X-Git-Url: https://git.giacomolli.uk/onechat/blobdiff_plain/c781f79f3c8cb9a7577ee1574d196988da2719b3..448c931a776c3e3f65ca2eab11da0c062d597818:/whatsapp.go?ds=sidebyside

diff --git a/whatsapp.go b/whatsapp.go
index 738ef8d..df43e8e 100644
--- a/whatsapp.go
+++ b/whatsapp.go
@@ -230,6 +230,34 @@ func openWhatsApp(ctx context.Context, dir string, clock func() time.Time, logge
 	return w, nil
 }
 
+func (w *WhatsApp) sessionPath() string {
+	return filepath.Join(w.dir, whatsappSessionFileName)
+}
+
+// openSession opens the session database and its first device. The caller holds
+// the mutex, or no other goroutine uses w yet.
+func (w *WhatsApp) openSession(ctx context.Context) error {
+	address, err := whatsappSessionAddress(w.sessionPath())
+	if err != nil {
+		return err
+	}
+
+	container, err := sqlstore.New(ctx, "sqlite", address, waLog.Noop)
+	if err != nil {
+		return fmt.Errorf("open WhatsApp session: %w", err)
+	}
+
+	device, err := container.GetFirstDevice(ctx)
+	if err != nil {
+		return errors.Join(fmt.Errorf("read WhatsApp device: %w", err), container.Close())
+	}
+
+	w.container = container
+	w.device = device
+
+	return nil
+}
+
 // Run connects a linked device, logs the closed batches in l, runs the pair and
 // unlink commands, and handles a logout from the phone, until ctx ends. Its
 // notes go to the log of l, and notify gets the notices for all clients. A
@@ -281,6 +309,7 @@ func (w *WhatsApp) Run(ctx context.Context, l *TurnLoop, notify func(Event)) err
 
 	cancel := func() {
 	}
+
 	defer func() {
 		cancel()
 		pairing.Wait()
@@ -343,177 +372,166 @@ func (w *WhatsApp) Run(ctx context.Context, l *TurnLoop, notify func(Event)) err
 	}
 }
 
-// Command runs the WhatsApp command args, the text after /whatsapp, and gives
-// each answer to answer. The answers go only to the client that sent the
-// command.
-func (w *WhatsApp) Command(args string, answer func(text string)) {
-	fields := strings.Fields(args)
-	request := WhatsAppRequest{
-		answer: answer,
+// connect tries the starting connection of the linked device with one client.
+// It returns whether Run must retry. A failed call starts the shared outage
+// state and logs its redacted cause once, because a returned ConnectContext
+// error does not emit Disconnected. Connected logs recovery after
+// authentication.
+func (w *WhatsApp) connect(ctx context.Context) bool {
+	w.mutex.Lock()
+
+	if ctx.Err() != nil || !w.linked || !w.retrying || w.closed {
+		w.mutex.Unlock()
+
+		return false
 	}
 
-	switch {
-	case len(fields) == 1 && fields[0] == "status":
-		answer(w.Status())
+	if w.client == nil {
+		w.client = w.newClient(w.device, w.handle)
+	}
 
-		return
-	case len(fields) == 1 && fields[0] == "unlink":
-		request.unlink = true
-	case len(fields) >= 2 && fields[0] == "pair":
-		phone, valid := whatsappPhone(strings.Join(fields[1:], ""))
-		if !valid {
-			answer("PHONE must be the number of your WhatsApp account with its country code: 7 to 15 digits, such as +15550001111.")
+	client := w.client
+	w.mutex.Unlock()
 
-			return
-		}
+	err := client.ConnectContext(ctx)
 
-		request.phone = phone
-	default:
-		answer(whatsappUsage)
+	w.mutex.Lock()
 
-		return
+	if err == nil || ctx.Err() != nil || !w.retrying || !w.linked {
+		w.retrying = false
+		w.mutex.Unlock()
+
+		return false
 	}
 
-	select {
-	case w.requests <- request:
-	default:
-		answer("Too many WhatsApp commands wait. Try again in a minute.")
+	first := w.startOutage()
+	cause := whatsappRedact(w.own, err.Error())
+	w.mutex.Unlock()
+
+	if first {
+		w.logger.Warn("first connect failed, retrying", "err", cause)
 	}
+
+	return true
 }
 
-// Status returns the state of the link: not linked, linked and connected, or
-// linked and disconnected, with the times of the connection and the routes.
-// Route source IDs can hold the phone numbers of other chats.
-func (w *WhatsApp) Status() string {
+// close ends the connection and the timer of the notice, and stops all notices.
+func (w *WhatsApp) close() {
 	w.mutex.Lock()
-	defer w.mutex.Unlock()
 
-	routes := ""
-	if w.routes != nil {
-		listed := w.routes.List()
-		if listed != "No routes." {
-			routes = "\nWhatsApp routes:\n" + listed
-		}
+	w.closed = true
+	if w.timer != nil {
+		w.timer.Stop()
 	}
 
