feat: export selected hunk to pi

.gitignore

@@ -39,4 +39,5 @@ report.[0-9]_.[0-9]_.[0-9]_.[0-9]_.json
 tmp
 .hunk/latest.json
 .hunk/config.toml
+.hunk/pi-selection.json
 .pi/

src/ui/App.tsx

@@ -38,6 +38,7 @@ import { buildAppMenus } from "./lib/appMenus";
 import { buildFileListEntry } from "./lib/files";
 import { buildHunkCursors, findNextHunkCursor } from "./lib/hunks";
 import { fileRowId } from "./lib/ids";
+import { buildPiSelectionPayload, writePiSelectionPayload } from "./lib/piSelection";
 import { resolveResponsiveLayout } from "./lib/responsive";
 import { resizeSidebarWidth } from "./lib/sidebar";
 import { resolveTheme, THEMES } from "./themes";
@@ -97,7 +98,9 @@ function AppShell({
   const [dismissedAgentNoteIds, setDismissedAgentNoteIds] = useState<string[]>([]);
   const [selectedFileId, setSelectedFileId] = useState(bootstrap.changeset.files[0]?.id ?? "");
   const [selectedHunkIndex, setSelectedHunkIndex] = useState(0);
+  const [statusMessage, setStatusMessage] = useState<string | undefined>();
   const deferredFilter = useDeferredValue(filter);
+  const statusMessageTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
 
   const pagerMode = Boolean(bootstrap.input.options.pager);
   const activeTheme = resolveTheme(themeId, renderer.themeMode);
@@ -211,6 +214,14 @@ function AppShell({
     renderer.intermediateRender();
   }, [renderer, resolvedLayout, showFilesPane, terminal.height, terminal.width]);
 
+  useEffect(() => {
+    return () => {
+      if (statusMessageTimeoutRef.current) {
+        clearTimeout(statusMessageTimeoutRef.current);
+      }
+    };
+  }, []);
+
   useEffect(() => {
     if (!selectedFile && filteredFiles[0]) {
       setSelectedFileId(filteredFiles[0].id);
@@ -348,6 +359,38 @@ function AppShell({
     onQuit();
   }, [onQuit]);
 
+  /** Show one short-lived footer message after local actions like exporting a hunk to pi. */
+  const flashStatusMessage = useCallback((message: string) => {
+    setStatusMessage(message);
+    if (statusMessageTimeoutRef.current) {
+      clearTimeout(statusMessageTimeoutRef.current);
+    }
+
+    statusMessageTimeoutRef.current = setTimeout(() => {
+      setStatusMessage(undefined);
+      statusMessageTimeoutRef.current = null;
+    }, 2200);
+  }, []);
+
+  /** Export the focused hunk to the project-local pi selection bridge file. */
+  const sendSelectionToPi = useCallback(() => {
+    if (!selectedFile) {
+      flashStatusMessage("No file selected for Pi.");
+      return;
+    }
+
+    const payload = buildPiSelectionPayload(bootstrap.changeset, selectedFile, selectedHunkIndex);
+    if (!payload) {
+      flashStatusMessage("No hunk selected for Pi.");
+      return;
+    }
+
+    const selectionPath = writePiSelectionPayload(payload);
+    flashStatusMessage(
+      `Sent ${selectedFile.path} hunk ${selectedHunkIndex + 1} to Pi (${selectionPath}).`,
+    );
+  }, [bootstrap.changeset, flashStatusMessage, selectedFile, selectedHunkIndex]);
+
   const menus = useMemo(
     () =>
       buildAppMenus({
@@ -360,6 +403,7 @@ function AppShell({
         requestQuit,
         selectLayoutMode: setLayoutMode,
         selectThemeId: setThemeId,
+        sendSelectionToPi,
         showAgentNotes,
         showHelp,
         showHunkHeaders,
@@ -379,6 +423,7 @@ function AppShell({
       moveAnnotatedFile,
       moveHunk,
       requestQuit,
+      sendSelectionToPi,
       showAgentNotes,
       showHelp,
       showHunkHeaders,
@@ -699,6 +744,12 @@ function AppShell({
       return;
     }
 
+    if (key.name === "p" || key.sequence === "p") {
+      sendSelectionToPi();
+      closeMenu();
+      return;
+    }
+
     if (key.name === "[") {
       moveHunk(-1);
       closeMenu();
@@ -813,6 +864,7 @@ function AppShell({
           canResizeDivider={showFilesPane}
           filter={filter}
           filterFocused={focusArea === "filter"}
+          message={statusMessage}
           terminalWidth={terminal.width}
           theme={activeTheme}
           onCloseMenu={closeMenu}

