feat: add IRC wire protocol listener with shared service layer

Add a traditional IRC wire protocol listener (RFC 1459/2812) on configurable port (default :6667), sharing business logic with the HTTP API via a new service layer. - IRC listener: NICK, USER, PASS, JOIN, PART, PRIVMSG, NOTICE, TOPIC, MODE, KICK, QUIT, NAMES, LIST, WHOIS, WHO, AWAY, OPER, INVITE, LUSERS, MOTD, PING/PONG, CAP - Service layer: shared logic for both transports including channel join (with Tier 2 checks: ban/invite/key/limit), message send (with ban + moderation checks), nick change, topic, kick, mode, quit broadcast, away, oper, invite - BroadcastQuit uses FanOut pattern (one insert, N enqueues) - HTTP handlers delegate to service for all command logic - Tier 2 mode operations (+b/+i/+s/+k/+l) use service methods Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-25 18:01:36 -07:00
parent 9a79d92c0d
commit 92d5145ac6
19 changed files with 4795 additions and 1112 deletions
--- a/internal/service/service.go
+++ b/internal/service/service.go
@@ -0,0 +1,745 @@
+// Package service provides shared business logic for both
+// the IRC wire protocol and HTTP/JSON transports.
+package service
+
+import (
+	"context"
+	"crypto/subtle"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"strings"
+
+	"git.eeqj.de/sneak/neoirc/internal/broker"
+	"git.eeqj.de/sneak/neoirc/internal/config"
+	"git.eeqj.de/sneak/neoirc/internal/db"
+	"git.eeqj.de/sneak/neoirc/internal/logger"
+	"git.eeqj.de/sneak/neoirc/pkg/irc"
+	"go.uber.org/fx"
+)
+
+// Params defines the dependencies for creating a Service.
+type Params struct {
+	fx.In
+
+	Logger   *logger.Logger
+	Config   *config.Config
+	Database *db.Database
+	Broker   *broker.Broker
+}
+
+// Service provides shared business logic for IRC commands.
+type Service struct {
+	DB     *db.Database
+	Broker *broker.Broker
+	Config *config.Config
+	Log    *slog.Logger
+}
+
+// New creates a new Service.
+func New(params Params) *Service {
+	return &Service{
+		DB:     params.Database,
+		Broker: params.Broker,
+		Config: params.Config,
+		Log:    params.Logger.Get(),
+	}
+}
+
+// IRCError represents an IRC protocol-level error with a
+// numeric code that both transports can map to responses.
+type IRCError struct {
+	Code    irc.IRCMessageType
+	Params  []string
+	Message string
+}
+
+func (e *IRCError) Error() string { return e.Message }
+
+// JoinResult contains the outcome of a channel join.
+type JoinResult struct {
+	ChannelID int64
+	IsCreator bool
+}
+
+// DirectMsgResult contains the outcome of a direct message.
+type DirectMsgResult struct {
+	UUID    string
+	AwayMsg string
+}
+
+// FanOut inserts a message and enqueues it to all given
+// session IDs, notifying each via the broker.
+func (s *Service) FanOut(
+	ctx context.Context,
+	command, from, to string,
+	params, body, meta json.RawMessage,
+	sessionIDs []int64,
+) (int64, string, error) {
+	dbID, msgUUID, err := s.DB.InsertMessage(
+		ctx, command, from, to, params, body, meta,
+	)
+	if err != nil {
+		return 0, "", fmt.Errorf("insert message: %w", err)
+	}
+
+	for _, sid := range sessionIDs {
+		_ = s.DB.EnqueueToSession(ctx, sid, dbID)
+		s.Broker.Notify(sid)
+	}
+
+	return dbID, msgUUID, nil
+}
+
+// excludeSession returns a copy of ids without the given
+// session.
+func excludeSession(
+	ids []int64,
+	exclude int64,
+) []int64 {
+	out := make([]int64, 0, len(ids))
+
+	for _, id := range ids {
+		if id != exclude {
+			out = append(out, id)
+		}
+	}
+
+	return out
+}
+
+// SendChannelMessage validates membership and moderation,
+// then fans out a message to all channel members except
+// the sender. Returns the database row ID, message UUID,
+// and any error. The dbID lets callers enqueue the same
+// message to the sender when echo is needed (HTTP
+// transport).