-	switch {
-	case !w.linked:
-		return "WhatsApp is not linked. Run /whatsapp pair PHONE to link it." + routes
-	case w.connected:
-		return "WhatsApp is linked and connected since " + w.connectedAt.Format(whatsappTimeLayout) + "." + routes
-	case w.disconnectedAt.IsZero():
-		return "WhatsApp is linked and not connected yet." + routes
-	case w.connectedAt.IsZero():
-		return "WhatsApp is linked and disconnected since " + w.disconnectedAt.Format(whatsappTimeLayout) + "." + routes
-	default:
-		return "WhatsApp is linked and disconnected since " + w.disconnectedAt.Format(whatsappTimeLayout) + ". The last connection started at " + w.connectedAt.Format(whatsappTimeLayout) + "." + routes
+	client := w.client
+	w.client = nil
+	w.mutex.Unlock()
+
+	w.inbox.close()
+
+	if client != nil {
+		client.Disconnect()
 	}
 }
 
-// BackupSession writes a consistent SQLite snapshot to path while the session
-// cannot be created, closed, or removed. The source opens without creation
-// permission. No session file means no linked state to copy.
-func (w *WhatsApp) BackupSession(ctx context.Context, path string) (err error) {
-	w.sessionMutex.Lock()
-	defer w.sessionMutex.Unlock()
-
+// link returns a copy of the link of the device: whether it is linked, the
+// device, the client, whether it is connected, and the own IDs.
+func (w *WhatsApp) link() WhatsAppLink {
 	w.mutex.Lock()
 	defer w.mutex.Unlock()
 
-	_, err = os.Stat(w.sessionPath())
-	if errors.Is(err, os.ErrNotExist) {
-		return nil
+	return WhatsAppLink{
+		linked:    w.linked,
+		device:    w.device,
+		client:    w.client,
+		connected: w.connected,
+		own:       slices.Clone(w.own),
 	}
+}
 
-	if err != nil {
-		return fmt.Errorf("read session file: %w", err)
+// loggedOut logs the open batches, deletes the session after a logout from the
+// phone, notes it in the log of l, and tells all clients one time.
+func (w *WhatsApp) loggedOut(ctx context.Context, l *TurnLoop) error {
+	if !w.isLinked() {
+		return nil
 	}
 
-	err = os.MkdirAll(filepath.Dir(path), 0o700)
-	if err != nil {
-		return fmt.Errorf("create session snapshot directory: %w", err)
-	}
+	w.logger.Error("logged out by the phone")
 
-	address, err := whatsappSessionAddress(w.sessionPath())
+	err := w.inbox.deliver(ctx, l, w.link(), true)
 	if err != nil {
-		return fmt.Errorf("find session database: %w", err)
+		return err
 	}
 
-	database, err := sql.Open("sqlite", address+"&mode=rw")
+	err = w.removeSession()
 	if err != nil {
-		return fmt.Errorf("open session snapshot source: %w", err)
+		w.logger.Error("session delete failed", "err", err)
 	}
 
-	defer func() {
-		err = errors.Join(err, database.Close())
-	}()
-
-	_, err = database.ExecContext(ctx, "VACUUM INTO ?", path)
+	err = l.note("WhatsApp was unlinked from the phone.")
 	if err != nil {
-		return fmt.Errorf("snapshot session database: %w", err)
+		w.logger.Error("chat note failed", "err", err)
 	}
 
-	err = os.Chmod(path, 0o600)
-	if err != nil {
-		return fmt.Errorf("set session snapshot mode: %w", err)
-	}
+	w.broadcast("WhatsApp was unlinked from the phone. Run /whatsapp pair PHONE to link it again.")
 
 	return nil
 }
 
-// Close closes the session database.
-func (w *WhatsApp) Close() error {
-	w.sessionMutex.Lock()
-	defer w.sessionMutex.Unlock()
-
+// unlink logs the open batches, logs out the linked device, and deletes the
+// session. When the logout call fails, as it does while WhatsApp is
+// disconnected, the session is deleted all the same, and answer tells the user
+// to remove the device in the phone. Its error is one of the log or the state
+// file.
+func (w *WhatsApp) unlink(ctx context.Context, l *TurnLoop, answer func(text string)) error {
 	w.mutex.Lock()
-	defer w.mutex.Unlock()
 
-	if w.container == nil {
+	linked := w.linked
+	client := w.client
+	w.mutex.Unlock()
+
+	if !linked {
+		answer("WhatsApp is not linked.")
+
 		return nil
 	}
 
-	err := w.container.Close()
-	w.container = nil
-
-	return err
-}
+	err := w.inbox.deliver(ctx, l, w.link(), true)
+	if err != nil {
+		return err
+	}
 
-// Find returns the answer of whatsapp_find for name, as whatsappFind says.
-func (w *WhatsApp) Find(ctx context.Context, name string) (string, error) {
-	return whatsappFind(ctx, w.link(), w.groups, name)
-}
+	var logoutErr error
 
-// Send returns the answer of whatsapp_send for text and an optional stored
-// image to chat, with the durable send id that whatsappSend describes.
-func (w *WhatsApp) Send(ctx context.Context, id, chat, text, image string) (string, error) {
-	return whatsappSend(ctx, w.link(), w.groups, w.state, w.inbox.images, w.logger, w.clock, id, chat, text, image)
-}
+	if client != nil {
+		ctx, cancel := context.WithTimeout(ctx, whatsappLogoutTimeout)
+		defer cancel()
 
