/**
 * Express application factory for SentryAgent.ai AgentIdP.
 * Creates and configures the Express app with all middleware and routes.
 * Exported as a factory function — does NOT call listen (testable).
 */

import express, { Application } from 'express';
import helmet from 'helmet';
import cors from 'cors';
import morgan from 'morgan';
import Stripe from 'stripe';

import { getPool } from './db/pool.js';
import { getRedisClient } from './cache/redis.js';

import { AgentRepository } from './repositories/AgentRepository.js';
import { CredentialRepository } from './repositories/CredentialRepository.js';
import { TokenRepository } from './repositories/TokenRepository.js';
import { AuditRepository } from './repositories/AuditRepository.js';
import { OrgRepository } from './repositories/OrgRepository.js';

import { AuditService } from './services/AuditService.js';
import { AgentService } from './services/AgentService.js';
import { AnalyticsService } from './services/AnalyticsService.js';
import { MarketplaceService } from './services/MarketplaceService.js';
import { BillingService } from './services/BillingService.js';
import { UsageService } from './services/UsageService.js';
import { CredentialService } from './services/CredentialService.js';
import { OAuth2Service } from './services/OAuth2Service.js';
import { OrgService } from './services/OrgService.js';
import { DIDService } from './services/DIDService.js';
import { OIDCKeyService } from './services/OIDCKeyService.js';
import { IDTokenService } from './services/IDTokenService.js';
import { FederationService } from './services/FederationService.js';
import { WebhookService } from './services/WebhookService.js';
import { EventPublisher } from './services/EventPublisher.js';
import { WebhookDeliveryWorker } from './workers/WebhookDeliveryWorker.js';
import { createKafkaProducer } from './adapters/KafkaAdapter.js';

import { AnalyticsController } from './controllers/AnalyticsController.js';
import { AgentController } from './controllers/AgentController.js';
import { MarketplaceController } from './controllers/MarketplaceController.js';
import { BillingController } from './controllers/BillingController.js';
import { OIDCTrustPolicyController } from './controllers/OIDCTrustPolicyController.js';
import { OIDCTokenExchangeController } from './controllers/OIDCTokenExchangeController.js';
import { TokenController } from './controllers/TokenController.js';
import { CredentialController } from './controllers/CredentialController.js';
import { AuditController } from './controllers/AuditController.js';
import { OrgController } from './controllers/OrgController.js';
import { DIDController } from './controllers/DIDController.js';
import { OIDCController } from './controllers/OIDCController.js';
import { FederationController } from './controllers/FederationController.js';
import { WebhookController } from './controllers/WebhookController.js';
import { ComplianceController } from './controllers/ComplianceController.js';
import { ComplianceService } from './services/ComplianceService.js';

import { createAnalyticsRouter } from './routes/analytics.js';
import { createAgentsRouter } from './routes/agents.js';
import { createMarketplaceRouter } from './routes/marketplace.js';
import { createBillingRouter } from './routes/billing.js';
import { createOIDCTrustPoliciesRouter } from './routes/oidcTrustPolicies.js';
import { createOIDCTokenExchangeRouter } from './routes/oidcTokenExchange.js';
import { OIDCTrustPolicyService } from './services/OIDCTrustPolicyService.js';
import { createTokenRouter } from './routes/token.js';
import { createCredentialsRouter } from './routes/credentials.js';
import { createAuditRouter } from './routes/audit.js';
import { createHealthRouter } from './routes/health.js';
import { createMetricsRouter } from './routes/metrics.js';
import { createOrgsRouter } from './routes/organizations.js';
import { createDIDRouter } from './routes/did.js';
import { createOIDCRouter } from './routes/oidc.js';
import { createFederationRouter } from './routes/federation.js';
import { createWebhooksRouter } from './routes/webhooks.js';
import { createComplianceRouter } from './routes/compliance.js';
import { createDelegationRouter } from './routes/delegation.js';
import { DelegationService } from './services/DelegationService.js';
import { DelegationController } from './controllers/DelegationController.js';
import { createScaffoldRouter } from './routes/scaffold.js';
import { ScaffoldService } from './services/ScaffoldService.js';
import { ScaffoldController } from './controllers/ScaffoldController.js';
import { TierService } from './services/TierService.js';
import { TierController } from './controllers/TierController.js';
import { createTiersRouter } from './routes/tiers.js';