+func (s *Service) SendChannelMessage(
+	ctx context.Context,
+	sessionID int64,
+	nick, command, channel string,
+	body, meta json.RawMessage,
+) (int64, string, error) {
+	chID, err := s.DB.GetChannelByName(ctx, channel)
+	if err != nil {
+		return 0, "", &IRCError{
+			irc.ErrNoSuchChannel,
+			[]string{channel},
+			"No such channel",
+		}
+	}
+
+	isMember, _ := s.DB.IsChannelMember(
+		ctx, chID, sessionID,
+	)
+	if !isMember {
+		return 0, "", &IRCError{
+			irc.ErrCannotSendToChan,
+			[]string{channel},
+			"Cannot send to channel",
+		}
+	}
+
+	moderated, _ := s.DB.IsChannelModerated(ctx, chID)
+	if moderated {
+		isOp, _ := s.DB.IsChannelOperator(
+			ctx, chID, sessionID,
+		)
+		isVoiced, _ := s.DB.IsChannelVoiced(
+			ctx, chID, sessionID,
+		)
+
+		if !isOp && !isVoiced {
+			return 0, "", &IRCError{
+				irc.ErrCannotSendToChan,
+				[]string{channel},
+				"Cannot send to channel (+m)",
+			}
+		}
+	}
+
+	memberIDs, _ := s.DB.GetChannelMemberIDs(ctx, chID)
+	recipients := excludeSession(memberIDs, sessionID)
+
+	dbID, uuid, fanErr := s.FanOut(
+		ctx, command, nick, channel,
+		nil, body, meta, recipients,
+	)
+	if fanErr != nil {
+		return 0, "", fanErr
+	}
+
+	return dbID, uuid, nil
+}
+
+// SendDirectMessage validates the target and sends a
+// direct message, returning the message UUID and any away
+// message set on the target.
+func (s *Service) SendDirectMessage(
+	ctx context.Context,
+	sessionID int64,
+	nick, command, target string,
+	body, meta json.RawMessage,
+) (*DirectMsgResult, error) {
+	targetSID, err := s.DB.GetSessionByNick(ctx, target)
+	if err != nil {
+		return nil, &IRCError{
+			irc.ErrNoSuchNick,
+			[]string{target},
+			"No such nick",
+		}
+	}
+
+	away, _ := s.DB.GetAway(ctx, targetSID)
+
+	recipients := []int64{targetSID}
+	if targetSID != sessionID {
+		recipients = append(recipients, sessionID)
+	}
+
+	_, uuid, fanErr := s.FanOut(
+		ctx, command, nick, target,
+		nil, body, meta, recipients,
+	)
+	if fanErr != nil {
+		return nil, fanErr
+	}
+
+	return &DirectMsgResult{UUID: uuid, AwayMsg: away}, nil
+}
+
+// JoinChannel creates or joins a channel, making the
+// first joiner the operator. Fans out the JOIN to all
+// channel members.
+func (s *Service) JoinChannel(
+	ctx context.Context,
+	sessionID int64,
+	nick, channel string,
+) (*JoinResult, error) {
+	chID, err := s.DB.GetOrCreateChannel(ctx, channel)
+	if err != nil {
+		return nil, fmt.Errorf("get/create channel: %w", err)
+	}
+
+	memberCount, countErr := s.DB.CountChannelMembers(
+		ctx, chID,
+	)
+	isCreator := countErr == nil && memberCount == 0
+
+	if isCreator {
+		err = s.DB.JoinChannelAsOperator(
+			ctx, chID, sessionID,
+		)
+	} else {
+		err = s.DB.JoinChannel(ctx, chID, sessionID)
+	}
+
+	if err != nil {
+		return nil, fmt.Errorf("join channel: %w", err)
+	}
+
+	memberIDs, _ := s.DB.GetChannelMemberIDs(ctx, chID)
+	body, _ := json.Marshal([]string{channel}) //nolint:errchkjson
+
+	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
+		ctx, irc.CmdJoin, nick, channel,
+		nil, body, nil, memberIDs,
+	)
+
+	return &JoinResult{
+		ChannelID: chID,
+		IsCreator: isCreator,
+	}, nil
+}
+
+// PartChannel validates membership, broadcasts PART to
+// remaining members, removes the user, and cleans up empty
+// channels.
