Don't unnecessarily fetch lines for notification

When a notification is received for the current buffer and we're still
connected (but in the background), new lines will already have loaded
when the app resumes However, the lines may not have rendered yet, so
they cannot be scrolled to reliably.

Work around this by changing the FlatList key, resetting its internal
measurement state. Subsequent scroll will then either make it to the
target or cycle trigger onScrollToIndexFailed.

__tests__/usecase/App.tsx

@@ -5,10 +5,7 @@ import { act, render } from '../../src/test-utils';
 import { configureStore } from '@reduxjs/toolkit';
 import { reducer } from '../../src/store';
 import { AppState } from '../../src/store/app';
-import {
-  bufferNotificationAction,
-  changeCurrentBufferAction
-} from '../../src/store/actions';
+import { bufferNotificationAction } from '../../src/store/actions';
 
 jest.mock('react-native-drawer-layout');
 
@@ -68,59 +65,5 @@ describe('App', () => {
       expect(clearHotlistForBuffer).toHaveBeenCalledWith(null);
       expect(fetchBufferInfo).toHaveBeenCalledWith(bufferId);
     });
-
-    it('fetches buffer info if the notification is for the current buffer', () => {
-      const bufferId = '86c417600';
-      const store = configureStore({
-        reducer,
-        preloadedState: {
-          buffers: {
-            [bufferId]: {
-              full_name: 'irc.libera.#weechat',
-              hidden: 0,
-              id: bufferId,
-              local_variables: {
-                channel: '#weechat',
-                name: 'libera.#weechat',
-                plugin: 'irc',
-                type: 'channel'
-              },
-              notify: 3,
-              number: 2,
-              pointers: [bufferId],
-              short_name: '#weechat',
-              title: '',
-              type: 0
-            }
-          }
-        }
-      });
-      const fetchBufferInfo = jest.fn();
-      const clearHotlistForBuffer = jest.fn();
-
-      render(
-        <App
-          disconnect={() => {}}
-          fetchBufferInfo={fetchBufferInfo}
-          sendMessageToBuffer={() => {}}
-          clearHotlistForBuffer={clearHotlistForBuffer}
-        />,
-        { store }
-      );
-
-      act(() => {
-        store.dispatch(changeCurrentBufferAction(bufferId));
-        store.dispatch(
-          bufferNotificationAction({
-            bufferId,
-            lineId: '8580dcc40',
-            identifier: '1fb4fc1d-530b-466f-85be-de27772de0a9'
-          })
-        );
-      });
-
-      expect(fetchBufferInfo).toHaveBeenCalledWith(bufferId);
-      expect(clearHotlistForBuffer).not.toHaveBeenCalled();
-    });
   });
 });

__tests__/usecase/buffers/ui/Buffer.tsx

@@ -54,6 +54,7 @@ describe(Buffer, () => {
           parseArgs={[]}
           bufferId={''}
           fetchMoreLines={() => {}}
+          clearNotification={() => {}}
         />
       );
 

__tests__/usecase/buffers/ui/BufferContainer.tsx

@@ -1,19 +1,23 @@
 import 'react-native';
+import Buffer from '../../../../src/usecase/buffers/ui/Buffer';
 import BufferContainer from '../../../../src/usecase/buffers/ui/BufferContainer';
-import { act, render } from '../../../../src/test-utils';
+import { act, render, screen } from '../../../../src/test-utils';
 import { reducer } from '../../../../src/store';
 import { configureStore } from '@reduxjs/toolkit';
 import {
   bufferNotificationAction,
   changeCurrentBufferAction,
   fetchLinesAction
 } from '../../../../src/store/actions';
-import Buffer from '../../../../src/usecase/buffers/ui/Buffer';
 
-jest.mock('.../../../../src/usecase/buffers/ui/Buffer');
+jest.mock('../../../../src/usecase/buffers/ui/Buffer');
 
 describe('BufferContainer', () => {
-  it('scrolls to line and clears notification after fetching lines', () => {
+  beforeEach(() => {
+    jest.mocked(Buffer).mockImplementation();
+  });
+
+  it('defers notification until buffer change and line fetch', () => {
     const bufferId = '86c417600';
     const store = configureStore({
       reducer,
@@ -40,7 +44,97 @@ describe('BufferContainer', () => {
       }
     });
 
