package main

import (
	"log"
	"os"
	"path/filepath"
	"github.com/fsnotify/fsnotify"
	"regexp"
	"slices"
	"io/ioutil"
	"strings"
)

func main() {
	// Create new watcher.
	watcher, err := fsnotify.NewWatcher()
	if err != nil {
		log.Fatal(err)
	}
	defer watcher.Close()

	// Start listening for events.
	go func() {
		for {
			select {
			case event, ok := <-watcher.Events:
				if !ok {
					return
				}

				archive_basedir := "/tmp/newmails/"	
				var mailbox                string
				var dovecot_uidlist_src    string
				var dovecot_indexlog_src   string
				var dovecot_indexcache_src string
				var dovecot_dest           string 

				if event.Has(fsnotify.Create) {

					re := regexp.MustCompile(`^.*\.archival\.Incoming\/new\/.*$`)
					new_mail        := re.FindString(event.Name)
					last_mail       := regexp.MustCompile(`/`).Split(new_mail, -1)
					username_index  := slices.Index(last_mail, "home")
					username        := last_mail[username_index+1]
					archive_mailbox := archive_basedir + username + ".Incoming/new/"	
					archive_err     := ensureDir(archive_mailbox)
					new_loc         := archive_mailbox	+ last_mail[len(last_mail)-1]

					// Get archive mailbox path
					mailbox_index := username_index+4
					if len(last_mail) > 1 {
            mailbox = strings.Join(last_mail[0:mailbox_index], "/")
					  dovecot_uidlist_src    = mailbox + "/dovecot-uidlist"
					  dovecot_indexlog_src   = mailbox + "/dovecot.index.log"
					  dovecot_indexcache_src = mailbox + "/dovecot.index.cache"
					  dovecot_dest           = archive_basedir + last_mail[mailbox_index] 
					  log.Println(mailbox)
					}
					//log.Println(len(last_mail))
					log.Println("dovecot")
					log.Println(dovecot_dest)
					log.Println(dovecot_uidlist_src)
					log.Println(dovecot_indexlog_src)
					log.Println(dovecot_indexcache_src)
					if archive_err != nil {
						log.Fatal(archive_err)
					}
					if len(new_mail) > 0 {
						log.Println("moving user ",username,"files to ", new_loc)
						err := os.Rename(new_mail, new_loc)
						if err != nil {
							panic(err)
						}
						//uidlist_err := copyFiles(dovecot_uidlist_src, dovecot_dest)
					  //log_err := copyFiles(dovecot_indexlog_src, dovecot_dest)
						//cache_err := copyFiles(dovecot_indexcache_src, dovecot_dest)
						//if uidlist_err != nil || log_err != nil || cache_err != nil {
						//	panic(err)
						//}
					}
				}
				

			case err, ok := <-watcher.Errors:
				if !ok {
					return
				}
				log.Println("error:", err)
			}
		}
	}()

	// Add a path.
	filepath.Walk("/home/",  func(path  string, info os.FileInfo, err error) error{
		if info.IsDir() {
			watcher.Add(path)
		}
		return nil
	})
	// Block main goroutine forever.
	<-make(chan struct{})
}

// Create archive directory
func ensureDir(dirName string) error {
    err := os.MkdirAll(dirName, 0755)
    if err == nil || os.IsExist(err) {
        return nil
    } else {
        return err
    }
}

// Copy dovecot index and cache
func copyFiles(src string, dest string) error {
    bytesRead, err := ioutil.ReadFile(src)
    if err != nil {
        log.Fatal(err)
    }
    err = ioutil.WriteFile(dest, bytesRead, 0644)
    if err == nil {
			return nil
		} else {
      return err
    }
}