+func (s *Service) PartChannel(
+	ctx context.Context,
+	sessionID int64,
+	nick, channel, reason string,
+) error {
+	chID, err := s.DB.GetChannelByName(ctx, channel)
+	if err != nil {
+		return &IRCError{
+			irc.ErrNoSuchChannel,
+			[]string{channel},
+			"No such channel",
+		}
+	}
+
+	isMember, _ := s.DB.IsChannelMember(
+		ctx, chID, sessionID,
+	)
+	if !isMember {
+		return &IRCError{
+			irc.ErrNotOnChannel,
+			[]string{channel},
+			"You're not on that channel",
+		}
+	}
+
+	memberIDs, _ := s.DB.GetChannelMemberIDs(ctx, chID)
+	recipients := excludeSession(memberIDs, sessionID)
+	body, _ := json.Marshal([]string{reason}) //nolint:errchkjson
+
+	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
+		ctx, irc.CmdPart, nick, channel,
+		nil, body, nil, recipients,
+	)
+
+	s.DB.PartChannel(ctx, chID, sessionID) //nolint:errcheck,gosec
+	s.DB.DeleteChannelIfEmpty(ctx, chID)   //nolint:errcheck,gosec
+
+	return nil
+}
+
+// SetTopic validates membership and topic-lock, sets the
+// topic, and broadcasts the change.
+func (s *Service) SetTopic(
+	ctx context.Context,
+	sessionID int64,
+	nick, channel, topic string,
+) error {
+	chID, err := s.DB.GetChannelByName(ctx, channel)
+	if err != nil {
+		return &IRCError{
+			irc.ErrNoSuchChannel,
+			[]string{channel},
+			"No such channel",
+		}
+	}
+
+	isMember, _ := s.DB.IsChannelMember(
+		ctx, chID, sessionID,
+	)
+	if !isMember {
+		return &IRCError{
+			irc.ErrNotOnChannel,
+			[]string{channel},
+			"You're not on that channel",
+		}
+	}
+
+	topicLocked, _ := s.DB.IsChannelTopicLocked(ctx, chID)
+	if topicLocked {
+		isOp, _ := s.DB.IsChannelOperator(
+			ctx, chID, sessionID,
+		)
+		if !isOp {
+			return &IRCError{
+				irc.ErrChanOpPrivsNeeded,
+				[]string{channel},
+				"You're not channel operator",
+			}
+		}
+	}
+
+	if setErr := s.DB.SetTopic(
+		ctx, channel, topic,
+	); setErr != nil {
+		return fmt.Errorf("set topic: %w", setErr)
+	}
+
+	_ = s.DB.SetTopicMeta(ctx, channel, topic, nick)
+
+	memberIDs, _ := s.DB.GetChannelMemberIDs(ctx, chID)
+	body, _ := json.Marshal([]string{topic}) //nolint:errchkjson
+
+	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
+		ctx, irc.CmdTopic, nick, channel,
+		nil, body, nil, memberIDs,
+	)
+
+	return nil
+}
+
+// KickUser validates operator status and target
+// membership, broadcasts the KICK, removes the target,
+// and cleans up empty channels.
