, data).Do()
	if err != nil {
		return
	}

	if len(c.response.Values) == 0 {
		return utils.ErrNotFound
	}
	c.nrFields = nrFields
	return
}

func (c *csvGoogle) getNextRow() (row []interface{}, err error) {
	if len(c.response.Values) <= c.indx {
		return nil, io.EOF
	}
	row = c.response.Values[c.indx]
	c.indx++
	if len(row) == 0 {
		return c.getNextRow()
	}
	return
}

func (c *csvGoogle) Read() (record []string, err error) {
	row, err := c.getNextRow()
	if err != nil {
		return
	}
	record = make([]string, c.nrFields)
	for i := 0; i < c.nrFields; i++ {
		if i < len(row) {
			record[i] = utils.IfaceAsString(row[i])
			if i == 0 && strings.HasPrefix(record[i], "#") {
				return c.Read() // ignore row if starts with #
			}
		} else {
			record[i] = ""
		}
	}
	return
}

func (c *csvGoogle) Close() { // no need for close
}

type csvURL struct {
	csvReader *csv.Reader
	page      io.ReadCloser
}

func (c *csvURL) Open(fn string, sep rune, nrFields int) (err error) {
	if _, err = url.ParseRequestURI(fn); err != nil {
		return
	}
	var myClient = &http.Client{
		Timeout: config.CgrConfig().GeneralCfg().ReplyTimeout,
	}
	var req *http.Response
	req, err = myClient.Get(fn)
	if err != nil {
		return utils.ErrPathNotReachable(fn)
	}
	if req.StatusCode != http.StatusOK {
		return utils.ErrNotFound
	}
	c.page = req.Body

	c.csvReader = csv.NewReader(c.page)
	c.csvReader.Comma = sep
	c.csvReader.Comment = utils.CommentChar
	c.csvReader.FieldsPerRecord = nrFields
	c.csvReader.TrailingComma = true
	return
}

func (c *csvURL) Read() (record []string, err error) {
	return c.csvReader.Read()
}

func (c *csvURL) Close() {
	if c.page != nil {
		c.page.Close()
	}
}