src/ui/components/chrome/HelpDialog.tsx

@@ -32,7 +32,9 @@ export function HelpDialog({
     >
       <text fg={theme.text}>Keyboard</text>
       <text fg={theme.muted}>F10 menus arrows navigate menus Enter select Esc close menu</text>
-      <text fg={theme.muted}>1 split 2 stack 0 auto t theme a notes l lines w wrap m meta</text>
+      <text fg={theme.muted}>
+        1 split 2 stack 0 auto t theme a notes l lines w wrap m meta p pi
+      </text>
       <text fg={theme.muted}>
         ↑/↓ line scroll space next page b previous page Home/End jump [ previous hunk ] next hunk
       </text>

src/ui/components/chrome/StatusBar.tsx

@@ -6,6 +6,7 @@ export function StatusBar({
   canResizeDivider = false,
   filter,
   filterFocused,
+  message,
   terminalWidth,
   theme,
   onCloseMenu,
@@ -15,6 +16,7 @@ export function StatusBar({
   canResizeDivider?: boolean;
   filter: string;
   filterFocused: boolean;
+  message?: string;
   terminalWidth: number;
   theme: AppTheme;
   onCloseMenu: () => void;
@@ -37,6 +39,7 @@ export function StatusBar({
     "l lines",
     "w wrap",
     "m meta",
+    "p pi",
     "q quit",
   );
 
@@ -68,9 +71,9 @@ export function StatusBar({
           />
         </>
       ) : (
-        <text fg={theme.muted}>
+        <text fg={message ? theme.badgeNeutral : theme.muted}>
           {fitText(
-            `${hintParts.join("  ")}${filter ? `  filter=${filter}` : ""}`,
+            message ?? `${hintParts.join("  ")}${filter ? `  filter=${filter}` : ""}`,
             terminalWidth - 2,
           )}
         </text>

src/ui/lib/appMenus.ts

@@ -12,6 +12,7 @@ export interface BuildAppMenusOptions {
   requestQuit: () => void;
   selectLayoutMode: (mode: LayoutMode) => void;
   selectThemeId: (themeId: string) => void;
+  sendSelectionToPi: () => void;
   showAgentNotes: boolean;
   showHelp: boolean;
   showHunkHeaders: boolean;
@@ -37,6 +38,7 @@ export function buildAppMenus({
   requestQuit,
   selectLayoutMode,
   selectThemeId,
+  sendSelectionToPi,
   showAgentNotes,
   showHelp,
   showHunkHeaders,
@@ -179,6 +181,13 @@ export function buildAppMenus({
         label: "Previous annotated file",
         action: () => moveAnnotatedFile(-1),
       },
+      { kind: "separator" },
+      {
+        kind: "item",
+        label: "Send hunk to Pi",
+        hint: "p",
+        action: sendSelectionToPi,
+      },
     ],
     help: [
       {