+func (s *Service) KickUser(
+	ctx context.Context,
+	sessionID int64,
+	nick, channel, targetNick, reason string,
+) error {
+	chID, err := s.DB.GetChannelByName(ctx, channel)
+	if err != nil {
+		return &IRCError{
+			irc.ErrNoSuchChannel,
+			[]string{channel},
+			"No such channel",
+		}
+	}
+
+	isOp, _ := s.DB.IsChannelOperator(
+		ctx, chID, sessionID,
+	)
+	if !isOp {
+		return &IRCError{
+			irc.ErrChanOpPrivsNeeded,
+			[]string{channel},
+			"You're not channel operator",
+		}
+	}
+
+	targetSID, err := s.DB.GetSessionByNick(
+		ctx, targetNick,
+	)
+	if err != nil {
+		return &IRCError{
+			irc.ErrNoSuchNick,
+			[]string{targetNick},
+			"No such nick/channel",
+		}
+	}
+
+	isMember, _ := s.DB.IsChannelMember(
+		ctx, chID, targetSID,
+	)
+	if !isMember {
+		return &IRCError{
+			irc.ErrUserNotInChannel,
+			[]string{targetNick, channel},
+			"They aren't on that channel",
+		}
+	}
+
+	memberIDs, _ := s.DB.GetChannelMemberIDs(ctx, chID)
+	body, _ := json.Marshal([]string{reason}) //nolint:errchkjson
+	params, _ := json.Marshal(                //nolint:errchkjson
+		[]string{targetNick},
+	)
+
+	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
+		ctx, irc.CmdKick, nick, channel,
+		params, body, nil, memberIDs,
+	)
+
+	s.DB.PartChannel(ctx, chID, targetSID) //nolint:errcheck,gosec
+	s.DB.DeleteChannelIfEmpty(ctx, chID)   //nolint:errcheck,gosec
+
+	return nil
+}
+
+// ChangeNick changes a user's nickname and broadcasts the
+// change to all users sharing channels.
+func (s *Service) ChangeNick(
+	ctx context.Context,
+	sessionID int64,
+	oldNick, newNick string,
+) error {
+	err := s.DB.ChangeNick(ctx, sessionID, newNick)
+	if err != nil {
+		if strings.Contains(err.Error(), "UNIQUE") ||
+			db.IsUniqueConstraintError(err) {
+			return &IRCError{
+				irc.ErrNicknameInUse,
+				[]string{newNick},
+				"Nickname is already in use",
+			}
+		}
+
+		return &IRCError{
+			irc.ErrErroneusNickname,
+			[]string{newNick},
+			"Erroneous nickname",
+		}
+	}
+
+	s.broadcastNickChange(ctx, sessionID, oldNick, newNick)
+
+	return nil
+}
+
+// BroadcastQuit broadcasts a QUIT to all channel peers,
+// parts all channels, and deletes the session. Uses the
+// FanOut pattern: one message row fanned out to all unique
+// peer sessions.
+func (s *Service) BroadcastQuit(
+	ctx context.Context,
+	sessionID int64,
+	nick, reason string,
+) {
+	channels, err := s.DB.GetSessionChannels(
+		ctx, sessionID,
+	)
+	if err != nil {
+		return
+	}
+
+	notified := make(map[int64]bool)
+
+	for _, ch := range channels {
+		memberIDs, memErr := s.DB.GetChannelMemberIDs(
+			ctx, ch.ID,
+		)
+		if memErr != nil {
+			continue
+		}
+
+		for _, mid := range memberIDs {
+			if mid == sessionID || notified[mid] {
+				continue
+			}
+
+			notified[mid] = true
+		}
+	}
+
+	if len(notified) > 0 {
+		recipients := make([]int64, 0, len(notified))
+		for sid := range notified {
+			recipients = append(recipients, sid)
+		}
+
+		body, _ := json.Marshal([]string{reason}) //nolint:errchkjson
+
+		_, _, _ = s.FanOut(
+			ctx, irc.CmdQuit, nick, "",
+			nil, body, nil, recipients,
+		)
+	}
+
+	for _, ch := range channels {
+		s.DB.PartChannel(ctx, ch.ID, sessionID) //nolint:errcheck,gosec
+		s.DB.DeleteChannelIfEmpty(ctx, ch.ID)   //nolint:errcheck,gosec
+	}
+
+	s.DB.DeleteSession(ctx, sessionID) //nolint:errcheck,gosec
+}
+
+// SetAway sets or clears the away message. Returns true
+// if the message was cleared (empty string).
+func (s *Service) SetAway(
+	ctx context.Context,
+	sessionID int64,
+	message string,
+) (bool, error) {
+	err := s.DB.SetAway(ctx, sessionID, message)
+	if err != nil {
+		return false, fmt.Errorf("set away: %w", err)
+	}
+
+	return message == "", nil
+}
+
+// Oper validates operator credentials and grants oper
+// status to the session.
