Publish Discord inbound replies on the post event bus.

Reviewed-on: #18

cmd/server/main.go

@@ -38,7 +38,7 @@ func main() {
 	}
 	bus := events.New()
 	mail.Subscribe(bus, store.NewPostgres(db), notifier)
-	bot, err := discord.FromEnv(store.NewDiscordLinks(db), bus, store.NewPostgres(db), notifier)
+	bot, err := discord.FromEnv(store.NewDiscordLinks(db), bus, store.NewPostgres(db))
 	if err != nil {
 		log.Fatalf("discord: %v", err)
 	}

internal/discord/bot.go

@@ -13,7 +13,6 @@ import (
 	"github.com/bwmarrin/discordgo"
 
 	"plumber/internal/events"
-	"plumber/internal/mail"
 	"plumber/internal/store"
 )
 
@@ -25,7 +24,7 @@ type Bot struct {
 	links     store.DiscordLinkStore
 	api       API
 	store     store.Store
-	mail      mail.Notifier
+	bus       events.Publisher
 	admins    map[string]string
 	botUserID string
 }
@@ -36,7 +35,7 @@ func New(channelID string, links store.DiscordLinkStore, api API) *Bot {
 }
 
 // FromEnv builds a bot when Discord env is set. Missing config is a no-op.
-func FromEnv(links store.DiscordLinkStore, bus *events.Bus, st store.Store, mailer mail.Notifier) (*Bot, error) {
+func FromEnv(links store.DiscordLinkStore, bus *events.Bus, st store.Store) (*Bot, error) {
 	token := strings.TrimSpace(os.Getenv("DISCORD_BOT_TOKEN"))
 	channelID := strings.TrimSpace(os.Getenv("DISCORD_CHANNEL_ID"))
 	if token == "" && channelID == "" {
@@ -56,12 +55,9 @@ func FromEnv(links store.DiscordLinkStore, bus *events.Bus, st store.Store, mail
 		return nil, err
 	}
 	session.Identify.Intents = discordgo.IntentsGuilds | discordgo.IntentsGuildMessages | discordgo.IntentsMessageContent
-	if mailer == nil {
-		mailer = mail.Nop{}
-	}
 	bot := New(channelID, links, &sessionAPI{session: session})
 	bot.store = st
-	bot.mail = mailer
+	bot.bus = bus
 	bot.admins = parseAdminMap(os.Getenv("DISCORD_ADMIN_MAP"))
 	session.AddHandler(bot.onMessageCreate)
 	if bus != nil {
@@ -102,6 +98,14 @@ func (b *Bot) Handle(_ context.Context, ev any) {
 }
 
 func (b *Bot) onCreated(ctx context.Context, ev events.PostEvent) {
+	_, err := b.links.GetByPostID(ctx, ev.PostID)
+	if err == nil {
+		return
+	}
+	if !errors.Is(err, sql.ErrNoRows) {
+		log.Printf("discord: load link %s: %v", ev.PostID, err)
+		return
+	}
 	if isRoot(ev) {
 		b.createRoot(ctx, ev)
 		return

internal/discord/bot_test.go

@@ -161,6 +161,36 @@ func TestOutboundSkipsReplyWithoutRootLink(t *testing.T) {
 	}
 }
 
+func TestOutboundSkipsAlreadyLinkedPost(t *testing.T) {
+	t.Parallel()
+
+	links := newMemoryLinks()
+	api := &fakeAPI{}
+	bot := New("channel-1", links, api)
+	if err := links.Upsert(context.Background(), store.DiscordLink{
+		PostID:    "reply-1",
+		MessageID: "d-reply-1",
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if err := links.Upsert(context.Background(), store.DiscordLink{
+		PostID:    "root-1",
+		MessageID: "d-root",
+		ThreadID:  "thread-1",
+	}); err != nil {
+		t.Fatal(err)
+	}
+	bot.Handle(context.Background(), events.PostCreated{PostEvent: events.PostEvent{
+		PostID:   "reply-1",
+		RootID:   "root-1",
+		ParentID: "root-1",
+		Body:     "Already on Discord.",
+	}})
+	if len(api.sends) != 0 {
+		t.Fatalf("echoed already-linked reply: %+v", api.sends)
+	}
+}
+
 func TestOutboundUpdateWithoutLinkCreates(t *testing.T) {
 	t.Parallel()
 
@@ -218,7 +248,7 @@ func TestFormatMessage(t *testing.T) {
 func TestFromEnvDisabled(t *testing.T) {
 	t.Setenv("DISCORD_BOT_TOKEN", "")
 	t.Setenv("DISCORD_CHANNEL_ID", "")
-	bot, err := FromEnv(newMemoryLinks(), nil, nil, nil)
+	bot, err := FromEnv(newMemoryLinks(), nil, nil)
 	if err != nil || bot != nil {
 		t.Fatalf("disabled FromEnv = (%v, %v)", bot, err)
 	}
@@ -227,12 +257,12 @@ func TestFromEnvDisabled(t *testing.T) {
 func TestFromEnvRequiresBoth(t *testing.T) {
 	t.Setenv("DISCORD_BOT_TOKEN", "token")
 	t.Setenv("DISCORD_CHANNEL_ID", "")
-	if _, err := FromEnv(newMemoryLinks(), nil, nil, nil); err == nil {
+	if _, err := FromEnv(newMemoryLinks(), nil, nil); err == nil {
 		t.Fatal("expected error when channel is missing")
 	}
 	t.Setenv("DISCORD_BOT_TOKEN", "")
 	t.Setenv("DISCORD_CHANNEL_ID", "channel")
-	if _, err := FromEnv(newMemoryLinks(), nil, nil, nil); err == nil {
+	if _, err := FromEnv(newMemoryLinks(), nil, nil); err == nil {
 		t.Fatal("expected error when token is missing")
 	}
 }

internal/discord/inbound.go

@@ -7,11 +7,10 @@ import (
 	"fmt"
 	"log"
 	"strings"
-	"time"
 
