import { act, render, screen, waitFor } from "@testing-library/react";
import userEvent from "@testing-library/user-event";
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
import { beforeEach, expect, test, vi } from "vitest";
import { http, HttpResponse } from "msw";
import { AppShell } from "./AppShell";
import { server } from "../test/msw";
import { FakeEventSource } from "../test/fakeEventSource";
import { clearAuthState, setAuthState } from "../auth/authState";
import { useSessionStore } from "../store/sessionStore";

function renderShell() {
  const client = new QueryClient({ defaultOptions: { queries: { retry: false } } });
  return render(<QueryClientProvider client={client}><AppShell canLogout={false} /></QueryClientProvider>);
}

function deferred() {
  let resolve!: () => void;
  const promise = new Promise<void>((onResolve) => { resolve = onResolve; });
  return { promise, resolve };
}

beforeEach(() => {
  clearAuthState();
  setAuthState({
    issuer: "local", subject: "user-a", roles: ["user"], permissions: ["session.use"],
    isAdmin: false, csrfToken: null, session: null,
  });
  FakeEventSource.instances = [];
  (globalThis as { EventSource: typeof EventSource }).EventSource = FakeEventSource as unknown as typeof EventSource;
  useSessionStore.getState().resetSession();
  server.use(
    http.get("/api/me", () => HttpResponse.json({ issuer: "local", subject: "user-a", isAdmin: false })),
    http.get("/api/settings", () => HttpResponse.json({ workspace: "default", provider: "test", model: "test", thinking: "low" })),
    http.get("/api/workspaces", () => HttpResponse.json([])),
    http.get("/api/models", () => HttpResponse.json({ models: [] })),
    http.post("/api/runtime/prewarm", () => new HttpResponse(null, { status: 202 })),
  );
});

test("a held stop for s1 cannot reset the newer active s2 session", async () => {
  const closeGate = deferred();
  const closeStarted = deferred();
  const active = (id: string, question: string) => ({
    id, status: "open", question, summary: null, created_at: "2026-01-02T00:00:00Z",
    updated_at: null, author: null, name: null, group: null, archived: false, active: true,
  });
  server.use(
    http.get("/api/sessions", () => HttpResponse.json([active("s1", "Active one"), active("s2", "Active two")])),
    http.post("/api/sessions/:id/resume", ({ params }) => HttpResponse.json({ id: params.id, alreadyActive: false })),
    http.get("/api/sessions/:id", ({ params }) => HttpResponse.json({ id: params.id, status: "open", phase: 1 })),
    http.post("/api/sessions/s1/close", async () => {
      closeStarted.resolve();
      await closeGate.promise;
      return new HttpResponse(null, { status: 204 });
    }),
  );
  renderShell();
  await userEvent.click(await screen.findByTestId("session-item-s1"));
  await waitFor(() => expect(FakeEventSource.instances.at(-1)?.url).toContain("/sessions/s1/events"));
  await userEvent.click(screen.getByRole("button", { name: /stop and save session/i }));
  await userEvent.click(await screen.findByRole("button", { name: "Stop & save" }));
  await closeStarted.promise;

  await userEvent.click(screen.getByTestId("session-item-s2"));
  await waitFor(() => expect(FakeEventSource.instances.at(-1)?.url).toContain("/sessions/s2/events"));
  act(() => useSessionStore.setState({ currentPhase: "F2" }));
  closeGate.resolve();
  await new Promise((resolve) => setImmediate(resolve));

  expect(FakeEventSource.instances.at(-1)?.url).toContain("/sessions/s2/events");
  expect(FakeEventSource.instances.at(-1)?.closed).toBe(false);
  expect(useSessionStore.getState().currentPhase).toBe("F2");
});

test("a held new-session completion cannot replace the newer active s2 target", async () => {
  const createGate = deferred();
  const createStarted = deferred();
  server.use(
    http.get("/api/sessions", () => HttpResponse.json([{
      id: "s2", status: "open", question: "Current session", summary: null,
      created_at: "2026-01-02T00:00:00Z", updated_at: null, author: null, name: null,
      group: null, archived: false, active: true,
    }])),
    http.post("/api/sessions", async () => {
      createStarted.resolve();
      await createGate.promise;
      return HttpResponse.json({ id: "s3" });
    }),
    http.post("/api/sessions/:id/resume", ({ params }) => HttpResponse.json({ id: params.id, alreadyActive: false })),
    http.get("/api/sessions/:id", ({ params }) => HttpResponse.json({ id: params.id, status: "open", phase: 1 })),
  );
  renderShell();
  const composer = screen.getByRole("textbox", { name: /new question/i });
  await userEvent.type(composer, "Held new question");
  await userEvent.click(screen.getByRole("button", { name: /send/i }));
  await createStarted.promise;

  await userEvent.click(screen.getByTestId("session-item-s2"));
  await waitFor(() => expect(FakeEventSource.instances.at(-1)?.url).toContain("/sessions/s2/events"));
  act(() => useSessionStore.setState({ currentPhase: "F2" }));
  createGate.resolve();
  await new Promise((resolve) => setImmediate(resolve));

  expect(FakeEventSource.instances.at(-1)?.url).toContain("/sessions/s2/events");
  expect(FakeEventSource.instances.at(-1)?.closed).toBe(false);
  expect(useSessionStore.getState().currentPhase).toBe("F2");
});