hicli,web: add support for joining rooms

Fixes #503

desktop/go.mod

@@ -67,7 +67,7 @@ require (
 	golang.org/x/exp v0.0.0-20241215155358-4a5509556b9e // indirect
 	golang.org/x/image v0.23.0 // indirect
 	golang.org/x/mod v0.22.0 // indirect
-	golang.org/x/net v0.32.0 // indirect
+	golang.org/x/net v0.33.0 // indirect
 	golang.org/x/sync v0.10.0 // indirect
 	golang.org/x/sys v0.28.0 // indirect
 	golang.org/x/text v0.21.0 // indirect
@@ -75,7 +75,7 @@ require (
 	gopkg.in/natefinch/lumberjack.v2 v2.2.1 // indirect
 	gopkg.in/warnings.v0 v0.1.2 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
-	maunium.net/go/mautrix v0.22.1 // indirect
+	maunium.net/go/mautrix v0.22.2-0.20241219213402-918ed4bf23ce // indirect
 	mvdan.cc/xurls/v2 v2.5.0 // indirect
 )
 

desktop/go.sum

@@ -187,8 +187,8 @@ golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug
 golang.org/x/net v0.2.0/go.mod h1:KqCZLdyyvdV855qA2rE3GC2aiw5xGR5TEjj8smXukLY=
 golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
 golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
-golang.org/x/net v0.32.0 h1:ZqPmj8Kzc+Y6e0+skZsuACbx+wzMgo5MQsJh9Qd6aYI=
+golang.org/x/net v0.33.0 h1:74SYHlV8BIgHIFC/LrYkOGIwL19eTYXQ5wc6TBuO36I=
-golang.org/x/net v0.32.0/go.mod h1:CwU0IoeOlnQQWJ6ioyFrfRuomB8GKF6KbYXZVyeXNfs=
+golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -250,7 +250,7 @@ gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-maunium.net/go/mautrix v0.22.1 h1:2lCM37vmVzZGE0tWD7UOySMtAuC5hq6Pw33KlY2VU/c=
+maunium.net/go/mautrix v0.22.2-0.20241219213402-918ed4bf23ce h1:wkVN87Hlq63YCuUhVYhvSy0qeAUCzbD5quEtd95rxyE=
-maunium.net/go/mautrix v0.22.1/go.mod h1:1rhqwH34Rz54ZqzdQYkmNW6rQUymNeTdaLA4l9LK6AI=
+maunium.net/go/mautrix v0.22.2-0.20241219213402-918ed4bf23ce/go.mod h1:1rhqwH34Rz54ZqzdQYkmNW6rQUymNeTdaLA4l9LK6AI=
 mvdan.cc/xurls/v2 v2.5.0 h1:lyBNOm8Wo71UknhUs4QTFUNNMyxy2JEIaKKo0RWOh+8=
 mvdan.cc/xurls/v2 v2.5.0/go.mod h1:yQgaGQ1rFtJUzkmKiHYSSfuQxqfYmd//X6PxvholpeE=

go.mod

@@ -21,11 +21,11 @@ require (
 	go.mau.fi/zeroconfig v0.1.3
 	golang.org/x/crypto v0.31.0
 	golang.org/x/image v0.23.0
-	golang.org/x/net v0.32.0
+	golang.org/x/net v0.33.0
 	golang.org/x/text v0.21.0
 	gopkg.in/yaml.v3 v3.0.1
 	maunium.net/go/mauflag v1.0.0
-	maunium.net/go/mautrix v0.22.1
+	maunium.net/go/mautrix v0.22.2-0.20241219213402-918ed4bf23ce
 	mvdan.cc/xurls/v2 v2.5.0
 )
 

go.sum

@@ -73,8 +73,8 @@ golang.org/x/exp v0.0.0-20241215155358-4a5509556b9e h1:4qufH0hlUYs6AO6XmZC3GqfDP
 golang.org/x/exp v0.0.0-20241215155358-4a5509556b9e/go.mod h1:qj5a5QZpwLU2NLQudwIN5koi3beDhSAlJwa67PuM98c=
 golang.org/x/image v0.23.0 h1:HseQ7c2OpPKTPVzNjG5fwJsOTCiiwS4QdsYi5XU6H68=
 golang.org/x/image v0.23.0/go.mod h1:wJJBTdLfCCf3tiHa1fNxpZmUI4mmoZvwMCPP0ddoNKY=
-golang.org/x/net v0.32.0 h1:ZqPmj8Kzc+Y6e0+skZsuACbx+wzMgo5MQsJh9Qd6aYI=
+golang.org/x/net v0.33.0 h1:74SYHlV8BIgHIFC/LrYkOGIwL19eTYXQ5wc6TBuO36I=
-golang.org/x/net v0.32.0/go.mod h1:CwU0IoeOlnQQWJ6ioyFrfRuomB8GKF6KbYXZVyeXNfs=
+golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
 golang.org/x/sys v0.0.0-20220310020820-b874c991c1a5/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -91,7 +91,7 @@ gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 maunium.net/go/mauflag v1.0.0 h1:YiaRc0tEI3toYtJMRIfjP+jklH45uDHtT80nUamyD4M=
 maunium.net/go/mauflag v1.0.0/go.mod h1:nLivPOpTpHnpzEh8jEdSL9UqO9+/KBJFmNRlwKfkPeA=
-maunium.net/go/mautrix v0.22.1 h1:2lCM37vmVzZGE0tWD7UOySMtAuC5hq6Pw33KlY2VU/c=
+maunium.net/go/mautrix v0.22.2-0.20241219213402-918ed4bf23ce h1:wkVN87Hlq63YCuUhVYhvSy0qeAUCzbD5quEtd95rxyE=
-maunium.net/go/mautrix v0.22.1/go.mod h1:1rhqwH34Rz54ZqzdQYkmNW6rQUymNeTdaLA4l9LK6AI=
+maunium.net/go/mautrix v0.22.2-0.20241219213402-918ed4bf23ce/go.mod h1:1rhqwH34Rz54ZqzdQYkmNW6rQUymNeTdaLA4l9LK6AI=
 mvdan.cc/xurls/v2 v2.5.0 h1:lyBNOm8Wo71UknhUs4QTFUNNMyxy2JEIaKKo0RWOh+8=
 mvdan.cc/xurls/v2 v2.5.0/go.mod h1:yQgaGQ1rFtJUzkmKiHYSSfuQxqfYmd//X6PxvholpeE=

pkg/hicli/database/database.go

@@ -20,6 +20,7 @@ type Database struct {
 	Account        AccountQuery
 	AccountData    AccountDataQuery
 	Room           RoomQuery
+	InvitedRoom    InvitedRoomQuery
 	Event          EventQuery
 	CurrentState   CurrentStateQuery
 	Timeline       TimelineQuery
@@ -37,6 +38,7 @@ func New(rawDB *dbutil.Database) *Database {
 		Account:        AccountQuery{QueryHelper: dbutil.MakeQueryHelper(rawDB, newAccount)},
 		AccountData:    AccountDataQuery{QueryHelper: dbutil.MakeQueryHelper(rawDB, newAccountData)},
 		Room:           RoomQuery{QueryHelper: dbutil.MakeQueryHelper(rawDB, newRoom)},
+		InvitedRoom:    InvitedRoomQuery{QueryHelper: dbutil.MakeQueryHelper(rawDB, newInvitedRoom)},
 		Event:          EventQuery{QueryHelper: eventQH},
 		CurrentState:   CurrentStateQuery{QueryHelper: eventQH},
 		Timeline:       TimelineQuery{QueryHelper: eventQH},
@@ -58,6 +60,10 @@ func newRoom(_ *dbutil.QueryHelper[*Room]) *Room {
 	return &Room{}
 }
 
