package dataservice

import (
	"context"
	"encoding/csv"
	"fmt"
	"io/fs"
	"os"
	"sync"
	"time"

	"gittea.marcokittel.de/elio/eliotools/datawriter/internal/event"
	"gittea.marcokittel.de/elio/eliotools/eliofile"
	"gittea.marcokittel.de/elio/eliotools/logger"
	"gittea.marcokittel.de/elio/eliotools/tools"
)

// Daten über Channel aus der Goroutine ausführen. CounterID stellt sicher, dass das Herkunftsland der Daten bekannt ist.

// Rückgabe eines Closures zur Verbeitung einer CSV Datei. Posix Only. No Windows.
func DataServiceDebugHandler(log logger.Logger, baseDir string, processedDir string) func(ctx context.Context, filename string, data chan<- eliofile.CountryCsvData) bool {
	return func(ctx context.Context, filename string, data chan<- eliofile.CountryCsvData) bool {
		log.Infof("%s %s \n", baseDir, processedDir)
		if !tools.IsFilenameValid(filename) {
			log.Warning(filename + "Überspringe Datei: " + filename + "\n")
			return false
		}
		t, err := tools.ExtractDateAndConvertToDate(filename)
		if err != nil {
			log.Warning(filename + "\n" + err.Error())
			return false
		}
		log.Info("Datei gefunden.: " + filename + " " + t.String() + "\n")
		file, err := os.Open(baseDir + "/" + filename)
		defer file.Close()
		if err != nil {
			log.Warning(err.Error())
		}
		r := csv.NewReader(file)
		record, err := r.Read()
		if err != nil {
			log.Critical(err.Error())
			return false
		}
		for {
			record, err = r.Read()
			if err != nil {
				break
			}
			data <- eliofile.CountryCsvData{CountryID: filename[26:28], Data: record}
		}
		err = os.Rename(baseDir+"/"+filename, processedDir+"/"+filename)
		if err != nil {
			log.Critical(err.Error())
		}
		log.Infof("%s abgearbeitet.\n", filename)
		return true
	}
}

type DataService struct {
	listener            []event.EventListener
	log                 logger.Logger
	ef                  eliofile.ElioDateiFoo
	newFolderPath       string
	processedFolderPath string
	dirCreationRights   int
}

func (d *DataService) ListenerCount() int {
	return len(d.listener)
}

func (d *DataService) Run(ctx context.Context, wg *sync.WaitGroup) {
	defer wg.Done()
	for {
		select {
		case <-ctx.Done():
			fmt.Println("Ende")
			return
		default:
			//Hier nach neuen Dateien suchen
			for _, l := range d.listener {
				select {
				case <-ctx.Done():
					return
				default:
					data := make(chan eliofile.CountryCsvData, 100)
					go func() {
						defer close(data)
						err := d.ef.ScanCsv(ctx, data)
						if err != nil {
							fmt.Println(err)
						}
					}()
					for warehouseDataItem := range data {
						err := l.HandleData(ctx, warehouseDataItem)
						if err != nil {
							fmt.Println(err)
						}
					}
				}
				time.Sleep(time.Second * 5)
			}
		}
	}
}

func (d *DataService) AddListener(ev event.EventListener) {
	d.listener = append(d.listener, ev)
}

type Option func(*DataService)

func WithCustomCsvProcesser(process eliofile.ElioHandleFunc) Option {
	return func(ds *DataService) {
		ds.ef = *eliofile.NewElioDateiFoo(ds.newFolderPath, process)
	}
}

// func WithCustomLookupDirectory(lookupDirectory string) Option {
// 	return func(ds *DataService) {
// 		ds.newFolderPath = lookupDirectory
// 	}
// }

// func WithCustomProcessedDirectory(processedDirectory string) Option {
// 	return func(ds *DataService) {
// 		ds.processedFolderPath = processedDirectory
// 	}
// }

func WithCustomDirectoryPermissions(permissions int) Option {
	return func(ds *DataService) {
		ds.dirCreationRights = permissions
	}
}

func NewDataService(ctx context.Context, options ...Option) *DataService {
	lookUpFolderPath, err := os.Getwd()
	if err != nil {
		panic(err)
	}
	newFolderPath := "/new"
	processedFolderPath := "/processed"
	dirCreationRights := 0755
	l := logger.NewMarcoLogger()
	ds := DataService{listener: make([]event.EventListener, 0),
		log:                 l,
		newFolderPath:       lookUpFolderPath + newFolderPath,
		processedFolderPath: lookUpFolderPath + processedFolderPath,
		dirCreationRights:   dirCreationRights}

	ds.ef = *eliofile.NewElioDateiFoo(ds.newFolderPath, DataServiceDebugHandler(l, ds.newFolderPath, ds.processedFolderPath))

	for _, opt := range options {
		opt(&ds)
	}

	l.Infof("Suche CSV Dateien in %s.\n Verarbeitete Dateien gelangen in %s.\n", ds.newFolderPath, ds.processedFolderPath)
	exists, err := tools.CheckDir(ds.newFolderPath)
	if err == nil && !exists {
		l.Infof("Erzeuge Verzeichnis: %s\n", ds.newFolderPath)
		tools.Createdir(ds.newFolderPath, fs.FileMode(ds.dirCreationRights))
	}
	exists, err = tools.CheckDir(ds.processedFolderPath)
	if err == nil && !exists {
		l.Infof("Erzeuge Verzeichnis: %s\n", ds.processedFolderPath)
		tools.Createdir(ds.processedFolderPath, fs.FileMode(ds.dirCreationRights))
	}
	return &ds
}