Improve missed message backfilling

backfill.go

@@ -0,0 +1,259 @@
+package main
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"sort"
+
+	"github.com/bwmarrin/discordgo"
+	"github.com/rs/zerolog"
+	"maunium.net/go/mautrix"
+	"maunium.net/go/mautrix/bridge/bridgeconfig"
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
+
+	"go.mau.fi/mautrix-discord/database"
+)
+
+func (portal *Portal) ForwardBackfillMissed(source *User, meta *discordgo.Channel) {
+	limit := portal.bridge.Config.Bridge.Backfill.Limits.Missed.Channel
+	if portal.GuildID == "" {
+		limit = portal.bridge.Config.Bridge.Backfill.Limits.Missed.DM
+	}
+	if limit == 0 {
+		return
+	}
+	log := portal.zlog.With().
+		Str("action", "missed event backfill").
+		Int("limit", limit).
+		Logger()
+
+	portal.forwardBackfillLock.Lock()
+	defer portal.forwardBackfillLock.Unlock()
+
+	lastMessage := portal.bridge.DB.Message.GetLast(portal.Key)
+	if lastMessage == nil || meta.LastMessageID == "" {
+		log.Debug().Msg("Not backfilling, no last message in database or no last message in metadata")
+		return
+	} else if !shouldBackfill(lastMessage.DiscordID, meta.LastMessageID) {
+		log.Debug().
+			Str("last_bridged_message", lastMessage.DiscordID).
+			Str("last_server_message", meta.LastMessageID).
+			Msg("Not backfilling, last message in database is newer than last message in metadata")
+		return
+	}
+	log.Debug().
+		Str("last_bridged_message", lastMessage.DiscordID).
+		Str("last_server_message", meta.LastMessageID).
+		Msg("Backfilling missed messages")
+	if limit < 0 {
+		portal.backfillUnlimitedMissed(log, source, lastMessage.DiscordID)
+	} else {
+		portal.backfillLimitedMissed(log, source, limit, lastMessage.DiscordID)
+	}
+}
+
+const messageFetchChunkSize = 50
+
+func (portal *Portal) collectBackfillMessages(log zerolog.Logger, source *User, limit int, until string) ([]*discordgo.Message, bool, error) {
+	var messages []*discordgo.Message
+	var before string
+	var foundAll bool
+	for {
+		log.Debug().Str("before_id", before).Msg("Fetching messages for backfill")
+		newMessages, err := source.Session.ChannelMessages(portal.Key.ChannelID, messageFetchChunkSize, before, "", "")
+		if err != nil {
+			return nil, false, err
+		}
+		for i, msg := range newMessages {
+			if compareMessageIDs(msg.ID, until) <= 0 {
+				log.Debug().
+					Str("message_id", msg.ID).
+					Str("until_id", until).
+					Msg("Found message that was already bridged")
+				newMessages = newMessages[:i]
+				foundAll = true
+				break
+			}
+		}
+		messages = append(messages, newMessages...)
+		log.Debug().Int("count", len(newMessages)).Msg("Added messages to backfill collection")
+		if len(newMessages) <= messageFetchChunkSize || len(messages) >= limit {
+			break
+		}
+		before = newMessages[len(newMessages)-1].ID
+	}
+	if len(messages) > limit {
+		messages = messages[:limit]
+	}
+	return messages, foundAll, nil
+}
+
+func (portal *Portal) backfillLimitedMissed(log zerolog.Logger, source *User, limit int, after string) {
+	messages, foundAll, err := portal.collectBackfillMessages(log, source, limit, after)
+	if err != nil {
+		log.Err(err).Msg("Error collecting messages to forward backfill")
+		return
+	}
+	log.Info().
+		Int("count", len(messages)).
+		Bool("found_all", foundAll).
+		Msg("Collected messages to backfill")
+	sort.Sort(MessageSlice(messages))
+	if !foundAll {
+		_, err = portal.sendMatrixMessage(portal.MainIntent(), event.EventMessage, &event.MessageEventContent{
+			MsgType: event.MsgNotice,
+			Body:    "Some messages may have been missed here while the bridge was offline.",
+		}, nil, 0)
+		if err != nil {
+			log.Warn().Err(err).Msg("Failed to send missed message warning")
+		} else {
+			log.Debug().Msg("Sent warning about possibly missed messages")
+		}
+	}
+	portal.sendBackfillBatch(log, source, messages)
+}
+
+func (portal *Portal) backfillUnlimitedMissed(log zerolog.Logger, source *User, after string) {
+	for {
+		log.Debug().Str("after_id", after).Msg("Fetching chunk of messages to backfill")
+		messages, err := source.Session.ChannelMessages(portal.Key.ChannelID, messageFetchChunkSize, "", after, "")
+		if err != nil {
+			log.Err(err).Msg("Error fetching chunk of messages to forward backfill")
