/**
 * Unit Tests: Service Account Authentication
 * 
 * Tests T033-T034: Test JWT authentication and credential validation
 * Tests the auth.js module in isolation
 * 
 * @module tests/unit/auth
 */

import { describe, it, beforeEach } from 'node:test';
import assert from 'node:assert/strict';

// =============================================================================
// T033: Unit test for Service Account JWT authentication
// =============================================================================

describe('T033: Service Account JWT Authentication', () => {
  let originalEnv;

  beforeEach(() => {
    // Save original env
    originalEnv = process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
  });

  it('should create GoogleAuth client from GOOGLE_SERVICE_ACCOUNT_KEY env var', async () => {
    // Mock credentials as inline JSON (per clarification #1)
    const mockCredentials = {
      type: 'service_account',
      project_id: 'test-project',
      private_key_id: 'key123',
      private_key: '-----BEGIN PRIVATE KEY-----\nMOCK_KEY\n-----END PRIVATE KEY-----\n',
      client_email: 'test@test-project.iam.gserviceaccount.com',
      client_id: '123456789',
      auth_uri: 'https://accounts.google.com/o/oauth2/auth',
      token_uri: 'https://oauth2.googleapis.com/token',
      auth_provider_x509_cert_url: 'https://www.googleapis.com/oauth2/v1/certs'
    };

    // Set env var with inline JSON
    process.env.GOOGLE_SERVICE_ACCOUNT_KEY = JSON.stringify(mockCredentials);

    // TODO: Import and call initializeAuth from src/auth.js
    // const { initializeAuth } = await import('../../src/auth.js');
    // const auth = await initializeAuth();

    // Verify GoogleAuth was created with correct credentials
    // assert.ok(auth, 'Should return auth client');
    // assert.equal(auth.credentials.client_email, mockCredentials.client_email, 'Should use client_email from env var');

    // Restore env
    if (originalEnv) {
      process.env.GOOGLE_SERVICE_ACCOUNT_KEY = originalEnv;
    } else {
      delete process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
    }
  });

  it('should use correct Drive API scope (read-only)', async () => {
    const mockCredentials = {
      type: 'service_account',
      project_id: 'test-project',
      private_key: '-----BEGIN PRIVATE KEY-----\nMOCK_KEY\n-----END PRIVATE KEY-----\n',
      client_email: 'test@test-project.iam.gserviceaccount.com'
    };

    process.env.GOOGLE_SERVICE_ACCOUNT_KEY = JSON.stringify(mockCredentials);

    // TODO: Import and call initializeAuth
    // const { initializeAuth } = await import('../../src/auth.js');
    // const auth = await initializeAuth();

    // Verify scope is read-only
    const expectedScope = 'https://www.googleapis.com/auth/drive.readonly';
    // assert.ok(auth.scopes.includes(expectedScope), 'Should use drive.readonly scope');

    // Restore env
    if (originalEnv) {
      process.env.GOOGLE_SERVICE_ACCOUNT_KEY = originalEnv;
    } else {
      delete process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
    }
  });

  it('should parse inline JSON from env var correctly', async () => {
    // Test with different JSON formatting (whitespace, escaped quotes)
    const mockCredentials = {
      client_email: 'test@project.iam.gserviceaccount.com',
      private_key: '-----BEGIN PRIVATE KEY-----\nMOCK_KEY\n-----END PRIVATE KEY-----\n',
      project_id: 'test-project'
    };

    // Set with extra whitespace
    process.env.GOOGLE_SERVICE_ACCOUNT_KEY = JSON.stringify(mockCredentials, null, 2);

    // TODO: Import and call initializeAuth
    // const { initializeAuth } = await import('../../src/auth.js');
    // const auth = await initializeAuth();

    // Should parse correctly despite formatting
    // assert.ok(auth, 'Should parse JSON with whitespace');

    // Restore env
    if (originalEnv) {
      process.env.GOOGLE_SERVICE_ACCOUNT_KEY = originalEnv;
    } else {
      delete process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
    }
  });
});

// =============================================================================
// T034: Unit test for credential validation
// =============================================================================

describe('T034: Credential Validation', () => {
  it('should detect missing client_email field', async () => {
    const invalidCredentials = {
      private_key: '-----BEGIN PRIVATE KEY-----\nMOCK_KEY\n-----END PRIVATE KEY-----\n',
      project_id: 'test-project'
      // Missing client_email
    };

    process.env.GOOGLE_SERVICE_ACCOUNT_KEY = JSON.stringify(invalidCredentials);