import { errorHandler } from './middleware/errorHandler.js';
import { createOpaMiddleware } from './middleware/opa.js';
import { metricsMiddleware } from './middleware/metrics.js';
import { createOrgContextMiddleware } from './middleware/orgContext.js';
import { authMiddleware } from './middleware/auth.js';
import { createUsageMeteringMiddleware, startUsageMeteringFlush } from './middleware/usageMeteringMiddleware.js';
import { createTierEnforcementMiddleware } from './middleware/tierEnforcement.js';
import { tlsEnforcementMiddleware } from './middleware/TLSEnforcementMiddleware.js';
import { createVaultClientFromEnv } from './vault/VaultClient.js';
import { getEncryptionService } from './services/EncryptionService.js';
import { getAuditVerificationService } from './services/AuditVerificationService.js';
import { startSecretsRotationJob } from './jobs/SecretsRotationJob.js';
import { startAuditChainVerificationJob } from './jobs/AuditChainVerificationJob.js';
import { RedisClientType } from 'redis';
import path from 'path';

/**
 * Creates and returns a configured Express application.
 * All infrastructure dependencies (DB pool, Redis) are initialised here.
 *
 * @returns Promise resolving to the configured Express Application.
 * @throws Error if required environment variables are missing.
 */
export async function createApp(): Promise<Application> {
  const app = express();

  // ────────────────────────────────────────────────────────────────
  // TLS enforcement — MUST be first middleware (SOC 2 CC6.7)
  // In production, redirects all non-HTTPS requests to HTTPS.
  // ────────────────────────────────────────────────────────────────
  app.use(tlsEnforcementMiddleware);

  // ────────────────────────────────────────────────────────────────
  // Security headers
  // ────────────────────────────────────────────────────────────────
  app.use(helmet());

  // ────────────────────────────────────────────────────────────────
  // CORS
  // ────────────────────────────────────────────────────────────────
  const corsOrigin = process.env['CORS_ORIGIN'] ?? '*';
  app.use(cors({ origin: corsOrigin }));

  // ────────────────────────────────────────────────────────────────
  // Request logging
  // ────────────────────────────────────────────────────────────────
  if (process.env['NODE_ENV'] !== 'test') {
    app.use(morgan('combined'));
  }

  // ────────────────────────────────────────────────────────────────
  // Body parsers
  // JSON body parser for most routes
  // urlencoded parser for token endpoint (application/x-www-form-urlencoded)
  // ────────────────────────────────────────────────────────────────
  app.use(express.json());
  app.use(express.urlencoded({ extended: false }));

  // ────────────────────────────────────────────────────────────────
  // Prometheus HTTP metrics middleware — must be before all routes
  // ────────────────────────────────────────────────────────────────
  app.use(metricsMiddleware);

  // ────────────────────────────────────────────────────────────────
  // Infrastructure singletons
  // ────────────────────────────────────────────────────────────────
  const pool = getPool();
  const redis = await getRedisClient();

  // ────────────────────────────────────────────────────────────────
  // Repository layer
  // ────────────────────────────────────────────────────────────────
  const agentRepo = new AgentRepository(pool);
  const credentialRepo = new CredentialRepository(pool);
  // eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
  const tokenRepo = new TokenRepository(pool, redis as RedisClientType);
  const auditRepo = new AuditRepository(pool);
  const orgRepo = new OrgRepository(pool);

  // ────────────────────────────────────────────────────────────────
  // Optional integrations
  // ────────────────────────────────────────────────────────────────
  // Vault is optional. When VAULT_ADDR + VAULT_TOKEN are set, new credentials
  // are stored in Vault KV v2. When not set, bcrypt is used (Phase 1 behaviour).
  const vaultClient = createVaultClientFromEnv();
  if (vaultClient !== null) {
    console.log('[AgentIdP] Vault integration enabled — new credentials will use Vault KV v2');
  }