+			return
+		}
+		log.Debug().Int("count", len(messages)).Msg("Fetched chunk of messages to backfill")
+		sort.Sort(MessageSlice(messages))
+
+		portal.sendBackfillBatch(log, source, messages)
+
+		if len(messages) < messageFetchChunkSize {
+			// Assume that was all the missing messages
+			log.Debug().Msg("Chunk had less than 50 messages, stopping backfill")
+			return
+		}
+		after = messages[len(messages)-1].ID
+	}
+}
+
+func (portal *Portal) sendBackfillBatch(log zerolog.Logger, source *User, messages []*discordgo.Message) {
+	if portal.bridge.Config.Homeserver.Software == bridgeconfig.SoftwareHungry {
+		log.Debug().Msg("Using hungryserv, sending messages with batch send endpoint")
+		portal.forwardBatchSend(log, source, messages)
+	} else {
+		log.Debug().Msg("Not using hungryserv, sending messages one by one")
+		for _, msg := range messages {
+			portal.handleDiscordMessageCreate(source, msg, nil)
+		}
+	}
+}
+
+func (portal *Portal) forwardBatchSend(log zerolog.Logger, source *User, messages []*discordgo.Message) {
+	evts := make([]*event.Event, 0, len(messages))
+	dbMessages := make([]database.Message, 0, len(messages))
+	for _, msg := range messages {
+		for _, mention := range msg.Mentions {
+			puppet := portal.bridge.GetPuppetByID(mention.ID)
+			puppet.UpdateInfo(nil, mention)
+		}
+
+		puppet := portal.bridge.GetPuppetByID(msg.Author.ID)
+		puppet.UpdateInfo(source, msg.Author)
+		intent := puppet.IntentFor(portal)
+		replyTo := portal.getReplyTarget(source, msg.MessageReference, true)
+
+		ts, _ := discordgo.SnowflakeTimestamp(msg.ID)
+		parts := portal.convertDiscordMessage(intent, msg)
+		for i, part := range parts {
+			if replyTo != nil {
+				part.Content.RelatesTo = &event.RelatesTo{InReplyTo: replyTo}
+				// Only set reply for first event
+				replyTo = nil
+			}
+			partName := part.AttachmentID
+			// Always use blank part name for first part so that replies and other things
+			// can reference it without knowing about attachments.
+			if i == 0 {
+				partName = ""
+			}
+			evts = append(evts, &event.Event{
+				ID:        portal.deterministicEventID(msg.ID, partName),
+				Type:      part.Type,
+				Sender:    intent.UserID,
+				Timestamp: ts.UnixMilli(),
+				Content: event.Content{
+					Parsed: part.Content,
+					Raw:    part.Extra,
+				},
+			})
+			dbMessages = append(dbMessages, database.Message{
+				Channel:      portal.Key,
+				DiscordID:    msg.ID,
+				SenderID:     msg.Author.ID,
+				Timestamp:    ts,
+				AttachmentID: part.AttachmentID,
+			})
+		}
+	}
+	log.Info().Int("parts", len(evts)).Msg("Converted messages to backfill")
+	resp, err := portal.MainIntent().BatchSend(portal.MXID, &mautrix.ReqBatchSend{
+		BeeperNewMessages: true,
+		Events:            evts,
+	})
+	if err != nil {
+		log.Err(err).Msg("Error sending backfill batch")
+		return
+	}
+	for i, evtID := range resp.EventIDs {
+		dbMessages[i].MXID = evtID
+	}
+	portal.bridge.DB.Message.MassInsert(portal.Key, dbMessages)
+	log.Info().Msg("Inserted backfilled batch to database")
+}
+
+func (portal *Portal) deterministicEventID(messageID, partName string) id.EventID {
+	data := fmt.Sprintf("%s/discord/%s/%s", portal.MXID, messageID, partName)
+	sum := sha256.Sum256([]byte(data))
+	return id.EventID(fmt.Sprintf("$%s:discord.com", base64.RawURLEncoding.EncodeToString(sum[:])))
+}
+
+// compareMessageIDs compares two Discord message IDs.
+//
+// If the first ID is lower, -1 is returned.
+// If the second ID is lower, 1 is returned.
+// If the IDs are equal, 0 is returned.
+func compareMessageIDs(id1, id2 string) int {
+	if id1 == id2 {
+		return 0
+	}
+	if len(id1) < len(id2) {
+		return -1
+	} else if len(id2) < len(id1) {
+		return 1
+	}
+	if id1 < id2 {
+		return -1
+	}
+	return 1
+}
+
+func shouldBackfill(latestBridgedIDStr, latestIDFromServerStr string) bool {
+	return compareMessageIDs(latestBridgedIDStr, latestIDFromServerStr) == -1
+}
+
+type MessageSlice []*discordgo.Message
+
+var _ sort.Interface = (MessageSlice)(nil)
+
+func (a MessageSlice) Len() int {
+	return len(a)
+}
+
+func (a MessageSlice) Swap(i, j int) {
+	a[i], a[j] = a[j], a[i]
+}
+
+func (a MessageSlice) Less(i, j int) bool {
+	return compareMessageIDs(a[i].ID, a[j].ID) == -1
+}