-func (w *WhatsApp) sessionPath() string {
-	return filepath.Join(w.dir, whatsappSessionFileName)
-}
+		logoutErr = client.Logout(ctx)
+	}
 
-// openSession opens the session database and its first device. The caller holds
-// the mutex, or no other goroutine uses w yet.
-func (w *WhatsApp) openSession(ctx context.Context) error {
-	address, err := whatsappSessionAddress(w.sessionPath())
+	err = w.removeSession()
 	if err != nil {
-		return err
+		answer("The unlink failed: " + w.redact(err.Error()))
+
+		return nil
 	}
 
-	container, err := sqlstore.New(ctx, "sqlite", address, waLog.Noop)
+	w.logger.Info("unlinked")
+
+	err = l.note("WhatsApp is unlinked.")
 	if err != nil {
-		return fmt.Errorf("open WhatsApp session: %w", err)
+		w.logger.Error("chat note failed", "err", err)
 	}
 
-	device, err := container.GetFirstDevice(ctx)
-	if err != nil {
-		return errors.Join(fmt.Errorf("read WhatsApp device: %w", err), container.Close())
+	if client == nil || logoutErr != nil {
+		answer("WhatsApp is unlinked here, but the phone did not get the logout. In WhatsApp on your phone, open Linked devices and remove the device.")
+
+		return nil
 	}
 
-	w.container = container
-	w.device = device
+	answer("WhatsApp is unlinked.")
 
 	return nil
 }
@@ -525,236 +543,6 @@ func (w *WhatsApp) isLinked() bool {
 	return w.linked
 }
 