+func (s *Service) Oper(
+	ctx context.Context,
+	sessionID int64,
+	name, password string,
+) error {
+	cfgName := s.Config.OperName
+	cfgPassword := s.Config.OperPassword
+
+	// Use constant-time comparison and return the same
+	// error for all failures to prevent information
+	// leakage about valid operator names.
+	if cfgName == "" || cfgPassword == "" ||
+		subtle.ConstantTimeCompare(
+			[]byte(name), []byte(cfgName),
+		) != 1 ||
+		subtle.ConstantTimeCompare(
+			[]byte(password), []byte(cfgPassword),
+		) != 1 {
+		return &IRCError{
+			irc.ErrNoOperHost,
+			nil,
+			"No O-lines for your host",
+		}
+	}
+
+	_ = s.DB.SetSessionOper(ctx, sessionID, true)
+
+	return nil
+}
+
+// ValidateChannelOp checks that the session is a channel
+// operator. Returns the channel ID.
+func (s *Service) ValidateChannelOp(
+	ctx context.Context,
+	sessionID int64,
+	channel string,
+) (int64, error) {
+	chID, err := s.DB.GetChannelByName(ctx, channel)
+	if err != nil {
+		return 0, &IRCError{
+			irc.ErrNoSuchChannel,
+			[]string{channel},
+			"No such channel",
+		}
+	}
+
+	isOp, _ := s.DB.IsChannelOperator(
+		ctx, chID, sessionID,
+	)
+	if !isOp {
+		return 0, &IRCError{
+			irc.ErrChanOpPrivsNeeded,
+			[]string{channel},
+			"You're not channel operator",
+		}
+	}
+
+	return chID, nil
+}
+
+// ApplyMemberMode applies +o/-o or +v/-v on a channel
+// member after validating the target.
+func (s *Service) ApplyMemberMode(
+	ctx context.Context,
+	chID int64,
+	channel, targetNick string,
+	mode rune,
+	adding bool,
+) error {
+	targetSID, err := s.DB.GetSessionByNick(
+		ctx, targetNick,
+	)
+	if err != nil {
+		return &IRCError{
+			irc.ErrNoSuchNick,
+			[]string{targetNick},
+			"No such nick/channel",
+		}
+	}
+
+	isMember, _ := s.DB.IsChannelMember(
+		ctx, chID, targetSID,
+	)
+	if !isMember {
+		return &IRCError{
+			irc.ErrUserNotInChannel,
+			[]string{targetNick, channel},
+			"They aren't on that channel",
+		}
+	}
+
+	switch mode {
+	case 'o':
+		_ = s.DB.SetChannelMemberOperator(
+			ctx, chID, targetSID, adding,
+		)
+	case 'v':
+		_ = s.DB.SetChannelMemberVoiced(
+			ctx, chID, targetSID, adding,
+		)
+	}
+
+	return nil
+}
+
+// SetChannelFlag applies +m/-m or +t/-t on a channel.
+func (s *Service) SetChannelFlag(
+	ctx context.Context,
+	chID int64,
+	flag rune,
+	setting bool,
+) error {
+	switch flag {
+	case 'm':
+		if err := s.DB.SetChannelModerated(
+			ctx, chID, setting,
+		); err != nil {
+			return fmt.Errorf("set moderated: %w", err)
+		}
+	case 't':
+		if err := s.DB.SetChannelTopicLocked(
+			ctx, chID, setting,
+		); err != nil {
+			return fmt.Errorf("set topic locked: %w", err)
+		}
+	}
+
+	return nil
+}
+
+// BroadcastMode fans out a MODE change to all channel
+// members.
+func (s *Service) BroadcastMode(
+	ctx context.Context,
+	nick, channel string,
+	chID int64,
+	modeText string,
+) {
+	memberIDs, _ := s.DB.GetChannelMemberIDs(ctx, chID)
+	body, _ := json.Marshal([]string{modeText}) //nolint:errchkjson
+
+	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
+		ctx, irc.CmdMode, nick, channel,
+		nil, body, nil, memberIDs,
+	)
+}
+
+// QueryChannelMode returns the channel mode string.