  // ────────────────────────────────────────────────────────────────
  // Kafka (optional) — activated when KAFKA_BROKERS env var is set
  // ────────────────────────────────────────────────────────────────
  const kafkaProducer = await createKafkaProducer();
  if (kafkaProducer !== null) {
    console.log('[AgentIdP] Kafka integration enabled — events will be produced to agentidp-events');
  }

  // ────────────────────────────────────────────────────────────────
  // Encryption service — column-level AES-256-CBC (SOC 2 CC6.1)
  // Only initialised when Vault is configured (key stored in Vault).
  // ────────────────────────────────────────────────────────────────
  const encryptionService =
    vaultClient !== null ? getEncryptionService(vaultClient) : null;
  if (encryptionService !== null) {
    console.log('[AgentIdP] EncryptionService enabled — sensitive columns encrypted at rest (SOC 2 CC6.1)');
  }

  // ────────────────────────────────────────────────────────────────
  // Webhook infrastructure
  // ────────────────────────────────────────────────────────────────
  const redisUrl = process.env['REDIS_URL'] ?? 'redis://localhost:6379';
  const webhookService = new WebhookService(pool, vaultClient, redis as RedisClientType, encryptionService);
  const webhookWorker = new WebhookDeliveryWorker(pool, vaultClient, redis as RedisClientType, redisUrl);
  webhookWorker.start();
  const eventPublisher = new EventPublisher(webhookWorker, pool, kafkaProducer);

  // ────────────────────────────────────────────────────────────────
  // Stripe client + TierService — created early so both BillingService
  // and AgentService can receive TierService via constructor injection.
  // ────────────────────────────────────────────────────────────────
  const stripe = new Stripe(process.env['STRIPE_SECRET_KEY'] ?? '', { apiVersion: '2026-03-25.dahlia' });
  const tierService = new TierService(pool, redis as RedisClientType, stripe);

  // ────────────────────────────────────────────────────────────────
  // Service layer
  // ────────────────────────────────────────────────────────────────
  const auditService = new AuditService(auditRepo);
  const didService = new DIDService(pool, vaultClient, redis as RedisClientType, encryptionService);

  // ────────────────────────────────────────────────────────────────
  // Phase 6 WS3: Analytics Service
  // ────────────────────────────────────────────────────────────────
  const analyticsService = new AnalyticsService(pool);

  const agentService = new AgentService(agentRepo, credentialRepo, auditService, didService, eventPublisher, analyticsService, tierService);
  const marketplaceService = new MarketplaceService(agentRepo);
  const credentialService = new CredentialService(credentialRepo, agentRepo, auditService, vaultClient, eventPublisher, encryptionService);
  const orgService = new OrgService(orgRepo, agentRepo);

  const privateKey = process.env['JWT_PRIVATE_KEY'];
  const publicKey = process.env['JWT_PUBLIC_KEY'];
  if (!privateKey || !publicKey) {
    throw new Error('JWT_PRIVATE_KEY and JWT_PUBLIC_KEY environment variables are required');
  }

  // OIDC services — initialised after DB pool is ready
  const oidcKeyService = new OIDCKeyService(pool, redis as RedisClientType);
  await oidcKeyService.ensureCurrentKey();
  const idTokenService = new IDTokenService(oidcKeyService);

  const oauth2Service = new OAuth2Service(
    tokenRepo,
    credentialRepo,
    agentRepo,
    auditService,
    privateKey,
    publicKey,
    vaultClient,
    idTokenService,
    eventPublisher,
    encryptionService,
    analyticsService,
  );

  // ────────────────────────────────────────────────────────────────
  // OPA authorization middleware (created once — shared across all routers)
  // ────────────────────────────────────────────────────────────────
  const opaMiddleware = await createOpaMiddleware();