-// link returns a copy of the link of the device: whether it is linked, the
-// device, the client, whether it is connected, and the own IDs.
-func (w *WhatsApp) link() WhatsAppLink {
-	w.mutex.Lock()
-	defer w.mutex.Unlock()
-
-	return WhatsAppLink{
-		linked:    w.linked,
-		device:    w.device,
-		client:    w.client,
-		connected: w.connected,
-		own:       slices.Clone(w.own),
-	}
-}
-
-// connect tries the starting connection of the linked device with one client.
-// It returns whether Run must retry. A failed call starts the shared outage
-// state and logs its redacted cause once, because a returned ConnectContext
-// error does not emit Disconnected. Connected logs recovery after
-// authentication.
-func (w *WhatsApp) connect(ctx context.Context) bool {
-	w.mutex.Lock()
-
-	if ctx.Err() != nil || !w.linked || !w.retrying || w.closed {
-		w.mutex.Unlock()
-
-		return false
-	}
-
-	if w.client == nil {
-		w.client = w.newClient(w.device, w.handle)
-	}
-
-	client := w.client
-	w.mutex.Unlock()
-
-	err := client.ConnectContext(ctx)
-
-	w.mutex.Lock()
-
-	if err == nil || ctx.Err() != nil || !w.retrying || !w.linked {
-		w.retrying = false
-		w.mutex.Unlock()
-
-		return false
-	}
-
-	first := w.startOutage()
-	cause := whatsappRedact(w.own, err.Error())
-	w.mutex.Unlock()
-
-	if first {
-		w.logger.Warn("first connect failed, retrying", "err", cause)
-	}
-
-	return true
-}
-
-// startOutage starts the shared outage time and notice timer once. The caller
-// holds the mutex. Its result tells whether this is the first failure.
-func (w *WhatsApp) startOutage() bool {
-	first := w.linked && (w.connected || w.disconnectedAt.IsZero())
-	if first {
-		w.disconnectedAt = w.clock()
-		w.disconnections++
-		disconnections := w.disconnections
-		w.timer = time.AfterFunc(whatsappOutageNoticeDelay, func() {
-			w.disconnectedLong(disconnections)
-		})
-	}
-
-	w.connected = false
-
-	return first
-}
-
-// close ends the connection and the timer of the notice, and stops all notices.
-func (w *WhatsApp) close() {
-	w.mutex.Lock()
-
-	w.closed = true
-	if w.timer != nil {
-		w.timer.Stop()
-	}
-
-	client := w.client
-	w.client = nil
-	w.mutex.Unlock()
-
-	w.inbox.close()
-
-	if client != nil {
-		client.Disconnect()
-	}
-}
-
-// loggedOut logs the open batches, deletes the session after a logout from the
-// phone, notes it in the log of l, and tells all clients one time.
-func (w *WhatsApp) loggedOut(ctx context.Context, l *TurnLoop) error {
-	if !w.isLinked() {
-		return nil
-	}
-
-	w.logger.Error("logged out by the phone, run /whatsapp pair PHONE")
-
-	err := w.inbox.deliver(ctx, l, w.link(), true)
-	if err != nil {
-		return err
-	}
-
-	err = w.removeSession()
-	if err != nil {
-		w.logger.Error("session delete failed", "err", err)
-	}
-
-	err = l.note("WhatsApp was unlinked from the phone.")
-	if err != nil {
-		w.logger.Error("chat note failed", "err", err)
-	}
-
-	w.broadcast("WhatsApp was unlinked from the phone. Run /whatsapp pair PHONE to link it again.")
-
-	return nil
-}
-
-// unlink logs the open batches, logs out the linked device, and deletes the
-// session. When the logout call fails, as it does while WhatsApp is
-// disconnected, the session is deleted all the same, and answer tells the user
-// to remove the device in the phone. Its error is one of the log or the state
-// file.
-func (w *WhatsApp) unlink(ctx context.Context, l *TurnLoop, answer func(text string)) error {
-	w.mutex.Lock()
-
-	linked := w.linked
-	client := w.client
-	w.mutex.Unlock()
-
-	if !linked {
-		answer("WhatsApp is not linked.")
-
-		return nil
-	}
-
-	err := w.inbox.deliver(ctx, l, w.link(), true)
-	if err != nil {
-		return err
-	}
-
-	var logoutErr error
-
-	if client != nil {
-		ctx, cancel := context.WithTimeout(ctx, whatsappLogoutTimeout)
-		defer cancel()
-
-		logoutErr = client.Logout(ctx)
-	}
-
-	err = w.removeSession()
-	if err != nil {
-		answer("The unlink failed: " + w.redact(err.Error()))
-
-		return nil
-	}
-
-	w.logger.Info("unlinked")
-
-	err = l.note("WhatsApp is unlinked.")
-	if err != nil {
-		w.logger.Error("chat note failed", "err", err)
-	}
-
-	if client == nil || logoutErr != nil {
-		answer("WhatsApp is unlinked here, but the phone did not get the logout. In WhatsApp on your phone, open Linked devices and remove the device.")
-
-		return nil
-	}
-
-	answer("WhatsApp is unlinked.")
-
-	return nil
-}
-
-// removeSession ends the connection, closes the session database, and deletes
-// its files. The session lock covers the cleanup after mutex is released, so a
-// snapshot or a new session cannot open files that cleanup removes.
-func (w *WhatsApp) removeSession() error {
-	w.sessionMutex.Lock()
-	defer w.sessionMutex.Unlock()
-
-	w.mutex.Lock()
-
-	client := w.client
-	w.client = nil
-	w.linked = false
-	w.retrying = false
-	w.own = nil
-	w.connected = false
-	w.disconnectedAt = time.Time{}
-	if w.timer != nil {
-		w.timer.Stop()
-	}
-
-	w.noticed = false
-	container := w.container
-	w.container = nil
-	w.device = nil
-	w.mutex.Unlock()
-
-	w.inbox.stopCatchup()
-
-	if client != nil {
-		client.Disconnect()
-	}
-
-	var err error
-
-	if container != nil {
-		err = container.Close()
-	}
-
-	for _, suffix := range []string{"", "-wal", "-shm"} {
-		removeErr := os.Remove(w.sessionPath() + suffix)
-		if !errors.Is(removeErr, os.ErrNotExist) {
-			err = errors.Join(err, removeErr)
-		}
-	}
-
-	return err
-}
-
 // pair links a new device to the account of phone with a pairing code. It gives
 // the steps and the code to answer, and then the end of the pairing: the linked
 // number, an expired code, or a failure. A pairing that a new one ends gives no
@@ -863,23 +651,229 @@ func (w *WhatsApp) pair(ctx, runCtx context.Context, l *TurnLoop, phone string,
 	}
 }
 
-// newDevice returns a new device in the session database. It makes the
-// directory and the file of the session first, with their modes, when they do
-// not exist.
-func (w *WhatsApp) newDevice(ctx context.Context) (*store.Device, error) {
-	w.sessionMutex.Lock()
-	defer w.sessionMutex.Unlock()
-
+// handle takes one event of the library and tells if it was handled. A message
+// goes to the inbox. The names of the groups follow the events of the groups. A
+// connection starts a catch-up of the inbox, which ends at OfflineSyncCompleted
+// or after whatsappCatchupTimeout. A disconnection keeps the time of its start
+// while Run or the library tries again. After whatsappOutageNoticeDelay of a
+// disconnection, all clients get one notice, and they get one more when the
+// connection comes back. A disconnection that the library does not try again
+// gives a notice at once.
+//
+// The log of the daemon gets one line for each change of the connection of the
+// linked device: connected, a failed first connection, a lost connection, and
+// connected again with the length of the outage. The retries of the library and
+// Run between them log nothing.
+func (w *WhatsApp) handle(event any) bool {
 	w.mutex.Lock()
-	defer w.mutex.Unlock()
 
-	if w.container == nil {
-		err := os.MkdirAll(w.dir, 0o700)
-		if err != nil {
-			return nil, fmt.Errorf("create WhatsApp directory: %w", err)
+	ctx := w.ctx
+	w.mutex.Unlock()
+
+	switch event := event.(type) {
+	case *events.Message:
+		return w.inbox.receive(ctx, w.link(), event)
+	case *events.GroupInfo:
+		if event.Name != nil {
+			w.groups.set(event.JID.String(), event.Name.Name)
 		}
 
