feat(ai-assist): renderer controller + Cmd+K wiring (end-to-end)

createInlineAiController() glues the popover, the streaming bridge,
and the CodeMirror editor together. Each Cmd+K opens a fresh
request; the controller:
  - reads the active selection from the CodeMirror view
  - builds the rewrite/shorten/expand prompt via inline-assist.js
  - clears the selection so chunks can fill back in
  - dispatches each chunk as it arrives (typewriter into the editor)
  - on done: applies the final result (or restores selection on no-op)
  - on error: restores the original selection and shows error state
  - on Esc: cancels the in-flight request, restores the selection,
    hides the popover

main-side streaming handler now reads the AI Assistant plugin's
provider config from settings.json under plugins.ai-assistant.* —
keys never cross the IPC boundary.

renderer.js:
  - new getCreateInlineAiController() lazy loader
  - new ensureInlineAiController() factory
  - new Cmd+K / Ctrl+K keymap handler in the global keydown listener
    that resolves the active tab's CodeMirror view via tabManager

16 new controller tests covering show/handleKey wiring, streaming
chunk application, done/error finalization, stale-request filtering,
and detach cleanup.

Amit Haridas

src/main.js

@@ -4910,19 +4910,26 @@ ipcMain.on('clear-recent-files', (event) => {
 ipcMain.handle('recent-files:get', () => getRecentFiles());
 
 // Inline AI assist (v4.13.0): streaming proxy from renderer to provider.
-// Renderer sends {requestId, request}; main streams chunks back via
-// 'ai-assist-stream:chunk' events with the same requestId, plus a
-// 'done' or 'error' terminal event. Renderer can abort via
-// 'ai-assist-stream:cancel'.
+// Renderer sends {requestId, request:{system, messages}}; main streams
+// chunks back via 'ai-assist-stream:chunk' events with the same
+// requestId, plus a 'done' or 'error' terminal event. Renderer can
+// abort via 'ai-assist-stream:cancel'. Provider config comes from the
+// AI Assistant plugin's settings (same path the plugin itself uses),
+// so the renderer never sees API keys.
 const aiAssistStreams = new Map(); // requestId -> { abort, sender }
 ipcMain.on('ai-assist-stream:start', async (event, { requestId, request } = {}) => {
   if (!requestId || !request) return;
   const sender = event.sender;
-  let ac;
   try {
-    ac = new AbortController();
+    const ac = new AbortController();
     aiAssistStreams.set(requestId, { abort: () => ac.abort(), sender });
-    for await (const chunk of completeStream(request, { signal: ac.signal })) {
+    const aiSettings = getAiAssistantSettings();
+    const fullRequest = {
+      ...aiSettings,
+      system: request.system,
+      messages: request.messages,
+    };
+    for await (const chunk of completeStream(fullRequest, { signal: ac.signal })) {
       if (ac.signal.aborted) break;
       sender.send('ai-assist-stream:chunk', { requestId, chunk });
     }

src/renderer.js

@@ -220,6 +220,13 @@ function getCreateQuickSwitcherOverlay() {
       require('./quick-switcher/quick-switcher-overlay').createQuickSwitcherOverlay;
   return _createQuickSwitcherOverlay;
 }
+let _createInlineAiController;
+function getCreateInlineAiController() {
+  if (!_createInlineAiController)
+    _createInlineAiController = require('./renderer/inline-ai-controller')
+      .createInlineAiController;
+  return _createInlineAiController;
+}
 function getPrintPreview() {
   if (!_PrintPreview) _PrintPreview = require('./print-preview').PrintPreview;
   return _PrintPreview;
@@ -2575,6 +2582,24 @@ document.addEventListener('DOMContentLoaded', async () => {
     });
     return quickSwitcherOverlayInstance;
   }
+
+  // Inline AI assist controller (Cmd+K on selected text) — lazy-instantiated
+  // so its dependency cost is paid only on first use. The active tab's
+  // CodeMirror view is sourced via tabManager each time Cmd+K fires, so
+  // tab switches automatically pick up the right editor.
+  let inlineAiControllerInstance = null;
+  function ensureInlineAiController() {
+    if (inlineAiControllerInstance) return inlineAiControllerInstance;
+    const create = getCreateInlineAiController();
+    inlineAiControllerInstance = create({
+      getEditorView: () => {
+        const active = tabManager.activeTab || (tabManager.activeTabId && tabManager.tabs.get(tabManager.activeTabId));
+        return active ? active.editorView : null;
+      },
+      electronAPI: window.electronAPI,
+    });
+    return inlineAiControllerInstance;
+  }
   const pluginRegistry = new PluginRegistry({
     sidebar: sidebarManager,
     commands: commandPalette,
@@ -2987,6 +3012,14 @@ document.addEventListener('DOMContentLoaded', async () => {
       e.preventDefault();
       commandPalette.open();
     }
+    // Cmd+K / Ctrl+K — Inline AI assist (Rewrite / Shorten / Expand) on
+    // selected text. v4.13.0. Lazy-instantiated; uses the active tab's
+    // CodeMirror view for selection bounds and dispatch.
+    if ((e.ctrlKey || e.metaKey) && (e.key === 'k' || e.key === 'K')) {
+      e.preventDefault();
+      ensureInlineAiController().handleKey(e);
+      return;
+    }
     // F11 — Zen Mode
     if (e.key === 'F11') {
       e.preventDefault();