+func newInvitedRoom(_ *dbutil.QueryHelper[*InvitedRoom]) *InvitedRoom {
+	return &InvitedRoom{}
+}
+
 func newReceipt(_ *dbutil.QueryHelper[*Receipt]) *Receipt {
 	return &Receipt{}
 }

pkg/hicli/database/invitedroom.go

@@ -0,0 +1,73 @@
+// Copyright (c) 2024 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package database
+
+import (
+	"context"
+
+	"go.mau.fi/util/dbutil"
+	"go.mau.fi/util/jsontime"
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
+)
+
+const (
+	getInvitedRoomsQuery = `
+		SELECT room_id, received_at, invite_state
+		FROM invited_room
+		ORDER BY received_at DESC
+	`
+	deleteInvitedRoomQuery = `
+		DELETE FROM invited_room WHERE room_id = $1
+	`
+	upsertInvitedRoomQuery = `
+		INSERT INTO invited_room (room_id, received_at, invite_state)
+		VALUES ($1, $2, $3)
+		ON CONFLICT (room_id) DO UPDATE
+			SET received_at = $2, invite_state = $3
+	`
+)
+
+type InvitedRoomQuery struct {
+	*dbutil.QueryHelper[*InvitedRoom]
+}
+
+func (irq *InvitedRoomQuery) GetAll(ctx context.Context) ([]*InvitedRoom, error) {
+	return irq.QueryMany(ctx, getInvitedRoomsQuery)
+}
+
+func (irq *InvitedRoomQuery) Upsert(ctx context.Context, room *InvitedRoom) error {
+	return irq.Exec(ctx, upsertInvitedRoomQuery, room.sqlVariables()...)
+}
+
+func (irq *InvitedRoomQuery) Delete(ctx context.Context, roomID id.RoomID) error {
+	return irq.Exec(ctx, deleteInvitedRoomQuery, roomID)
+}
+
+type InvitedRoom struct {
+	ID          id.RoomID          `json:"room_id"`
+	CreatedAt   jsontime.UnixMilli `json:"created_at"`
+	InviteState []*event.Event     `json:"invite_state"`
+}
+
+func (r *InvitedRoom) sqlVariables() []any {
+	return []any{
+		r.ID,
+		dbutil.UnixMilliPtr(r.CreatedAt.Time),
+		dbutil.JSON{Data: &r.InviteState},
+	}
+}
+
+func (r *InvitedRoom) Scan(row dbutil.Scannable) (*InvitedRoom, error) {
+	var createdAt int64
+	err := row.Scan(&r.ID, &createdAt, dbutil.JSON{Data: &r.InviteState})
+	if err != nil {
+		return nil, err
+	}
+	r.CreatedAt = jsontime.UMInt(createdAt)
+	return r, nil
+}

pkg/hicli/database/room.go

@@ -262,7 +262,7 @@ func (r *Room) Scan(row dbutil.Scannable) (*Room, error) {
 	}
 	r.PrevBatch = prevBatch.String
 	r.PreviewEventRowID = EventRowID(previewEventRowID.Int64)
-	r.SortingTimestamp = jsontime.UM(time.UnixMilli(sortingTimestamp.Int64))
+	r.SortingTimestamp = jsontime.UMInt(sortingTimestamp.Int64)
 	return r, nil
 }
 

pkg/hicli/database/upgrades/00-latest-revision.sql

@@ -41,6 +41,19 @@ CREATE INDEX room_preview_idx ON room (preview_event_rowid);
 -- CREATE INDEX room_sorting_timestamp_idx ON room (unread_notifications > 0);
 -- CREATE INDEX room_sorting_timestamp_idx ON room (unread_messages > 0);
 
+CREATE TABLE invited_room (
+	room_id      TEXT    NOT NULL PRIMARY KEY,
+	received_at  INTEGER NOT NULL,
+	invite_state TEXT    NOT NULL
+) STRICT;
+
+CREATE TRIGGER invited_room_delete_on_room_insert
+	AFTER INSERT
+	ON room
+BEGIN
+	DELETE FROM invited_room WHERE room_id = NEW.room_id;
+END;
+
 CREATE TABLE account_data (
 	user_id TEXT NOT NULL,
 	type    TEXT NOT NULL,

pkg/hicli/database/upgrades/09-invited-rooms.sql

@@ -0,0 +1,13 @@
+-- v9 (compatible with v5+): Add table for invited rooms
+CREATE TABLE invited_room (
+	room_id      TEXT    NOT NULL PRIMARY KEY,
+	received_at  INTEGER NOT NULL,
+	invite_state TEXT    NOT NULL
+) STRICT;
+
+CREATE TRIGGER invited_room_delete_on_room_insert
+	AFTER INSERT
+	ON room
+BEGIN
+	DELETE FROM invited_room WHERE room_id = NEW.room_id;
+END;

pkg/hicli/events.go

@@ -33,13 +33,14 @@ type SyncNotification struct {
 type SyncComplete struct {
 	Since        *string                              `json:"since,omitempty"`
 	ClearState   bool                                 `json:"clear_state,omitempty"`
-	Rooms       map[id.RoomID]*SyncRoom              `json:"rooms"`
 	AccountData  map[event.Type]*database.AccountData `json:"account_data"`
+	Rooms        map[id.RoomID]*SyncRoom              `json:"rooms"`
 	LeftRooms    []id.RoomID                          `json:"left_rooms"`
+	InvitedRooms []*database.InvitedRoom              `json:"invited_rooms"`
 }
 
 func (c *SyncComplete) IsEmpty() bool {
-	return len(c.Rooms) == 0 && len(c.LeftRooms) == 0 && len(c.AccountData) == 0
+	return len(c.Rooms) == 0 && len(c.LeftRooms) == 0 && len(c.InvitedRooms) == 0 && len(c.AccountData) == 0
 }
 
