/**
 * ABE API Server
 * Express + socket.io on port 3001.
 * Manages exploration sessions and serves REST + WebSocket API.
 */

import express, { Request, Response, NextFunction } from 'express';
import cors from 'cors';
import http from 'http';
import rateLimit from 'express-rate-limit';
import { Server as SocketIOServer } from 'socket.io';
import { createSessionRouter } from './routes/sessions';
import { createAnomalyRouter } from './routes/anomalies';
import { createConfigRouter } from './routes/config';
import { createScheduleRouter } from './routes/schedules';
import { createVisualRouter } from './routes/visual';
import { SessionStore } from './SessionStore';
import { apiKeyAuth } from './middleware/auth';
import { log } from './logger';
import { SchedulerService } from './scheduler/SchedulerService';
import { ScheduleRepository } from '../db/ScheduleRepository';
import { VisualBaselineRepository } from '../db/VisualBaselineRepository';
import { AIEnrichmentService } from './enrichment/AIEnrichmentService';

const PORT = process.env['ABE_PORT']
  ? parseInt(process.env['ABE_PORT'], 10)
  : process.env['PORT']
    ? parseInt(process.env['PORT'], 10)
    : 3001;

export function createApp(
  store: SessionStore,
  dbCheck?: () => boolean,
  scheduleRepo?: ScheduleRepository,
  scheduler?: SchedulerService,
  visualRepo?: VisualBaselineRepository,
  enrichmentService?: AIEnrichmentService
) {
  const corsOrigin = process.env['ABE_CORS_ORIGIN'] ?? 'http://localhost:5173';
  const app = express();

  app.use(cors({ origin: corsOrigin }));
  app.use(express.json());

  // Health endpoints — no auth required
  app.get('/health', (_req: Request, res: Response) => {
    const uptime = Math.floor(process.uptime());
    res.json({ status: 'ok', version: '0.1.0', uptime_seconds: uptime });
  });

  app.get('/ready', (_req: Request, res: Response) => {
    const stats = store.getStats();
    if (dbCheck && !dbCheck()) {
      res.status(503).json({ status: 'not_ready', db: 'disconnected', active_sessions: stats.runningSessions });
      return;
    }
    res.json({ status: 'ready', db: 'connected', active_sessions: stats.runningSessions });
  });

  // Apply API key auth to all /api/* routes
  app.use('/api', apiKeyAuth);

  // Global rate limit: 200 req/min
  const globalLimiter = rateLimit({
    windowMs: 60 * 1000,
    max: 200,
    standardHeaders: true,
    legacyHeaders: false,
  });
  app.use('/api', globalLimiter);

  // POST /api/sessions rate limit: 20/hour
  const sessionCreateLimiter = rateLimit({
    windowMs: 60 * 60 * 1000,
    max: 20,
    standardHeaders: true,
    legacyHeaders: false,
  });
  app.post('/api/sessions', sessionCreateLimiter);

  app.get('/api/stats', (_req: Request, res: Response) => {
    res.json(store.getStats());
  });

  app.use('/api/sessions', createSessionRouter(store));
  app.use('/api/anomalies', createAnomalyRouter(store, enrichmentService));
  app.use('/api/config', createConfigRouter());
  if (scheduleRepo && scheduler) {
    app.use('/api/schedules', createScheduleRouter(scheduleRepo, scheduler));
  }
  if (visualRepo) {
    app.use('/api/visual', createVisualRouter(visualRepo));
  }

  // Global error handler
  app.use((err: unknown, _req: Request, res: Response, _next: NextFunction) => {
    const isDev = process.env['NODE_ENV'] !== 'production';
    const message = isDev && err instanceof Error ? err.message : 'Internal server error';
    res.status(500).json({
      error: message,
      code: 'INTERNAL_ERROR',
      timestamp: Date.now(),
    });
  });

  return app;
}

export function createServer(
  store: SessionStore,
  dbCheck?: () => boolean,
  scheduleRepo?: ScheduleRepository,
  scheduler?: SchedulerService,
  visualRepo?: VisualBaselineRepository
) {
  const corsOrigin = process.env['ABE_CORS_ORIGIN'] ?? 'http://localhost:5173';

  // Deferred emitter: AIEnrichmentService is created before io, using a closure
  let ioEmit: (event: string, payload: unknown) => void = () => undefined;
  const enrichmentService = new AIEnrichmentService((event, payload) => ioEmit(event, payload));

  const app = createApp(store, dbCheck, scheduleRepo, scheduler, visualRepo, enrichmentService);
  const httpServer = http.createServer(app);
  const io = new SocketIOServer(httpServer, {
    cors: { origin: corsOrigin },
  });

