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>

internal/ircserver/server_test.go

@@ -0,0 +1,625 @@
+package ircserver_test
+
+import (
+	"bufio"
+	"database/sql"
+	"fmt"
+	"log/slog"
+	"net"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	"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/ircserver"
+
+	_ "modernc.org/sqlite"
+)
+
+const testTimeout = 5 * time.Second
+
+func TestMain(m *testing.M) {
+	db.SetBcryptCost(4)
+
+	os.Exit(m.Run())
+}
+
+// testEnv holds the shared test infrastructure.
+type testEnv struct {
+	database *db.Database
+	brk      *broker.Broker
+	cfg      *config.Config
+	srv      *ircserver.Server
+}
+
+func newTestEnv(t *testing.T) *testEnv {
+	t.Helper()
+
+	dsn := fmt.Sprintf(
+		"file:%s?mode=memory&cache=shared&_journal_mode=WAL",
+		t.Name(),
+	)
+
+	conn, err := sql.Open("sqlite", dsn)
+	if err != nil {
+		t.Fatalf("open db: %v", err)
+	}
+
+	conn.SetMaxOpenConns(1)
+
+	_, err = conn.ExecContext(
+		t.Context(), "PRAGMA foreign_keys = ON",
+	)
+	if err != nil {
+		t.Fatalf("pragma: %v", err)
+	}
+
+	database := db.NewTestDatabaseFromConn(conn)
+
+	err = database.RunMigrations(t.Context())
+	if err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+
+	brk := broker.New()
+
+	cfg := &config.Config{ //nolint:exhaustruct
+		ServerName: "test.irc",
+		MOTD:       "Welcome to test IRC",
+	}
+
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("listen: %v", err)
+	}
+
+	addr := listener.Addr().String()
+
+	err = listener.Close()
+	if err != nil {
+		t.Fatalf("close listener: %v", err)
+	}
+
+	log := slog.New(slog.NewTextHandler(
+		os.Stderr,
+		&slog.HandlerOptions{Level: slog.LevelError}, //nolint:exhaustruct
+	))
+
+	srv := ircserver.NewTestServer(log, cfg, database, brk)
+
+	err = srv.Start(addr)
+	if err != nil {
+		t.Fatalf("start irc server: %v", err)
+	}
+
+	t.Cleanup(func() {
+		srv.Stop()
+
+		err := conn.Close()
+		if err != nil {
+			t.Logf("close db: %v", err)
+		}
+	})
+
+	return &testEnv{
+		database: database,
+		brk:      brk,
+		cfg:      cfg,
+		srv:      srv,
+	}
+}
+
+// dial connects to the test server.
+func (env *testEnv) dial(t *testing.T) *testClient {
+	t.Helper()
+
+	conn, err := net.DialTimeout(
+		"tcp",
+		env.srv.Listener().Addr().String(),
+		testTimeout,
+	)
+	if err != nil {
+		t.Fatalf("dial: %v", err)
+	}
+
+	t.Cleanup(func() {
+		err := conn.Close()
+		if err != nil {
+			t.Logf("close conn: %v", err)
+		}
+	})
+
+	return &testClient{
+		t:       t,
+		conn:    conn,
+		scanner: bufio.NewScanner(conn),
+	}
+}
+
+// testClient wraps a raw TCP connection with helpers.
+type testClient struct {
+	t       *testing.T
+	conn    net.Conn
+	scanner *bufio.Scanner
+}
+
+func (tc *testClient) send(line string) {
+	tc.t.Helper()
+
+	_ = tc.conn.SetWriteDeadline(
+		time.Now().Add(testTimeout),
+	)
+
+	_, err := fmt.Fprintf(tc.conn, "%s\r\n", line)
+	if err != nil {
+		tc.t.Fatalf("send: %v", err)
+	}
+}
+
+func (tc *testClient) readLine() string {
+	tc.t.Helper()
+
+	_ = tc.conn.SetReadDeadline(
+		time.Now().Add(testTimeout),
+	)
+
+	if !tc.scanner.Scan() {
+		err := tc.scanner.Err()
+		if err != nil {
+			tc.t.Fatalf("read: %v", err)
+		}
+
+		tc.t.Fatal("connection closed unexpectedly")
+	}
+
+	return tc.scanner.Text()
+}
+
+// readUntil reads lines until one matches the predicate.
+func (tc *testClient) readUntil(
+	pred func(string) bool,
+) []string {
+	tc.t.Helper()
+
+	var lines []string
+
+	for {
+		line := tc.readLine()
+		lines = append(lines, line)
+
+		if pred(line) {
+			return lines
+		}
+	}
+}
+
+// register sends NICK + USER and reads through the welcome
+// burst.