src/ui/lib/piSelection.ts

@@ -0,0 +1,125 @@
+import { existsSync, mkdirSync, statSync, writeFileSync } from "node:fs";
+import { dirname, isAbsolute, resolve } from "node:path";
+import { hunkLineRange } from "../../core/liveComments";
+import type { Changeset, DiffFile } from "../../core/types";
+
+const PI_SELECTION_RELATIVE_PATH = ".hunk/pi-selection.json";
+
+type DiffHunk = DiffFile["metadata"]["hunks"][number];
+
+export interface PiSelectionPayload {
+  version: 1;
+  source: "hunk";
+  createdAt: string;
+  repoRoot?: string;
+  selectionPath: string;
+  changesetTitle: string;
+  filePath: string;
+  previousPath?: string;
+  hunkIndex: number;
+  oldRange: [number, number];
+  newRange: [number, number];
+  patch: string;
+  prompt: string;
+}
+
+/** Reuse the git repo root source label when this changeset came from a repo-backed review. */
+function resolveRepoRoot(changeset: Changeset) {
+  if (!isAbsolute(changeset.sourceLabel) || !existsSync(changeset.sourceLabel)) {
+    return undefined;
+  }
+
+  return statSync(changeset.sourceLabel).isDirectory() ? changeset.sourceLabel : undefined;
+}
+
+/** Match the visible hunk header text used by the review stream. */
+function hunkHeader(hunk: DiffHunk) {
+  const specs =
+    hunk.hunkSpecs ??
+    `@@ -${hunk.deletionStart},${hunk.deletionLines} +${hunk.additionStart},${hunk.additionLines} @@`;
+  return hunk.hunkContext ? `${specs} ${hunk.hunkContext}` : specs;
+}
+
+/** Rebuild one hunk as a compact diff snippet suitable for pasting into pi. */
+export function buildPiSelectionPatch(file: DiffFile, hunkIndex: number) {
+  const hunk = file.metadata.hunks[hunkIndex];
+  if (!hunk) {
+    return null;
+  }
+
+  const lines = [hunkHeader(hunk)];
+  let deletionLineIndex = hunk.deletionLineIndex;
+  let additionLineIndex = hunk.additionLineIndex;
+
+  for (const content of hunk.hunkContent) {
+    if (content.type === "context") {
+      for (let offset = 0; offset < content.lines; offset += 1) {
+        lines.push(` ${file.metadata.additionLines[additionLineIndex + offset] ?? ""}`);
+      }
+
+      deletionLineIndex += content.lines;
+      additionLineIndex += content.lines;
+      continue;
+    }
+
+    for (let offset = 0; offset < content.deletions; offset += 1) {
+      lines.push(`-${file.metadata.deletionLines[deletionLineIndex + offset] ?? ""}`);
+    }
+
+    for (let offset = 0; offset < content.additions; offset += 1) {
+      lines.push(`+${file.metadata.additionLines[additionLineIndex + offset] ?? ""}`);
+    }
+
+    deletionLineIndex += content.deletions;
+    additionLineIndex += content.additions;
+  }
+
+  return lines.join("\n");
+}
+
+/** Build the payload the pi extension watches and pastes into the editor. */
+export function buildPiSelectionPayload(changeset: Changeset, file: DiffFile, hunkIndex: number) {
+  const hunk = file.metadata.hunks[hunkIndex];
+  const patch = buildPiSelectionPatch(file, hunkIndex);
+  if (!hunk || !patch) {
+    return null;
+  }
+
+  const repoRoot = resolveRepoRoot(changeset);
+  const selectionPath = resolve(repoRoot ?? process.cwd(), PI_SELECTION_RELATIVE_PATH);
+  const { oldRange, newRange } = hunkLineRange(hunk);
+  const prompt = [
+    `Selected hunk from Hunk: ${file.path}`,
+    `Hunk: ${hunkIndex + 1}`,
+    `Old lines: ${oldRange[0]}-${oldRange[1]}`,
+    `New lines: ${newRange[0]}-${newRange[1]}`,
+    "",
+    "```diff",
+    patch,
+    "```",
+    "",
+  ].join("\n");
+
+  return {
+    version: 1 as const,
+    source: "hunk" as const,
+    createdAt: new Date().toISOString(),
+    repoRoot,
+    selectionPath,
+    changesetTitle: changeset.title,
+    filePath: file.path,
+    previousPath: file.previousPath,
+    hunkIndex,
+    oldRange,
+    newRange,
+    patch,
+    prompt,
+  } satisfies PiSelectionPayload;
+}
+
+/** Persist the current Hunk selection where the project-local pi extension can pick it up. */
+export function writePiSelectionPayload(payload: PiSelectionPayload) {
+  mkdirSync(dirname(payload.selectionPath), { recursive: true });
+  writeFileSync(payload.selectionPath, `${JSON.stringify(payload, null, 2)}\n`);
+  return payload.selectionPath;
+}

test/app-interactions.test.tsx

@@ -1,4 +1,7 @@
 import { describe, expect, mock, test } from "bun:test";
+import { existsSync, mkdtempSync, readFileSync, rmSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
 import { testRender } from "@opentui/react/test-utils";
 import { parseDiffFromFile } from "@pierre/diffs";
 import { act } from "react";
@@ -237,6 +240,52 @@ describe("App interactions", () => {
     }
   });
 
+  test("keyboard shortcut exports the selected hunk to the pi selection bridge file", async () => {
+    const tempRoot = mkdtempSync(join(tmpdir(), "hunk-pi-bridge-"));
+    const baseBootstrap = createSingleFileBootstrap();
+    const bootstrap = {
+      ...baseBootstrap,
+      changeset: {
+        ...baseBootstrap.changeset,
+        sourceLabel: tempRoot,
+      },
+    } satisfies AppBootstrap;
+    const setup = await testRender(<App bootstrap={bootstrap} />, {
+      width: 240,
+      height: 24,
+    });
+
+    try {
+      await flush(setup);
+
+      await act(async () => {
+        await setup.mockInput.typeText("p");
+      });
+      await flush(setup);
+
+      const selectionPath = join(tempRoot, ".hunk", "pi-selection.json");
+      expect(existsSync(selectionPath)).toBe(true);
+
+      const payload = JSON.parse(readFileSync(selectionPath, "utf8")) as {
+        filePath: string;
+        hunkIndex: number;
+        prompt: string;
+        patch: string;
+      };
+      expect(payload.filePath).toBe("alpha.ts");
+      expect(payload.hunkIndex).toBe(0);
+      expect(payload.prompt).toContain("Selected hunk from Hunk: alpha.ts");
+      expect(payload.patch).toContain("@@ -1,1 +1,2 @@");
+      expect(payload.patch).toContain("-export const alpha = 1;");
+      expect(payload.patch).toContain("+export const alpha = 2;");
+    } finally {
+      await act(async () => {
+        setup.renderer.destroy();
+      });
+      rmSync(tempRoot, { recursive: true, force: true });
+    }
+  });
+
   test("keyboard shortcut can wrap long lines in the app shell", async () => {
     const setup = await testRender(<App bootstrap={createWrapBootstrap()} />, {
       width: 140,