'use strict';

// courses.routes.js used to re-declare `router.use(authenticate, requireAdmin(), adminLimiter)`
// on top of the guard chain admin.routes.js already applies to every mounted admin sub-router.
// That double-application silently halved the effective adminLimiter budget (each request
// incremented the shared store twice) and surfaced as premature "Too many admin requests"
// errors. This suite locks in the invariant: the guard chain is applied exactly once, in
// admin.routes.js, and never re-declared by the sub-routers it mounts.

process.env.NODE_ENV = 'test';

const path = require('path');
const fs = require('fs');

const { authenticate } = require('../../middleware/auth.middleware');
const { adminLimiter } = require('../../middleware/rateLimiter.middleware');

const adminRoutesDir = path.join(__dirname, '../../routes/admin');

// Every admin sub-router mounted by admin.routes.js, discovered dynamically so newly
// added route files are covered automatically.
const subRouterFiles = fs
  .readdirSync(adminRoutesDir)
  .filter((f) => f.endsWith('.routes.js') && f !== 'admin.routes.js');

function stackHandles(router) {
  return router.stack.map((layer) => layer.handle);
}

describe('admin sub-routers do not re-declare inherited guards', () => {
  test.each(subRouterFiles)('%s does not re-apply authenticate or adminLimiter', (file) => {
    const router = require(path.join(adminRoutesDir, file));
    const handles = stackHandles(router);

    expect(handles).not.toContain(authenticate);
    expect(handles).not.toContain(adminLimiter);
  });

  // Explicit named cases for clarity: the one that broke, plus known-good references.
  test('courses.routes.js (regression case) has no top-level guard layer', () => {
    const router = require(path.join(adminRoutesDir, 'courses.routes.js'));
    const handles = stackHandles(router);

    expect(handles).not.toContain(authenticate);
    expect(handles).not.toContain(adminLimiter);
  });

  test('units.routes.js (already correct) has no top-level guard layer', () => {
    const router = require(path.join(adminRoutesDir, 'units.routes.js'));
    const handles = stackHandles(router);

    expect(handles).not.toContain(authenticate);
    expect(handles).not.toContain(adminLimiter);
  });

  test('lessons.routes.js (already correct) has no top-level guard layer', () => {
    const router = require(path.join(adminRoutesDir, 'lessons.routes.js'));
    const handles = stackHandles(router);

    expect(handles).not.toContain(authenticate);
    expect(handles).not.toContain(adminLimiter);
  });
});

describe('admin.routes.js applies the guard chain exactly once', () => {
  test('authenticate and adminLimiter each appear exactly one time in the stack', () => {
    const adminRouter = require(path.join(adminRoutesDir, 'admin.routes.js'));
    const handles = stackHandles(adminRouter);

    const authCount  = handles.filter((h) => h === authenticate).length;
    const limitCount = handles.filter((h) => h === adminLimiter).length;

    expect(authCount).toBe(1);
    expect(limitCount).toBe(1);
  });
});