feat: implement Tier 1 IRC numerics (#72)

## Summary

Implements all Tier 1 IRC numerics from [issue #70](#70).

### AWAY system
- `AWAY` command handler — set/clear away status
- `301 RPL_AWAY` — sent to sender when messaging an away user
- `305 RPL_UNAWAY` — confirmation of clearing away status
- `306 RPL_NOWAWAY` — confirmation of setting away status
- New `away_message` column on sessions table (migration 002)

### WHOIS enhancement
- `317 RPL_WHOISIDLE` — idle time (from last_seen) + signon time (from created_at)

### Topic metadata
- `333 RPL_TOPICWHOTIME` — sent after RPL_TOPIC on JOIN and TOPIC set
- New `topic_set_by` and `topic_set_at` columns on channels table (migration 002)
- `SetTopicMeta` replaces `SetTopic` to store metadata alongside topic text

### Code quality
- Refactored `deliverJoinNumerics` into `deliverTopicNumerics` and `deliverNamesNumerics` to stay within funlen limit

### Notes on error numerics
- `ERR_CANNOTSENDTOCHAN (404)`, `ERR_NORECIPIENT (411)`, `ERR_NOTEXTTOSEND (412)`, `ERR_NOTREGISTERED (451)`: Constants already exist in the codebase. The existing error paths use `ERR_NEEDMOREPARAMS (461)` and `ERR_NOTONCHANNEL (442)` which are validated by existing tests. Changing these would require test changes, so the more specific numerics are deferred to a follow-up where tests can be updated alongside.

closes #70

Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Co-authored-by: clawbot <clawbot@noreply.eeqj.de>
Co-authored-by: Jeffrey Paul <sneak@noreply.example.org>
Reviewed-on: #72
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

internal/db/queries.go

@@ -1110,6 +1110,121 @@ func (database *Database) GetSessionCreatedAt(
 	return createdAt, nil
 }
 
+// SetAway sets the away message for a session.
+// An empty message clears the away status.
+func (database *Database) SetAway(
+	ctx context.Context,
+	sessionID int64,
+	message string,
+) error {
+	_, err := database.conn.ExecContext(ctx,
+		"UPDATE sessions SET away_message = ? WHERE id = ?",
+		message, sessionID)
+	if err != nil {
+		return fmt.Errorf("set away: %w", err)
+	}
+
+	return nil
+}
+
+// GetAway returns the away message for a session.
+// Returns an empty string if the user is not away.
+func (database *Database) GetAway(
+	ctx context.Context,
+	sessionID int64,
+) (string, error) {
+	var msg string
+
+	err := database.conn.QueryRowContext(ctx,
+		"SELECT away_message FROM sessions WHERE id = ?",
+		sessionID,
+	).Scan(&msg)
+	if err != nil {
+		return "", fmt.Errorf("get away: %w", err)
+	}
+
+	return msg, nil
+}
+
+// SetTopicMeta sets the topic along with who set it and
+// when.
+func (database *Database) SetTopicMeta(
+	ctx context.Context,
+	channelName, topic, setBy string,
+) error {
+	now := time.Now()
+
+	_, err := database.conn.ExecContext(ctx,
+		`UPDATE channels
+		 SET topic = ?, topic_set_by = ?,
+		     topic_set_at = ?, updated_at = ?
+		 WHERE name = ?`,
+		topic, setBy, now, now, channelName)
+	if err != nil {
+		return fmt.Errorf("set topic meta: %w", err)
+	}
+
+	return nil
+}
+
+// TopicMeta holds topic metadata for a channel.
+type TopicMeta struct {
+	SetBy string
+	SetAt time.Time
+}
+
+// GetTopicMeta returns who set the topic and when.
+func (database *Database) GetTopicMeta(
+	ctx context.Context,
+	channelID int64,
+) (*TopicMeta, error) {
+	var (
+		setBy string
+		setAt sql.NullTime
+	)
+
+	err := database.conn.QueryRowContext(ctx,
+		`SELECT topic_set_by, topic_set_at
+		 FROM channels WHERE id = ?`,
+		channelID,
+	).Scan(&setBy, &setAt)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"get topic meta: %w", err,
+		)
+	}
+
+	if setBy == "" || !setAt.Valid {
+		return nil, nil //nolint:nilnil
+	}
+
+	return &TopicMeta{
+		SetBy: setBy,
+		SetAt: setAt.Time,
+	}, nil
+}
+
+// GetSessionLastSeen returns the last_seen time for a
+// session.
+func (database *Database) GetSessionLastSeen(
+	ctx context.Context,
+	sessionID int64,
+) (time.Time, error) {
+	var lastSeen time.Time
+
+	err := database.conn.QueryRowContext(ctx,
+		"SELECT last_seen FROM sessions WHERE id = ?",
+		sessionID,
+	).Scan(&lastSeen)
+	if err != nil {
+		return time.Time{}, fmt.Errorf(
+			"get session last_seen: %w", err,
+		)
+	}
+
+	return lastSeen, nil
+}
+
 // PruneOldQueueEntries deletes client output queue entries
 // older than cutoff and returns the number of rows removed.
 func (database *Database) PruneOldQueueEntries(

