import { act, fireEvent, render, screen, waitFor } from '@testing-library/react';
import { useState } from 'react';
import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
import { AgentBrowserPanel } from '@/pages/Chat/AgentBrowserPanel';
import type { AgentBrowserSnapshot } from '../../shared/agent-browser';

const hostApiFetchMock = vi.hoisted(() => vi.fn());
const hostEventListeners = vi.hoisted(
  () => new Map<string, (payload: unknown) => void>(),
);

vi.mock('@/lib/host-api', () => ({
  hostApiFetch: (...args: unknown[]) => hostApiFetchMock(...args),
}));

vi.mock('@/lib/host-events', () => ({
  subscribeHostEvent: (eventName: string, handler: (payload: unknown) => void) => {
    hostEventListeners.set(eventName, handler);
    return () => hostEventListeners.delete(eventName);
  },
}));

class MockResizeObserver {
  constructor(private readonly callback: ResizeObserverCallback) {}

  observe(element: Element) {
    this.callback([{ target: element } as ResizeObserverEntry], this as unknown as ResizeObserver);
  }

  disconnect() {}
  unobserve() {}
}

function snapshot(overrides: Partial<AgentBrowserSnapshot> = {}): AgentBrowserSnapshot {
  return {
    browserId: 'browser-a',
    projectId: 'project-a',
    projectPath: 'D:/repo',
    state: 'attached',
    generation: 1,
    url: 'http://127.0.0.1:4173/',
    title: 'App',
    visible: false,
    bounds: null,
    canGoBack: false,
    canGoForward: false,
    eventCursor: 0,
    ...overrides,
  };
}

function body(init?: RequestInit): Record<string, unknown> {
  return JSON.parse(String(init?.body ?? '{}')) as Record<string, unknown>;
}

function Harness({ initialOpen = false }: { initialOpen?: boolean }) {
  const [open, setOpen] = useState(initialOpen);
  return (
    <AgentBrowserPanel
      projectId="project-a"
      open={open}
      onOpenChange={setOpen}
    />
  );
}

describe('AgentBrowserPanel', () => {
  beforeEach(() => {
    hostApiFetchMock.mockReset();
    hostEventListeners.clear();
    Object.defineProperty(globalThis, 'ResizeObserver', {
      configurable: true,
      value: MockResizeObserver,
    });
    vi.spyOn(HTMLElement.prototype, 'getBoundingClientRect').mockReturnValue({
      x: 600, y: 80, left: 600, top: 80, right: 1000, bottom: 680,
      width: 400, height: 600, toJSON: () => ({}),
    } as DOMRect);
    hostApiFetchMock.mockImplementation(async (path: string, init?: RequestInit) => {
      if (path.startsWith('/api/agent-browser/state?')) {
        return { success: true, browser: snapshot() };
      }
      if (path === '/api/agent-browser/present') {
        return {
          success: true,
          browser: snapshot({
            visible: body(init).visible === true,
            bounds: body(init).bounds as AgentBrowserSnapshot['bounds'],
          }),
        };
      }
      if (path === '/api/agent-browser/diagnostics') {
        return { success: true, browser: snapshot({ visible: true }) };
      }
      if (path === '/api/agent-browser/close') {
        return {
          success: true,
          browser: snapshot({ browserId: null, state: 'closed', visible: false }),
        };
      }
      if (path === '/api/agent-browser/cdp/events') {
        return { success: true, page: { events: [], nextCursor: 0, hasMore: false } };
      }
      throw new Error(`Unexpected request: ${path}`);
    });
  });

  afterEach(() => {
    vi.restoreAllMocks();
  });

  it('does no browser API work while closed and presents an agent-opened snapshot', async () => {
    render(<Harness />);

    expect(screen.queryByTestId('agent-browser-panel')).not.toBeInTheDocument();
    expect(hostApiFetchMock).not.toHaveBeenCalled();

    act(() => {
      hostEventListeners.get('agent-browser:show')?.(snapshot());
    });

    expect(await screen.findByTestId('agent-browser-panel')).toBeInTheDocument();
    await waitFor(() => {
      expect(hostApiFetchMock).toHaveBeenCalledWith(
        '/api/agent-browser/present',
        expect.anything(),
      );
    });
    const presentation = hostApiFetchMock.mock.calls.find(
      ([path, init]) => path === '/api/agent-browser/present'
        && body(init as RequestInit).visible === true,
    );
    expect(body(presentation?.[1] as RequestInit)).toMatchObject({
      visible: true,
      bounds: { x: 600, y: 80, width: 400, height: 600 },
    });
  });

  it('enables Renderer diagnostics only after the drawer is explicitly expanded', async () => {
    render(<Harness initialOpen />);
    await screen.findByTestId('agent-browser-panel');
    await waitFor(() => expect(hostApiFetchMock.mock.calls.some(
      ([path]) => String(path).startsWith('/api/agent-browser/state?'),
    )).toBe(true));
    expect(hostApiFetchMock.mock.calls.some(([path]) => path === '/api/agent-browser/diagnostics')).toBe(false);

    fireEvent.click(screen.getByRole('button', { name: '展开调试面板' }));
    await waitFor(() => {
      const request = hostApiFetchMock.mock.calls.find(([path]) => path === '/api/agent-browser/diagnostics');
      expect(body(request?.[1] as RequestInit)).toMatchObject({ enabled: true });
    });
  });

  it('refreshes browser state once when the app regains focus', async () => {
    render(<Harness initialOpen />);
    await waitFor(() => expect(hostApiFetchMock.mock.calls.filter(
      ([path]) => String(path).startsWith('/api/agent-browser/state?'),
    )).toHaveLength(1));

    hostApiFetchMock.mockClear();
    act(() => window.dispatchEvent(new Event('focus')));

    await waitFor(() => expect(hostApiFetchMock.mock.calls.filter(
      ([path]) => String(path).startsWith('/api/agent-browser/state?'),
    )).toHaveLength(1));
  });
});