Simplify history visibility settings

src/components/views/settings/tabs/room/SecurityRoomSettingsTab.tsx

@@ -414,36 +414,58 @@ export default class SecurityRoomSettingsTab extends React.Component<IProps, ISt
         const state = this.props.room.currentState;
         const canChangeHistory = state?.mayClientSendStateEvent(EventType.RoomHistoryVisibility, client);
 
-        const options = [
-            {
-                value: HistoryVisibility.Shared,
-                label: _t("room_settings|security|history_visibility_shared"),
-            },
-            {
+        // Map 'joined' to 'invited' for display purposes
+        const displayHistory = history === HistoryVisibility.Joined ? HistoryVisibility.Invited : history;
+
+        const isPublicRoom = this.props.room.getJoinRule() === JoinRule.Public;
+        const isEncrypted = this.state.encrypted;
+
+        const options: Array<{ value: HistoryVisibility; label: string }> = [];
+
+        // Show "invited" when room's join rule is NOT public OR E2EE is turned on, or if currently selected
+        if (
+            !isPublicRoom ||
+            isEncrypted ||
+            history === HistoryVisibility.Invited ||
+            history === HistoryVisibility.Joined
+        ) {
+            options.push({
                 value: HistoryVisibility.Invited,
                 label: _t("room_settings|security|history_visibility_invited"),
-            },
-            {
-                value: HistoryVisibility.Joined,
-                label: _t("room_settings|security|history_visibility_joined"),
-            },
-        ];
+            });
+        }
 
-        // World readable doesn't make sense for encrypted rooms
-        if (!this.state.encrypted || history === HistoryVisibility.WorldReadable) {
-            options.unshift({
+        // Always show "shared" option
+        options.push({
+            value: HistoryVisibility.Shared,
+            label: _t("room_settings|security|history_visibility_shared"),
+        });
+
+        // Show "world_readable" when (is public AND not encrypted) OR currently selected
+        if ((isPublicRoom && !isEncrypted) || history === HistoryVisibility.WorldReadable) {
+            options.push({
                 value: HistoryVisibility.WorldReadable,
                 label: _t("room_settings|security|history_visibility_world_readable"),
             });
         }
 
-        const description = _t("room_settings|security|history_visibility_warning");
+        const description = (
+            <>
+                {_t(
+                    "room_settings|security|history_visibility_warning",
+                    {},
+                    {
+                        a: (sub) => <ExternalLink href="https://element.io/help#encryption20">{sub}</ExternalLink>,
+                    },
+                )}
+            </>
+        );
 
         return (
             <SettingsFieldset legend={_t("room_settings|security|history_visibility_legend")} description={description}>
                 <StyledRadioGroup
                     name="historyVis"
-                    value={history}
+                    value={displayHistory}
                     onChange={this.onHistoryRadioToggle}
                     disabled={!canChangeHistory}
                     definitions={options}

test/unit-tests/components/views/settings/tabs/room/SecurityRoomSettingsTab-test.tsx

@@ -313,7 +313,7 @@
 
             getComponent(room);
 
             expect(screen.getByText("Who can read history?").parentElement).toMatchSnapshot();
             expect(screen.getByDisplayValue(HistoryVisibility.Shared)).toBeChecked();
         });
 