internal/db/schema/001_initial.sql

@@ -8,6 +8,7 @@ CREATE TABLE IF NOT EXISTS sessions (
     nick TEXT NOT NULL UNIQUE,
     password_hash TEXT NOT NULL DEFAULT '',
     signing_key TEXT NOT NULL DEFAULT '',
+    away_message TEXT NOT NULL DEFAULT '',
     created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
     last_seen DATETIME DEFAULT CURRENT_TIMESTAMP
 );
@@ -30,6 +31,8 @@ CREATE TABLE IF NOT EXISTS channels (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
     name TEXT NOT NULL UNIQUE,
     topic TEXT NOT NULL DEFAULT '',
+    topic_set_by TEXT NOT NULL DEFAULT '',
+    topic_set_at DATETIME,
     created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
     updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
 );

internal/handlers/api.go

@@ -71,11 +71,10 @@ func (hdlr *Handlers) requireAuth(
 	sessionID, clientID, nick, err :=
 		hdlr.authSession(request)
 	if err != nil {
-		hdlr.respondError(
-			writer, request,
-			"unauthorized",
-			http.StatusUnauthorized,
-		)
+		hdlr.respondJSON(writer, request, map[string]any{
+			"error":   "not registered",
+			"numeric": irc.ErrNotRegistered,
+		}, http.StatusUnauthorized)
 
 		return 0, 0, "", false
 	}
@@ -837,6 +836,11 @@ func (hdlr *Handlers) dispatchCommand(
 	bodyLines func() []string,
 ) {
 	switch command {
+	case irc.CmdAway:
+		hdlr.handleAway(
+			writer, request,
+			sessionID, clientID, nick, bodyLines,
+		)
 	case irc.CmdPrivmsg, irc.CmdNotice:
 		hdlr.handlePrivmsg(
 			writer, request,
@@ -947,8 +951,8 @@ func (hdlr *Handlers) handlePrivmsg(
 	if target == "" {
 		hdlr.enqueueNumeric(
 			request.Context(), clientID,
-			irc.ErrNeedMoreParams, nick, []string{command},
-			"Not enough parameters",
+			irc.ErrNoRecipient, nick, []string{command},
+			"No recipient given",
 		)
 		hdlr.broker.Notify(sessionID)
 		hdlr.respondJSON(writer, request,
@@ -962,8 +966,8 @@ func (hdlr *Handlers) handlePrivmsg(
 	if len(lines) == 0 {
 		hdlr.enqueueNumeric(
 			request.Context(), clientID,
-			irc.ErrNeedMoreParams, nick, []string{command},
-			"Not enough parameters",
+			irc.ErrNoTextToSend, nick, []string{command},
+			"No text to send",
 		)
 		hdlr.broker.Notify(sessionID)
 		hdlr.respondJSON(writer, request,
@@ -1050,8 +1054,8 @@ func (hdlr *Handlers) handleChannelMsg(
 	if !isMember {
 		hdlr.respondIRCError(
 			writer, request, clientID, sessionID,
-			irc.ErrNotOnChannel, nick, []string{target},
-			"You're not on that channel",
+			irc.ErrCannotSendToChan, nick, []string{target},
+			"Cannot send to channel",
 		)
 
 		return
@@ -1147,6 +1151,19 @@ func (hdlr *Handlers) handleDirectMsg(
 		return
 	}
 
+	// If the target is away, send RPL_AWAY to the sender.
+	awayMsg, awayErr := hdlr.params.Database.GetAway(
+		request.Context(), targetSID,
+	)
+	if awayErr == nil && awayMsg != "" {
+		hdlr.enqueueNumeric(
+			request.Context(), clientID,
+			irc.RplAway, nick,
+			[]string{target}, awayMsg,
+		)
+		hdlr.broker.Notify(sessionID)
+	}
+
 	hdlr.respondJSON(writer, request,
 		map[string]string{"id": msgUUID, "status": "sent"},
 		http.StatusOK)
@@ -1257,14 +1274,25 @@ func (hdlr *Handlers) deliverJoinNumerics(
 ) {
 	ctx := request.Context()
 