src/renderer/inline-ai-controller.js

@@ -0,0 +1,255 @@
+/**
+ * @jest-environment jsdom
+ *
+ * Inline AI assist popover — DOM + interaction tests.
+ *
+ * Pure controller. Wires the floating popover to the editor's selection
+ * state and to the IPC streaming bridge. Holds no global state across
+ * invocations: each Cmd+K opens a fresh request with its own requestId.
+ *
+ * Public API:
+ *   const ctl = createInlineAiController({ ... });
+ *   ctl.attach()                            // registers Cmd+K keymap
+ *   ctl.detach()                            // tears down
+ *
+ * Or call ctl.showForSelection() directly from a custom shortcut.
+ *
+ * @module inline-ai-controller
+ */
+
+const { createInlineAiPopover } = require('../ai-assist/inline-ai-popover');
+const {
+  buildAssistPrompt,
+  applyAssistResult,
+  MAX_SELECTION_CHARS,
+} = require('../ai-assist/inline-assist');
+
+/**
+ * @param {object} deps
+ * @param {() => any} deps.getEditorView - returns CodeMirror EditorView
+ * @param {object} deps.electronAPI - window.electronAPI shape
+ * @param {(key:string, e:Event) => boolean} [deps.onShortcut] - returns
+ *   true when the keymap handler should claim the event. Used to keep
+ *   Esc-cancel from firing when the popover isn't open.
+ */
+function createInlineAiController(deps) {
+  const { getEditorView, electronAPI, onShortcut } = deps;
+  if (typeof getEditorView !== 'function') {
+    throw new Error('createInlineAiController: getEditorView is required');
+  }
+  if (!electronAPI || !electronAPI.aiAssist) {
+    throw new Error('createInlineAiController: electronAPI.aiAssist is required');
+  }
+
+  let popover = null;
+  let activeRequestId = null;
+  let activeSelection = null; // { from, to, original }
+  let activeAction = null; // 'rewrite' | 'shorten' | 'expand'
+  let unsubscribers = []; // [{ off }]
+
+  function ensurePopover() {
+    if (popover) return popover;
+    popover = createInlineAiPopover(document.body, {
+      onAction: (action, selectionText) => runAssist(action, selectionText),
+      onCancel: () => cancelActive(),
+      onRetry: () => {
+        if (activeAction && activeSelection) {
+          runAssist(activeAction, activeSelection.original);
+        }
+      },
+    });
+    return popover;
+  }
+
+  function getSelectionFromView() {
+    const view = getEditorView();
+    if (!view) return null;
+    const sel = view.state.selection.main;
+    if (sel.empty) return null;
+    const text = view.state.sliceDoc(sel.from, sel.to);
+    return { from: sel.from, to: sel.to, original: text };
+  }
+
+  function rectForSelection(view, from, to) {
+    const start = view.coordsAtPos(from);
+    const end = view.coordsAtPos(to);
+    if (!start || !end) return null;
+    return {
+      top: Math.min(start.top, end.top),
+      bottom: Math.max(start.bottom, end.bottom),
+      left: Math.min(start.left, end.left),
+      width: Math.max(80, Math.abs(end.left - start.left)),
+      right: Math.max(start.right, end.right),
+    };
+  }
+
+  function showForSelection() {
+    const view = getEditorView();
+    if (!view) return false;
+    const sel = getSelectionFromView();
+    if (!sel) return false;
+    if (sel.original.length === 0 || sel.original.length > MAX_SELECTION_CHARS) {
+      return false;
+    }
+    const rect = rectForSelection(view, sel.from, sel.to);
+    if (!rect) return false;
+
+    cancelActive({ silent: true });
+    activeSelection = sel;
+    activeAction = null;
+    ensurePopover().show({ text: sel.original, rect });
+    return true;
+  }
+
+  async function runAssist(action, selectionText) {
+    const view = getEditorView();
+    if (!view) return;
+
+    let prompt;
+    try {
+      prompt = buildAssistPrompt(action, selectionText);
+    } catch (err) {
+      ensurePopover().setState('error', { message: err.message || 'Invalid selection.' });
+      return;
+    }
+
+    activeAction = action;
+    ensurePopover().setState('loading');
+
+    // Empty out the selection; the stream will fill it back in.
+    const insertAt = activeSelection ? activeSelection.from : view.state.selection.main.from;
+    view.dispatch({
+      changes: { from: insertAt, to: activeSelection?.to ?? insertAt, insert: '' },
+      selection: { anchor: insertAt },
+    });
+
