BUG some date time exif tags are not correctly parsed

Fixes #727

Author: simulot

internal/exif/direct.go

@@ -172,41 +172,21 @@ func readDateTime(x *exif.Exif, dateTag exif.FieldName, subSecTag exif.FieldName
 	if err == nil {
 		subSec += "000"
 		date = date + "." + subSec[:3]
-		return time.ParseInLocation("2006:01:02 15:04:05.000", date, local)
 	}
-	return time.ParseInLocation("2006:01:02 15:04:05", date, local)
+	return parseExifTime(date, local)
 }
 
-/*
-// readGPSTimeStamp extract the date from the GPS data
-
-	func readGPSTimeStamp(x *exif.Exif, _ *time.Location) (time.Time, error) {
-		tag, err := getTagSting(x, exif.GPSDateStamp)
-		if err == nil {
-			var tags *tiff.Tag
-			tags, err = x.Get(exif.GPSTimeStamp)
-			if err == nil {
-				tag = tag + " " + fmt.Sprintf("%02d:%02d:%02dZ", ratToInt(tags, 0), ratToInt(tags, 1), ratToInt(tags, 2))
-				t, err := time.ParseInLocation("2006:01:02 15:04:05Z", tag, time.UTC)
-				if err == nil {
-					return t, nil
-				}
-			}
-		}
-		return time.Time{}, err
+func parseExifTime(date string, local *time.Location) (time.Time, error) {
+	var year, month, day, hour, min, sec, milli int
+	date = strings.ReplaceAll(date, "-", ":")
+	date = strings.ReplaceAll(date, "/", ":")
+	fmt.Sscanf(date, "%d:%d:%d %d:%d:%d.%d", &year, &month, &day, &hour, &min, &sec, &milli)
+	if year < 1900 || month == 0 || day == 0 {
+		return time.Time{}, fmt.Errorf("invalid date format")
 	}
-
-	func ratToInt(t *tiff.Tag, i int) int {
-		n, d, err := t.Rat2(i)
-		if err != nil {
-			return 0
-		}
-		if d == 1 {
-			return int(n)
-		}
-		return int(float64(n) / float64(d))
-	}
-*/
+	d := time.Date(year, time.Month(month), day, hour, min, sec, milli*int(time.Millisecond), local)
+	return d, nil
+}
 
 func getTagSting(x *exif.Exif, tagName exif.FieldName) (string, error) {
 	t, err := x.Get(tagName)

internal/exif/direct_test.go

@@ -81,6 +81,43 @@ func Test_MetadataFromDirectRead(t *testing.T) {
 	}
 }
 
+func Test_parseExifTime(t *testing.T) {
+	tests := []struct {
+		name     string
+		date     string
+		location *time.Location
+		want     time.Time
+		wantErr  bool
+	}{
+		{
+			name:     "valid date with different separators  in local timezone",
+			date:     "2023-10-06 08:30:00",
+			location: time.Local,
+			want:     time.Date(2023, 10, 6, 8, 30, 0, 0, time.Local),
+			wantErr:  false,
+		},
+		{
+			name:     "valid date with milliseconds  in local timezone",
+			date:     "2023-10-06 08:30:00.123",
+			location: time.Local,
+			want:     time.Date(2023, 10, 6, 8, 30, 0, int(123*time.Millisecond), time.Local),
+			wantErr:  false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := parseExifTime(tt.date, tt.location)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("parseExifTime() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !tt.want.IsZero() && !got.Equal(tt.want) {
+				t.Errorf("parseExifTime() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
 func floatEquals(a, b, epsilon float64) bool {
 	return (a-b) < epsilon && (b-a) < epsilon
 }