+func (tc *testClient) register(nick string) []string {
+	tc.t.Helper()
+
+	tc.send("NICK " + nick)
+	tc.send("USER " + nick + " 0 * :Test User")
+
+	return tc.readUntil(func(line string) bool {
+		return strings.Contains(line, " 376 ") ||
+			strings.Contains(line, " 422 ")
+	})
+}
+
+// assertContains checks that at least one line matches the
+// given substring.
+func assertContains(
+	t *testing.T,
+	lines []string,
+	substr, description string,
+) {
+	t.Helper()
+
+	for _, line := range lines {
+		if strings.Contains(line, substr) {
+			return
+		}
+	}
+
+	t.Errorf("did not find %q in output: %s", substr, description)
+}
+
+// joinAndDrain joins a channel and reads until
+// RPL_ENDOFNAMES.
+func (tc *testClient) joinAndDrain(channel string) {
+	tc.t.Helper()
+
+	tc.send("JOIN " + channel)
+
+	tc.readUntil(func(line string) bool {
+		return strings.Contains(line, " 366 ")
+	})
+}
+
+// sendAndExpect sends a command and reads until a line
+// containing the expected substring is found.
+func (tc *testClient) sendAndExpect(
+	cmd, expect string,
+) []string {
+	tc.t.Helper()
+
+	tc.send(cmd)
+
+	return tc.readUntil(func(line string) bool {
+		return strings.Contains(line, expect)
+	})
+}
+
+func TestRegistration(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	lines := client.register("alice")
+	assertContains(t, lines, " 001 ", "RPL_WELCOME")
+}
+
+func TestWelcomeContainsNick(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	lines := client.register("bob")
+
+	for _, line := range lines {
+		if strings.Contains(line, " 001 ") &&
+			!strings.Contains(line, "bob") {
+			t.Errorf("001 should contain nick: %s", line)
+		}
+	}
+}
+
+func TestPingPong(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("pingtest")
+	lines := client.sendAndExpect("PING :hello", "PONG")
+	assertContains(t, lines, "PONG", "PONG response")
+}
+
+func TestJoinChannel(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("joiner")
+	client.send("JOIN #test")
+
+	lines := client.readUntil(func(line string) bool {
+		return strings.Contains(line, " 366 ")
+	})
+
+	assertContains(t, lines, "JOIN", "JOIN echo")
+	assertContains(t, lines, " 366 ", "RPL_ENDOFNAMES")
+}
+
+func TestPrivmsgBetweenClients(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	alice := env.dial(t)
+	alice.register("alice_pm")
+
+	bob := env.dial(t)
+	bob.register("bob_pm")
+
+	alice.joinAndDrain("#chat")
+	bob.joinAndDrain("#chat")
+
+	alice.send("PRIVMSG #chat :hello bob!")
+	lines := bob.sendAndExpect("PING :sync", "hello bob!")
+	assertContains(t, lines, "hello bob!", "channel PRIVMSG")
+}
+
+func TestNickChange(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("oldnick")
+	lines := client.sendAndExpect("NICK newnick", "newnick")
+	assertContains(t, lines, "NICK", "NICK change echo")
+}
+
+func TestDuplicateNick(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	first := env.dial(t)
+	first.register("taken")
+
+	second := env.dial(t)
+	second.send("NICK taken")
+	second.send("USER taken 0 * :Test")
+
+	lines := second.readUntil(func(line string) bool {
+		return strings.Contains(line, " 433 ")
+	})
+
+	assertContains(t, lines, " 433 ", "ERR_NICKNAMEINUSE")
+}
+
+func TestListChannels(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("lister")
+	client.joinAndDrain("#listtest")
+	lines := client.sendAndExpect("LIST", " 323 ")
+	assertContains(t, lines, " 323 ", "RPL_LISTEND") //nolint:misspell // IRC term
+}
+
+func TestWhois(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("whoistest")
+	lines := client.sendAndExpect(
+		"WHOIS whoistest", " 318 ",
+	)
+
+	assertContains(t, lines, " 311 ", "RPL_WHOISUSER")
+	assertContains(t, lines, " 318 ", "RPL_ENDOFWHOIS")
+}
+
+func TestQuit(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("quitter")
+	lines := client.sendAndExpect(
+		"QUIT :goodbye", "ERROR",
+	)
+
+	assertContains(t, lines, "goodbye", "QUIT reason")
+}
+
+func TestTopicSetAndGet(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("topicuser")
+	client.joinAndDrain("#topictest")
+	lines := client.sendAndExpect(
+		"TOPIC #topictest :New topic here",
+		"New topic here",
+	)
+
+	assertContains(
+		t, lines, "New topic here", "TOPIC echo",
+	)
+}
+
+func TestUnknownCommand(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("unknowncmd")
+	lines := client.sendAndExpect("FOOBAR", " 421 ")
+	assertContains(t, lines, " 421 ", "ERR_UNKNOWNCOMMAND")
+}
+
+func TestDirectMessage(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	sender := env.dial(t)
+	sender.register("dmsender")
+
+	receiver := env.dial(t)
+	receiver.register("dmreceiver")
+
+	// Give relay goroutines time to start.