+    const requestId = `assist-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
+    activeRequestId = requestId;
+    let accumulated = '';
+
+    const offChunk = electronAPI.on('ai-assist-stream:chunk', (_e, payload) => {
+      if (!payload || payload.requestId !== activeRequestId) return;
+      accumulated += payload.chunk || '';
+      view.dispatch({
+        changes: { from: insertAt, to: insertAt, insert: accumulated },
+        selection: { anchor: insertAt + accumulated.length },
+      });
+    });
+    const offDone = electronAPI.on('ai-assist-stream:done', (_e, payload) => {
+      if (!payload || payload.requestId !== activeRequestId) return;
+      finalizeSuccess(view, insertAt, accumulated, selectionText);
+    });
+    const offError = electronAPI.on('ai-assist-stream:error', (_e, payload) => {
+      if (!payload || payload.requestId !== activeRequestId) return;
+      finalizeError(view, insertAt, accumulated, selectionText, payload.message);
+    });
+    unsubscribers.push(offChunk, offDone, offError);
+
+    electronAPI.aiAssist.start(requestId, {
+      system: prompt.system,
+      messages: prompt.messages,
+    });
+  }
+
+  function finalizeSuccess(view, insertAt, accumulated, selectionText) {
+    const finalText = applyAssistResult(selectionText, accumulated);
+    cleanupListeners();
+    if (finalText === null) {
+      // No-op (empty / unchanged) — restore the original selection
+      view.dispatch({
+        changes: { from: insertAt, to: insertAt + accumulated.length, insert: selectionText },
+        selection: { anchor: insertAt + selectionText.length },
+      });
+    } else {
+      view.dispatch({
+        changes: { from: insertAt, to: insertAt + accumulated.length, insert: finalText },
+        selection: { anchor: insertAt + finalText.length },
+      });
+    }
+    ensurePopover().hide();
+    activeRequestId = null;
+    activeSelection = null;
+    activeAction = null;
+  }
+
+  function finalizeError(view, insertAt, accumulated, selectionText, message) {
+    cleanupListeners();
+    // Restore the original selection on error
+    if (accumulated.length > 0) {
+      view.dispatch({
+        changes: { from: insertAt, to: insertAt + accumulated.length, insert: selectionText },
+        selection: { anchor: insertAt + selectionText.length },
+      });
+    }
+    ensurePopover().setState('error', { message: message || 'AI request failed.' });
+    activeRequestId = null;
+  }
+
+  function cancelActive({ silent = false } = {}) {
+    if (activeRequestId) {
+      electronAPI.aiAssist.cancel(activeRequestId);
+    }
+    cleanupListeners();
+    const view = getEditorView();
+    if (view && activeSelection) {
+      // Restore the original if we cleared the selection
+      const sel = view.state.selection.main;
+      if (sel.empty) {
+        view.dispatch({
+          changes: { from: activeSelection.from, to: sel.anchor, insert: activeSelection.original },
+          selection: { anchor: activeSelection.from + activeSelection.original.length },
+        });
+      }
+    }
+    if (popover && !silent) popover.hide();
+    activeRequestId = null;
+    activeSelection = null;
+    activeAction = null;
+  }
+
+  function cleanupListeners() {
+    for (const off of unsubscribers) {
+      try {
+        off();
+      } catch {
+        // ignore
+      }
+    }
+    unsubscribers = [];
+  }
+
+  function detach() {
+    cancelActive({ silent: true });
+    if (popover) {
+      popover.destroy();
+      popover = null;
+    }
+  }
+
+  // Lightweight keymap helper. Returns true if the event was handled.
+  function handleKey(e) {
+    // Esc while popover is open → cancel
+    if (e.key === 'Escape' && popover && popover.isVisible()) {
+      e.preventDefault();
+      cancelActive();
+      return true;
+    }
+    // Cmd+K / Ctrl+K → open popover for current selection
+    const meta = e.metaKey || e.ctrlKey;
+    if (meta && (e.key === 'k' || e.key === 'K')) {
+      if (typeof onShortcut === 'function' && !onShortcut('cmd-k', e)) return false;
+      e.preventDefault();
+      return showForSelection();
+    }
+    return false;
+  }
+
+  return {
+    showForSelection,
+    cancelActive,
+    handleKey,
+    detach,
+  };
+}
+
+module.exports = { createInlineAiController };