  // ────────────────────────────────────────────────────────────────
  // Controller layer
  // ────────────────────────────────────────────────────────────────
  const agentController = new AgentController(agentService);
  const analyticsController = new AnalyticsController(analyticsService);
  const tokenController = new TokenController(oauth2Service);
  const credentialController = new CredentialController(credentialService);
  const auditController = new AuditController(auditService);
  const orgController = new OrgController(orgService);
  const didController = new DIDController(didService, agentRepo);
  const oidcController = new OIDCController(oidcKeyService, agentRepo);
  const federationService = new FederationService(pool, redis as RedisClientType);
  const federationController = new FederationController(federationService);
  const webhookController = new WebhookController(webhookService);
  const marketplaceController = new MarketplaceController(marketplaceService);

  // ────────────────────────────────────────────────────────────────
  // Billing & Usage Metering (WS6)
  // ────────────────────────────────────────────────────────────────
  const billingService = new BillingService(pool, stripe, tierService);
  const usageService = new UsageService(pool);
  const billingController = new BillingController(billingService, usageService);

  // Start periodic flush of in-memory usage counters to DB (every 60s)
  startUsageMeteringFlush(pool);

  // OIDC trust policy management + GitHub Actions token exchange
  const oidcTrustPolicyService = new OIDCTrustPolicyService(pool);
  const oidcTrustPolicyController = new OIDCTrustPolicyController(oidcTrustPolicyService);
  const oidcTokenExchangeController = new OIDCTokenExchangeController(oidcTrustPolicyService, privateKey);

  // ────────────────────────────────────────────────────────────────
  // Compliance services and background jobs (SOC 2 Type II)
  // ────────────────────────────────────────────────────────────────
  const auditVerificationService = getAuditVerificationService(pool);
  const complianceService = new ComplianceService(pool, redis as RedisClientType);
  const complianceController = new ComplianceController(auditVerificationService, complianceService);

  // Start background compliance monitoring jobs (non-blocking)
  startSecretsRotationJob(pool);
  startAuditChainVerificationJob(auditVerificationService);

  // ────────────────────────────────────────────────────────────────
  // Org context middleware — sets PostgreSQL session variable app.organization_id
  // Must run after auth (so req.user is populated) and before route handlers.
  // Applied globally here; routes that don't require auth skip it gracefully.
  // ────────────────────────────────────────────────────────────────
  app.use(createOrgContextMiddleware(pool));

  // ────────────────────────────────────────────────────────────────
  // Usage metering — records per-tenant API call counts in-memory
  // Applied after auth middleware so req.user is populated.
  // ────────────────────────────────────────────────────────────────
  app.use(createUsageMeteringMiddleware(pool));

  // ────────────────────────────────────────────────────────────────
  // Tier enforcement — Redis-backed daily API call rate limits per
  // tenant tier (free/pro/enterprise). Runs after auth; skipped when
  // TIER_ENFORCEMENT=false or for enterprise tenants. Supersedes
  // the legacy freeTierEnforcementMiddleware (removed Phase 6 WS4).
  // ────────────────────────────────────────────────────────────────
  app.use(createTierEnforcementMiddleware(pool, redis as RedisClientType));

  // ────────────────────────────────────────────────────────────────
  // Routes
  // ────────────────────────────────────────────────────────────────
  const API_BASE = '/api/v1';

  // Health check — unauthenticated, no OPA
  app.use('/health', createHealthRouter(pool, redis as RedisClientType));

  // Prometheus metrics — unauthenticated, internal scraping only
  app.use('/metrics', createMetricsRouter());

  // Well-known DID Document for the AgentIdP instance — unauthenticated
  app.get('/.well-known/did.json', (req, res, next) => {
    void didController.getInstanceDIDDocument(req, res, next);
  });