 type SyncStatusType string

pkg/hicli/init.go

@@ -84,8 +84,18 @@ func (h *HiClient) GetInitialSync(ctx context.Context, batchSize int) iter.Seq[*
 				AccountData: make(map[event.Type]*database.AccountData),
 			}
 			if i == 0 {
+				payload.InvitedRooms, err = h.DB.InvitedRoom.GetAll(ctx)
+				if err != nil {
+					if ctx.Err() == nil {
+						zerolog.Ctx(ctx).Err(err).Msg("Failed to get invited rooms to send to client")
+					}
+					return
+				}
 				payload.ClearState = true
 			}
+			if payload.InvitedRooms == nil {
+				payload.InvitedRooms = make([]*database.InvitedRoom, 0)
+			}
 			for _, room := range rooms {
 				if room.SortingTimestamp == rooms[len(rooms)-1].SortingTimestamp {
 					break
@@ -107,7 +117,8 @@ func (h *HiClient) GetInitialSync(ctx context.Context, batchSize int) iter.Seq[*
 			return
 		}
 		payload := SyncComplete{
-			Rooms:       make(map[id.RoomID]*SyncRoom, 0),
+			Rooms:        make(map[id.RoomID]*SyncRoom),
+			InvitedRooms: make([]*database.InvitedRoom, 0),
 			LeftRooms:    make([]id.RoomID, 0),
 			AccountData:  make(map[event.Type]*database.AccountData, len(ad)),
 		}

pkg/hicli/json-commands.go

@@ -130,6 +130,21 @@ func (h *HiClient) handleJSONCommand(ctx context.Context, req *JSONCommand) (any
 		return unmarshalAndCall(req.Data, func(params *paginateParams) (*PaginationResponse, error) {
 			return h.PaginateServer(ctx, params.RoomID, params.Limit)
 		})
+	case "get_room_summary":
+		return unmarshalAndCall(req.Data, func(params *joinRoomParams) (*mautrix.RespRoomSummary, error) {
+			return h.Client.GetRoomSummary(ctx, params.RoomIDOrAlias, params.Via...)
+		})
+	case "join_room":
+		return unmarshalAndCall(req.Data, func(params *joinRoomParams) (*mautrix.RespJoinRoom, error) {
+			return h.Client.JoinRoom(ctx, params.RoomIDOrAlias, &mautrix.ReqJoinRoom{
+				Via:    params.Via,
+				Reason: params.Reason,
+			})
+		})
+	case "leave_room":
+		return unmarshalAndCall(req.Data, func(params *leaveRoomParams) (*mautrix.RespLeaveRoom, error) {
+			return h.Client.LeaveRoom(ctx, params.RoomID, &mautrix.ReqLeave{Reason: params.Reason})
+		})
 	case "ensure_group_session_shared":
 		return unmarshalAndCall(req.Data, func(params *ensureGroupSessionSharedParams) (bool, error) {
 			return true, h.EnsureGroupSessionShared(ctx, params.RoomID)
@@ -315,6 +330,17 @@ type paginateParams struct {
 	Limit         int                    `json:"limit"`
 }
 
+type joinRoomParams struct {
+	RoomIDOrAlias string   `json:"room_id_or_alias"`
+	Via           []string `json:"via"`
+	Reason        string   `json:"reason"`
+}
+
+type leaveRoomParams struct {
+	RoomID id.RoomID `json:"room_id"`
+	Reason string    `json:"reason"`
+}
+
 type getReceiptsParams struct {
 	RoomID   id.RoomID    `json:"room_id"`
 	EventIDs []id.EventID `json:"event_ids"`

pkg/hicli/paginate.go

@@ -165,6 +165,7 @@ func (h *HiClient) processGetRoomState(ctx context.Context, roomID id.RoomID, fe
 							Receipts:      make(map[id.EventID][]*database.Receipt),
 						},
 					},
+					InvitedRooms: make([]*database.InvitedRoom, 0),
 					AccountData:  make(map[event.Type]*database.AccountData),
 					LeftRooms:    make([]id.RoomID, 0),
 				})

pkg/hicli/sync.go

@@ -151,14 +151,20 @@ func (h *HiClient) processSyncResponse(ctx context.Context, resp *mautrix.RespSy
 		}
 	}
 	ctx.Value(syncContextKey).(*syncContext).evt.AccountData = accountData
+	for roomID, room := range resp.Rooms.Invite {
+		err = h.processSyncInvitedRoom(ctx, roomID, room)
+		if err != nil {
+			return fmt.Errorf("failed to process invited room %s: %w", roomID, err)
+		}
+	}
 	for roomID, room := range resp.Rooms.Join {
-		err := h.processSyncJoinedRoom(ctx, roomID, room)
+		err = h.processSyncJoinedRoom(ctx, roomID, room)
 		if err != nil {
 			return fmt.Errorf("failed to process joined room %s: %w", roomID, err)
 		}
 	}
 	for roomID, room := range resp.Rooms.Leave {
-		err := h.processSyncLeftRoom(ctx, roomID, room)
+		err = h.processSyncLeftRoom(ctx, roomID, room)
 		if err != nil {
 			return fmt.Errorf("failed to process left room %s: %w", roomID, err)
 		}
@@ -196,6 +202,27 @@ func (h *HiClient) receiptsToList(content *event.ReceiptEventContent) ([]*databa
 	return receiptList, newOwnReceipts
 }
 
+func (h *HiClient) processSyncInvitedRoom(ctx context.Context, roomID id.RoomID, room *mautrix.SyncInvitedRoom) error {
+	ir := &database.InvitedRoom{
+		ID:          roomID,
+		CreatedAt:   jsontime.UnixMilliNow(),
+		InviteState: room.State.Events,
+	}
+	for _, evt := range room.State.Events {
+		if evt.Type == event.StateMember && evt.GetStateKey() == h.Account.UserID.String() && evt.Timestamp != 0 {
+			ir.CreatedAt = jsontime.UM(time.UnixMilli(evt.Timestamp))
+			break
+		}
+	}
+	err := h.DB.InvitedRoom.Upsert(ctx, ir)
+	if err != nil {
+		return fmt.Errorf("failed to save invited room: %w", err)
+	}
+	syncEvt := ctx.Value(syncContextKey).(*syncContext).evt
+	syncEvt.InvitedRooms = append(syncEvt.InvitedRooms, ir)
+	return nil
+}
+
 func (h *HiClient) processSyncJoinedRoom(ctx context.Context, roomID id.RoomID, room *mautrix.SyncJoinedRoom) error {
 	existingRoomData, err := h.DB.Room.Get(ctx, roomID)
 	if err != nil {
@@ -265,6 +292,10 @@ func (h *HiClient) processSyncLeftRoom(ctx context.Context, roomID id.RoomID, ro
 	if err != nil {
 		return fmt.Errorf("failed to delete room: %w", err)
 	}
+	err = h.DB.InvitedRoom.Delete(ctx, roomID)
+	if err != nil {
+		return fmt.Errorf("failed to delete invited room: %w", err)
+	}
 	payload := ctx.Value(syncContextKey).(*syncContext).evt
 	payload.LeftRooms = append(payload.LeftRooms, roomID)
 	return nil

