Add private message reply command

README.md

@@ -96,6 +96,8 @@ Ctrl+C     - Exit chat
 :nick <name>         - Change nickname
 :msg <user> <message> - Send private message
 :w <user> <text>     - Short alias for :msg
+:reply <text>        - Reply to latest private message
+:r <text>            - Short alias for :reply
 :inbox               - Show private messages
 :last [N]            - Show last N messages from history (max 50, default 10)
 :search <keyword>    - Search message history (shows last 15 matches)
@@ -111,8 +113,8 @@ ESC                  - Return to NORMAL mode
 Command output pages use `j/k`, `Ctrl+D/U`, and `g/G` for paging.  `:inbox`
 shows incoming and sent private messages newest-first; press `r` to refresh it
 manually, and it refreshes when a new private message arrives while the inbox
-is open. Private messages are per-session only and are not written to
-`messages.log`.
+is open. `:reply text` and `:r text` send to the latest private-message peer.
+Private messages are per-session only and are not written to `messages.log`.
 
 **Special messages (INSERT mode)**
 ```

docs/EASY_SETUP.md

@@ -80,6 +80,7 @@ Common commands:
 :users                online users
 :nick <name>          change nickname
 :msg <user> <message> send private message
+:reply <message>      reply to latest private message
 :inbox                show private messages
 :last [N]             recent messages
 :search <keyword>     search message history

docs/INTERFACE.md

@@ -160,8 +160,10 @@ should configure `TNT_ACCESS_TOKEN` before relying on exec-post identity.
 ## Interactive Private Messages
 
 `:msg user message` and its `:w` alias deliver private messages only to online
-interactive clients.  They are not persisted to `messages.log` and are not
-included in exec `tail`, exec `dump`, `:last`, or `:search`.
+interactive clients.  `:reply message` and its `:r` alias send to the latest
+private-message peer in the current session.  Private messages are not
+persisted to `messages.log` and are not included in exec `tail`, exec `dump`,
+`:last`, or `:search`.
 
 Each participant keeps a bounded in-memory `:inbox` for the current session.
 Recipients see incoming private messages; senders see local sent-message

docs/QUICKREF.md

@@ -30,6 +30,8 @@ COMMANDS (COMMAND mode, prefix with :)
   nick <name>            change nickname
   msg <user> <message>   send private message
   w <user> <text>        alias for msg
+  reply <text>           reply to latest private message
+  r <text>               alias for reply
   inbox                  show private messages, newest first
   last [N]               last N messages from log (default 10, max 50)
   search <keyword>       search full history (case-insensitive, 15 results)

docs/USER_LIFECYCLE.md

@@ -12,8 +12,8 @@ The product path should stay short:
 5. User presses Esc to browse history with Vim-style movement.
 6. User uses `:help` for the concise manual or `?` for the full key reference.
 7. User searches from NORMAL with `/term`, or uses commands when needed:
-   `:users`, `:msg`, `:inbox`, `:last`, `:search`, `:nick`, `:mute-joins`,
-   and `:q`.
+   `:users`, `:msg`, `:reply`, `:inbox`, `:last`, `:search`, `:nick`,
+   `:mute-joins`, and `:q`.
 8. Scripts and operators use `tntctl` or SSH exec commands for `health`,
    `stats`, `users`, `tail`, `dump`, and `post`.
 
@@ -39,6 +39,9 @@ The product path should stay short:
 - `:inbox` is live enough for normal chat use: it can be refreshed with `r`
   and refreshes automatically when a new private message arrives while the
   inbox is open.
+- `:reply` / `:r` keeps the private-message path keyboard-short: it answers
+  the latest private-message peer in the current session without retyping a
+  username.
 - Long command output uses a small pager so `:last` and `:search` are readable
   on small terminals.