-		file, err := os.OpenFile(w.sessionPath(), os.O_CREATE|os.O_RDWR, 0o600)
+		return true
+	case *events.JoinedGroup:
+		w.groups.set(event.JID.String(), event.Name)
+
+		return true
+	case *events.OfflineSyncCompleted:
+		w.inbox.endCatchup()
+
+		return true
+	case *events.Connected:
+		w.inbox.startCatchup()
+	}
+
+	var notice, line string
+
+	level := slog.LevelInfo
+
+	var attrs []any
+
+	w.mutex.Lock()
+
+	switch event := event.(type) {
+	case *events.PairSuccess:
+		w.own = whatsappOwnIDs(event.ID.User, event.LID.User)
+	case *events.Connected:
+		switch {
+		case !w.linked || w.connected:
+		case w.disconnectedAt.IsZero():
+			line = "connected"
+		default:
+			line = "connected again"
+			attrs = append(attrs, "after", w.clock().Sub(w.disconnectedAt))
+		}
+
+		w.connected = true
+		w.retrying = false
+		w.connectedAt = w.clock()
+		if w.timer != nil {
+			w.timer.Stop()
+		}
+
+		if w.noticed {
+			w.noticed = false
+			notice = "WhatsApp is connected again."
+		}
+	case *events.Disconnected:
+		connected := w.connected
+		if w.startOutage() {
+			level = slog.LevelWarn
+			line = "disconnected, retrying"
+			if !connected {
+				line = "first connect failed, retrying"
+			}
+		}
+	case *events.LoggedOut:
+		w.retrying = false
+		select {
+		case w.logouts <- struct{}{}:
+		default:
+		}
+	case events.PermanentDisconnect:
+		w.retrying = false
+		if w.linked {
+			w.connected = false
+			w.noticed = true
+			notice = "WhatsApp is disconnected and does not connect again by itself: " + event.PermanentDisconnectDescription() + ". Restart the daemon to try again."
+			level = slog.LevelError
+			line = "disconnected for good, restart to retry"
+			attrs = append(attrs, "err", whatsappRedact(w.own, event.PermanentDisconnectDescription()))
+		}
+	}
+
+	if w.closed {
+		line = ""
+	}
+
+	w.mutex.Unlock()
+
+	if line != "" {
+		w.logger.Log(ctx, level, line, attrs...)
+	}
+
+	if notice != "" {
+		w.broadcast(notice)
+	}
+
+	return true
+}
+
+// startOutage starts the shared outage time and notice timer once. The caller
+// holds the mutex. Its result tells whether this is the first failure.
+func (w *WhatsApp) startOutage() bool {
+	first := w.linked && (w.connected || w.disconnectedAt.IsZero())
+	if first {
+		w.disconnectedAt = w.clock()
+		w.disconnections++
+		disconnections := w.disconnections
+		w.timer = time.AfterFunc(whatsappOutageNoticeDelay, func() {
+			w.disconnectedLong(disconnections)
+		})
+	}
+
+	w.connected = false
+
+	return first
+}
+
+// removeSession ends the connection, closes the session database, and deletes
+// its files. The session lock covers the cleanup after mutex is released, so a
+// snapshot or a new session cannot open files that cleanup removes.
+func (w *WhatsApp) removeSession() error {
+	w.sessionMutex.Lock()
+	defer w.sessionMutex.Unlock()
+
+	w.mutex.Lock()
+
+	client := w.client
+	w.client = nil
+	w.linked = false
+	w.retrying = false
+	w.own = nil
+	w.connected = false
+	w.disconnectedAt = time.Time{}
+	if w.timer != nil {
+		w.timer.Stop()
+	}
+
+	w.noticed = false
+	container := w.container
+	w.container = nil
+	w.device = nil
+	w.mutex.Unlock()
+
+	w.inbox.stopCatchup()
+
+	if client != nil {
+		client.Disconnect()
+	}
+
+	var err error
+
+	if container != nil {
+		err = container.Close()
+	}
+
+	for _, suffix := range []string{"", "-wal", "-shm"} {
+		removeErr := os.Remove(w.sessionPath() + suffix)
+		if !errors.Is(removeErr, os.ErrNotExist) {
+			err = errors.Join(err, removeErr)
+		}
+	}
+
+	return err
+}
+
+// broadcast gives text as a notice to all clients.
+func (w *WhatsApp) broadcast(text string) {
+	w.mutex.Lock()
+
+	notify := w.notify
+	closed := w.closed
+	w.mutex.Unlock()
+
+	if notify != nil && !closed {
+		notify(Event{
+			Kind: "notice",
+			Text: text,
+		})
+	}
+}
+
+// redact replaces the own number and the own LID in text with OWN.
+func (w *WhatsApp) redact(text string) string {
+	w.mutex.Lock()
+	defer w.mutex.Unlock()
+
+	return whatsappRedact(w.own, text)
+}
+
+// newDevice returns a new device in the session database. It makes the
+// directory and the file of the session first, with their modes, when they do
+// not exist.
+func (w *WhatsApp) newDevice(ctx context.Context) (*store.Device, error) {
+	w.sessionMutex.Lock()
+	defer w.sessionMutex.Unlock()
+
+	w.mutex.Lock()
+	defer w.mutex.Unlock()
+
+	if w.container == nil {
+		err := os.MkdirAll(w.dir, 0o700)
+		if err != nil {
+			return nil, fmt.Errorf("create WhatsApp directory: %w", err)
+		}
+
+		file, err := os.OpenFile(w.sessionPath(), os.O_CREATE|os.O_RDWR, 0o600)
 		if err != nil {
 			return nil, fmt.Errorf("create WhatsApp session: %w", err)
 		}
@@ -909,162 +903,229 @@ func (w *WhatsApp) linkedBy(client WhatsAppClient) {
 	w.linked = true
 }
 