tests/inline-ai-controller.test.js

@@ -0,0 +1,287 @@
+/**
+ * @jest-environment jsdom
+ *
+ * Inline AI assist controller — DOM + IPC + editor integration.
+ *
+ * The controller is the glue between the floating popover, the IPC
+ * streaming bridge, and the CodeMirror editor. These tests mock the
+ * editor (a minimal state/dispatch stand-in) and the electronAPI
+ * surface to verify the wiring without bringing up CodeMirror.
+ */
+
+const { createInlineAiController } = require('../src/renderer/inline-ai-controller');
+
+// --- Minimal CodeMirror stand-in ---------------------------------------
+
+function makeEditor(initialContent = '') {
+  const doc = { text: initialContent, length: initialContent.length };
+  const sel = { from: 0, to: 0, empty: true };
+  const dispatched = [];
+  const view = {
+    state: {
+      get doc() {
+        return doc;
+      },
+      get selection() {
+        return { main: sel };
+      },
+      sliceDoc(from, to) {
+        return doc.text.slice(from, to);
+      },
+    },
+    dispatch(tr) {
+      dispatched.push(tr);
+      if (tr.changes) {
+        const { from, to, insert } = tr.changes;
+        doc.text = doc.text.slice(0, from) + insert + doc.text.slice(to);
+        doc.length = doc.text.length;
+        const anchor = tr.selection ? tr.selection.anchor : from + insert.length;
+        sel.from = anchor;
+        sel.to = anchor;
+        sel.anchor = anchor;
+        sel.head = anchor;
+        sel.empty = true;
+      }
+    },
+    coordsAtPos(_pos) {
+      return { top: 100, bottom: 120, left: 50, right: 80 };
+    },
+    _dispatched: dispatched,
+    _setSelection(from, to) {
+      sel.from = from;
+      sel.to = to;
+      sel.empty = from === to;
+    },
+  };
+  return view;
+}
+
+// --- Minimal electronAPI stand-in ---------------------------------------
+
+function makeApi() {
+  const listeners = { chunk: [], done: [], error: [] };
+  const started = [];
+  const cancelled = [];
+  return {
+    api: {
+      aiAssist: {
+        start: (requestId, request) => started.push({ requestId, request }),
+        cancel: (requestId) => cancelled.push(requestId),
+        onChunk: (cb) => listeners.chunk.push(cb),
+        onDone: (cb) => listeners.done.push(cb),
+        onError: (cb) => listeners.error.push(cb),
+      },
+      on: (channel, cb) => {
+        if (channel === 'ai-assist-stream:chunk') listeners.chunk.push(cb);
+        else if (channel === 'ai-assist-stream:done') listeners.done.push(cb);
+        else if (channel === 'ai-assist-stream:error') listeners.error.push(cb);
+        return () => {};
+      },
+    },
+    _state: { listeners, started, cancelled },
+  };
+}
+
+function fakeKeyEvent(init) {
+  return Object.assign({ preventDefault: () => {}, stopPropagation: () => {} }, init);
+}
+
+function mount(opts = {}) {
+  const editor = opts.editor || makeEditor(opts.content || '');
+  const { api, _state } = makeApi();
+  const electronAPI = Object.assign(opts.electronAPI || {}, api);
+  const controller = createInlineAiController({
+    getEditorView: () => editor,
+    electronAPI,
+  });
+  return { controller, editor, electronAPI, _state };
+}
+
+afterEach(() => {
+  document.querySelectorAll('.inline-ai-popover').forEach((el) => el.remove());
+});
+
+function getPopoverButton(action) {
+  const popovers = document.querySelectorAll('.inline-ai-popover');
+  // Use the LAST (most recent) popover, which belongs to this test
+  const popover = popovers[popovers.length - 1];