+func (s *Service) QueryChannelMode(
+	ctx context.Context,
+	chID int64,
+) string {
+	modes := "+"
+
+	moderated, _ := s.DB.IsChannelModerated(ctx, chID)
+	if moderated {
+		modes += "m"
+	}
+
+	topicLocked, _ := s.DB.IsChannelTopicLocked(ctx, chID)
+	if topicLocked {
+		modes += "t"
+	}
+
+	return modes
+}
+
+// broadcastNickChange notifies channel peers of a nick
+// change.
+func (s *Service) broadcastNickChange(
+	ctx context.Context,
+	sessionID int64,
+	oldNick, newNick string,
+) {
+	channels, err := s.DB.GetSessionChannels(
+		ctx, sessionID,
+	)
+	if err != nil {
+		return
+	}
+
+	body, _ := json.Marshal([]string{newNick}) //nolint:errchkjson
+	notified := make(map[int64]bool)
+
+	dbID, _, insErr := s.DB.InsertMessage(
+		ctx, irc.CmdNick, oldNick, "",
+		nil, body, nil,
+	)
+	if insErr != nil {
+		return
+	}
+
+	// Notify the user themselves (for multi-client sync).
+	_ = s.DB.EnqueueToSession(ctx, sessionID, dbID)
+	s.Broker.Notify(sessionID)
+	notified[sessionID] = true
+
+	for _, ch := range channels {
+		memberIDs, memErr := s.DB.GetChannelMemberIDs(
+			ctx, ch.ID,
+		)
+		if memErr != nil {
+			continue
+		}
+
+		for _, mid := range memberIDs {
+			if notified[mid] {
+				continue
+			}
+
+			notified[mid] = true
+
+			_ = s.DB.EnqueueToSession(ctx, mid, dbID)
+			s.Broker.Notify(mid)
+		}
+	}
+}
--- a/internal/service/service_test.go
+++ b/internal/service/service_test.go
@@ -0,0 +1,365 @@
+// Tests use a global viper instance for configuration,
+// making parallel execution unsafe.
+//
+//nolint:paralleltest
+package service_test
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"testing"
+
+	"git.eeqj.de/sneak/neoirc/internal/broker"
+	"git.eeqj.de/sneak/neoirc/internal/config"
+	"git.eeqj.de/sneak/neoirc/internal/db"
+	"git.eeqj.de/sneak/neoirc/internal/globals"
+	"git.eeqj.de/sneak/neoirc/internal/logger"
+	"git.eeqj.de/sneak/neoirc/internal/service"
+	"git.eeqj.de/sneak/neoirc/pkg/irc"
+	"go.uber.org/fx"
+	"go.uber.org/fx/fxtest"
+	"golang.org/x/crypto/bcrypt"
+)
+
+func TestMain(m *testing.M) {
+	db.SetBcryptCost(bcrypt.MinCost)
+	os.Exit(m.Run())
+}
+
+// testEnv holds all dependencies for a service test.
+type testEnv struct {
+	svc    *service.Service
+	db     *db.Database
+	broker *broker.Broker
+	app    *fxtest.App
+}
+
+func newTestEnv(t *testing.T) *testEnv {
+	t.Helper()
+
+	dbURL := fmt.Sprintf(
+		"file:svc_test_%p?mode=memory&cache=shared",
+		t,
+	)
+
+	var (
+		database *db.Database
+		svc      *service.Service
+	)
+
+	brk := broker.New()
+
+	app := fxtest.New(t,
+		fx.Provide(
+			func() *globals.Globals {
+				return &globals.Globals{ //nolint:exhaustruct
+					Appname: "neoirc-test",
+					Version: "test",
+				}
+			},
+			logger.New,
+			func(
+				lifecycle fx.Lifecycle,
+				globs *globals.Globals,
+				log *logger.Logger,
+			) (*config.Config, error) {
+				cfg, err := config.New(
+					lifecycle, config.Params{ //nolint:exhaustruct
+						Globals: globs, Logger: log,
+					},
+				)
+				if err != nil {
+					return nil, fmt.Errorf(
+						"test config: %w", err,
+					)
+				}
+
+				cfg.DBURL = dbURL
+				cfg.Port = 0
+				cfg.OperName = "admin"
+				cfg.OperPassword = "secret"
+
+				return cfg, nil
+			},
+			func(
+				lifecycle fx.Lifecycle,
+				log *logger.Logger,
+				cfg *config.Config,
+			) (*db.Database, error) {
+				return db.New(lifecycle, db.Params{ //nolint:exhaustruct
+					Logger: log, Config: cfg,
+				})
+			},
+			func() *broker.Broker { return brk },
+			service.New,
+		),
+		fx.Populate(&database, &svc),
+	)
+
+	app.RequireStart()
+
+	t.Cleanup(func() {
+		app.RequireStop()
+	})
+
+	return &testEnv{
+		svc:    svc,
+		db:     database,
+		broker: brk,
+		app:    app,
+	}
+}
+
+// createSession is a test helper that creates a session
+// and returns the session ID.