pkg/hicli/syncwrap.go

@@ -15,6 +15,8 @@ import (
 	"github.com/mattn/go-sqlite3"
 	"maunium.net/go/mautrix"
 	"maunium.net/go/mautrix/id"
+
+	"go.mau.fi/gomuks/pkg/hicli/database"
 )
 
 type hiSyncer HiClient
@@ -33,6 +35,7 @@ func (h *hiSyncer) ProcessResponse(ctx context.Context, resp *mautrix.RespSync,
 	ctx = context.WithValue(ctx, syncContextKey, &syncContext{evt: &SyncComplete{
 		Since:        &since,
 		Rooms:        make(map[id.RoomID]*SyncRoom, len(resp.Rooms.Join)),
+		InvitedRooms: make([]*database.InvitedRoom, 0, len(resp.Rooms.Invite)),
 		LeftRooms:    make([]id.RoomID, 0, len(resp.Rooms.Leave)),
 	}})
 	err := c.preProcessSyncResponse(ctx, resp, since)
@@ -73,23 +76,23 @@ func (h *hiSyncer) OnFailedSync(_ *mautrix.RespSync, err error) (time.Duration,
 func (h *hiSyncer) GetFilterJSON(_ id.UserID) *mautrix.Filter {
 	if !h.Verified {
 		return &mautrix.Filter{
-			Presence: mautrix.FilterPart{
+			Presence: &mautrix.FilterPart{
 				NotRooms: []id.RoomID{"*"},
 			},
-			Room: mautrix.RoomFilter{
+			Room: &mautrix.RoomFilter{
 				NotRooms: []id.RoomID{"*"},
 			},
 		}
 	}
 	return &mautrix.Filter{
-		Presence: mautrix.FilterPart{
+		Presence: &mautrix.FilterPart{
 			NotRooms: []id.RoomID{"*"},
 		},
-		Room: mautrix.RoomFilter{
+		Room: &mautrix.RoomFilter{
-			State: mautrix.FilterPart{
+			State: &mautrix.FilterPart{
 				LazyLoadMembers: true,
 			},
-			Timeline: mautrix.FilterPart{
+			Timeline: &mautrix.FilterPart{
 				Limit:           100,
 				LazyLoadMembers: true,
 			},

web/src/api/client.ts

@@ -104,6 +104,7 @@ export default class Client {
 	#handleEvent = (ev: RPCEvent) => {
 		if (ev.command === "client_state") {
 			this.state.emit(ev.data)
+			this.store.userID = ev.data.is_logged_in ? ev.data.user_id : ""
 		} else if (ev.command === "sync_status") {
 			this.syncStatus.emit(ev.data)
 		} else if (ev.command === "init_complete") {

web/src/api/media.ts

@@ -13,9 +13,8 @@
 //
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
-import type { RoomListEntry } from "@/api/statestore"
 import { parseMXC } from "@/util/validation.ts"
-import { ContentURI, DBRoom, UserID, UserProfile } from "./types"
+import { ContentURI, LazyLoadSummary, RoomID, UserID, UserProfile } from "./types"
 
 export const getMediaURL = (mxc?: string, encrypted: boolean = false): string | undefined => {
 	const [server, mediaID] = parseMXC(mxc)
@@ -90,7 +89,16 @@ export const getAvatarURL = (userID: UserID, content?: UserProfile | null): stri
 	return `_gomuks/media/${server}/${mediaID}?encrypted=false&fallback=${encodeURIComponent(fallback)}`
 }
 
-export const getRoomAvatarURL = (room: DBRoom | RoomListEntry, avatarOverride?: ContentURI): string | undefined => {
+interface RoomForAvatarURL {
+	room_id: RoomID
+	name?: string
+	dm_user_id?: UserID
+	lazy_load_summary?: LazyLoadSummary
+	avatar?: ContentURI
+	avatar_url?: ContentURI
+}
+
+export const getRoomAvatarURL = (room: RoomForAvatarURL, avatarOverride?: ContentURI): string | undefined => {
 	let dmUserID: UserID | undefined
 	if ("dm_user_id" in room) {
 		dmUserID = room.dm_user_id
@@ -98,5 +106,8 @@ export const getRoomAvatarURL = (room: DBRoom | RoomListEntry, avatarOverride?:
 		dmUserID = room.lazy_load_summary?.heroes?.length === 1
 			? room.lazy_load_summary.heroes[0] : undefined
 	}
-	return getAvatarURL(dmUserID ?? room.room_id, { displayname: room.name, avatar_url: avatarOverride ?? room.avatar })
+	return getAvatarURL(dmUserID ?? room.room_id, {
+		displayname: room.name,
+		avatar_url: avatarOverride ?? room.avatar ?? room.avatar_url,
+	})
 }

web/src/api/rpc.ts

@@ -32,9 +32,11 @@ import type {
 	ReceiptType,
 	RelatesTo,
 	ResolveAliasResponse,
+	RespRoomJoin,
 	RoomAlias,
 	RoomID,
 	RoomStateGUID,
+	RoomSummary,
 	TimelineRowID,
 	UserID,
 	UserProfile,
@@ -220,6 +222,18 @@ export default abstract class RPCClient {
 		return this.request("paginate_server", { room_id, limit })
 	}
 
+	getRoomSummary(room_id_or_alias: RoomID | RoomAlias, via?: string[]): Promise<RoomSummary> {
+		return this.request("get_room_summary", { room_id_or_alias, via })
+	}
+
+	joinRoom(room_id_or_alias: RoomID | RoomAlias, via?: string[], reason?: string): Promise<RespRoomJoin> {
+		return this.request("join_room", { room_id_or_alias, via, reason })
+	}
+
+	leaveRoom(room_id: RoomID, reason?: string): Promise<Record<string, never>> {
+		return this.request("leave_room", { room_id, reason })
+	}
+
 	resolveAlias(alias: RoomAlias): Promise<ResolveAliasResponse> {
 		return this.request("resolve_alias", { alias })
 	}