+	time.Sleep(100 * time.Millisecond)
+
+	sender.send("PRIVMSG dmreceiver :hello privately")
+
+	lines := receiver.readUntil(func(line string) bool {
+		return strings.Contains(line, "hello privately")
+	})
+
+	assertContains(
+		t, lines, "hello privately", "direct PRIVMSG",
+	)
+}
+
+func TestCAPNegotiation(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.send("CAP LS 302")
+
+	line := client.readLine()
+	if !strings.Contains(line, "CAP") {
+		t.Errorf("expected CAP response, got: %s", line)
+	}
+
+	client.send("CAP END")
+	lines := client.register("capuser")
+	assertContains(t, lines, " 001 ", "registration after CAP")
+}
+
+func TestPartChannel(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("parter")
+	client.joinAndDrain("#parttest")
+	lines := client.sendAndExpect(
+		"PART #parttest :leaving", "PART",
+	)
+
+	assertContains(t, lines, "#parttest", "PART echo")
+}
+
+func TestModeQuery(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("modeuser")
+	client.joinAndDrain("#modetest")
+	lines := client.sendAndExpect(
+		"MODE #modetest", " 324 ",
+	)
+
+	assertContains(
+		t, lines, " 324 ", "RPL_CHANNELMODEIS",
+	)
+}
+
+func TestWhoChannel(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("whouser")
+	client.joinAndDrain("#whotest")
+	lines := client.sendAndExpect("WHO #whotest", " 315 ")
+	assertContains(t, lines, " 352 ", "RPL_WHOREPLY")
+}
+
+func TestLusers(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("luseruser")
+	lines := client.sendAndExpect("LUSERS", " 255 ")
+	assertContains(t, lines, " 251 ", "RPL_LUSERCLIENT")
+}
+
+func TestMotd(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("motduser")
+	lines := client.sendAndExpect("MOTD", " 376 ")
+	assertContains(t, lines, " 376 ", "RPL_ENDOFMOTD")
+}
+
+func TestAwaySetAndClear(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("awayuser")
+
+	setLines := client.sendAndExpect(
+		"AWAY :brb lunch", " 306 ",
+	)
+	assertContains(t, setLines, " 306 ", "RPL_NOWAWAY")
+
+	clearLines := client.sendAndExpect("AWAY", " 305 ")
+	assertContains(t, clearLines, " 305 ", "RPL_UNAWAY")
+}
+
+func TestHandlePassPostRegistration(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("passuser")
+	lines := client.sendAndExpect(
+		"PASS :mypassword123", "Password set",
+	)
+
+	assertContains(
+		t, lines, "Password set", "password confirmation",
+	)
+}
+
+func TestPreRegistrationNotRegistered(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.send("PRIVMSG #test :hello")
+
+	line := client.readLine()
+	if !strings.Contains(line, " 451 ") {
+		t.Errorf(
+			"expected ERR_NOTREGISTERED (451), got: %s",
+			line,
+		)
+	}
+}
+
+func TestNamesNonExistentChannel(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("namesuser")
+	lines := client.sendAndExpect(
+		"NAMES #doesnotexist", " 366 ",
+	)
+
+	assertContains(
+		t, lines, " 366 ",
+		"RPL_ENDOFNAMES for non-existent channel",
+	)
+}
+
+func BenchmarkParseMessage(b *testing.B) {
+	line := ":nick!user@host PRIVMSG #channel :Hello, world!"
+
+	b.ResetTimer()
+
+	for range b.N {
+		_ = ircserver.ParseMessage(line)
+	}
+}
+
+func BenchmarkFormatMessage(b *testing.B) {
+	b.ResetTimer()
+
+	for range b.N {
+		_ = ircserver.FormatMessage(
+			"nick!user@host", "PRIVMSG",
+			"#channel", "Hello, world!",
+		)
+	}
+}