-// handle takes one event of the library and tells if it was handled. A message
-// goes to the inbox. The names of the groups follow the events of the groups. A
-// connection starts a catch-up of the inbox, which ends at OfflineSyncCompleted
-// or after whatsappCatchupTimeout. A disconnection keeps the time of its start
-// while Run or the library tries again. After whatsappOutageNoticeDelay of a
-// disconnection, all clients get one notice, and they get one more when the
-// connection comes back. A disconnection that the library does not try again
-// gives a notice at once.
-//
-// The log of the daemon gets one line for each change of the connection of the
-// linked device: connected, a failed first connection, a lost connection, and
-// connected again with the length of the outage. The retries of the library and
-// Run between them log nothing.
-func (w *WhatsApp) handle(event any) bool {
+// disconnectedLong gives the notice of a long disconnection, unless the
+// disconnection with the number disconnections ended.
+func (w *WhatsApp) disconnectedLong(disconnections int) {
 	w.mutex.Lock()
 
-	ctx := w.ctx
-	w.mutex.Unlock()
+	long := !w.closed && w.linked && !w.connected && !w.noticed && w.disconnections == disconnections
+	if long {
+		w.noticed = true
+	}
+
+	since := w.disconnectedAt
+	w.mutex.Unlock()
+
+	if long {
+		w.broadcast("WhatsApp is disconnected since " + since.Format(whatsappTimeLayout) + ". OneChat tries again.")
+	}
+}
+
+// Command runs the WhatsApp command args, the text after /whatsapp, and gives
+// each answer to answer. The answers go only to the client that sent the
+// command.
+func (w *WhatsApp) Command(args string, answer func(text string)) {
+	fields := strings.Fields(args)
+	request := WhatsAppRequest{
+		answer: answer,
+	}
+
+	switch {
+	case len(fields) == 1 && fields[0] == "status":
+		answer(w.Status())
+
+		return
+	case len(fields) == 1 && fields[0] == "unlink":
+		request.unlink = true
+	case len(fields) >= 2 && fields[0] == "pair":
+		phone, valid := whatsappPhone(strings.Join(fields[1:], ""))
+		if !valid {
+			answer("PHONE must be the number of your WhatsApp account with its country code: 7 to 15 digits, such as +15550001111.")
+
+			return
+		}
+
+		request.phone = phone
+	default:
+		answer(whatsappUsage)
+
+		return
+	}
+
+	select {
+	case w.requests <- request:
+	default:
+		answer("Too many WhatsApp commands wait. Try again in a minute.")
+	}
+}
+
+// Status returns the state of the link: not linked, linked and connected, or
+// linked and disconnected, with the times of the connection and the routes.
+// Route source IDs can hold the phone numbers of other chats.
+func (w *WhatsApp) Status() string {
+	w.mutex.Lock()
+	defer w.mutex.Unlock()
+
+	routes := ""
+	if w.routes != nil {
+		listed := w.routes.List()
+		if listed != "No routes." {
+			routes = "\nWhatsApp routes:\n" + listed
+		}
+	}
+
+	switch {
+	case !w.linked:
+		return "WhatsApp is not linked. Run /whatsapp pair PHONE to link it." + routes
+	case w.connected:
+		return "WhatsApp is linked and connected since " + w.connectedAt.Format(whatsappTimeLayout) + "." + routes
+	case w.disconnectedAt.IsZero():
+		return "WhatsApp is linked and not connected yet." + routes
+	case w.connectedAt.IsZero():
+		return "WhatsApp is linked and disconnected since " + w.disconnectedAt.Format(whatsappTimeLayout) + "." + routes
+	default:
+		return "WhatsApp is linked and disconnected since " + w.disconnectedAt.Format(whatsappTimeLayout) + ". The last connection started at " + w.connectedAt.Format(whatsappTimeLayout) + "." + routes
+	}
+}
+
+// BackupSession writes a consistent SQLite snapshot to path while the session
+// cannot be created, closed, or removed. The source opens without creation
+// permission. No session file means no linked state to copy.
+func (w *WhatsApp) BackupSession(ctx context.Context, path string) (err error) {
+	w.sessionMutex.Lock()
+	defer w.sessionMutex.Unlock()
+
+	w.mutex.Lock()
+	defer w.mutex.Unlock()
+
+	_, err = os.Stat(w.sessionPath())
+	if errors.Is(err, os.ErrNotExist) {
+		return nil
+	}
+
+	if err != nil {
+		return fmt.Errorf("read session file: %w", err)
+	}
+
+	err = os.MkdirAll(filepath.Dir(path), 0o700)
+	if err != nil {
+		return fmt.Errorf("create session snapshot directory: %w", err)
+	}
 