web/src/api/statestore/invitedroom.ts

@@ -0,0 +1,130 @@
+// gomuks - A Matrix client written in Go.
+// Copyright (C) 2024 Tulir Asokan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import toSearchableString from "@/util/searchablestring.ts"
+import { ensureString, getDisplayname } from "@/util/validation.ts"
+import type {
+	ContentURI,
+	DBInvitedRoom, JoinRule,
+	MemberEventContent, Membership,
+	RoomAlias,
+	RoomID,
+	RoomSummary,
+	RoomType,
+	RoomVersion,
+	StrippedStateEvent,
+	UserID,
+} from "../types"
+import type { RoomListEntry, StateStore } from "./main.ts"
+
+export class InvitedRoomStore implements RoomListEntry, RoomSummary {
+	readonly room_id: RoomID
+	readonly sorting_timestamp: number
+	readonly name: string = ""
+	readonly search_name: string
+	readonly dm_user_id?: UserID
+	readonly canonical_alias?: RoomAlias
+	readonly topic?: string
+	readonly avatar?: ContentURI
+	readonly encryption?: "m.megolm.v1.aes-sha2"
+	readonly room_version?: RoomVersion
+	readonly join_rules?: JoinRule
+	readonly invited_by?: UserID
+	readonly inviter_profile?: MemberEventContent
+
+	constructor(public readonly meta: DBInvitedRoom, parent: StateStore) {
+		this.room_id = meta.room_id
+		this.sorting_timestamp = 1000000000000000 + meta.created_at
+		const members = new Map<UserID, StrippedStateEvent>()
+		for (const state of this.meta.invite_state) {
+			if (state.type === "m.room.name") {
+				this.name = ensureString(state.content.name)
+			} else if (state.type === "m.room.canonical_alias") {
+				this.canonical_alias = ensureString(state.content.alias)
+			} else if (state.type === "m.room.topic") {
+				this.topic = ensureString(state.content.topic)
+			} else if (state.type === "m.room.avatar") {
+				this.avatar = ensureString(state.content.url)
+			} else if (state.type === "m.room.encryption" && state.content.algorithm === "m.megolm.v1.aes-sha2") {
+				this.encryption = state.content.algorithm
+			} else if (state.type === "m.room.create") {
+				this.room_version = ensureString(state.content.version) as RoomVersion
+			} else if (state.type === "m.room.member") {
+				members.set(state.state_key, state)
+			} else if (state.type === "m.room.join_rules") {
+				this.join_rules = ensureString(state.content.join_rule) as JoinRule
+			}
+		}
+		this.search_name = toSearchableString(this.name ?? "")
+		const ownMemberEvt = members.get(parent.userID)
+		if (ownMemberEvt) {
+			this.invited_by = ownMemberEvt.sender
+			this.inviter_profile = members.get(ownMemberEvt.sender)?.content as MemberEventContent
+		}
+		if (
+			!this.name
+			&& !this.avatar
+			&& !this.topic
+			&& !this.canonical_alias
+			&& this.join_rules === "invite"
+			&& this.invited_by
+			&& ownMemberEvt?.content.is_direct
+		) {
+			this.dm_user_id = this.invited_by
+			this.name = getDisplayname(this.invited_by, this.inviter_profile)
+			this.avatar = this.inviter_profile?.avatar_url
+		}
+	}
+
+	get membership(): Membership {
+		return "invite"
+	}
+
+	get avatar_url(): ContentURI | undefined {
+		return this.avatar
+	}
+
+	get num_joined_members(): number {
+		return 0
+	}
+
+	get room_type(): RoomType {
+		return ""
+	}
+
+	get world_readable(): boolean {
+		return false
+	}
+
+	get guest_can_join(): boolean {
+		return false
+	}
+
+	get unread_messages(): number {
+		return 0
+	}
+
+	get unread_notifications(): number {
+		return 0
+	}
+
+	get unread_highlights(): number {
+		return 1
+	}
+
+	get marked_unread(): boolean {
+		return true
+	}
+}

web/src/api/statestore/main.ts

@@ -37,6 +37,7 @@ import {
 	UserID,
 	roomStateGUIDToString,
 } from "../types"
+import { InvitedRoomStore } from "./invitedroom.ts"
 import { RoomStateStore } from "./room.ts"
 
 export interface RoomListEntry {
@@ -67,7 +68,9 @@ window.gcSettings ??= {
 }
 
 export class StateStore {
+	userID: UserID = ""
 	readonly rooms: Map<RoomID, RoomStateStore> = new Map()
+	readonly inviteRooms: Map<RoomID, InvitedRoomStore> = new Map()
 	readonly roomList = new NonNullCachedEventDispatcher<RoomListEntry[]>([])
 	currentRoomListFilter: string = ""
 	readonly accountData: Map<string, UnknownEventContent> = new Map()
@@ -83,6 +86,7 @@ export class StateStore {
 	serverPreferenceCache: Preferences = {}
 	switchRoom?: (roomID: RoomID | null) => void
 	activeRoomID: RoomID | null = null
+	activeRoomIsPreview: boolean = false
 	imageAuthToken?: string
 
 	getFilteredRoomList(): RoomListEntry[] {
@@ -161,12 +165,26 @@ export class StateStore {
 		}
 		const resyncRoomList = this.roomList.current.length === 0
 		const changedRoomListEntries = new Map<RoomID, RoomListEntry | null>()
+		for (const data of sync.invited_rooms) {
+			const room = new InvitedRoomStore(data, this)
+			this.inviteRooms.set(room.room_id, room)
+			if (!resyncRoomList) {
+				changedRoomListEntries.set(room.room_id, room)
+			}
+			if (this.activeRoomID === room.room_id) {
+				this.switchRoom?.(room.room_id)
+			}
+		}
+		const hasInvites = this.inviteRooms.size > 0
 		for (const [roomID, data] of Object.entries(sync.rooms)) {
 			let isNewRoom = false
 			let room = this.rooms.get(roomID)
 			if (!room) {
 				room = new RoomStateStore(data.meta, this)
 				this.rooms.set(roomID, room)
+				if (hasInvites) {
+					this.inviteRooms.delete(roomID)
+				}
 				isNewRoom = true
 			}
 			const roomListEntryChanged = !resyncRoomList && (isNewRoom || this.#roomListEntryChanged(data, room))
@@ -190,6 +208,9 @@ export class StateStore {
 					this.showNotification(room, notification.event_rowid, notification.sound)
 				}
 			}
+			if (this.activeRoomID === roomID && this.activeRoomIsPreview) {
+				this.switchRoom?.(roomID)
+			}
 		}
 		for (const ad of Object.values(sync.account_data)) {
 			if (ad.type === "io.element.recent_emoji") {
@@ -211,9 +232,10 @@ export class StateStore {
 
 		let updatedRoomList: RoomListEntry[] | undefined
 		if (resyncRoomList) {
-			updatedRoomList = Object.values(sync.rooms)
+			updatedRoomList = this.inviteRooms.values().toArray()
+			updatedRoomList = updatedRoomList.concat(Object.values(sync.rooms)
 				.map(entry => this.#makeRoomListEntry(entry))
-				.filter(entry => entry !== null)
+				.filter(entry => entry !== null))
 			updatedRoomList.sort((r1, r2) => r1.sorting_timestamp - r2.sorting_timestamp)
 		} else if (changedRoomListEntries.size > 0) {
 			updatedRoomList = this.roomList.current.filter(entry => !changedRoomListEntries.has(entry.room_id))
@@ -410,6 +432,7 @@ export class StateStore {
 
 	clear() {
 		this.rooms.clear()
+		this.inviteRooms.clear()
 		this.roomList.emit([])
 		this.accountData.clear()
 		this.currentRoomListFilter = ""

web/src/api/types/hievents.ts

@@ -15,6 +15,7 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 import {
 	DBAccountData,
+	DBInvitedRoom,
 	DBReceipt,
 	DBRoom,
 	DBRoomAccountData,
@@ -86,6 +87,7 @@ export interface SyncNotification {
 
 export interface SyncCompleteData {
 	rooms: Record<RoomID, SyncRoom>
+	invited_rooms: DBInvitedRoom[]
 	left_rooms: RoomID[]
 	account_data: Record<EventType, DBAccountData>
 	since?: string

web/src/api/types/hitypes.ts

@@ -74,6 +74,19 @@ export interface DBRoom {
 //eslint-disable-next-line @typescript-eslint/no-explicit-any
 export type UnknownEventContent = Record<string, any>
 