  // OIDC well-known endpoints and agent-info — mounted at root so /.well-known/* paths resolve
  app.use('/', createOIDCRouter(oidcController, authMiddleware));

  app.use(`${API_BASE}/agents`, createAgentsRouter(agentController, opaMiddleware));
  app.use(`${API_BASE}`, createDIDRouter(didController, authMiddleware, opaMiddleware));
  app.use(
    `${API_BASE}/agents/:agentId/credentials`,
    createCredentialsRouter(credentialController, opaMiddleware),
  );
  app.use(`${API_BASE}/token`, createTokenRouter(tokenController, opaMiddleware));
  app.use(`${API_BASE}/audit`, createAuditRouter(auditController, opaMiddleware));
  app.use(`${API_BASE}/organizations`, createOrgsRouter(orgController, opaMiddleware));
  app.use(`${API_BASE}`, createFederationRouter(federationController, authMiddleware, opaMiddleware));
  app.use(`${API_BASE}/webhooks`, createWebhooksRouter(webhookController, authMiddleware, opaMiddleware));
  app.use(`${API_BASE}`, createComplianceRouter(complianceController));
  app.use(`${API_BASE}/marketplace`, createMarketplaceRouter(marketplaceController));

  // Billing & Usage Metering — checkout, webhook, usage summary
  app.use(`${API_BASE}/billing`, createBillingRouter(billingController, authMiddleware));

  // ────────────────────────────────────────────────────────────────
  // Phase 6 WS4: Tier management — status and upgrade endpoints
  // ────────────────────────────────────────────────────────────────
  const tierController = new TierController(tierService);
  app.use(`${API_BASE}/tiers`, createTiersRouter(tierController, authMiddleware));

  // OIDC trust-policy management (authenticated) and token exchange (unauthenticated)
  // Both routers mount under ${API_BASE}/oidc — trust-policy routes use /trust-policies prefix,
  // token exchange uses /token, so there are no path conflicts.
  app.use(`${API_BASE}/oidc`, createOIDCTrustPoliciesRouter(oidcTrustPolicyController, authMiddleware));
  app.use(`${API_BASE}/oidc`, createOIDCTokenExchangeRouter(oidcTokenExchangeController));

  // ────────────────────────────────────────────────────────────────
  // Phase 5 WS2: A2A Delegation (guarded by A2A_ENABLED flag)
  // ────────────────────────────────────────────────────────────────
  if (process.env['A2A_ENABLED'] !== 'false') {
    const delegationService = new DelegationService(pool, auditService);
    const delegationController = new DelegationController(delegationService);
    app.use(`${API_BASE}`, createDelegationRouter(delegationController, authMiddleware));
  }

  // ────────────────────────────────────────────────────────────────
  // Phase 6 WS3: Analytics (guarded by ANALYTICS_ENABLED flag)
  // When disabled, all /api/v1/analytics/* routes return 404.
  // ────────────────────────────────────────────────────────────────
  if (process.env['ANALYTICS_ENABLED'] !== 'false') {
    app.use(`${API_BASE}/analytics`, createAnalyticsRouter(analyticsController, authMiddleware));
  }

  // ────────────────────────────────────────────────────────────────
  // Phase 5 WS5: Scaffold Generator
  // ────────────────────────────────────────────────────────────────
  const scaffoldService = new ScaffoldService();
  const scaffoldController = new ScaffoldController(scaffoldService, agentRepo, credentialRepo, auditService);
  app.use(`${API_BASE}`, createScaffoldRouter(scaffoldController, authMiddleware));

  // ────────────────────────────────────────────────────────────────
  // Dashboard static assets (served from dashboard/dist/)
  // Placed after API routes so API routes take precedence.
  // __dirname is available because the project compiles to CommonJS.
  // ────────────────────────────────────────────────────────────────
  const dashboardDist = path.resolve(__dirname, '../../dashboard/dist');

  app.use('/dashboard', express.static(dashboardDist));

  // SPA fallback — serve index.html for all /dashboard/* routes not matching a static file
  app.get('/dashboard/*', (_req, res) => {
    res.sendFile(path.join(dashboardDist, 'index.html'));
  });

  // ────────────────────────────────────────────────────────────────
  // Global error handler (must be last)
  // ────────────────────────────────────────────────────────────────
  app.use(errorHandler);

  return app;
}