config/bridge.go

@@ -66,6 +66,14 @@ type BridgeConfig struct {
 	CommandPrefix      string                           `yaml:"command_prefix"`
 	ManagementRoomText bridgeconfig.ManagementRoomTexts `yaml:"management_room_text"`
 
+	Backfill struct {
+		Enabled bool `yaml:"enabled"`
+		Limits  struct {
+			Initial BackfillLimitPart `yaml:"initial"`
+			Missed  BackfillLimitPart `yaml:"missed"`
+		} `yaml:"limits"`
+	} `yaml:"backfill"`
+
 	Encryption bridgeconfig.EncryptionConfig `yaml:"encryption"`
 
 	Provisioning struct {
@@ -81,6 +89,11 @@ type BridgeConfig struct {
 	guildNameTemplate   *template.Template `yaml:"-"`
 }
 
+type BackfillLimitPart struct {
+	DM      int `yaml:"dm"`
+	Channel int `yaml:"channel"`
+}
+
 func (bc *BridgeConfig) GetResendBridgeInfo() bool {
 	return bc.ResendBridgeInfo
 }

config/upgrade.go

@@ -67,6 +67,11 @@ func DoUpgrade(helper *up.Helper) {
 	helper.Copy(up.Str, "bridge", "management_room_text", "welcome_connected")
 	helper.Copy(up.Str, "bridge", "management_room_text", "welcome_unconnected")
 	helper.Copy(up.Str|up.Null, "bridge", "management_room_text", "additional_help")
+	helper.Copy(up.Bool, "bridge", "backfill", "enabled")
+	helper.Copy(up.Int, "bridge", "backfill", "limits", "initial", "dm")
+	helper.Copy(up.Int, "bridge", "backfill", "limits", "initial", "channel")
+	helper.Copy(up.Int, "bridge", "backfill", "limits", "missed", "dm")
+	helper.Copy(up.Int, "bridge", "backfill", "limits", "missed", "channel")
 	helper.Copy(up.Bool, "bridge", "encryption", "allow")
 	helper.Copy(up.Bool, "bridge", "encryption", "default")
 	helper.Copy(up.Bool, "bridge", "encryption", "require")

database/message.go

@@ -95,6 +95,36 @@ func (mq *MessageQuery) GetByMXID(key PortalKey, mxid id.EventID) *Message {
 	return mq.New().Scan(row)
 }
 
+func (mq *MessageQuery) MassInsert(key PortalKey, msgs []Message) {
+	if len(msgs) == 0 {
+		return
+	}
+	valueStringFormat := "($%d, $%d, $1, $2, $%d, $%d, $%d, $%d, $%d)"
+	if mq.db.Dialect == dbutil.SQLite {
+		valueStringFormat = strings.ReplaceAll(valueStringFormat, "$", "?")
+	}
+	params := make([]interface{}, 2+len(msgs)*7)
+	placeholders := make([]string, len(msgs))
+	params[0] = key.ChannelID
+	params[1] = key.Receiver
+	for i, msg := range msgs {
+		baseIndex := 2 + i*7
+		params[baseIndex] = msg.DiscordID
+		params[baseIndex+1] = msg.AttachmentID
+		params[baseIndex+2] = msg.EditIndex
+		params[baseIndex+3] = msg.SenderID
+		params[baseIndex+4] = msg.Timestamp
+		params[baseIndex+5] = msg.ThreadID
+		params[baseIndex+6] = msg.MXID
+		placeholders[i] = fmt.Sprintf(valueStringFormat, baseIndex+1, baseIndex+2, baseIndex+3, baseIndex+4, baseIndex+5, baseIndex+6, baseIndex+7)
+	}
+	_, err := mq.db.Exec(fmt.Sprintf(messageMassInsertTemplate, strings.Join(placeholders, ", ")), params...)
+	if err != nil {
+		mq.log.Warnfln("Failed to insert %d messages: %v", len(msgs), err)
+		panic(err)
+	}
+}
+
 type Message struct {
 	db  *Database
 	log log.Logger
@@ -152,7 +182,7 @@ type MessagePart struct {
 	MXID         id.EventID
 }
 
