support setting kickDetails in room summary

src/matrix/room/RoomSummary.js

@@ -28,13 +28,15 @@ function applyTimelineEntries(data, timelineEntries, isInitialSync, canMarkUnrea
 }
 
 
-function applySyncResponse(data, roomResponse, membership) {
+function applySyncResponse(data, roomResponse, membership, ownUserId) {
     if (roomResponse.summary) {
         data = updateSummary(data, roomResponse.summary);
     }
+    let needKickDetails = false;
     if (membership !== data.membership) {
         data = data.cloneIfNeeded();
         data.membership = membership;
+        needKickDetails = membership === "leave" || membership === "ban";
     }
     if (roomResponse.account_data) {
         data = roomResponse.account_data.events.reduce(processRoomAccountData, data);
@@ -42,7 +44,12 @@ function applySyncResponse(data, roomResponse, membership) {
     const stateEvents = roomResponse?.state?.events;
     // state comes before timeline
     if (Array.isArray(stateEvents)) {
-        data = stateEvents.reduce(processStateEvent, data);
+        data = stateEvents.reduce((data, event) => {
+            if (needKickDetails) {
+                data = findKickDetails(data, event, ownUserId);
+            }
+            return processStateEvent(data, event, ownUserId, needKickDetails);
+        }, data);
     }
     const timelineEvents = roomResponse?.timeline?.events;
     // process state events in timeline
@@ -51,6 +58,9 @@ function applySyncResponse(data, roomResponse, membership) {
     if (Array.isArray(timelineEvents)) {
         data = timelineEvents.reduce((data, event) => {
             if (typeof event.state_key === "string") {
+                if (needKickDetails) {
+                    data = findKickDetails(data, event, ownUserId);
+                }
                 return processStateEvent(data, event);
             }
             return data;
@@ -112,6 +122,22 @@ export function processStateEvent(data, event) {
     return data;
 }
 
+function findKickDetails(data, event, ownUserId) {
+    if (event.type === "m.room.member") {
+        // did we get kicked?
+        if (event.state_key === ownUserId && event.sender !== event.state_key) {
+            data = data.cloneIfNeeded();
+            data.kickDetails = {
+                // this is different from the room membership in the sync section, which can only be leave
+                membership: event.content?.membership, // could be leave or ban
+                reason: event.content?.reason,
+                sender: event.sender,
+            }
+        }
+    }
+    return data;
+}
+
 function processTimelineEvent(data, eventEntry, isInitialSync, canMarkUnread, ownUserId) {
     if (eventEntry.eventType === "m.room.message") {
         if (!data.lastMessageTimestamp || eventEntry.timestamp > data.lastMessageTimestamp) {
@@ -180,6 +206,7 @@ export class SummaryData {
         this.tags = copy ? copy.tags : null;
         this.isDirectMessage = copy ? copy.isDirectMessage : false;
         this.dmUserId = copy ? copy.dmUserId : null;
+        this.kickDetails = copy ? copy.kickDetails : null;
         this.cloned = copy ? true : false;
     }
 
@@ -217,8 +244,8 @@ export class SummaryData {
         return applyTimelineEntries(this, timelineEntries, isInitialSync, canMarkUnread, ownUserId);
     }
 
-    applySyncResponse(roomResponse, membership) {
+    applySyncResponse(roomResponse, membership, ownUserId) {
-        return applySyncResponse(this, roomResponse, membership);
+        return applySyncResponse(this, roomResponse, membership, ownUserId);
     }
 
     applyInvite(invite) {
@@ -301,6 +328,17 @@ export class RoomSummary {
 }
 
 export function tests() {
+    function createMemberEvent(sender, target, membership, reason) {
+        return {
+            sender,
+            state_key: target,
+            type: "m.room.member",
+            content: { reason, membership }
+        };
+    }
+    const bob = "@bob:hs.tld";
+    const alice = "@alice:hs.tld";
+
     return {
         "serialize doesn't include null fields or cloned": assert => {
             const roomId = "!123:hs.tld";
@@ -312,6 +350,37 @@ export function tests() {
             const nullCount = Object.values(serialized).reduce((count, value) => count + value === null ? 1 : 0, 0);
             assert.strictEqual(nullCount, 0);
         },
+        "ban/kick sets kickDetails from state event": assert => {
+            const reason = "Bye!";
+            const leaveEvent = createMemberEvent(alice, bob, "ban", reason);
+            const data = new SummaryData(null, "!123:hs.tld");
+            const newData = data.applySyncResponse({state: {events: [leaveEvent]}}, "leave", bob);
+            assert.equal(newData.membership, "leave");
+            assert.equal(newData.kickDetails.membership, "ban");
+            assert.equal(newData.kickDetails.reason, reason);
+            assert.equal(newData.kickDetails.sender, alice);
+        },
+        "ban/kick sets kickDetails from timeline state event, taking precedence over state": assert => {
+            const reason = "Bye!";
+            const inviteEvent = createMemberEvent(alice, bob, "invite");
+            const leaveEvent = createMemberEvent(alice, bob, "ban", reason);
+            const data = new SummaryData(null, "!123:hs.tld");
+            const newData = data.applySyncResponse({
+                state: { events: [inviteEvent] },
+                timeline: {events: [leaveEvent] }
+            }, "leave", bob);
+            assert.equal(newData.membership, "leave");
+            assert.equal(newData.kickDetails.membership, "ban");
+            assert.equal(newData.kickDetails.reason, reason);
+            assert.equal(newData.kickDetails.sender, alice);
+        },
+        "leaving without being kicked doesn't produce kickDetails": assert => {
+            const leaveEvent = createMemberEvent(bob, bob, "leave");
+            const data = new SummaryData(null, "!123:hs.tld");
+            const newData = data.applySyncResponse({state: {events: [leaveEvent]}}, "leave", bob);
+            assert.equal(newData.membership, "leave");
+            assert.equal(newData.kickDetails, null);
+        },
         "membership trigger change": function(assert) {
             const summary = new RoomSummary("id");
             let written = false;