 	"github.com/bwmarrin/discordgo"
 
-	"plumber/internal/mail"
+	"plumber/internal/events"
 	"plumber/internal/store"
 )
 
@@ -127,8 +126,9 @@ func (b *Bot) handleInbound(in inboundMessage) {
 		MessageID: in.ID,
 	}); err != nil {
 		log.Printf("discord: save inbound link %s: %v", reply.ID, err)
+		return
 	}
-	b.notifyInboundReply(parent, root, reply, author)
+	b.publishInbound(reply, root, author)
 	log.Printf("discord: inbound reply %s -> post %s", in.ID, reply.ID)
 }
 
@@ -184,44 +184,20 @@ func (b *Bot) postAndRoot(ctx context.Context, postID string) (*store.Post, *sto
 	return post, current, nil
 }
 
-func (b *Bot) notifyInboundReply(parent, root, reply *store.Post, author *store.User) {
-	if parent == nil || root == nil || reply == nil || author == nil || b.mail == nil {
+func (b *Bot) publishInbound(reply, root *store.Post, author *store.User) {
+	if b == nil || b.bus == nil || reply == nil || root == nil || author == nil {
 		return
 	}
-	if _, disabled := b.mail.(mail.Nop); disabled {
-		return
-	}
-	recipientID := parent.AuthorID
-	if author.Admin() {
-		recipientID = root.AuthorID
-	}
-	if recipientID == author.ID {
-		return
-	}
-	msg := mail.PostReply{
+	ev := events.PostEvent{
+		PostID:     reply.ID,
 		RootID:     root.ID,
-		RootTitle:       root.Title,
-		ReplyID:         reply.ID,
-		ReplyBody:       reply.Body,
-		ReplyAuthorName: author.Name,
+		Body:       reply.Body,
+		AuthorID:   author.ID,
+		AuthorName: author.Name,
+		AuthorRole: string(author.Role),
 	}
-	go func() {
-		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
-		defer cancel()
-		recipient, err := b.store.UserByID(ctx, recipientID)
-		if err != nil {
-			log.Printf("notify reply %s: load recipient: %v", msg.ReplyID, err)
-			return
+	if reply.ParentID != nil {
+		ev.ParentID = *reply.ParentID
 	}
-		if recipient == nil || strings.TrimSpace(recipient.Email) == "" {
-			return
-		}
-		msg.ToEmail = recipient.Email
-		msg.ToName = recipient.Name
-		if err := b.mail.NotifyPostReply(ctx, msg); err != nil {
-			log.Printf("notify reply %s: %v", msg.ReplyID, err)
-			return
-		}
-		log.Printf("notify reply %s: accepted", msg.ReplyID)
-	}()
+	b.bus.Publish(context.Background(), events.PostCreated{PostEvent: ev})
 }

internal/discord/inbound_test.go

@@ -27,9 +27,11 @@ func TestInboundCreatesSiteReply(t *testing.T) {
 	links := newMemoryLinks()
 	api := &fakeAPI{}
 	mailer := &mail.Recording{}
-	bot := inboundTestBot(mem, links, api, mailer, admin.Username)
+	bot := inboundTestBot(mem, links, api, admin.Username)
 	bus := events.New()
 	defer bus.Close()
+	bot.bus = bus
+	mail.Subscribe(bus, mem, mailer)
 	bus.Subscribe(bot.Handle)
 	root := seedLinkedRoot(t, mem, links, homeowner.ID, "thread-1")
 
@@ -68,7 +70,7 @@ func TestInboundParentsFromReference(t *testing.T) {
 
 	mem, homeowner, admin := seedInboundUsers(t)
 	links := newMemoryLinks()
-	bot := inboundTestBot(mem, links, &fakeAPI{}, &mail.Recording{}, admin.Username)
+	bot := inboundTestBot(mem, links, &fakeAPI{}, admin.Username)
 	root := seedLinkedRoot(t, mem, links, homeowner.ID, "thread-1")
 	plumberReply := &store.Post{ParentID: &root.ID, AuthorID: admin.ID, Body: "First look."}
 	if err := mem.CreatePost(context.Background(), plumberReply); err != nil {
@@ -106,7 +108,7 @@ func TestInboundIgnoresAllowlistHiddenAndEchoSources(t *testing.T) {
 	mem, homeowner, admin := seedInboundUsers(t)
 	links := newMemoryLinks()
 	api := &fakeAPI{}
-	bot := inboundTestBot(mem, links, api, mail.Nop{}, admin.Username)
+	bot := inboundTestBot(mem, links, api, admin.Username)
 	root := seedLinkedRoot(t, mem, links, homeowner.ID, "thread-1")
 	hidden := &store.Post{
 		AuthorID:  homeowner.ID,
@@ -148,10 +150,9 @@ func TestInboundIgnoresAllowlistHiddenAndEchoSources(t *testing.T) {
 	}
 }
 
-func inboundTestBot(mem *store.Memory, links *memoryLinks, api *fakeAPI, mailer mail.Notifier, adminUsername string) *Bot {
+func inboundTestBot(mem *store.Memory, links *memoryLinks, api *fakeAPI, adminUsername string) *Bot {
 	bot := New("channel-1", links, api)
 	bot.store = mem
-	bot.mail = mailer
 	bot.admins = map[string]string{"snow-admin": adminUsername}
 	bot.botUserID = "bot-1"
 	return bot