+export interface StrippedStateEvent {
+	type: EventType
+	sender: UserID
+	state_key: string
+	content: UnknownEventContent
+}
+
+export interface DBInvitedRoom {
+	room_id: RoomID
+	created_at: number
+	invite_state: StrippedStateEvent[]
+}
+
 export enum UnreadType {
 	None = 0b0000,
 	Normal = 0b0001,

web/src/api/types/mxtypes.ts

@@ -68,8 +68,10 @@ export interface UserProfile {
 	[custom: string]: unknown
 }
 
+export type Membership = "join" | "leave" | "ban" | "invite" | "knock"
+
 export interface MemberEventContent extends UserProfile {
-	membership: "join" | "leave" | "ban" | "invite" | "knock"
+	membership: Membership
 	reason?: string
 }
 
@@ -235,3 +237,30 @@ export interface ImagePackRooms {
 export interface ElementRecentEmoji {
 	recent_emoji: [string, number][]
 }
+
+export type JoinRule = "public" | "knock" | "restricted" | "knock_restricted" | "invite" | "private"
+
+export interface RoomSummary {
+	room_id: RoomID
+	membership?: Membership
+
+	room_version?: RoomVersion
+	"im.nheko.summary.room_version"?: RoomVersion
+	"im.nheko.summary.version"?: RoomVersion
+	encryption?: "m.megolm.v1.aes-sha2"
+	"im.nheko.summary.encryption"?: "m.megolm.v1.aes-sha2"
+
+	avatar_url?: ContentURI
+	canonical_alias?: RoomAlias
+	guest_can_join: boolean
+	join_rule?: JoinRule
+	name?: string
+	num_joined_members: number
+	room_type: RoomType
+	topic?: string
+	world_readable: boolean
+}
+
+export interface RespRoomJoin {
+	room_id: RoomID
+}

web/src/ui/MainScreen.tsx

@@ -19,7 +19,7 @@ import Client from "@/api/client.ts"
 import { RoomStateStore } from "@/api/statestore"
 import type { RoomID } from "@/api/types"
 import { useEventAsState } from "@/util/eventdispatcher.ts"
-import { parseMatrixURI } from "@/util/validation.ts"
+import { ensureString, ensureStringArray, parseMatrixURI } from "@/util/validation.ts"
 import ClientContext from "./ClientContext.ts"
 import MainScreenContext, { MainScreenContextFields } from "./MainScreenContext.ts"
 import StylePreferences from "./StylePreferences.tsx"
@@ -27,6 +27,7 @@ import Keybindings from "./keybindings.ts"
 import { ModalWrapper } from "./modal/Modal.tsx"
 import RightPanel, { RightPanelProps } from "./rightpanel/RightPanel.tsx"
 import RoomList from "./roomlist/RoomList.tsx"
+import RoomPreview, { RoomPreviewProps } from "./roomview/RoomPreview.tsx"
 import RoomView from "./roomview/RoomView.tsx"
 import { useResizeHandle } from "./util/useResizeHandle.tsx"
 import "./MainScreen.css"
@@ -50,7 +51,7 @@ class ContextFields implements MainScreenContextFields {
 
 	constructor(
 		private directSetRightPanel: (props: RightPanelProps | null) => void,
-		private directSetActiveRoom: (room: RoomStateStore | null) => void,
+		private directSetActiveRoom: (room: RoomStateStore | RoomPreviewProps | null) => void,
 		private client: Client,
 	) {
 		this.keybindings = new Keybindings(client.store, this)
@@ -94,16 +95,43 @@ class ContextFields implements MainScreenContextFields {
 		}
 	}
 
-	setActiveRoom = (roomID: RoomID | null, pushState = true) => {
+	setActiveRoom = (roomID: RoomID | null, previewMeta?: Partial<RoomPreviewProps>, pushState = true) => {
 		console.log("Switching to room", roomID)
-		const room = (roomID && this.client.store.rooms.get(roomID)) || null
+		if (roomID) {
+			const room = this.client.store.rooms.get(roomID)
+			if (room) {
+				this.#setActiveRoom(room, pushState)
+			} else {
+				this.#setPreviewRoom(roomID, pushState, previewMeta)
+			}
+		} else {
+			this.#closeActiveRoom(pushState)
+		}
+	}
+
+	#setPreviewRoom(roomID: RoomID, pushState: boolean, meta?: Partial<RoomPreviewProps>) {
+		const invite = this.client.store.inviteRooms.get(roomID)
+		this.#closeActiveRoom(false)
+		this.directSetActiveRoom({ roomID, ...(meta ?? {}), invite })
+		this.client.store.activeRoomID = roomID
+		this.client.store.activeRoomIsPreview = true
+		if (pushState) {
+			history.pushState({
+				room_id: roomID,
+				source_via: meta?.via,
+				source_alias: meta?.alias,
+			}, "")
+		}
+	}
+
+	#setActiveRoom(room: RoomStateStore, pushState: boolean) {
 		window.activeRoom = room
 		this.directSetActiveRoom(room)
 		this.directSetRightPanel(null)
 		this.rightPanelStack = []
-		this.client.store.activeRoomID = room?.roomID ?? null
+		this.client.store.activeRoomID = room.roomID
+		this.client.store.activeRoomIsPreview = false
 		this.keybindings.activeRoom = room
-		if (room) {
 		room.lastOpened = Date.now()
 		if (!room.stateLoaded) {
 			this.client.loadRoomState(room.roomID)
@@ -112,15 +140,28 @@ class ContextFields implements MainScreenContextFields {
 		document
 			.querySelector(`div.room-entry[data-room-id="${CSS.escape(room.roomID)}"]`)
 			?.scrollIntoView({ block: "nearest" })
-		}
 		if (pushState) {
-			history.pushState({ room_id: roomID }, "")
+			history.pushState({ room_id: room.roomID }, "")
 		}
-		let roomNameForTitle = room?.meta.current.name
+		let roomNameForTitle = room.meta.current.name
 		if (roomNameForTitle && roomNameForTitle.length > 48) {
 			roomNameForTitle = roomNameForTitle.slice(0, 45) + "…"
 		}
-		document.title = roomNameForTitle ? `${roomNameForTitle} - gomuks web` : "gomuks web"
+		document.title = `${roomNameForTitle} - gomuks web`
+	}
+
+	#closeActiveRoom(pushState: boolean) {
+		window.activeRoom = null
+		this.directSetActiveRoom(null)
+		this.directSetRightPanel(null)
+		this.rightPanelStack = []
+		this.client.store.activeRoomID = null
+		this.client.store.activeRoomIsPreview = false
+		this.keybindings.activeRoom = null
+		if (pushState) {
+			history.pushState({}, "")
+		}
+		document.title = "gomuks web"
 	}
 
