/**
 * @ai-summary Fastify app configuration with feature registration
 * @ai-context Each feature capsule registers its routes independently
 */
import Fastify, { FastifyInstance } from 'fastify';
import cors from '@fastify/cors';
import helmet from '@fastify/helmet';
import fastifyMultipart from '@fastify/multipart';

// Core plugins
import authPlugin from './core/plugins/auth.plugin';
import adminGuardPlugin, { setAdminGuardPool } from './core/plugins/admin-guard.plugin';
import tierGuardPlugin from './core/plugins/tier-guard.plugin';
import loggingPlugin from './core/plugins/logging.plugin';
import errorPlugin from './core/plugins/error.plugin';
import { appConfig } from './core/config/config-loader';

// Fastify feature routes
import { authRoutes } from './features/auth';
import { vehiclesRoutes } from './features/vehicles/api/vehicles.routes';
import { fuelLogsRoutes } from './features/fuel-logs/api/fuel-logs.routes';
import { stationsRoutes } from './features/stations/api/stations.routes';
import { communityStationsRoutes } from './features/stations/api/community-stations.routes';
import { documentsRoutes } from './features/documents/api/documents.routes';
import { maintenanceRoutes } from './features/maintenance';
import { platformRoutes } from './features/platform';
import { adminRoutes } from './features/admin/api/admin.routes';
import { auditLogRoutes } from './features/audit-log/api/audit-log.routes';
import { notificationsRoutes } from './features/notifications';
import { userProfileRoutes } from './features/user-profile';
import { onboardingRoutes } from './features/onboarding';
import { userPreferencesRoutes } from './features/user-preferences';
import { userExportRoutes } from './features/user-export';
import { pool } from './core/config/database';
import { configRoutes } from './core/config/config.routes';

async function buildApp(): Promise<FastifyInstance> {
  const app = Fastify({
    logger: false, // Use custom logging plugin instead
    maxParamLength: 1000, // Required for long Google Maps photo references
  });

  // Core middleware plugins
  await app.register(helmet);
  await app.register(cors);
  await app.register(loggingPlugin);
  await app.register(errorPlugin);

  // Multipart upload support with config-driven size limits
  const parseSizeToBytes = (val: string): number => {
    // Accept forms like "10MB", "5M", "1048576", "20kb", case-insensitive
    const s = String(val).trim().toLowerCase();
    const match = s.match(/^(\d+)(b|kb|k|mb|m|gb|g)?$/i);
    if (!match) {
      // Fallback: try to parse integer bytes
      const n = parseInt(s, 10);
      return Number.isFinite(n) && n > 0 ? n : 10 * 1024 * 1024; // default 10MB
    }
    const num = parseInt(match[1], 10);
    const unit = match[2] || 'b';
    switch (unit) {
      case 'b': return num;
      case 'k':
      case 'kb': return num * 1024;
      case 'm':
      case 'mb': return num * 1024 * 1024;
      case 'g':
      case 'gb': return num * 1024 * 1024 * 1024;
      default: return num;
    }
  };
  const fileSizeLimit = parseSizeToBytes(appConfig.config.performance.max_request_size);
  await app.register(fastifyMultipart, {
    limits: {
      fileSize: fileSizeLimit,
    },
  });
  
  // Authentication plugin
  await app.register(authPlugin);

  // Admin guard plugin - initializes after auth plugin
  await app.register(adminGuardPlugin);
  setAdminGuardPool(pool);

  // Tier guard plugin - for subscription tier enforcement
  await app.register(tierGuardPlugin);

  // Health check
  app.get('/health', async (_request, reply) => {
    return reply.code(200).send({
      status: 'healthy',
      timestamp: new Date().toISOString(),
      environment: process.env['NODE_ENV'],
      features: ['admin', 'auth', 'config', 'onboarding', 'vehicles', 'documents', 'fuel-logs', 'stations', 'maintenance', 'platform', 'notifications', 'user-profile', 'user-preferences', 'user-export']
    });
  });

  // API-prefixed health for Traefik route validation and diagnostics
  app.get('/api/health', async (_request, reply) => {
    return reply.code(200).send({
      status: 'healthy',
      scope: 'api',
      timestamp: new Date().toISOString(),
      features: ['admin', 'auth', 'config', 'onboarding', 'vehicles', 'documents', 'fuel-logs', 'stations', 'maintenance', 'platform', 'notifications', 'user-profile', 'user-preferences', 'user-export']
    });
  });

  // Traefik forward-auth integration endpoint
  app.get('/auth/verify', {
    preHandler: [app.authenticate]
  }, async (request, reply) => {
    const user = request.user;
    const userId = user?.sub || 'unknown';
    const rolesClaim = user?.['https://motovaultpro.com/roles'];
    const roles = Array.isArray(rolesClaim) ? rolesClaim : [];

    reply
      .header('X-Auth-User', userId)
      .header('X-Auth-Roles', roles.join(','))
      .code(200)
      .send({
        status: 'verified',
        userId,
        roles,
        verifiedAt: new Date().toISOString()
      });
  });

  // Register Fastify feature routes
  await app.register(authRoutes, { prefix: '/api' });
  await app.register(onboardingRoutes, { prefix: '/api' });
  await app.register(platformRoutes, { prefix: '/api' });
  await app.register(vehiclesRoutes, { prefix: '/api' });
  await app.register(documentsRoutes, { prefix: '/api' });
  await app.register(fuelLogsRoutes, { prefix: '/api' });
  await app.register(stationsRoutes, { prefix: '/api' });
  await app.register(communityStationsRoutes, { prefix: '/api' });
  await app.register(maintenanceRoutes, { prefix: '/api' });
  await app.register(adminRoutes, { prefix: '/api' });
  await app.register(auditLogRoutes, { prefix: '/api' });
  await app.register(notificationsRoutes, { prefix: '/api' });
  await app.register(userProfileRoutes, { prefix: '/api' });
  await app.register(userPreferencesRoutes, { prefix: '/api' });
  await app.register(userExportRoutes, { prefix: '/api' });
  await app.register(configRoutes, { prefix: '/api' });

  // 404 handler
  app.setNotFoundHandler(async (_request, reply) => {
    return reply.code(404).send({ error: 'Route not found' });
  });

  return app;
}

export { buildApp };

// For compatibility with existing server.ts
let appInstance: FastifyInstance | null = null;

export async function getApp(): Promise<FastifyInstance> {
  if (!appInstance) {
    appInstance = await buildApp();
  }
  return appInstance;
}

export default buildApp;