    // TODO: Import validateCredentials from src/auth.js
    // const { validateCredentials } = await import('../../src/auth.js');
    
    // Should throw error for missing client_email
    // await assert.rejects(
    //   async () => await validateCredentials(invalidCredentials),
    //   { message: /client_email/ },
    //   'Should reject credentials without client_email'
    // );

    delete process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
  });

  it('should detect missing private_key field', async () => {
    const invalidCredentials = {
      client_email: 'test@project.iam.gserviceaccount.com',
      project_id: 'test-project'
      // Missing private_key
    };

    process.env.GOOGLE_SERVICE_ACCOUNT_KEY = JSON.stringify(invalidCredentials);

    // TODO: Import validateCredentials
    // const { validateCredentials } = await import('../../src/auth.js');
    
    // Should throw error for missing private_key
    // await assert.rejects(
    //   async () => await validateCredentials(invalidCredentials),
    //   { message: /private_key/ },
    //   'Should reject credentials without private_key'
    // );

    delete process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
  });

  it('should detect missing project_id field', async () => {
    const invalidCredentials = {
      client_email: 'test@project.iam.gserviceaccount.com',
      private_key: '-----BEGIN PRIVATE KEY-----\nMOCK_KEY\n-----END PRIVATE KEY-----\n'
      // Missing project_id
    };

    process.env.GOOGLE_SERVICE_ACCOUNT_KEY = JSON.stringify(invalidCredentials);

    // TODO: Import validateCredentials
    // const { validateCredentials } = await import('../../src/auth.js');
    
    // Should throw error for missing project_id
    // await assert.rejects(
    //   async () => await validateCredentials(invalidCredentials),
    //   { message: /project_id/ },
    //   'Should reject credentials without project_id'
    // );

    delete process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
  });

  it('should detect empty credential fields', async () => {
    const invalidCredentials = {
      client_email: '',  // Empty
      private_key: '-----BEGIN PRIVATE KEY-----\nMOCK_KEY\n-----END PRIVATE KEY-----\n',
      project_id: 'test-project'
    };

    process.env.GOOGLE_SERVICE_ACCOUNT_KEY = JSON.stringify(invalidCredentials);

    // TODO: Import validateCredentials
    // const { validateCredentials } = await import('../../src/auth.js');
    
    // Should throw error for empty client_email
    // await assert.rejects(
    //   async () => await validateCredentials(invalidCredentials),
    //   { message: /client_email.*empty/ },
    //   'Should reject empty client_email'
    // );

    delete process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
  });

  it('should accept valid credentials', async () => {
    const validCredentials = {
      type: 'service_account',
      project_id: 'test-project',
      private_key: '-----BEGIN PRIVATE KEY-----\nMOCK_KEY\n-----END PRIVATE KEY-----\n',
      client_email: 'test@test-project.iam.gserviceaccount.com'
    };

    process.env.GOOGLE_SERVICE_ACCOUNT_KEY = JSON.stringify(validCredentials);

    // TODO: Import validateCredentials
    // const { validateCredentials } = await import('../../src/auth.js');
    
    // Should not throw for valid credentials
    // await assert.doesNotReject(
    //   async () => await validateCredentials(validCredentials),
    //   'Should accept valid credentials'
    // );

    delete process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
  });

  it('should trigger fatal error handler on invalid credentials (exit code 1)', async () => {
    // Per T016: Fatal error handler should log to stderr and exit with code 1
    const invalidCredentials = {
      invalid: 'structure'
    };

    process.env.GOOGLE_SERVICE_ACCOUNT_KEY = JSON.stringify(invalidCredentials);

    // TODO: Import initializeAuth which should call fatal error handler
    // const { initializeAuth } = await import('../../src/auth.js');

    // Mock process.exit to prevent actual exit
    // let exitCode;
    // const originalExit = process.exit;
    // process.exit = (code) => { exitCode = code; throw new Error('EXIT'); };

    // try {
    //   await initializeAuth();
    // } catch (e) {
    //   if (e.message === 'EXIT') {
    //     assert.equal(exitCode, 1, 'Should exit with code 1 on invalid credentials');
    //   } else {
    //     throw e;
    //   }
    // } finally {
    //   process.exit = originalExit;
    // }

    delete process.env.GOOGLE_SERVICE_ACCOUNT_KEY;
  });
});