  // Now wire the real io emitter
  ioEmit = (event, payload) => io.emit(event, payload);

  io.on('connection', (socket) => {
    socket.on('session:stop', (data: { sessionId: string }) => {
      store.stopSession(data.sessionId);
    });
  });

  store.setEmitter((event, payload) => {
    io.emit(event, payload);
    // Auto-enrich high/critical anomalies
    if (event === 'anomaly:detected') {
      const p = payload as { anomalyId?: string };
      if (p?.anomalyId) {
        const anomaly = store.getAnomaly(p.anomalyId);
        if (anomaly && enrichmentService.shouldAutoEnrich(anomaly)) {
          const context = {
            domSnapshot: '',
            httpLog: anomaly.evidence.httpLog ?? [],
            consoleErrors: anomaly.evidence.rawErrors ?? [],
            actionTrace: anomaly.actionTrace,
            pageTitle: '',
            url: anomaly.actionTrace[anomaly.actionTrace.length - 1]?.url ?? '',
          };
          void enrichmentService.enrich(anomaly, context);
        }
      }
    }
  });

  return httpServer;
}

if (require.main === module) {
  // eslint-disable-next-line @typescript-eslint/no-require-imports
  const { getDb } = require('../db/connection') as typeof import('../db/connection');
  // eslint-disable-next-line @typescript-eslint/no-require-imports
  const { SessionRepository } = require('../db/SessionRepository') as typeof import('../db/SessionRepository');
  // eslint-disable-next-line @typescript-eslint/no-require-imports
  const { AnomalyRepository } = require('../db/AnomalyRepository') as typeof import('../db/AnomalyRepository');
  // eslint-disable-next-line @typescript-eslint/no-require-imports
  const { NotificationService } = require('./notifications/NotificationService') as typeof import('./notifications/NotificationService');

  const db = getDb();
  const sessionRepo = new SessionRepository(db);
  const anomalyRepo = new AnomalyRepository(db);

  const notificationService = new NotificationService({
    persister: (record) => {
      db.prepare(
        `INSERT OR REPLACE INTO notifications (id, anomaly_id, channel, status, sent_at, error)
         VALUES (?, ?, ?, ?, ?, ?)`
      ).run(
        record.id,
        record.anomalyId,
        record.channel,
        record.status,
        record.sentAt ?? null,
        record.error ?? null
      );
    },
  });

  const outputDir = process.env['ABE_REPORTS_DIR'] ?? './reports';
  const maxConcurrent = process.env['ABE_MAX_CONCURRENT_SESSIONS']
    ? parseInt(process.env['ABE_MAX_CONCURRENT_SESSIONS'], 10)
    : 3;
  // eslint-disable-next-line @typescript-eslint/no-require-imports
  const { VisualBaselineRepository: VisualRepo } = require('../db/VisualBaselineRepository') as typeof import('../db/VisualBaselineRepository');
  const visualRepo = new VisualRepo(db);
  const store = new SessionStore(outputDir, sessionRepo, anomalyRepo, maxConcurrent, notificationService, visualRepo);
  const dbCheck = (): boolean => { try { db.prepare('SELECT 1').run(); return true; } catch { return false; } };

  // Scheduler
  // eslint-disable-next-line @typescript-eslint/no-require-imports
  const { ScheduleRepository: SchedRepo } = require('../db/ScheduleRepository') as typeof import('../db/ScheduleRepository');
  // eslint-disable-next-line @typescript-eslint/no-require-imports
  const { SchedulerService: SchedSvc } = require('./scheduler/SchedulerService') as typeof import('./scheduler/SchedulerService');
  const scheduleRepo = new SchedRepo(db);
  const scheduler = new SchedSvc(scheduleRepo, store);
  scheduler.start();

  const server = createServer(store, dbCheck, scheduleRepo, scheduler, visualRepo);

  // Graceful shutdown
  let shuttingDown = false;

  function shutdown(signal: string): void {
    if (shuttingDown) return;
    shuttingDown = true;
    log.info({ signal }, 'Graceful shutdown initiated');
    scheduler.stop();
    server.close(() => {
      try { db.close(); } catch { /* ignore */ }
      process.exit(0);
    });
    setTimeout(() => {
      log.error('Forced shutdown after 30s');
      process.exit(1);
    }, 30000);
  }

  process.on('SIGTERM', () => shutdown('SIGTERM'));
  process.on('SIGINT', () => shutdown('SIGINT'));

  server.listen(PORT, () => {
    log.info({ port: PORT }, 'ABE API server listening');
  });
}