/**
 * Property-Based Tests for auth guard and routes
 * Feature: degree-management-refactor
 * Uses: fast-check + jest + supertest (no MongoDB needed)
 */

const fc = require('fast-check');
const express = require('express');
const session = require('express-session');
const request = require('supertest');

// Routes
const authRoutes = require('../routes/auth');
const adminRoutes = require('../routes/admin');
const indexRoutes = require('../routes/index');

// Middleware
const { ensureAuthenticated } = require('../middleware/auth');

jest.setTimeout(120000);

// ─── Minimal App Factory ─────────────────────────────────────────────────────

/**
 * Build a minimal Express app that:
 * - Uses in-memory session (no MongoDB store)
 * - Mounts /auth, /admin, / routes
 * - Has a 404 handler
 */
function buildApp() {
  const app = express();

  app.use(express.json());
  app.use(express.urlencoded({ extended: true }));

  // In-memory session (no MongoStore needed for auth/route tests)
  app.use(
    session({
      secret: 'test-secret',
      resave: false,
      saveUninitialized: false,
    })
  );

  // Stub flash so auth routes don't crash
  app.use((req, res, next) => {
    req.flash = () => {};
    next();
  });

  // Stub res.locals used by views/middleware
  app.use((req, res, next) => {
    res.locals.user = null;
    res.locals.currentPath = req.path;
    res.locals.frontendUrl = '';
    next();
  });

  // Mount routes
  app.use('/auth', authRoutes);
  app.use('/admin', adminRoutes);
  app.use('/', indexRoutes);

  // 404 handler (mirrors server.js)
  app.use((req, res) => {
    res.status(404);
    if (req.accepts('json')) return res.json({ error: 'Not found' });
    res.type('txt').send('Not found');
  });

  return app;
}

// ─── Known route prefixes (whitelist) ────────────────────────────────────────

const KNOWN_PREFIXES = ['/api/degree/', '/api/certificate/', '/admin/', '/auth/'];

function isKnownRoute(path) {
  return KNOWN_PREFIXES.some((prefix) => path.startsWith(prefix));
}

// ─── Property 1: Route ngoài phạm vi trả về 404 ──────────────────────────────

// Feature: degree-management-refactor, Property 1: Route ngoài phạm vi trả về 404
test('Property 1: unknown routes return 404', async () => {
  // Validates: Requirements 1.3
  const app = buildApp();

  // Arbitrary: random path segments that don't start with known prefixes
  const unknownPathArb = fc
    .array(fc.stringMatching(/^[a-z0-9_-]{1,10}$/), { minLength: 1, maxLength: 4 })
    .map((parts) => '/' + parts.join('/'))
    .filter((path) => !isKnownRoute(path));

  await fc.assert(
    fc.asyncProperty(unknownPathArb, async (path) => {
      const res = await request(app).get(path).set('Accept', 'application/json');
      expect(res.status).toBe(404);
    }),
    { numRuns: 100 }
  );
}, 120000);

// ─── Property 11: Authentication guard trên admin routes ─────────────────────

// Feature: degree-management-refactor, Property 11: Authentication guard trên admin routes
test('Property 11: unauthenticated requests to /admin/* are redirected to /auth/login', async () => {
  // Validates: Requirements 3.11
  const app = buildApp();

  // Known admin sub-paths to test
  const adminSubPathArb = fc
    .constantFrom(
      '/admin/dashboard',
      '/admin/degree',
      '/admin/degree/create',
      '/admin/department',
      '/admin/level',
      '/admin/audit-logs'
    );

  await fc.assert(
    fc.asyncProperty(adminSubPathArb, async (path) => {
      // No session cookie → not authenticated
      const res = await request(app).get(path);

      expect(res.status).toBe(302);
      expect(res.headers.location).toBe('/auth/login');
    }),
    { numRuns: 100 }
  );
}, 120000);

// ─── Property 18: Login, logout, request /admin/* → redirect ─────────────────

// Feature: degree-management-refactor, Property 18: Login, logout, request /admin/* → redirect
test('Property 18: after logout, requests to /admin/* redirect to /auth/login', async () => {
  // Validates: Requirements 6.5
  const app = buildApp();

  const adminSubPathArb = fc.constantFrom(
    '/admin/dashboard',
    '/admin/degree',
    '/admin/department',
    '/admin/level',
    '/admin/audit-logs'
  );

  await fc.assert(
    fc.asyncProperty(adminSubPathArb, async (path) => {
      // Step 1: Simulate an authenticated session by injecting isAuthenticated
      // We do this by adding a one-time setup route that sets the session flag
      const testApp = express();
      testApp.use(express.json());
      testApp.use(express.urlencoded({ extended: true }));
      testApp.use(
        session({
          secret: 'test-secret',
          resave: false,
          saveUninitialized: false,
        })
      );
      testApp.use((req, res, next) => {
        req.flash = () => {};
        next();
      });
      testApp.use((req, res, next) => {
        res.locals.user = null;
        res.locals.currentPath = req.path;
        res.locals.frontendUrl = '';
        next();
      });

      // Helper route: sets isAuthenticated = true in session
      testApp.get('/__test_login', (req, res) => {
        req.session.isAuthenticated = true;
        req.session.user = { id: 'test', username: 'testuser' };
        res.json({ ok: true });
      });

      // Helper route: destroys session (simulates logout)
      testApp.get('/__test_logout', (req, res) => {
        req.session.destroy(() => res.json({ ok: true }));
      });

      testApp.use('/auth', authRoutes);
      testApp.use('/admin', adminRoutes);
      testApp.use('/', indexRoutes);

      testApp.use((req, res) => {
        res.status(404);
        if (req.accepts('json')) return res.json({ error: 'Not found' });
        res.type('txt').send('Not found');
      });

      const agent = request.agent(testApp);

      // Step 2: Login (set session)
      await agent.get('/__test_login');

      // Step 3: Logout (destroy session)
      await agent.get('/__test_logout');

      // Step 4: Request admin route — should redirect to /auth/login
      const res = await agent.get(path);

      expect(res.status).toBe(302);
      expect(res.headers.location).toBe('/auth/login');
    }),
    { numRuns: 100 }
  );
}, 120000);