feat: integrate Pi backend and Pi Web

pi-web/app/api/worktrees/route.ts

@@ -0,0 +1,97 @@
+import { NextResponse } from "next/server";
+import { existsSync } from "fs";
+import { addWorktree, listWorktrees, removeWorktree, resolveProject } from "@/lib/worktree";
+import { allowFileRoot, getAllowedFileRoots, isExistingFilePathAllowed, isFilePathAllowed } from "@/lib/file-access";
+
+/** Same gate as /api/files: only session cwds / project roots / explicitly
+ *  allowed dirs may be inspected or mutated through this endpoint. */
+async function checkCwdAllowed(cwd: string): Promise<NextResponse | null> {
+  const allowedRoots = await getAllowedFileRoots();
+  if (!isFilePathAllowed(cwd, allowedRoots) || !isExistingFilePathAllowed(cwd, allowedRoots)) {
+    return NextResponse.json({ error: "Access denied" }, { status: 403 });
+  }
+  return null;
+}
+
+// GET /api/worktrees?cwd=  →  { projectRoot, isGit, isTopLevel, worktrees }
+export async function GET(req: Request) {
+  try {
+    const cwd = new URL(req.url).searchParams.get("cwd");
+    if (!cwd) {
+      return NextResponse.json({ error: "cwd is required" }, { status: 400 });
+    }
+    const denied = await checkCwdAllowed(cwd);
+    if (denied) return denied;
+
+    const project = await resolveProject(cwd);
+    let worktrees: Awaited<ReturnType<typeof listWorktrees>> = [];
+    let isGit = true;
+    try {
+      // For a removed-worktree cwd (session of a deleted worktree), fall back
+      // to the inferred project root so the switcher still shows the project.
+      worktrees = await listWorktrees(existsSync(cwd) ? cwd : project.projectRoot);
+    } catch {
+      isGit = false;
+    }
+    // Every listed path is a git-verified worktree of this project; allow the
+    // file explorer to browse them even before they have any session (the
+    // in-memory allowlist from addWorktree does not survive server restarts).
+    for (const w of worktrees) allowFileRoot(w.path);
+    return NextResponse.json({
+      projectRoot: project.projectRoot,
+      isGit,
+      isTopLevel: project.isTopLevel,
+      worktrees,
+    });
+  } catch (error) {
+    return NextResponse.json({ error: String(error) }, { status: 500 });
+  }
+}
+
+// POST /api/worktrees  body: { cwd, branch }  →  { path, branch }
+export async function POST(req: Request) {
+  try {
+    const body = await req.json() as { cwd?: string; branch?: string };
+    if (!body.cwd || typeof body.cwd !== "string") {
+      return NextResponse.json({ error: "cwd is required" }, { status: 400 });
+    }
+    if (!body.branch || typeof body.branch !== "string") {
+      return NextResponse.json({ error: "branch is required" }, { status: 400 });
+    }
+    const denied = await checkCwdAllowed(body.cwd);
+    if (denied) return denied;
+    if (!existsSync(body.cwd)) {
+      return NextResponse.json({ error: `Directory does not exist: ${body.cwd}` }, { status: 400 });
+    }
+
+    const result = await addWorktree(body.cwd, body.branch);
+    return NextResponse.json(result);
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    return NextResponse.json({ error: message }, { status: 400 });
+  }
+}
+
+// DELETE /api/worktrees  body: { cwd, path, force? }
+export async function DELETE(req: Request) {
+  try {
+    const body = await req.json() as { cwd?: string; path?: string; force?: boolean };
+    if (!body.cwd || typeof body.cwd !== "string") {
+      return NextResponse.json({ error: "cwd is required" }, { status: 400 });
+    }
+    if (!body.path || typeof body.path !== "string") {
+      return NextResponse.json({ error: "path is required" }, { status: 400 });
+    }
+    const denied = await checkCwdAllowed(body.cwd);
+    if (denied) return denied;
+
+    await removeWorktree(body.cwd, body.path, body.force === true);
+    return NextResponse.json({ success: true });
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    // git refuses to remove dirty worktrees without --force; surface that so
+    // the UI can offer a force-remove confirmation.
+    const dirty = /contains modified or untracked files|is dirty/i.test(message);
+    return NextResponse.json({ error: message, dirty }, { status: dirty ? 409 : 400 });
+  }
+}