-func (m *Message) MassInsert(msgs []MessagePart) {
+func (m *Message) MassInsertParts(msgs []MessagePart) {
 	if len(msgs) == 0 {
 		return
 	}

example-config.yaml

@@ -186,6 +186,20 @@ bridge:
         # Optional extra text sent when joining a management room.
         additional_help: ""
 
+    backfill:
+        # Should backfill be enabled at all?
+        enabled: false
+        # Limits for backfilling. Set to 0 to disable that type of backfill, or -1 for unlimited.
+        limits:
+            # Initial backfill (when creating portal).
+            initial:
+                dm: 50
+                channel: 0
+            # Missed message backfill (on startup).
+            missed:
+                dm: 50
+                channel: 0
+
     # End-to-bridge encryption support options.
     #
     # See https://docs.mau.fi/bridges/general/end-to-bridge-encryption.html for more info.

portal.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
-	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -13,8 +12,10 @@ import (
 
 	"github.com/bwmarrin/discordgo"
 	"github.com/gabriel-vasile/mimetype"
+	"github.com/rs/zerolog"
+	"maunium.net/go/maulogger/v2/maulogadapt"
 
-	log "maunium.net/go/maulogger/v2"
+	"maunium.net/go/maulogger/v2"
 
 	"maunium.net/go/mautrix"
 	"maunium.net/go/mautrix/appservice"
@@ -52,7 +53,9 @@ type Portal struct {
 	Guild  *Guild
 
 	bridge *DiscordBridge
-	log    log.Logger
+	// Deprecated
+	log  maulogger.Logger
+	zlog zerolog.Logger
 
 	roomCreateLock sync.Mutex
 	encryptLock    sync.Mutex
@@ -65,6 +68,8 @@ type Portal struct {
 	commands     map[string]*discordgo.ApplicationCommand
 	commandsLock sync.RWMutex
 
+	forwardBackfillLock sync.Mutex
+
 	currentlyTyping     []id.UserID
 	currentlyTypingLock sync.Mutex
 }
@@ -233,7 +238,10 @@ func (br *DiscordBridge) NewPortal(dbPortal *database.Portal) *Portal {
 	portal := &Portal{
 		Portal: dbPortal,
 		bridge: br,
-		log:    br.Log.Sub(fmt.Sprintf("Portal/%s", dbPortal.Key)),
+		zlog: br.ZLog.With().
+			Str("channel_id", dbPortal.Key.ChannelID).
+			Str("channel_receiver", dbPortal.Key.Receiver).
+			Logger(),
 
 		discordMessages: make(chan portalDiscordMessage, br.Config.Bridge.PortalMessageBuffer),
 		matrixMessages:  make(chan portalMatrixMessage, br.Config.Bridge.PortalMessageBuffer),
@@ -242,6 +250,7 @@ func (br *DiscordBridge) NewPortal(dbPortal *database.Portal) *Portal {
 
 		commands: make(map[string]*discordgo.ApplicationCommand),
 	}
+	portal.log = maulogadapt.ZeroAsMau(&portal.zlog)
 
 	go portal.messageLoop()
 
@@ -252,10 +261,13 @@ func (portal *Portal) messageLoop() {
 	for {
 		select {
 		case msg := <-portal.matrixMessages:
+			portal.forwardBackfillLock.Lock()
 			portal.handleMatrixMessages(msg)
 		case msg := <-portal.discordMessages:
+			portal.forwardBackfillLock.Lock()
 			portal.handleDiscordMessages(msg)
 		}
+		portal.forwardBackfillLock.Unlock()
 	}
 }
 