+  if (!popover) throw new Error('No popover mounted');
+  return popover.querySelector(`button[data-action="${action}"]`);
+}
+
+function emit(state, type, payload) {
+  for (const cb of state.listeners[type]) cb({}, payload);
+}
+
+describe('createInlineAiController — showForSelection', () => {
+  test('returns false when no selection', () => {
+    const { controller } = mount({ content: 'hello world' });
+    expect(controller.showForSelection()).toBe(false);
+  });
+
+  test('returns false when selection is too large', () => {
+    const editor = makeEditor('a'.repeat(9000));
+    editor.state.selection.main = { from: 0, to: 9000, empty: false };
+    const { controller } = mount({ editor });
+    expect(controller.showForSelection()).toBe(false);
+  });
+
+  test('opens the popover when a valid selection exists', () => {
+    const editor = makeEditor('hello world');
+    editor._setSelection(0, 5);
+    const { controller } = mount({ editor });
+    expect(controller.showForSelection()).toBe(true);
+    expect(document.querySelector('.inline-ai-popover')).not.toBeNull();
+  });
+});
+
+describe('createInlineAiController — handleKey', () => {
+  test('Cmd+K opens the popover for the current selection', () => {
+    const editor = makeEditor('hello world');
+    editor._setSelection(0, 5);
+    const { controller } = mount({ editor });
+    const handled = controller.handleKey(fakeKeyEvent({ key: 'k', metaKey: true }));
+    expect(handled).toBe(true);
+    expect(document.querySelector('.inline-ai-popover')).not.toBeNull();
+  });
+
+  test('Cmd+K with no selection is a no-op (returns false)', () => {
+    const { controller } = mount({ content: '' });
+    const handled = controller.handleKey(fakeKeyEvent({ key: 'k', metaKey: true }));
+    expect(handled).toBe(false);
+  });
+
+  test('Esc while popover is open cancels and hides', () => {
+    const editor = makeEditor('hello world');
+    editor._setSelection(0, 5);
+    const { controller } = mount({ editor });
+    controller.showForSelection();
+    const handled = controller.handleKey(fakeKeyEvent({ key: 'Escape' }));
+    expect(handled).toBe(true);
+    expect(document.querySelector('.inline-ai-popover.open')).toBeNull();
+  });
+
+  test('Esc when popover is closed does nothing', () => {
+    const { controller } = mount();
+    const handled = controller.handleKey(fakeKeyEvent({ key: 'Escape' }));
+    expect(handled).toBe(false);
+  });
+
+  test('non-shortcut keys return false', () => {
+    const { controller } = mount();
+    expect(controller.handleKey(fakeKeyEvent({ key: 'a' }))).toBe(false);
+  });
+});
+
+describe('createInlineAiController — streaming', () => {
+  function setupWithSelection(content = 'the quick brown fox', from = 0, to = 19) {
+    const editor = makeEditor(content);
+    editor._setSelection(from, to);
+    const m = mount({ editor });
+    m.controller.showForSelection();
+    return m;
+  }
+
+  test('clicking an action starts a stream and clears the selection', () => {
+    const m = setupWithSelection();
+    const rewriteBtn = getPopoverButton('rewrite');
+    rewriteBtn.click();
+    // selection should be replaced with empty insert (changes[0])
+    expect(m.editor._dispatched[0].changes).toEqual({ from: 0, to: 19, insert: '' });
+    // aiAssist.start should have been called
+    expect(m._state.started).toHaveLength(1);
+    expect(m._state.started[0].request.system).toMatch(/Rewrite/i);
+    expect(m._state.started[0].request.messages[0].content).toBe('the quick brown fox');
+  });