-	switch event := event.(type) {
-	case *events.Message:
-		return w.inbox.receive(ctx, w.link(), event)
-	case *events.GroupInfo:
-		if event.Name != nil {
-			w.groups.set(event.JID.String(), event.Name.Name)
-		}
+	address, err := whatsappSessionAddress(w.sessionPath())
+	if err != nil {
+		return fmt.Errorf("find session database: %w", err)
+	}
 
-		return true
-	case *events.JoinedGroup:
-		w.groups.set(event.JID.String(), event.Name)
+	database, err := sql.Open("sqlite", address+"&mode=rw")
+	if err != nil {
+		return fmt.Errorf("open session snapshot source: %w", err)
+	}
 
-		return true
-	case *events.OfflineSyncCompleted:
-		w.inbox.endCatchup()
+	defer func() {
+		err = errors.Join(err, database.Close())
+	}()
 
-		return true
-	case *events.Connected:
-		w.inbox.startCatchup()
+	_, err = database.ExecContext(ctx, "VACUUM INTO ?", path)
+	if err != nil {
+		return fmt.Errorf("snapshot session database: %w", err)
 	}
 
-	var notice, line string
+	err = os.Chmod(path, 0o600)
+	if err != nil {
+		return fmt.Errorf("set session snapshot mode: %w", err)
+	}
 
-	level := slog.LevelInfo
+	return nil
+}
 
-	var attrs []any
+// Close closes the session database.
+func (w *WhatsApp) Close() error {
+	w.sessionMutex.Lock()
+	defer w.sessionMutex.Unlock()
 
 	w.mutex.Lock()
+	defer w.mutex.Unlock()
 
-	switch event := event.(type) {
-	case *events.PairSuccess:
-		w.own = whatsappOwnIDs(event.ID.User, event.LID.User)
-	case *events.Connected:
-		switch {
-		case !w.linked || w.connected:
-		case w.disconnectedAt.IsZero():
-			line = "connected"
-		default:
-			line = "connected again"
-			attrs = append(attrs, "after", w.clock().Sub(w.disconnectedAt))
-		}
+	if w.container == nil {
+		return nil
+	}
 
-		w.connected = true
-		w.retrying = false
-		w.connectedAt = w.clock()
-		if w.timer != nil {
-			w.timer.Stop()
-		}
+	err := w.container.Close()
+	w.container = nil
 
-		if w.noticed {
-			w.noticed = false
-			notice = "WhatsApp is connected again."
-		}
-	case *events.Disconnected:
-		connected := w.connected
-		if w.startOutage() {
-			level = slog.LevelWarn
-			line = "disconnected, retrying"
-			if !connected {
-				line = "first connect failed, retrying"
-			}
-		}
-	case *events.LoggedOut:
-		w.retrying = false
-		select {
-		case w.logouts <- struct{}{}:
-		default:
-		}
-	case events.PermanentDisconnect:
-		w.retrying = false
-		if w.linked {
-			w.connected = false
-			w.noticed = true
-			notice = "WhatsApp is disconnected and does not connect again by itself: " + event.PermanentDisconnectDescription() + ". Restart the daemon to try again."
-			level = slog.LevelError
-			line = "disconnected for good, restart to retry"
-			attrs = append(attrs, "err", whatsappRedact(w.own, event.PermanentDisconnectDescription()))
-		}
-	}
+	return err
+}
 
-	if w.closed {
-		line = ""
-	}
+// Find returns the answer of whatsapp_find for name, as whatsappFind says.
+func (w *WhatsApp) Find(ctx context.Context, name string) (string, error) {
+	return whatsappFind(ctx, w.link(), w.groups, name)
+}
 
-	w.mutex.Unlock()
+// Send returns the answer of whatsapp_send for text and an optional stored
+// image to chat, with the durable send id that whatsappSend describes.
+func (w *WhatsApp) Send(ctx context.Context, id, chat, text, image string) (string, error) {
+	return whatsappSend(ctx, w.link(), w.groups, w.state, w.inbox.images, w.logger, w.clock, id, chat, text, image)
+}
 
-	if line != "" {
-		w.logger.Log(ctx, level, line, attrs...)
-	}
+// whatsappOwnIDs returns the own number and the own LID that are not empty.
+func whatsappOwnIDs(ids ...string) []string {
+	var own []string
 
-	if notice != "" {
-		w.broadcast(notice)
+	for _, id := range ids {
+		if id != "" {
+			own = append(own, id)
+		}
 	}
 
-	return true
+	return own
 }
 
-// disconnectedLong gives the notice of a long disconnection, unless the
-// disconnection with the number disconnections ended.
-func (w *WhatsApp) disconnectedLong(disconnections int) {
-	w.mutex.Lock()
-
-	long := !w.closed && w.linked && !w.connected && !w.noticed && w.disconnections == disconnections
-	if long {
-		w.noticed = true
+// whatsappSessionAddress returns the SQLite address of the session database at
+// path, with foreign keys on, as the library needs, and a wait for a busy
+// database.
+func whatsappSessionAddress(path string) (string, error) {
+	path, err := filepath.Abs(path)
+	if err != nil {
+		return "", fmt.Errorf("find WhatsApp session: %w", err)
 	}
 