@@ -549,7 +561,7 @@ func (portal *Portal) markMessageHandled(discordID string, editIndex int, author
 	msg.SenderID = authorID
 	msg.Timestamp = timestamp
 	msg.ThreadID = threadID
-	msg.MassInsert(parts)
+	msg.MassInsertParts(parts)
 }
 
 func (portal *Portal) handleDiscordMessageCreate(user *User, msg *discordgo.Message, thread *Thread) {
@@ -578,7 +590,7 @@ func (portal *Portal) handleDiscordMessageCreate(user *User, msg *discordgo.Mess
 	intent := puppet.IntentFor(portal)
 
 	var discordThreadID string
-	var threadRootEvent, lastThreadEvent, replyToEvent id.EventID
+	var threadRootEvent, lastThreadEvent id.EventID
 	if thread != nil {
 		discordThreadID = thread.ID
 		threadRootEvent = thread.RootMXID
@@ -588,30 +600,25 @@ func (portal *Portal) handleDiscordMessageCreate(user *User, msg *discordgo.Mess
 			lastThreadEvent = lastInThread.MXID
 		}
 	}
-
+	replyTo := portal.getReplyTarget(user, msg.MessageReference, false)
-	if msg.MessageReference != nil {
-		// This could be used to find cross-channel replies, but Matrix doesn't support those currently.
-		//key := database.PortalKey{msg.MessageReference.ChannelID, user.ID}
-		replyToMsg := portal.bridge.DB.Message.GetByDiscordID(portal.Key, msg.MessageReference.MessageID)
-		if len(replyToMsg) > 0 {
-			replyToEvent = replyToMsg[0].MXID
-		}
-	}
 
 	ts, _ := discordgo.SnowflakeTimestamp(msg.ID)
 	parts := portal.convertDiscordMessage(intent, msg)
 	dbParts := make([]database.MessagePart, 0, len(parts))
 	for i, part := range parts {
-		if (replyToEvent != "" || threadRootEvent != "") && part.Content.RelatesTo == nil {
+		if (replyTo != nil || threadRootEvent != "") && part.Content.RelatesTo == nil {
 			part.Content.RelatesTo = &event.RelatesTo{}
 		}
 		if threadRootEvent != "" {
 			part.Content.RelatesTo.SetThread(threadRootEvent, lastThreadEvent)
 		}
-		if replyToEvent != "" {
+		if replyTo != nil {
-			part.Content.RelatesTo.SetReplyTo(replyToEvent)
+			part.Content.RelatesTo.SetReplyTo(replyTo.EventID)
+			if replyTo.UnstableRoomID != "" {
+				part.Content.RelatesTo.InReplyTo.UnstableRoomID = replyTo.UnstableRoomID
+			}
 			// Only set reply for first event
-			replyToEvent = ""
+			replyTo = nil
 		}
 		resp, err := portal.sendMatrixMessage(intent, part.Type, part.Content, part.Extra, ts.UnixMilli())
 		if err != nil {
@@ -630,6 +637,42 @@ func (portal *Portal) handleDiscordMessageCreate(user *User, msg *discordgo.Mess
 	}
 }
 
+func (portal *Portal) getReplyTarget(source *User, ref *discordgo.MessageReference, allowNonExistent bool) *event.InReplyTo {
+	if ref == nil {
+		return nil
+	}
+	isHungry := portal.bridge.Config.Homeserver.Software == bridgeconfig.SoftwareHungry
+	if !isHungry {
+		allowNonExistent = false
+	}
+	// TODO add config option for cross-room replies
+	crossRoomReplies := isHungry
+
+	targetPortal := portal
+	if ref.ChannelID != portal.Key.ChannelID && crossRoomReplies {
+		targetPortal = portal.bridge.GetExistingPortalByID(database.PortalKey{ChannelID: ref.ChannelID, Receiver: source.DiscordID})
+		if targetPortal == nil {
+			return nil
+		}
+	}
+	replyToMsg := portal.bridge.DB.Message.GetByDiscordID(targetPortal.Key, ref.MessageID)
+	if len(replyToMsg) > 0 {
+		if !crossRoomReplies {
+			return &event.InReplyTo{EventID: replyToMsg[0].MXID}
+		}
+		return &event.InReplyTo{
+			EventID:        replyToMsg[0].MXID,
+			UnstableRoomID: targetPortal.MXID,
+		}
+	} else if allowNonExistent {
+		return &event.InReplyTo{
+			EventID:        targetPortal.deterministicEventID(ref.MessageID, ""),
+			UnstableRoomID: targetPortal.MXID,
+		}
+	}
+	return nil
+}
+
 const JoinThreadReaction = "join thread"
 