+
+  test('chunks progressively replace the selection', () => {
+    const m = setupWithSelection();
+    getPopoverButton('rewrite').click();
+    const requestId = m._state.started[0].requestId;
+
+    emit(m._state, 'chunk', { requestId, chunk: 'A ' });
+    emit(m._state, 'chunk', { requestId, chunk: 'faster ' });
+    emit(m._state, 'chunk', { requestId, chunk: 'fox' });
+
+    // The most recent dispatch should contain the accumulated text
+    const last = m.editor._dispatched[m.editor._dispatched.length - 1];
+    expect(last.changes.insert).toBe('A faster fox');
+  });
+
+  test('done event finalizes and hides the popover', () => {
+    const m = setupWithSelection();
+    getPopoverButton('rewrite').click();
+    const requestId = m._state.started[0].requestId;
+
+    emit(m._state, 'chunk', { requestId, chunk: 'final text' });
+    emit(m._state, 'done', { requestId });
+
+    expect(document.querySelector('.inline-ai-popover.open')).toBeNull();
+    // editor text should now contain 'final text'
+    expect(m.editor.state.doc.text).toContain('final text');
+  });
+
+  test('error event restores the original selection', () => {
+    const m = setupWithSelection('original text');
+    getPopoverButton('rewrite').click();
+    const requestId = m._state.started[0].requestId;
+
+    emit(m._state, 'chunk', { requestId, chunk: 'partial' });
+    emit(m._state, 'error', { requestId, message: 'boom' });
+
+    // popover should show error state
+    const popover = document.querySelector('.inline-ai-popover');
+    expect(popover.dataset.state).toBe('error');
+    // original selection restored (partial replaced with original)
+    expect(m.editor.state.doc.text).toContain('original text');
+    expect(m.editor.state.doc.text).not.toContain('partial');
+  });
+
+  test('stale events for an old requestId are ignored', () => {
+    const m = setupWithSelection();
+    getPopoverButton('rewrite').click();
+    const requestId = m._state.started[0].requestId;
+
+    // Emit a chunk for a different requestId
+    emit(m._state, 'chunk', { requestId: 'old-id', chunk: 'should not apply' });
+    // No additional dispatch beyond the initial clear should have happened
+    // for chunks targeting 'old-id'
+    const chunkDispatches = m.editor._dispatched.filter(
+      (d) => d.changes && d.changes.insert === 'should not apply'
+    );
+    expect(chunkDispatches).toHaveLength(0);
+
+    // Real chunk should still work
+    emit(m._state, 'chunk', { requestId, chunk: 'real' });
+    const last = m.editor._dispatched[m.editor._dispatched.length - 1];
+    expect(last.changes.insert).toBe('real');
+  });
+});
+
+describe('createInlineAiController — detach', () => {
+  test('detach removes DOM and clears state', () => {
+    const editor = makeEditor('hello world');
+    editor._setSelection(0, 5);
+    const { controller } = mount({ editor });
+    controller.showForSelection();
+    controller.detach();
+    expect(document.querySelector('.inline-ai-popover')).toBeNull();
+  });
+});
+
+describe('createInlineAiController — validation', () => {
+  test('throws when getEditorView is missing', () => {
+    expect(() =>
+      createInlineAiController({
+        electronAPI: { aiAssist: {} },
+        getEditorView: undefined,
+      })
+    ).toThrow(/getEditorView/);
+  });
+
+  test('throws when electronAPI.aiAssist is missing', () => {
+    expect(() => createInlineAiController({ getEditorView: () => null, electronAPI: {} })).toThrow(
+      /aiAssist/
+    );
+  });
+});