-	since := w.disconnectedAt
-	w.mutex.Unlock()
-
-	if long {
-		w.broadcast("WhatsApp is disconnected since " + since.Format(whatsappTimeLayout) + ". OneChat tries again.")
+	address := url.URL{
+		Scheme:   "file",
+		Path:     path,
+		RawQuery: "_pragma=foreign_keys(1)&_pragma=busy_timeout(5000)",
 	}
+
+	return address.String(), nil
 }
 
-// broadcast gives text as a notice to all clients.
-func (w *WhatsApp) broadcast(text string) {
-	w.mutex.Lock()
+// whatsappRedact replaces each of the own IDs own in text with OWN.
+func whatsappRedact(own []string, text string) string {
+	for _, id := range own {
+		text = strings.ReplaceAll(text, id, "OWN")
+	}
 
-	notify := w.notify
-	closed := w.closed
-	w.mutex.Unlock()
+	return text
+}
 
-	if notify != nil && !closed {
-		notify(Event{
-			Kind: "notice",
-			Text: text,
-		})
+// whatsappItemError returns the error of a pairing item that is not a code, a
+// success, or a timeout.
+func whatsappItemError(item whatsmeow.QRChannelItem) string {
+	if item.Error != nil {
+		return item.Error.Error()
 	}
+
+	return item.Event
 }
 
-// redact replaces the own number and the own LID in text with OWN.
-func (w *WhatsApp) redact(text string) string {
-	w.mutex.Lock()
-	defer w.mutex.Unlock()
+// whatsappPhone returns the digits of phone, a number with its country code and
+// an optional + and dashes, and tells if it has the form of a number: 7 to 15
+// digits, with no 0 first.
+func whatsappPhone(phone string) (string, bool) {
+	phone = strings.ReplaceAll(strings.TrimPrefix(phone, "+"), "-", "")
+	valid := len(phone) >= 7 && len(phone) <= 15 && phone[0] != '0' && strings.Trim(phone, "0123456789") == ""
 
-	return whatsappRedact(w.own, text)
+	return phone, valid
 }
 
 // whatsappSetDeviceProps sets the device properties that the library sends at
@@ -1134,19 +1195,6 @@ func whatsappContactName(ctx context.Context, device *store.Device, jid types.JI
 	}
 }
 
-// whatsappOwnIDs returns the own number and the own LID that are not empty.
-func whatsappOwnIDs(ids ...string) []string {
-	var own []string
-
-	for _, id := range ids {
-		if id != "" {
-			own = append(own, id)
-		}
-	}
-
-	return own
-}
-
 // whatsappChatHash returns a short hash of chat for the daemon log, so that a
 // log line can tell chats apart without a phone number.
 func whatsappChatHash(chat types.JID) string {
@@ -1155,33 +1203,6 @@ func whatsappChatHash(chat types.JID) string {
 	return fmt.Sprintf("%x", digest[:6])
 }
 
-// whatsappRedact replaces each of the own IDs own in text with OWN.
-func whatsappRedact(own []string, text string) string {
-	for _, id := range own {
-		text = strings.ReplaceAll(text, id, "OWN")
-	}
-
-	return text
-}
-
-// whatsappSessionAddress returns the SQLite address of the session database at
-// path, with foreign keys on, as the library needs, and a wait for a busy
-// database.
-func whatsappSessionAddress(path string) (string, error) {
-	path, err := filepath.Abs(path)
-	if err != nil {
-		return "", fmt.Errorf("find WhatsApp session: %w", err)
-	}
-
-	address := url.URL{
-		Scheme:   "file",
-		Path:     path,
-		RawQuery: "_pragma=foreign_keys(1)&_pragma=busy_timeout(5000)",
-	}
-
-	return address.String(), nil
-}
-
 // whatsappCommandArgs returns the text after /whatsapp of a line of a WhatsApp
 // command, or false for any other line.
 func whatsappCommandArgs(line string) (string, bool) {
@@ -1197,23 +1218,3 @@ func whatsappCommandArgs(line string) (string, bool) {
 
 	return strings.TrimSpace(args), true
 }
-
-// whatsappPhone returns the digits of phone, a number with its country code and
-// an optional + and dashes, and tells if it has the form of a number: 7 to 15
-// digits, with no 0 first.
-func whatsappPhone(phone string) (string, bool) {
-	phone = strings.ReplaceAll(strings.TrimPrefix(phone, "+"), "-", "")
-	valid := len(phone) >= 7 && len(phone) <= 15 && phone[0] != '0' && strings.Trim(phone, "0123456789") == ""
-
-	return phone, valid
-}
-
-// whatsappItemError returns the error of a pairing item that is not a code, a
-// success, or a timeout.
-func whatsappItemError(item whatsmeow.QRChannelItem) string {
-	if item.Error != nil {
-		return item.Error.Error()
-	}
-
-	return item.Event
-}