 func (portal *Portal) sendThreadCreationNotice(thread *Thread) {
@@ -1066,9 +1109,9 @@ func (portal *Portal) sendMessageMetrics(evt *event.Event, err error, part strin
 		evtDescription += fmt.Sprintf(" of %s", evt.Redacts)
 	}
 	if err != nil {
-		level := log.LevelError
+		level := maulogger.LevelError
 		if part == "Ignoring" {
-			level = log.LevelDebug
+			level = maulogger.LevelDebug
 		}
 		portal.log.Logfln(level, "%s %s %s from %s: %v", part, msgType, evtDescription, evt.Sender, err)
 		reason, statusCode, isCertain, sendNotice, _ := errorToStatusReason(err)
@@ -1376,7 +1419,7 @@ func (portal *Portal) cleanup(puppetsOnly bool) {
 	portal.bridge.cleanupRoom(intent, portal.MXID, puppetsOnly, portal.log)
 }
 
-func (br *DiscordBridge) cleanupRoom(intent *appservice.IntentAPI, mxid id.RoomID, puppetsOnly bool, log log.Logger) {
+func (br *DiscordBridge) cleanupRoom(intent *appservice.IntentAPI, mxid id.RoomID, puppetsOnly bool, log maulogger.Logger) {
 	members, err := intent.JoinedMembers(mxid)
 	if err != nil {
 		log.Errorln("Failed to get portal members for cleanup:", err)
@@ -1975,52 +2018,3 @@ func (portal *Portal) UpdateInfo(source *User, meta *discordgo.Channel) *discord
 	}
 	return meta
 }
-
-func (portal *Portal) ForwardBackfill(source *User, meta *discordgo.Channel) error {
-	portal.log.Debugln("Checking for missing messages to fill")
-	lastMessage := portal.bridge.DB.Message.GetLast(portal.Key)
-	if lastMessage == nil {
-		return nil
-	}
-
-	metaLastMessageID, err := strconv.ParseInt(meta.LastMessageID, 10, 0)
-	if err != nil {
-		portal.log.Errorfln("Last message ID %s isn't integer", meta.LastMessageID)
-		return err
-	}
-	dbLastMessageID, err := strconv.ParseInt(lastMessage.DiscordID, 10, 0)
-	if err != nil {
-		portal.log.Errorfln("Last message ID %s isn't integer", lastMessage.DiscordID)
-		return err
-	}
-	if metaLastMessageID <= dbLastMessageID {
-		return nil
-	}
-
-	// Get up to 50 messages at a time until everything is fetched
-	for {
-		messages, err := source.Session.ChannelMessages(portal.Key.ChannelID, 50, "", lastMessage.DiscordID, "")
-		if err != nil {
-			portal.log.Debugln("Error getting messages to forward backfill", err)
-			return err
-		}
-		// Discord seems to return messages in reverse order,
-		// but no specific order is guaranteed by their API docs?
-		sort.Slice(messages, func(i, j int) bool {
-			return messages[i].Timestamp.Before(messages[j].Timestamp)
-		})
-
-		for _, msg := range messages {
-			portal.handleDiscordMessageCreate(source, msg, nil)
-		}
-
-		if len(messages) < 100 {
-			// Assume that was all the missing messages
-			return nil
-		}
-		lastMessage = portal.bridge.DB.Message.GetLast(portal.Key)
-		if lastMessage == nil {
-			return nil
-		}
-	}
-}

user.go

@@ -728,7 +728,7 @@ func (user *User) handlePrivateChannel(portal *Portal, meta *discordgo.Channel,
 		}
 	} else {
 		portal.UpdateInfo(user, meta)
-		portal.ForwardBackfill(user, meta)
+		portal.ForwardBackfillMissed(user, meta)
 	}
 	user.MarkInPortal(database.UserPortal{
 		DiscordID: portal.Key.ChannelID,
@@ -843,7 +843,7 @@ func (user *User) handleGuild(meta *discordgo.Guild, timestamp time.Time, isInSp
 				}
 			} else {
 				portal.UpdateInfo(user, ch)
-				portal.ForwardBackfill(user, ch)
+				portal.ForwardBackfillMissed(user, ch)
 			}
 		}
 	}