 	clickRoom = (evt: React.MouseEvent) => {
@@ -192,14 +233,18 @@ const handleURLHash = (client: Client) => {
 		history.replaceState(newState, "", newURL.toString())
 		return newState
 	} else if (uri.identifier.startsWith("!")) {
-		const newState = { room_id: uri.identifier }
+		const newState = { room_id: uri.identifier, source_via: uri.params.getAll("via") }
 		history.replaceState(newState, "", newURL.toString())
 		return newState
 	} else if (uri.identifier.startsWith("#")) {
+		history.replaceState(history.state, "", newURL.toString())
 		// TODO loading indicator or something for this?
 		client.rpc.resolveAlias(uri.identifier).then(
 			res => {
-				history.pushState({ room_id: res.room_id }, "", newURL.toString())
+				window.mainScreenContext.setActiveRoom(res.room_id, {
+					alias: uri.identifier,
+					via: res.servers.slice(0, 3),
+				})
 			},
 			err => window.alert(`Failed to resolve room alias ${uri.identifier}: ${err}`),
 		)
@@ -210,9 +255,12 @@ const handleURLHash = (client: Client) => {
 	return history.state
 }
 
-type ActiveRoomType = [RoomStateStore | null, RoomStateStore | null]
+type ActiveRoomType = [RoomStateStore | RoomPreviewProps | null, RoomStateStore | RoomPreviewProps | null]
 
-const activeRoomReducer = (prev: ActiveRoomType, active: RoomStateStore | "clear-animation" | null): ActiveRoomType => {
+const activeRoomReducer = (
+	prev: ActiveRoomType,
+	active: RoomStateStore | RoomPreviewProps | "clear-animation" | null,
+): ActiveRoomType => {
 	if (active === "clear-animation") {
 		return prev[1] === null ? [null, null] : prev
 	} else if (window.innerWidth > 720 || window.matchMedia("(prefers-reduced-motion: reduce)").matches) {
@@ -240,7 +288,10 @@ const MainScreen = () => {
 			skipNextTransitionRef.current = evt.hasUAVisualTransition
 			const roomID = evt.state?.room_id ?? null
 			if (roomID !== client.store.activeRoomID) {
-				context.setActiveRoom(roomID, false)
+				context.setActiveRoom(roomID, {
+					alias: ensureString(evt?.state.source_alias) || undefined,
+					via: ensureStringArray(evt?.state.source_via),
+				}, false)
 			}
 			context.setRightPanel(evt.state?.right_panel ?? null, false)
 		}
@@ -303,6 +354,7 @@ const MainScreen = () => {
 			Sync failed permanently
 		</div>
 	}
+	const activeRealRoom = activeRoom instanceof RoomStateStore ? activeRoom : null
 	const renderedRoom = activeRoom ?? prevActiveRoom
 	useEffect(() => {
 		if (prevActiveRoom !== null && activeRoom === null) {
@@ -313,17 +365,19 @@ const MainScreen = () => {
 	}, [activeRoom, prevActiveRoom])
 	return <MainScreenContext value={context}>
 		<ModalWrapper>
-			<StylePreferences client={client} activeRoom={activeRoom}/>
+			<StylePreferences client={client} activeRoom={activeRealRoom}/>
 			<main className={classNames.join(" ")} style={extraStyle}>
 				<RoomList activeRoomID={activeRoom?.roomID ?? null}/>
 				{resizeHandle1}
 				{renderedRoom
+					? renderedRoom instanceof RoomStateStore
 						? <RoomView
 							key={renderedRoom.roomID}
 							room={renderedRoom}
 							rightPanel={rightPanel}
 							rightPanelResizeHandle={resizeHandle2}
 						/>
+						: <RoomPreview {...renderedRoom} />
 					: rightPanel && <>
 						<div className="room-view placeholder"/>
 						{resizeHandle2}

web/src/ui/MainScreenContext.ts

@@ -16,9 +16,10 @@
 import { createContext } from "react"
 import type { RoomID } from "@/api/types"
 import type { RightPanelProps } from "./rightpanel/RightPanel.tsx"
+import type { RoomPreviewProps } from "./roomview/RoomPreview.tsx"
 
 export interface MainScreenContextFields {
-	setActiveRoom: (roomID: RoomID | null) => void
+	setActiveRoom: (roomID: RoomID | null, previewMeta?: Partial<RoomPreviewProps>) => void
 	clickRoom: (evt: React.MouseEvent) => void
 	clearActiveRoom: () => void
 

web/src/ui/roomview/RoomPreview.css

@@ -0,0 +1,70 @@
+
+div.room-view.preview > div.preview-inner {
+	width: 100%;
+	max-height: 100%;
+	height: auto;
+	max-width: 30rem;
+
+	display: flex;
+	flex-direction: column;
+	align-items: center;
+	gap: .5rem;
+
+	> img.avatar {
+		width: 7.5rem;
+		height: 7.5rem;
+		border: 1px solid var(--border-color);
+	}
+
+	> h2.room-name {
+		margin: 0;
+	}
+
+	> div.mutual-rooms {
+		width: 100%;
+		max-height: 20rem;
+		overflow: auto;
+
+		> h4 {
+			margin: .5rem 0 0;
+		}
+	}
+
+	> div.error, > div.member-count, > div.inviter-info {
+		display: flex;
+		align-items: center;
+		gap: .25rem;
+	}
+
+	> div.room-topic {
+		white-space: pre-wrap;
+		max-height: 15rem;
+		overflow: auto;
+
+		@media screen and (max-height: 50rem) {
+			max-height: 7.5rem;
+		}
+	}
+
+	> div.error > svg {
+		flex-shrink: 0;
+		width: 1.5rem;
+		height: 1.5rem;
+	}
+
+	> div.buttons {
+		width: 100%;
+		display: flex;
+		gap: .25rem;
+
+		> button {
+			padding: .5rem;
+			width: 100%;
+
+			&.reject {
+				border: 2px solid var(--error-color);
+				padding: .25rem .5rem;
+			}
+		}
+	}
+}