 
@@ -49,10 +52,12 @@ The product path should stay short:
 - second user joins and is visible through `users --json`
 - first user opens `?`, checks `:users`, sends a public message, scrolls, uses
   `:last` and `:search`
-- first user toggles `:mute-joins`, sends two `:msg` messages, confirms sent
-  copies in `:inbox`, changes nickname, sends `/me`, and exits
-- second user opens `:inbox` before the private messages arrive and sees it
-  auto-refresh after delivery, newest first
+- first user toggles `:mute-joins`, sends two `:msg` messages, receives a
+  `:reply`, confirms private-message copies in `:inbox`, changes nickname,
+  sends `/me`, and exits
+- second user opens `:inbox` before the private messages arrive, sees it
+  auto-refresh after delivery, newest first, and replies without retyping the
+  sender's username
 - exec `tail` sees public messages
 - `messages.log` contains public history and excludes private-message content
 

include/command_catalog.h

@@ -8,6 +8,7 @@ typedef enum {
     TNT_COMMAND_HELP,
     TNT_COMMAND_LANG,
     TNT_COMMAND_MSG,
+    TNT_COMMAND_REPLY,
     TNT_COMMAND_INBOX,
     TNT_COMMAND_NICK,
     TNT_COMMAND_LAST,

include/i18n.h

@@ -45,6 +45,7 @@ typedef enum {
     I18N_USERS_TITLE,
     I18N_MSG_SENT_FORMAT,
     I18N_MSG_USER_NOT_FOUND_FORMAT,
+    I18N_REPLY_NO_TARGET,
     I18N_INBOX_TITLE,
     I18N_INBOX_EMPTY,
     I18N_INBOX_SENT_TO_FORMAT,

include/ssh_server.h

@@ -61,6 +61,7 @@ typedef struct client {
     _Atomic int pending_bells;       /* Bell nudges for this client's loop */
     _Atomic int unread_mentions;     /* @-mentions received since last reset */
     _Atomic int unread_whispers;     /* whispers received since last :inbox view */
+    char last_whisper_peer[MAX_USERNAME_LEN];  /* Most recent private-message peer */
     char *outbox;                    /* Bounded queued output for interactive writes */
     size_t outbox_len;
     size_t outbox_pos;

src/command_catalog.c

@@ -36,6 +36,18 @@ static const command_catalog_entry_t entries[] = {
                     "      w <user> <message>\n"),
         2, false, true
     },
+    {
+        {TNT_COMMAND_REPLY, "reply", {"reply", "r", NULL}},
+        I18N_STRING(":reply <message>, :r <message>",
+                    ":reply <message>, :r <message>"),
+        I18N_STRING("Reply to latest private message", "回复最近私信"),
+        I18N_STRING(":reply <message>", ":reply <message>"),
+        I18N_STRING("Usage: reply <message>\n"
+                    "       r <message>\n",
+                    "用法: reply <message>\n"
+                    "      r <message>\n"),
+        2, false, true
+    },
     {
         {TNT_COMMAND_INBOX, "inbox", {"inbox", NULL}},
         I18N_STRING(":inbox", ":inbox"),

src/commands.c

@@ -82,12 +82,57 @@ static void client_append_whisper(client_t *owner, const char *from,
     snprintf(owner->whisper_inbox[slot].content,
              sizeof(owner->whisper_inbox[slot].content), "%s", content);
     owner->whisper_inbox[slot].outgoing = outgoing;
+    snprintf(owner->last_whisper_peer, sizeof(owner->last_whisper_peer), "%s",
+             outgoing ? to : from);
     if (count_unread) {
         owner->unread_whispers++;
     }
     pthread_mutex_unlock(&owner->whisper_lock);
 }
 
+static void send_private_message(client_t *client, const char *target_name,
+                                 const char *content, char *output,
+                                 size_t buf_size, size_t *pos) {
+    bool found = false;
+    client_t *target = NULL;
+
+    pthread_rwlock_rdlock(&g_room->lock);
+    for (int i = 0; i < g_room->client_count; i++) {
+        if (strcmp(g_room->clients[i]->username, target_name) == 0) {
+            target = g_room->clients[i];
+            client_addref(target);
+            found = true;
+            break;
+        }
+    }
+    pthread_rwlock_unlock(&g_room->lock);
+
+    if (target) {
+        client_append_whisper(target, client->username, target_name,
+                              content, false, true);
+        if (target != client) {
+            client_append_whisper(client, client->username, target_name,
+                                  content, true, false);
+        }
+
+        /* Audible nudge: the title bar whisper counter carries the
+         * persistent signal without cross-client SSH writes. */
+        client_queue_bell(target);