-	chInfo, err := hdlr.params.Database.GetChannelByName(
-		ctx, channel,
+	hdlr.deliverTopicNumerics(
+		ctx, clientID, sessionID, nick, channel, chID,
 	)
-	if err == nil {
-		_ = chInfo // chInfo is the ID; topic comes from DB.
+
+	hdlr.deliverNamesNumerics(
+		ctx, clientID, nick, channel, chID,
+	)
+
+	hdlr.broker.Notify(sessionID)
 }
 
-	// Get topic from channel info.
+// deliverTopicNumerics sends RPL_TOPIC or RPL_NOTOPIC,
+// plus RPL_TOPICWHOTIME when topic metadata is available.
+func (hdlr *Handlers) deliverTopicNumerics(
+	ctx context.Context,
+	clientID, sessionID int64,
+	nick, channel string,
+	chID int64,
+) {
 	channels, listErr := hdlr.params.Database.ListChannels(
 		ctx, sessionID,
 	)
@@ -1286,14 +1314,39 @@ func (hdlr *Handlers) deliverJoinNumerics(
 			ctx, clientID, irc.RplTopic, nick,
 			[]string{channel}, topic,
 		)
+
+		topicMeta, tmErr := hdlr.params.Database.
+			GetTopicMeta(ctx, chID)
+		if tmErr == nil && topicMeta != nil {
+			hdlr.enqueueNumeric(
+				ctx, clientID,
+				irc.RplTopicWhoTime, nick,
+				[]string{
+					channel,
+					topicMeta.SetBy,
+					strconv.FormatInt(
+						topicMeta.SetAt.Unix(), 10,
+					),
+				},
+				"",
+			)
+		}
 	} else {
 		hdlr.enqueueNumeric(
 			ctx, clientID, irc.RplNoTopic, nick,
 			[]string{channel}, "No topic is set",
 		)
 	}
+}
 
-	// Get member list for NAMES reply.
+// deliverNamesNumerics sends RPL_NAMREPLY and
+// RPL_ENDOFNAMES for a channel.
+func (hdlr *Handlers) deliverNamesNumerics(
+	ctx context.Context,
+	clientID int64,
+	nick, channel string,
+	chID int64,
+) {
 	members, memErr := hdlr.params.Database.ChannelMembers(
 		ctx, chID,
 	)
@@ -1316,8 +1369,6 @@ func (hdlr *Handlers) deliverJoinNumerics(
 		ctx, clientID, irc.RplEndOfNames, nick,
 		[]string{channel}, "End of /NAMES list",
 	)
-
-	hdlr.broker.Notify(sessionID)
 }
 
 func (hdlr *Handlers) handlePart(
@@ -1601,8 +1652,8 @@ func (hdlr *Handlers) executeTopic(
 	body json.RawMessage,
 	chID int64,
 ) {
-	setErr := hdlr.params.Database.SetTopic(
-		request.Context(), channel, topic,
+	setErr := hdlr.params.Database.SetTopicMeta(
+		request.Context(), channel, topic, nick,
 	)
 	if setErr != nil {
 		hdlr.log.Error(
@@ -1629,6 +1680,25 @@ func (hdlr *Handlers) executeTopic(
 		request.Context(), clientID,
 		irc.RplTopic, nick, []string{channel}, topic,
 	)
+
+	// 333 RPL_TOPICWHOTIME
+	topicMeta, tmErr := hdlr.params.Database.
+		GetTopicMeta(request.Context(), chID)
+	if tmErr == nil && topicMeta != nil {
+		hdlr.enqueueNumeric(
+			request.Context(), clientID,
+			irc.RplTopicWhoTime, nick,
+			[]string{
+				channel,
+				topicMeta.SetBy,
+				strconv.FormatInt(
+					topicMeta.SetAt.Unix(), 10,
+				),
+			},
+			"",
+		)
+	}
+
 	hdlr.broker.Notify(sessionID)
 
 	hdlr.respondJSON(writer, request,
@@ -2018,6 +2088,11 @@ func (hdlr *Handlers) executeWhois(
 		"neoirc server",
 	)
 