web/src/ui/roomview/RoomPreview.tsx

@@ -0,0 +1,129 @@
+// gomuks - A Matrix client written in Go.
+// Copyright (C) 2024 Tulir Asokan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import { use, useCallback, useEffect, useState } from "react"
+import { ScaleLoader } from "react-spinners"
+import { getAvatarURL, getRoomAvatarURL } from "@/api/media.ts"
+import { InvitedRoomStore } from "@/api/statestore/invitedroom.ts"
+import { RoomID, RoomSummary } from "@/api/types"
+import { getDisplayname, getServerName } from "@/util/validation.ts"
+import ClientContext from "../ClientContext.ts"
+import MainScreenContext from "../MainScreenContext.ts"
+import { LightboxContext } from "../modal/Lightbox.tsx"
+import MutualRooms from "../rightpanel/UserInfoMutualRooms.tsx"
+import ErrorIcon from "@/icons/error.svg?react"
+import GroupIcon from "@/icons/group.svg?react"
+import "./RoomPreview.css"
+
+export interface RoomPreviewProps {
+	roomID: RoomID
+	via?: string[]
+	alias?: string
+	invite?: InvitedRoomStore
+}
+
+const RoomPreview = ({ roomID, via, alias, invite }: RoomPreviewProps) => {
+	const client = use(ClientContext)!
+	const mainScreen = use(MainScreenContext)
+	const [summary, setSummary] = useState<RoomSummary | null>(null)
+	const [loading, setLoading] = useState(false)
+	const [buttonClicked, setButtonClicked] = useState(false)
+	const [error, setError] = useState<string | null>(null)
+	const doJoinRoom = useCallback(() => {
+		let realVia = via
+		if (!via?.length && invite?.invited_by) {
+			realVia = [getServerName(invite.invited_by)]
+		}
+		setButtonClicked(true)
+		client.rpc.joinRoom(alias || roomID, alias ? undefined : realVia).then(
+			() => console.info("Successfully joined", roomID),
+			err => {
+				setError(`Failed to join room: ${err}`)
+				setButtonClicked(false)
+			},
+		)
+	}, [client, roomID, via, alias, invite])
+	const doRejectInvite = useCallback(() => {
+		setButtonClicked(true)
+		client.rpc.leaveRoom(roomID).then(
+			() => {
+				console.info("Successfully rejected invite to", roomID)
+				mainScreen.clearActiveRoom()
+			},
+			err => {
+				setError(`Failed to reject invite: ${err}`)
+				setButtonClicked(false)
+			},
+		)
+	}, [client, mainScreen, roomID])
+	useEffect(() => {
+		setSummary(null)
+		setError(null)
+		setLoading(true)
+		let realVia = via
+		if (!via?.length && invite?.invited_by) {
+			realVia = [getServerName(invite.invited_by)]
+		}
+		client.rpc.getRoomSummary(alias || roomID, realVia).then(
+			setSummary,
+			err => !invite && setError(`Failed to load room info: ${err}`),
+		).finally(() => setLoading(false))
+	}, [client, roomID, via, alias, invite])
+	const name = summary?.name ?? summary?.canonical_alias ?? invite?.name ?? invite?.canonical_alias ?? alias ?? roomID
+	const memberCount = summary?.num_joined_members || null
+	const topic = summary?.topic ?? invite?.topic ?? ""
+	return <div className="room-view preview">
+		<div className="preview-inner">
+			{invite?.invited_by && !invite.dm_user_id ? <div className="inviter-info">
+				<img
+					className="small avatar"
+					onClick={use(LightboxContext)}
+					src={getAvatarURL(invite.invited_by, invite.inviter_profile)}
+					alt=""
+				/>
+				{getDisplayname(invite.invited_by, invite.inviter_profile)} invited you to
+			</div> : null}
+			<h2 className="room-name">{name}</h2>
+			<img
+				src={getRoomAvatarURL(invite ?? summary ?? { room_id: roomID })}
+				className="large avatar"
+				onClick={use(LightboxContext)}
+				alt=""
+			/>
+			{loading && <ScaleLoader color="var(--primary-color)"/>}
+			{memberCount && <div className="member-count"><GroupIcon/> {memberCount} members</div>}
+			<div className="room-topic">{topic}</div>
+			{invite?.invited_by && <MutualRooms client={client} userID={invite.invited_by} />}
+			<div className="buttons">
+				{invite && <button
+					disabled={buttonClicked}
+					className="reject"
+					onClick={doRejectInvite}
+				>Reject</button>}
+				<button
+					disabled={buttonClicked}
+					className="primary-color-button"
+					onClick={doJoinRoom}
+				>{invite ? "Accept" : "Join room"}</button>
+			</div>
+			{error && <div className="error">
+				<ErrorIcon color="var(--error-color)"/>
+				{error}
+			</div>}
+		</div>
+	</div>
+}
+
+export default RoomPreview

web/src/ui/roomview/RoomView.css

@@ -12,4 +12,10 @@ div.room-view {
 		"typing" auto
 		/ 1fr;
 	contain: strict;
+
+	&.preview {
+		display: flex;
+		justify-content: center;
+		align-items: center;
+	}
 }

web/src/ui/timeline/TimelineEvent.tsx

@@ -27,9 +27,9 @@ import ReadReceipts from "./ReadReceipts.tsx"
 import { ReplyIDBody } from "./ReplyBody.tsx"
 import { ContentErrorBoundary, HiddenEvent, getBodyType, isSmallEvent } from "./content"
 import { EventFullMenu, EventHoverMenu, getModalStyleFromMouse } from "./menu"
-import ErrorIcon from "../../icons/error.svg?react"
+import ErrorIcon from "@/icons/error.svg?react"
-import PendingIcon from "../../icons/pending.svg?react"
+import PendingIcon from "@/icons/pending.svg?react"
-import SentIcon from "../../icons/sent.svg?react"
+import SentIcon from "@/icons/sent.svg?react"
 import "./TimelineEvent.css"
 
 export interface TimelineEventProps {

web/src/ui/timeline/content/TextMessageBody.tsx

@@ -34,10 +34,15 @@ function onClickMatrixURI(href: string) {
 			userID: uri.identifier,
 		})
 	case "!":
-		return window.mainScreenContext.setActiveRoom(uri.identifier)
+		return window.mainScreenContext.setActiveRoom(uri.identifier, {
+			via: uri.params.getAll("via"),
+		})
 	case "#":
 		return window.client.rpc.resolveAlias(uri.identifier).then(
-			res => window.mainScreenContext.setActiveRoom(res.room_id),
+			res => window.mainScreenContext.setActiveRoom(res.room_id, {
+				alias: uri.identifier,
+				via: res.servers.slice(0, 3),
+			}),
 			err => window.alert(`Failed to resolve room alias ${uri.identifier}: ${err}`),
 		)
 	}

web/src/util/validation.ts

@@ -82,6 +82,11 @@ export function getLocalpart(userID: UserID): string {
 	return idx > 0 ? userID.slice(1, idx) : userID.slice(1)
 }
 
+export function getServerName(userID: UserID): string {
+	const idx = userID.indexOf(":")
+	return userID.slice(idx+1)
+}
+
 export function getDisplayname(userID: UserID, profile?: UserProfile | null): string {
 	return profile?.displayname || getLocalpart(userID)
 }
@@ -108,6 +113,10 @@ export function ensureArray(val: unknown): unknown[] {
 	return Array.isArray(val) ? val : []
 }
 
-export function ensureStringArray(val: unknown): string[] {
+export function isString(val: unknown): val is string {
-	return ensureArray(val).map(ensureString)
+	return typeof val === "string"
+}
+
+export function ensureStringArray(val: unknown): string[] {
+	return ensureArray(val).filter(isString)
 }