+        client_release(target);
+    }
+
+    if (found) {
+        buffer_appendf(output, buf_size, pos,
+                       i18n_text(client->ui_lang, I18N_MSG_SENT_FORMAT),
+                       target_name);
+    } else {
+        buffer_appendf(output, buf_size, pos,
+                       i18n_text(client->ui_lang,
+                                 I18N_MSG_USER_NOT_FOUND_FORMAT),
+                       target_name);
+    }
+}
+
 static void append_inbox_output(client_t *client, char *output,
                                 size_t buf_size, size_t *pos) {
     whisper_t snapshot[WHISPER_INBOX_SIZE];
@@ -282,43 +327,31 @@ void commands_dispatch(client_t *client) {
             append_command_usage(output, sizeof(output), &pos,
                                  TNT_COMMAND_MSG, client->ui_lang);
         } else {
-            bool found = false;
-            client_t *target = NULL;
-            pthread_rwlock_rdlock(&g_room->lock);
-            for (int i = 0; i < g_room->client_count; i++) {
-                if (strcmp(g_room->clients[i]->username, target_name) == 0) {
-                    target = g_room->clients[i];
-                    client_addref(target);
-                    found = true;
-                    break;
-                }
-            }
-            pthread_rwlock_unlock(&g_room->lock);
-
-            if (target) {
-                client_append_whisper(target, client->username, target_name,
-                                      rest, false, true);
-                if (target != client) {
-                    client_append_whisper(client, client->username,
-                                          target_name, rest, true, false);
+            send_private_message(client, target_name, rest, output,
+                                 sizeof(output), &pos);
         }
 
-                /* Audible nudge — the title bar ✉ counter (UX-11 style)
-                 * carries the persistent signal. */
-                client_queue_bell(target);
-                client_release(target);
-            }
+    } else if (command_id == TNT_COMMAND_REPLY) {
+        const char *message = arg;
+        char target_name[MAX_USERNAME_LEN] = {0};
 
-            if (found) {
-                buffer_appendf(output, sizeof(output), &pos,
-                               i18n_text(client->ui_lang,
-                                         I18N_MSG_SENT_FORMAT),
-                               target_name);
+        while (*message == ' ') message++;
+        if (message[0] == '\0') {
+            append_command_usage(output, sizeof(output), &pos,
+                                 TNT_COMMAND_REPLY, client->ui_lang);
         } else {
-                buffer_appendf(output, sizeof(output), &pos,
+            pthread_mutex_lock(&client->whisper_lock);
+            snprintf(target_name, sizeof(target_name), "%s",
+                     client->last_whisper_peer);
+            pthread_mutex_unlock(&client->whisper_lock);
+
+            if (target_name[0] == '\0') {
+                buffer_appendf(output, sizeof(output), &pos, "%s",
                                i18n_text(client->ui_lang,
-                                         I18N_MSG_USER_NOT_FOUND_FORMAT),
-                               target_name);
+                                         I18N_REPLY_NO_TARGET));
+            } else {
+                send_private_message(client, target_name, message, output,
+                                     sizeof(output), &pos);
             }
         }
 

src/i18n_text.c

@@ -121,6 +121,10 @@ static const i18n_string_t text_catalog[I18N_TEXT_COUNT] = {
         "User '%s' not found\n",
         "未找到用户 '%s'\n"
     ),
+    [I18N_REPLY_NO_TARGET] = I18N_STRING(
+        "No private message to reply to\n",
+        "没有可回复的私信\n"
+    ),
     [I18N_INBOX_TITLE] = I18N_STRING(
         "Private messages",
         "私信"

tests/test_user_lifecycle.sh

@@ -37,6 +37,7 @@ SSH_OPTS="-e none -tt -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/nul
 SSH_EXEC_OPTS="-n -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o BatchMode=yes -p $PORT"
 BOB_READY="$STATE_DIR/bob.ready"
 PRIVATE_SENT="$STATE_DIR/private.sent"
+REPLY_SENT="$STATE_DIR/reply.sent"
 
 wait_for_health() {
     out=""
@@ -97,6 +98,14 @@ expect "private lifecycle first"
 expect "q:关闭"
 send -- "q"
 expect "NORMAL"
+send -- ":"
+expect ":"
