// Tool to write Exif Date to Snapchat Data Archive.
// It filters files, takes the date in the name of the file and writes it to EXIF Metadata.
// 
// Author : Zuma
// Date : 2025-03

package main

import (
  "io"
  "errors"
  "os"
  "github.com/tdewolff/argp"
  "path/filepath"
  "io/fs"
  "log"
  "fmt"
  "strings"
  "regexp"
  exif "github.com/barasher/go-exiftool"
)

func listFiles(dir string, ext string) []string {
  var files []string

  err := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
   if !d.IsDir() && filepath.Ext(path) == "." + ext {
    files = append(files, path)
   }
   return nil
  })
  if err != nil {
   log.Fatal(err)
  }

  return files
}

// https://github.com/barasher/go-exiftool/blob/master/exiftool_sample_test.go
func copyFile(src, dest string) (err error) {
	s, err := os.Open(src)
	if err != nil {
		return err
	}
	defer s.Close()

	d, err := os.Create(dest)
	if err != nil {
		return err
	}
	defer d.Close()

	_, err = io.Copy(d, s)
	if err != nil {
		return err
	}
	return nil
}

func copyFileAndSetMetadata(file string, outputFolder string, exif *exif.Exiftool) {
  newDirectory := filepath.Join(outputFolder, filepath.Base(filepath.Dir(file)))

  if _, err := os.Stat(newDirectory); errors.Is(err, os.ErrNotExist) {
    if err := os.Mkdir(newDirectory, 0755); err != nil {
      log.Fatalf("Cannot create directory : %s", newDirectory)
    }
  }

  date := filepath.Base(file)[:10]
  date_fields := strings.Split(date,"-")
  exif_date := fmt.Sprintf("%s:%s:%s 00:00:00\n", date_fields[0], date_fields[1], date_fields[2])

  exportFile := filepath.Join(newDirectory, filepath.Base(file))
  copyFile(file, exportFile)

  exifData := exif.ExtractMetadata(exportFile)
  exifData[0].SetString("DateTime", exif_date)
  exifData[0].SetString("DateTimeOriginal", exif_date)
  exifData[0].SetString("DateTimeDigitized", exif_date)
  exif.WriteMetadata(exifData)
}

func set_files_metadata(files []string, outputFolder string) {
  r, _ := regexp.Compile("[0-9]{4}-[0-9]{2}-[0-9]{2}")

  et, err := exif.NewExiftool()
  if err != nil {
      fmt.Printf("Error when intializing: %v\n", err)
      return
  }
  defer et.Close()

  for _, file := range files {
    datename := filepath.Base(file)[:10]
    if(r.MatchString(datename)) {
      fileInfos := et.ExtractMetadata(file)
      MIMEType, err := fileInfos[0].GetString("MIMEType")
      if err != nil {
        fmt.Printf("%s\nError when reading MIMEType : %v\n", file, err) 
        continue
      }

      if MIMEType == "video/mp4" {
        HandlerType, err := fileInfos[0].GetString("HandlerType")
        if err != nil {
          fmt.Printf("%s\nError when reading HandlerType : %v\n", file, err) 
          continue
        }

        if HandlerType == "Audio Track" {
          continue
        }

        copyFileAndSetMetadata(file, outputFolder, et) 
      } else if MIMEType == "image/jpeg" {
        filename := filepath.Base(file)
        // Skip thumbnails
        if len(filename) == 116 || len(filename) == 66 {
          continue
        }

        copyFileAndSetMetadata(file, outputFolder, et) 
      } else {
        fmt.Printf("Unknown MIMEType : %v\n", MIMEType)
      }
    }
  }
}

func main() {
  var inputFolder string
  var outputFolder string

  cmd := argp.New("write_metadata, un outil pour mettre la date dans les données EXIF d'une photo")
  cmd.AddArg(&inputFolder, "inputFolder", "Dossier à scanner")
  cmd.AddArg(&outputFolder, "outputFolder", "Dossier ou exporter les fichiers édités")
  cmd.Parse()

  if(inputFolder == "") {
    log.Fatal("ERROR : You must specify a folder to scan")
  }

  if(outputFolder == "") {
    log.Fatal("ERROR : You must specify a folder to export output")
  }

  jpeg_files := listFiles(inputFolder, "jpeg")
  jpg_files := listFiles(inputFolder, "jpg")
  mp4_files := listFiles(inputFolder, "mp4")
  var all_files []string
  all_files = append(all_files, jpeg_files[:]...)
  all_files = append(all_files, jpg_files[:]...)
  all_files = append(all_files, mp4_files[:]...)
  fmt.Println(fmt.Sprintf("%d files found.",len(all_files)))

  set_files_metadata(all_files, outputFolder)

}