+func createSession(
+	ctx context.Context,
+	t *testing.T,
+	database *db.Database,
+	nick string,
+) int64 {
+	t.Helper()
+
+	sessionID, _, _, err := database.CreateSession(
+		ctx, nick, nick, "localhost", "127.0.0.1",
+	)
+	if err != nil {
+		t.Fatalf("create session %s: %v", nick, err)
+	}
+
+	return sessionID
+}
+
+func TestFanOut(t *testing.T) {
+	env := newTestEnv(t)
+	ctx := t.Context()
+
+	sid1 := createSession(ctx, t, env.db, "alice")
+	sid2 := createSession(ctx, t, env.db, "bob")
+
+	body, _ := json.Marshal([]string{"hello"}) //nolint:errchkjson
+
+	dbID, uuid, err := env.svc.FanOut(
+		ctx, irc.CmdPrivmsg, "alice", "#test",
+		nil, body, nil,
+		[]int64{sid1, sid2},
+	)
+	if err != nil {
+		t.Fatalf("FanOut: %v", err)
+	}
+
+	if dbID == 0 {
+		t.Error("expected non-zero dbID")
+	}
+
+	if uuid == "" {
+		t.Error("expected non-empty UUID")
+	}
+}
+
+func TestJoinChannel(t *testing.T) {
+	env := newTestEnv(t)
+	ctx := t.Context()
+
+	sid := createSession(ctx, t, env.db, "alice")
+
+	result, err := env.svc.JoinChannel(
+		ctx, sid, "alice", "#general",
+	)
+	if err != nil {
+		t.Fatalf("JoinChannel: %v", err)
+	}
+
+	if result.ChannelID == 0 {
+		t.Error("expected non-zero channel ID")
+	}
+
+	if !result.IsCreator {
+		t.Error("first joiner should be creator")
+	}
+
+	// Second user joins — not creator.
+	sid2 := createSession(ctx, t, env.db, "bob")
+
+	result2, err := env.svc.JoinChannel(
+		ctx, sid2, "bob", "#general",
+	)
+	if err != nil {
+		t.Fatalf("JoinChannel bob: %v", err)
+	}
+
+	if result2.IsCreator {
+		t.Error("second joiner should not be creator")
+	}
+
+	if result2.ChannelID != result.ChannelID {
+		t.Error("both should join the same channel")
+	}
+}
+
+func TestPartChannel(t *testing.T) {
+	env := newTestEnv(t)
+	ctx := t.Context()
+
+	sid := createSession(ctx, t, env.db, "alice")
+
+	_, err := env.svc.JoinChannel(
+		ctx, sid, "alice", "#general",
+	)
+	if err != nil {
+		t.Fatalf("JoinChannel: %v", err)
+	}
+
+	err = env.svc.PartChannel(
+		ctx, sid, "alice", "#general", "bye",
+	)
+	if err != nil {
+		t.Fatalf("PartChannel: %v", err)
+	}
+
+	// Parting a non-existent channel returns error.