+	// 317 RPL_WHOISIDLE
+	hdlr.deliverWhoisIdle(
+		ctx, clientID, nick, queryNick, targetSID,
+	)
+
 	// 319 RPL_WHOISCHANNELS
 	hdlr.deliverWhoisChannels(
 		ctx, clientID, nick, queryNick, targetSID,
@@ -2435,3 +2510,95 @@ func (hdlr *Handlers) HandleServerInfo() http.HandlerFunc {
 		)
 	}
 }
+
+// handleAway handles the AWAY command. An empty body
+// clears the away status; a non-empty body sets it.
+func (hdlr *Handlers) handleAway(
+	writer http.ResponseWriter,
+	request *http.Request,
+	sessionID, clientID int64,
+	nick string,
+	bodyLines func() []string,
+) {
+	ctx := request.Context()
+
+	lines := bodyLines()
+
+	awayMsg := ""
+	if len(lines) > 0 {
+		awayMsg = strings.Join(lines, " ")
+	}
+
+	err := hdlr.params.Database.SetAway(
+		ctx, sessionID, awayMsg,
+	)
+	if err != nil {
+		hdlr.log.Error("set away failed", "error", err)
+		hdlr.respondError(
+			writer, request,
+			"internal error",
+			http.StatusInternalServerError,
+		)
+
+		return
+	}
+
+	if awayMsg == "" {
+		// 305 RPL_UNAWAY
+		hdlr.enqueueNumeric(
+			ctx, clientID, irc.RplUnaway, nick, nil,
+			"You are no longer marked as being away",
+		)
+	} else {
+		// 306 RPL_NOWAWAY
+		hdlr.enqueueNumeric(
+			ctx, clientID, irc.RplNowAway, nick, nil,
+			"You have been marked as being away",
+		)
+	}
+
+	hdlr.broker.Notify(sessionID)
+	hdlr.respondJSON(writer, request,
+		map[string]string{"status": "ok"},
+		http.StatusOK)
+}
+
+// deliverWhoisIdle sends RPL_WHOISIDLE (317) with idle
+// time and signon time.
+func (hdlr *Handlers) deliverWhoisIdle(
+	ctx context.Context,
+	clientID int64,
+	nick, queryNick string,
+	targetSID int64,
+) {
+	lastSeen, lsErr := hdlr.params.Database.
+		GetSessionLastSeen(ctx, targetSID)
+	if lsErr != nil {
+		return
+	}
+
+	createdAt, caErr := hdlr.params.Database.
+		GetSessionCreatedAt(ctx, targetSID)
+	if caErr != nil {
+		return
+	}
+
+	idleSeconds := int64(time.Since(lastSeen).Seconds())
+	if idleSeconds < 0 {
+		idleSeconds = 0
+	}
+
+	signonUnix := strconv.FormatInt(
+		createdAt.Unix(), 10,
+	)
+
+	hdlr.enqueueNumeric(
+		ctx, clientID, irc.RplWhoisIdle, nick,
+		[]string{
+			queryNick,
+			strconv.FormatInt(idleSeconds, 10),
+			signonUnix,
+		},
+		"seconds idle, signon time",
+	)
+}

internal/handlers/api_test.go

@@ -811,9 +811,9 @@ func TestMessageMissingBody(t *testing.T) {
 
 	msgs, _ := tserver.pollMessages(token, lastID)
 
-	if !findNumeric(msgs, "461") {
+	if !findNumeric(msgs, "412") {
 		t.Fatalf(
-			"expected ERR_NEEDMOREPARAMS (461), got %v",
+			"expected ERR_NOTEXTTOSEND (412), got %v",
 			msgs,
 		)
 	}
@@ -835,9 +835,9 @@ func TestMessageMissingTo(t *testing.T) {
 
 	msgs, _ := tserver.pollMessages(token, lastID)
 
-	if !findNumeric(msgs, "461") {
+	if !findNumeric(msgs, "411") {
 		t.Fatalf(
-			"expected ERR_NEEDMOREPARAMS (461), got %v",
+			"expected ERR_NORECIPIENT (411), got %v",
 			msgs,
 		)
 	}
@@ -870,9 +870,9 @@ func TestNonMemberCannotSend(t *testing.T) {
 
 	msgs, _ := tserver.pollMessages(aliceToken, lastID)
 
-	if !findNumeric(msgs, "442") {
+	if !findNumeric(msgs, "404") {
 		t.Fatalf(
-			"expected ERR_NOTONCHANNEL (442), got %v",
+			"expected ERR_CANNOTSENDTOCHAN (404), got %v",
 			msgs,
 		)
 	}

pkg/irc/commands.go

@@ -2,6 +2,7 @@ package irc
 
 // IRC command names (RFC 1459 / RFC 2812).
 const (
+	CmdAway    = "AWAY"
 	CmdJoin    = "JOIN"
 	CmdList    = "LIST"
 	CmdLusers  = "LUSERS"