@@ -377,6 +377,76 @@
             expect(screen.getByDisplayValue(HistoryVisibility.Shared)).toBeChecked();
             expect(logger.error).toHaveBeenCalledWith("oups");
         });
+
+        it("maps 'joined' history visibility to 'invited' for display", () => {
+            const room = new Room(roomId, client, userId);
+            setRoomStateEvents(room, undefined, undefined, HistoryVisibility.Joined);
+
+            getComponent(room);
+
+            // Should display as 'invited' even though underlying value is 'joined'
+            expect(screen.getByDisplayValue(HistoryVisibility.Invited)).toBeChecked();
+            // Should not have a 'joined' option visible
+            expect(screen.queryByDisplayValue(HistoryVisibility.Joined)).not.toBeInTheDocument();
+        });
+
+        it("shows 'invited' option for non-public rooms", () => {
+            const room = new Room(roomId, client, userId);
+            setRoomStateEvents(room, JoinRule.Invite);
+
+            getComponent(room);
+
+            expect(screen.getByDisplayValue(HistoryVisibility.Invited)).toBeInTheDocument();
+        });
+
+        it("shows 'invited' option for encrypted rooms even if public", async () => {
+            const room = new Room(roomId, client, userId);
+            jest.spyOn(client.getCrypto()!, "isEncryptionEnabledInRoom").mockResolvedValue(true);
+            setRoomStateEvents(room, JoinRule.Public);
+
+            getComponent(room);
+
+            await waitFor(() => expect(screen.getByDisplayValue(HistoryVisibility.Invited)).toBeInTheDocument());
+        });
+
+        it("does not show 'invited' option for public unencrypted rooms unless selected", async () => {
+            const room = new Room(roomId, client, userId);
+            setRoomStateEvents(room, JoinRule.Public, undefined, HistoryVisibility.Shared);
+
+            getComponent(room);
+
+            await waitFor(() => expect(screen.queryByDisplayValue(HistoryVisibility.Invited)).not.toBeInTheDocument());
+        });
+
+        it("shows 'world_readable' option for public unencrypted rooms", async () => {
+            const room = new Room(roomId, client, userId);
+            setRoomStateEvents(room, JoinRule.Public);
+
+            getComponent(room);
+
+            await waitFor(() => expect(screen.getByDisplayValue(HistoryVisibility.WorldReadable)).toBeInTheDocument());
+        });
+
+        it("does not show 'world_readable' option for private encrypted rooms unless selected", async () => {
+            const room = new Room(roomId, client, userId);
+            jest.spyOn(client.getCrypto()!, "isEncryptionEnabledInRoom").mockResolvedValue(true);
+            setRoomStateEvents(room, JoinRule.Invite);
+
+            getComponent(room);
+
+            await waitFor(() =>
+                expect(screen.queryByDisplayValue(HistoryVisibility.WorldReadable)).not.toBeInTheDocument(),
+            );
+        });
+
+        it("always shows 'shared' option", () => {
+            const room = new Room(roomId, client, userId);
+            setRoomStateEvents(room);
+
+            getComponent(room);
+
+            expect(screen.getByDisplayValue(HistoryVisibility.Shared)).toBeInTheDocument();
+        });
     });
 
     describe("encryption", () => {

test/unit-tests/components/views/settings/tabs/room/__snapshots__/SecurityRoomSettingsTab-test.tsx.snap

@@ -15,7 +15,20 @@ exports[`<SecurityRoomSettingsTab /> history visibility uses shared as default h
     <div
       class="mx_SettingsSubsection_text"
     >
-      The visibility of existing history will not be changed.
+      <span>
+        Changes won't affect past messages, only new ones. 
+        <a
+          class="mx_ExternalLink"
+          href="https://element.io/help#encryption20"
+          rel="noreferrer noopener"
+          target="_blank"
+        >
+          Learn more
+          <i
+            class="mx_ExternalLink_icon"
+          />
+        </a>
+      </span>
     </div>
   </div>
   <div
@@ -25,18 +38,18 @@ exports[`<SecurityRoomSettingsTab /> history visibility uses shared as default h
       class="mx_StyledRadioButton mx_StyledRadioButton_enabled"
     >
       <input
-        id="historyVis-world_readable"
+        id="historyVis-invited"
         name="historyVis"
         type="radio"
-        value="world_readable"
+        value="invited"
       />
       <div>
         <div />
       </div>
       <div
         class="mx_StyledRadioButton_content"
       >
-        Anyone
+        Members since invited
       </div>
       <div
         class="mx_StyledRadioButton_spacer"
@@ -58,49 +71,7 @@ exports[`<SecurityRoomSettingsTab /> history visibility uses shared as default h
       <div
         class="mx_StyledRadioButton_content"
       >
-        Members only (since the point in time of selecting this option)
-      </div>
-      <div
-        class="mx_StyledRadioButton_spacer"
-      />
-    </label>
-    <label
-      class="mx_StyledRadioButton mx_StyledRadioButton_enabled"
-    >
-      <input
-        id="historyVis-invited"
-        name="historyVis"
-        type="radio"
-        value="invited"
-      />
-      <div>
-        <div />
-      </div>
-      <div
-        class="mx_StyledRadioButton_content"
-      >
-        Members only (since they were invited)
-      </div>
-      <div
-        class="mx_StyledRadioButton_spacer"
-      />
-    </label>
-    <label
-      class="mx_StyledRadioButton mx_StyledRadioButton_enabled"
-    >
-      <input
-        id="historyVis-joined"
-        name="historyVis"
-        type="radio"
-        value="joined"
-      />
-      <div>
-        <div />
-      </div>
-      <div
-        class="mx_StyledRadioButton_content"
-      >
-        Members only (since they joined)
+        Members (full history)
       </div>
       <div
         class="mx_StyledRadioButton_spacer"