+	err = env.svc.PartChannel(
+		ctx, sid, "alice", "#nonexistent", "",
+	)
+	if err == nil {
+		t.Error("expected error for non-existent channel")
+	}
+
+	var ircErr *service.IRCError
+	if !errors.As(err, &ircErr) {
+		t.Errorf("expected IRCError, got %T", err)
+	}
+}
+
+func TestSendChannelMessage(t *testing.T) {
+	env := newTestEnv(t)
+	ctx := t.Context()
+
+	sid1 := createSession(ctx, t, env.db, "alice")
+	sid2 := createSession(ctx, t, env.db, "bob")
+
+	_, err := env.svc.JoinChannel(
+		ctx, sid1, "alice", "#chat",
+	)
+	if err != nil {
+		t.Fatalf("join alice: %v", err)
+	}
+
+	_, err = env.svc.JoinChannel(
+		ctx, sid2, "bob", "#chat",
+	)
+	if err != nil {
+		t.Fatalf("join bob: %v", err)
+	}
+
+	body, _ := json.Marshal([]string{"hello world"}) //nolint:errchkjson
+
+	dbID, uuid, err := env.svc.SendChannelMessage(
+		ctx, sid1, "alice",
+		irc.CmdPrivmsg, "#chat", body, nil,
+	)
+	if err != nil {
+		t.Fatalf("SendChannelMessage: %v", err)
+	}
+
+	if dbID == 0 {
+		t.Error("expected non-zero dbID")
+	}
+
+	if uuid == "" {
+		t.Error("expected non-empty UUID")
+	}
+
+	// Non-member cannot send.
+	sid3 := createSession(ctx, t, env.db, "charlie")
+
+	_, _, err = env.svc.SendChannelMessage(
+		ctx, sid3, "charlie",
+		irc.CmdPrivmsg, "#chat", body, nil,
+	)
+	if err == nil {
+		t.Error("expected error for non-member send")
+	}
+}
+
+func TestBroadcastQuit(t *testing.T) {
+	env := newTestEnv(t)
+	ctx := t.Context()
+
+	sid1 := createSession(ctx, t, env.db, "alice")
+	sid2 := createSession(ctx, t, env.db, "bob")
+
+	_, err := env.svc.JoinChannel(
+		ctx, sid1, "alice", "#room",
+	)
+	if err != nil {
+		t.Fatalf("join alice: %v", err)
+	}
+
+	_, err = env.svc.JoinChannel(
+		ctx, sid2, "bob", "#room",
+	)
+	if err != nil {
+		t.Fatalf("join bob: %v", err)
+	}
+
+	// BroadcastQuit should not panic and should clean up.
+	env.svc.BroadcastQuit(
+		ctx, sid1, "alice", "Goodbye",
+	)
+
+	// Session should be deleted.
+	_, lookupErr := env.db.GetSessionByNick(ctx, "alice")
+	if lookupErr == nil {
+		t.Error("expected session to be deleted after quit")
+	}
+}
+
+func TestSendChannelMessage_Moderated(t *testing.T) {
+	env := newTestEnv(t)
+	ctx := t.Context()
+
+	sid1 := createSession(ctx, t, env.db, "alice")
+	sid2 := createSession(ctx, t, env.db, "bob")
+
+	result, err := env.svc.JoinChannel(
+		ctx, sid1, "alice", "#modchat",
+	)
+	if err != nil {
+		t.Fatalf("join alice: %v", err)
+	}
+
+	_, err = env.svc.JoinChannel(
+		ctx, sid2, "bob", "#modchat",
+	)
+	if err != nil {
+		t.Fatalf("join bob: %v", err)
+	}
+
+	// Set channel to moderated.
+	chID := result.ChannelID
+	_ = env.svc.SetChannelFlag(ctx, chID, 'm', true)
+
+	body, _ := json.Marshal([]string{"test"}) //nolint:errchkjson
+
+	// Bob (non-op, non-voiced) should fail to send.
+	_, _, err = env.svc.SendChannelMessage(
+		ctx, sid2, "bob",
+		irc.CmdPrivmsg, "#modchat", body, nil,
+	)
+	if err == nil {
+		t.Error("expected error for non-voiced user in moderated channel")
+	}
+
+	// Alice (operator) should succeed.
+	_, _, err = env.svc.SendChannelMessage(
+		ctx, sid1, "alice",
+		irc.CmdPrivmsg, "#modchat", body, nil,
+	)
+	if err != nil {
+		t.Errorf("operator should be able to send in moderated channel: %v", err)
+	}
+}