X-Git-Url: https://git.giacomolli.uk/onechat/blobdiff_plain/baf7a940be8927278e3b4b87e7366cebfc16532f..f5c601f1801aaa276f8c335fcb51c373edc0b50c:/log.go

diff --git a/log.go b/log.go
index d34f459..2b9f32f 100644
--- a/log.go
+++ b/log.go
@@ -21,6 +21,38 @@ var logKinds = map[string]bool{
 	"note":  true,
 }
 
+// Log is the append-only message log of one chat. It writes one JSON line for
+// each message to main/YYYY-MM-DD.jsonl, named for the local day of the
+// message. It never edits or deletes a line. Each line goes to the operating
+// system before Append returns, so a crash of the process loses no message. An
+// exclusive lock on the lock file makes sure that only one process writes the
+// log. After a failed write, the end of the file is not known, so the log
+// refuses all writes until it is opened again. The caller serializes all calls.
+//
+// The log keeps no message in memory. The index index/main.idx holds the
+// position of message i in record i, so a read of a message is one read of the
+// index and one of its day file. At open the log indexes the lines after the
+// last indexed one, so a missing index is built again from the day files.
+type Log struct {
+	clock   func() time.Time
+	lock    *os.File
+	journal Journal
+	index   *Records
+	failure error
+}
+
+// Message is one entry of the chat log. ID is its position in the log, from 0.
+// A rebuild assigns positions in the merged log. Size is the UTF-8 byte length
+// of Text. Date is the message time in RFC 3339 format, supplied at append or
+// taken from the clock.
+type Message struct {
+	ID   int    `json:"i"`
+	Kind string `json:"kind"`
+	Text string `json:"text"`
+	Size int    `json:"size"`
+	Date string `json:"date"`
+}
+
 // openLog locks the chat in root and indexes its new lines. The clock gives the
 // date of each new message.
 func openLog(ctx context.Context, root string, clock func() time.Time) (*Log, error) {
@@ -57,26 +89,6 @@ func openLog(ctx context.Context, root string, clock func() time.Time) (*Log, er
 	return l, nil
 }
 
-// Log is the append-only message log of one chat. It writes one JSON line for
-// each message to main/YYYY-MM-DD.jsonl, named for the local day of the write.
-// It never edits or deletes a line. Each line goes to the operating system
-// before Append returns, so a crash of the process loses no message. An
-// exclusive lock on the lock file makes sure that only one process writes the
-// log. After a failed write, the end of the file is not known, so the log
-// refuses all writes until it is opened again. The caller serializes all calls.
-//
-// The log keeps no message in memory. The index index/main.idx holds the
-// position of message i in record i, so a read of a message is one read of the
-// index and one of its day file. At open the log indexes the lines after the
-// last indexed one, so a missing index is built again from the day files.
-type Log struct {
-	clock   func() time.Time
-	lock    *os.File
-	journal Journal
-	index   *Records
-	failure error
-}
-
 // Close releases the lock. The log refuses all calls after Close.
 func (l *Log) Close() error {
 	err := l.journal.Close()
@@ -96,26 +108,45 @@ func (l *Log) Close() error {
 // Append writes a new message to the log and returns it with its ID, size, and
 // date.
 func (l *Log) Append(kind, text string) (Message, error) {
+	return l.AppendDated(kind, text, "")
+}
+
+// AppendDated writes a message with date in RFC 3339 format. An empty date uses
+// the clock. The day file uses the local day of the given date.
+func (l *Log) AppendDated(kind, text, date string) (Message, error) {
 	if l.lock == nil {
-		return Message{}, os.ErrClosed
+		return Message{}, fmt.Errorf("append dated message: %w", os.ErrClosed)
 	}
 
 	if l.failure != nil {
 		return Message{}, fmt.Errorf("log needs a reopen after a failed write: %w", l.failure)
 	}
 
+	var err error
+
 	now := l.clock()
+	if date == "" {
+		date = now.Format(time.RFC3339Nano)
+	} else {
+		now, err = time.Parse(time.RFC3339Nano, date)
+		if err != nil {
+			return Message{}, fmt.Errorf("parse message date: %w", err)
+		}
+
+		now = now.In(time.Local)
+	}
+
 	message := Message{
 		ID:   l.index.count,
 		Kind: kind,
 		Text: text,
 		Size: len(text),
-		Date: now.Format(time.RFC3339Nano),
+		Date: date,
 	}
 
-	err := logValidateMessage(message)
+	err = logValidateMessage(message)
 	if err != nil {
-		return Message{}, err
+		return Message{}, fmt.Errorf("validate dated message: %w", err)
 	}
 
 	line, err := json.Marshal(message)
@@ -158,6 +189,7 @@ func (l *Log) Message(id int) (Message, error) {
 	}
 
 	var message Message
+
 	err = json.Unmarshal(line, &message)
 	if err != nil {
 		return Message{}, fmt.Errorf("decode message %d: %w", id, err)
@@ -188,9 +220,10 @@ func (l *Log) catchUp(ctx context.Context) error {
 
 	return l.journal.Scan(ctx, start, func(line []byte, place Position) error {
 		var message Message
+
 		err := json.Unmarshal(line, &message)
 		if err != nil {
-			return err
+			return fmt.Errorf("decode log message: %w", err)
 		}
 
 		if message.ID != l.index.count {
@@ -213,17 +246,6 @@ func (l *Log) addIndex(place Position) error {
 	return l.index.Append(record)
 }
 
-// Message is one entry of the chat log. ID is the permanent position of the
-// message in the chat, from 0. Size is the UTF-8 byte length of Text. Date is
-// the time of the write in RFC 3339 format.
-type Message struct {
-	ID   int    `json:"i"`
-	Kind string `json:"kind"`
-	Text string `json:"text"`
-	Size int    `json:"size"`
-	Date string `json:"date"`
-}
-
 // logValidateMessage makes sure that a message has a known kind, valid UTF-8
 // text, the size of its text, and a valid date.
 func logValidateMessage(message Message) error {