package main

import (
	"fmt"
	"github.com/spf13/cobra"
	"log"
	"os"
	"time"
)

func main() {
	rootCmd := &cobra.Command{
		Use:   "calanonsync",
		Short: "Synchronize a calendar from EWS to CalDAV by event time and an anonymized title only.",
		Run:   runSynchronization,
	}

	rootCmd.AddCommand(InitSettingsCmd())

	if err := rootCmd.Execute(); err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
}

func runSynchronization(cmd *cobra.Command, args []string) {
	s := LoadSettings()

	e := NewEWSCalendar(s.EWS.URL, s.EWS.Username, s.EWS.Password)
	id, err := e.getCalendarFolderID()
	if err != nil {
		log.Fatalln(err)
	}

	items, err := e.getCalendarItems(id,
		time.Now().AddDate(0, -1, 0), // One month past
		time.Now().AddDate(0, 2, 0))  // Two months ahead
	if err != nil {
		log.Fatalf("Could not get EWS items: %s\n", err)
	}

	relevantEWSItems := make(map[string]CalendarItem)

	for _, item := range items {
		// Ignore private items.
		if item.Sensitivity != "Private" && !item.IsCancelled() {
			// None-private items though ... remember them by hash.
			// The hash will equal the CalDAV UID (and its filename).
			relevantEWSItems[item.Hash()] = item
		}
	}

	c := NewCalDAV(s.CalDAV)
	calDavItems, err := c.GetEvents()
	if err != nil {
		log.Fatalf("Could not get CalDAV items: %s\n", err)
	}
	// Build a map for easier lookup by UID
	calDavItemMap := make(map[string]CalDAVItem)
	for _, item := range calDavItems {
		calDavItemMap[item.UID()] = item
	}

	// First step: find items that were changed or that were removed
	// and update the CalDAV side accordingly.
	for uid, calDavItem := range calDavItemMap {
		if ewsItem, ok := relevantEWSItems[uid]; ok {
			// Good, so we still know the item at least.
			if !ewsItem.Start.Equal(calDavItem.Start()) ||
				!ewsItem.End.Equal(calDavItem.End()) {

				// So times have changed. Update.
				calDavItem.Update(ewsItem.Start, ewsItem.End, ewsItem.IsAllDayEvent)

				err := c.UploadItem(calDavItem)
				if err == nil {
					log.Printf("Updated item %s (%s)\n", uid, ewsItem.Subject)
				} else {
					// Not fatal, but worth a note.
					log.Println(err)
				}
			}
		} else {
			// Oops, seems the item vanished.
			err := c.DeleteItem(calDavItem)
			if err == nil {
				log.Printf("Deleted item %s (%s)\n", calDavItem.UID(), calDavItem.Summary())
			} else {
				// Not fatal, but worth a note.
				log.Println(err)
			}
		}
	}

	// Find items we don't know so far and create them.
	for uid, ewsItem := range relevantEWSItems {
		if _, ok := calDavItemMap[uid]; !ok {
			title := s.Anonymize.Title.Apply(ewsItem.Subject)
			ical := CreateICal(ewsItem.Hash(), title, ewsItem.Start, ewsItem.End, ewsItem.IsAllDayEvent)
			calDavItem := CalDAVItem{HRef: uid + ".ics", ICal: ical}

			err := c.UploadItem(calDavItem)
			if err == nil {
				log.Printf("Created item %s (%s)\n", uid, ewsItem.Subject)
			} else {
				log.Println(err)
			}
		}
	}
}