-    Buffer.prototype.scrollToLine = jest.fn();
+    render(
+      <BufferContainer
+        bufferId={bufferId}
+        showTopic={false}
+        sendMessage={() => {}}
+        fetchMoreLines={() => {}}
+      />,
+      { store }
+    );
+
+    const bufferContainer = screen.UNSAFE_getByType(
+      BufferContainer.WrappedComponent
+    );
+
+    act(() => {
+      store.dispatch(
+        bufferNotificationAction({
+          bufferId,
+          lineId: '86c2ff040',
+          identifier: '1fb4fc1d-530b-466f-85be-de27772de0a9'
+        })
+      );
+    });
+
+    expect(bufferContainer.props.notification).toBeNull();
+
+    act(() => {
+      store.dispatch(changeCurrentBufferAction(bufferId));
+    });
+
+    expect(bufferContainer.props.notification).toBeNull();
+
+    act(() => {
+      store.dispatch(
+        fetchLinesAction([
+          {
+            buffer: '86c417600',
+            date: '2024-04-05T02:40:09.000Z',
+            date_printed: '2024-04-06T17:20:30.000Z',
+            displayed: 1,
+            highlight: 0,
+            message: 'Second message',
+            pointers: ['86c417600', '8580eeec0', '8580dcc40', '86c2ff040'],
+            prefix: 'user',
+            tags_array: ['irc_privmsg', 'notify_message']
+          } as WeechatLine
+        ])
+      );
+    });
+
+    expect(bufferContainer.props.notification).toEqual({
+      bufferId,
+      lineId: '86c2ff040',
+      identifier: '1fb4fc1d-530b-466f-85be-de27772de0a9'
+    });
+  });
+
+  it('clears notification after being handled by the buffer component', () => {
+    const ActualBuffer = jest.requireActual<
+      typeof import('../../../../src/usecase/buffers/ui/Buffer')
+    >('../../../../src/usecase/buffers/ui/Buffer').default;
+    jest.mocked(Buffer).mockImplementation((props) => {
+      return new ActualBuffer(props);
+    });
+    jest.spyOn(ActualBuffer.prototype, 'componentDidUpdate');
+
+    const bufferId = '86c417600';
+    const store = configureStore({
+      reducer,
+      preloadedState: {
+        buffers: {
+          [bufferId]: {
+            full_name: 'irc.libera.#weechat',
+            hidden: 0,
+            id: bufferId,
+            local_variables: {
+              channel: '#weechat',
+              name: 'libera.#weechat',
+              plugin: 'irc',
+              type: 'channel'
+            },
+            notify: 3,
+            number: 2,
+            pointers: [bufferId],
+            short_name: '#weechat',
+            title: '',
+            type: 0
+          }
+        }
+      }
+    });
 
     render(
       <BufferContainer
@@ -56,16 +150,19 @@ describe('BufferContainer', () => {
       store.dispatch(
         bufferNotificationAction({
           bufferId,
-          lineId: '8580dcc40',
+          lineId: '86c2ff040',
           identifier: '1fb4fc1d-530b-466f-85be-de27772de0a9'
         })
       );
     });
 
-    expect(Buffer.prototype.scrollToLine).not.toHaveBeenCalled();
+    expect(store.getState().app.notification).not.toBeNull();
 
     act(() => {
       store.dispatch(changeCurrentBufferAction(bufferId));
+    });
+
+    act(() => {
       store.dispatch(
         fetchLinesAction([
           {
@@ -83,7 +180,11 @@ describe('BufferContainer', () => {
       );
     });
 
-    expect(Buffer.prototype.scrollToLine).toHaveBeenCalledWith('8580dcc40');
+    expect(ActualBuffer.prototype.componentDidUpdate).toHaveBeenCalledWith(
+      expect.objectContaining({ notificationLineId: '86c2ff040' }),
+      expect.anything(),
+      undefined
+    );
     expect(store.getState().app.notification).toBeNull();
   });
 });

src/store/app.ts

@@ -15,21 +15,22 @@ export type AppState = {
   connected: boolean;
   currentBufferId: string | null;
   notification: { bufferId: string; lineId: string; identifier: string } | null;
-  notificationBufferLinesFetched: boolean;
+  currentBufferLinesFetched: boolean;
 };
 
 const initialState: AppState = {
   connected: false,
   currentBufferId: null,
   notification: null,
-  notificationBufferLinesFetched: false
+  currentBufferLinesFetched: false
 };
 
 export const app = createReducer(initialState, (builder) => {
   builder.addCase(disconnectAction, (state) => {
     return {
       ...state,
-      connected: false
+      connected: false,
+      currentBufferLinesFetched: false
     };
   });
   builder.addCase(fetchVersionAction, (state) => {
@@ -41,30 +42,29 @@ export const app = createReducer(initialState, (builder) => {
   builder.addCase(changeCurrentBufferAction, (state, action) => {
     return {
       ...state,
-      currentBufferId: action.payload
+      currentBufferId: action.payload,
+      currentBufferLinesFetched: false
     };
   });
   builder.addCase(fetchLinesAction, (state, action) => {
     return {
       ...state,
-      notificationBufferLinesFetched:
-        (state.notification &&
-          action.payload[0].buffer === state.notification.bufferId) ||
-        state.notificationBufferLinesFetched
+      currentBufferLinesFetched:
+        (state.currentBufferId &&
+          action.payload[0].buffer === state.currentBufferId) ||
+        state.currentBufferLinesFetched
     };
   });
   builder.addCase(bufferNotificationAction, (state, action) => {
     return {
       ...state,
-      notification: action.payload,
-      notificationBufferLinesFetched: false
+      notification: action.payload
     };
   });
   builder.addCase(clearBufferNotificationAction, (state) => {
     return {
       ...state,
-      notification: null,
-      notificationBufferLinesFetched: false
+      notification: null
     };
   });
   builder.addCase(bufferClosedAction, (state, action) => {

src/usecase/App.tsx

@@ -159,11 +159,7 @@ class App extends React.Component<Props, State> {
       notification &&
       notification.identifier !== prevProps.notification?.identifier
     ) {
-      if (currentBufferId !== notification.bufferId)
-        this.changeCurrentBuffer(notification.bufferId);
-      else {
-        this.props.fetchBufferInfo(notification.bufferId);
-      }
+      this.changeCurrentBuffer(notification.bufferId);
 
       return;
     }