+send -- "reply private lifecycle reply\r"
+expect "私信已发送给 alice"
+exec touch "$REPLY_SENT"
+expect "q:关闭"
+send -- "q"
+expect "NORMAL"
 sleep 0.2
 send -- "\003"
 sleep 0.2
@@ -215,9 +224,12 @@ exec touch "$PRIVATE_SENT"
 expect "q:关闭"
 send -- "q"
 expect "NORMAL"
+exec sh -c "while \[ ! -f '$REPLY_SENT' \]; do sleep 1; done"
 send -- ":"
 expect ":"
 send -- "inbox\r"
+expect "bob"
+expect "private lifecycle reply"
 expect "你 -> bob"
 expect "private lifecycle second"
 expect "private lifecycle first"

tests/unit/test_command_catalog.c

@@ -35,6 +35,14 @@ TEST(matches_canonical_names_and_aliases) {
     assert(id == TNT_COMMAND_MSG);
     assert(strcmp(args, "alice hello") == 0);
 
+    assert(command_catalog_match("reply hello back", &id, &args));
+    assert(id == TNT_COMMAND_REPLY);
+    assert(strcmp(args, "hello back") == 0);
+
+    assert(command_catalog_match("r hello back", &id, &args));
+    assert(id == TNT_COMMAND_REPLY);
+    assert(strcmp(args, "hello back") == 0);
+
     assert(command_catalog_match("language zh", &id, &args));
     assert(id == TNT_COMMAND_LANG);
     assert(strcmp(args, "zh") == 0);
@@ -65,6 +73,8 @@ TEST(validates_argument_shapes) {
 
     assert(!command_catalog_args_valid(TNT_COMMAND_MSG, NULL));
     assert(command_catalog_args_valid(TNT_COMMAND_MSG, "alice hello"));
+    assert(!command_catalog_args_valid(TNT_COMMAND_REPLY, ""));
+    assert(command_catalog_args_valid(TNT_COMMAND_REPLY, "hello back"));
     assert(!command_catalog_args_valid(TNT_COMMAND_SEARCH, ""));
     assert(command_catalog_args_valid(TNT_COMMAND_SEARCH, "needle"));
 
@@ -92,6 +102,7 @@ TEST(generates_localized_help_sections) {
     assert(strstr(en, ":users, :list, :who") != NULL);
     assert(strstr(en, "Show online users") != NULL);
     assert(strstr(en, ":msg <user> <message>") != NULL);
+    assert(strstr(en, ":reply <message>") != NULL);
     assert(strstr(en, "Show private messages") != NULL);
     assert(strstr(en, ":support") == NULL);
 
@@ -99,6 +110,7 @@ TEST(generates_localized_help_sections) {
     assert(strstr(zh, "显示在线用户") != NULL);
     assert(strstr(zh, "查看私信") != NULL);
     assert(strstr(zh, ":msg <user> <message>") != NULL);
+    assert(strstr(zh, ":reply <message>") != NULL);
     assert(strstr(zh, "<用户>") == NULL);
     assert(strstr(zh, "<消息>") == NULL);
     assert(strstr(zh, ":support") == NULL);
@@ -120,6 +132,13 @@ TEST(generates_localized_usage) {
     assert(strcmp(zh, "用法: msg <user> <message>\n"
                       "      w <user> <message>\n") == 0);
 
+    en[0] = '\0';
+    en_pos = 0;
+    command_catalog_append_usage(en, sizeof(en), &en_pos,
+                                 TNT_COMMAND_REPLY, UI_LANG_EN);
+    assert(strcmp(en, "Usage: reply <message>\n"
+                      "       r <message>\n") == 0);
+
     en[0] = '\0';
     en_pos = 0;
     command_catalog_append_usage(en, sizeof(en), &en_pos,

tests/unit/test_i18n.c

@@ -148,6 +148,10 @@ TEST(text_lookup_matches_language) {
                   "Private message sent") != NULL);
     assert(strstr(i18n_text(UI_LANG_ZH, I18N_MSG_SENT_FORMAT),
                   "私信已发送") != NULL);
+    assert(strstr(i18n_text(UI_LANG_EN, I18N_REPLY_NO_TARGET),
+                  "No private message") != NULL);
+    assert(strstr(i18n_text(UI_LANG_ZH, I18N_REPLY_NO_TARGET),
+                  "可回复") != NULL);
     assert(strstr(i18n_text(UI_LANG_EN, I18N_INBOX_TITLE),
                   "Private messages") != NULL);
     assert(strstr(i18n_text(UI_LANG_ZH, I18N_INBOX_TITLE),

tnt.1

@@ -220,6 +220,8 @@ l l.
 :name \fIname\fR	Alias for :nick
 :msg \fIuser message\fR	Send private message
 :w \fIuser text\fR	Short alias for :msg
+:reply \fItext\fR	Reply to latest private message
+:r \fItext\fR	Short alias for :reply
 :inbox	Show private messages, newest first
 :last [\fIN\fR]	Show last N messages from history (1\-50, default 10)
 :search \fIkeyword\fR	Case\-insensitive search; shows the last 15 matches
@@ -251,7 +253,11 @@ The
 .B :inbox
 page shows incoming messages and local sent-message copies for the current
 session.  It refreshes automatically when a new private message arrives while
-it is open.  Private messages are not written to
+it is open.  Use
+.B :reply
+or
+.B :r
+to answer the latest private-message peer.  Private messages are not written to
 .IR messages.log .
 .SH EXEC INTERFACE
 Commands can be run non\-interactively for scripting: