Add ID field to Entry struct with auto-generation on marshal/unmarshal

models/entry.go

@@ -20,18 +20,47 @@ import (
 const DateFormat = tools.DateFormat
 
 type Entry struct {
+	// ID is an optional, but recommended field.
+	// When marshaling/unmarshaling, if ID is empty, one is generated.
+	ID     string
 	Title  string
 	Date   time.Time
 	Fields Metas
 }
 
+func GenerateID() string {
+	host, hostErr := os.Hostname()
+	if hostErr != nil {
+		host = "localhost"
+	}
+	return fmt.Sprintf(
+		"tag:%s,%s:my-log/%s",
+		host,
+		time.Now().Local().Format("2006"),
+		uuid.NewString(),
+	)
+}
+
+func EnsureID(id *string, fields Metas) {
+	if *id != "" {
+		return
+	}
+
+	metaID, hasMetaID := fields.Get("id")
+	var isStringID bool
+	*id, isStringID = metaID.(string)
+	if !hasMetaID || !isStringID {
+		*id = GenerateID()
+	}
+}
+
 type metaRes struct {
 	out []byte
 	err error
 }
 
-func (e Entry) getFieldMarshalChan() chan metaRes {
-	size := len(e.Fields)
+func getFieldMarshalChan(fields Metas) chan metaRes {
+	size := len(fields)
 	ch := make(chan metaRes, size)
 	var wg sync.WaitGroup
 
@@ -53,7 +82,7 @@ func (e Entry) getFieldMarshalChan() chan metaRes {
 				ch <- metaRes{o, er}
 			}
 
-		}(e.Fields[i])
+		}(fields[i])
 	}
 
 	go func() {
@@ -71,16 +100,10 @@ func (e Entry) MarshalText() ([]byte, error) {
 	if e.Date.IsZero() {
 		return []byte{}, ErrorMissingDate
 	}
+	EnsureID(&e.ID, e.Fields)
+	fields := e.Fields.Set("id", e.ID)
 
-	if _, hasId := e.Fields.Get("id"); !hasId {
-		host, hostErr := os.Hostname()
-		if hostErr != nil {
-			host = "localhost"
-		}
-		e.Fields = e.Fields.Set("id", fmt.Sprintf("tag:%s,%s:my-log/%s", host, time.Now().Format("2006"), uuid.NewString()))
-	}
-
-	ch := e.getFieldMarshalChan()
+	ch := getFieldMarshalChan(fields)
 	buff := &bytes.Buffer{}
 	buff.WriteString("@begin ")
 	buff.WriteString(e.Date.Format(DateFormat))
@@ -124,8 +147,14 @@ func (m *Entry) UnmarshalText(in []byte) error {
 	m.Date = d
 
 	for meta := range ch {
+		if meta.Key == "id" {
+			if id, idIsString := meta.Value.(string); idIsString {
+				m.ID = id
+			}
+		}
 		m.Fields = append(m.Fields, meta)
 	}
+	EnsureID(&m.ID, m.Fields)
 
 	return nil
 }
@@ -195,11 +224,13 @@ func (e Entry) MarshalJSON() ([]byte, error) {
 	if e.Date == (time.Time{}) {
 		return []byte{}, ErrorMissingDate
 	}
+	EnsureID(&e.ID, e.Fields)
+	fields := e.Fields.Set("id", e.ID)
 
 	out := map[string]any{}
 	out["title"] = e.Title
 	out["date"] = e.Date.Format(time.RFC3339)
-	maps.Copy(out, e.Fields.Map())
+	maps.Copy(out, fields.Map())
 	return json.Marshal(out)
 }
 
@@ -281,5 +312,6 @@ func (e *Entry) UnmarshalJSON(in []byte) error {
 		}
 		e.Fields = append(e.Fields, m)
 	}
+	EnsureID(&e.ID, e.Fields)
 	return nil
 }