require('dotenv').config();
const express = require('express');
const cors = require('cors');
const helmet = require('helmet');
const rateLimit = require('express-rate-limit');
const cookieParser = require('cookie-parser');
const path = require('path');
const http = require('http');
const loggingMiddleware = require('./src/middleware/logging');

const app = express();
const server = http.createServer(app);

// ============================================================
// SECURITY — Helmet with CSP
// ============================================================
app.use(helmet({
  crossOriginEmbedderPolicy: false,
  contentSecurityPolicy: {
    directives: {
      defaultSrc: ["'self'"],
      scriptSrc: ["'self'"],
      scriptSrcAttr: ["'none'"],
      styleSrc: ["'self'", "'unsafe-inline'", 'https://fonts.googleapis.com', 'https://cdnjs.cloudflare.com'],
      fontSrc: ["'self'", 'https://fonts.gstatic.com', 'https://cdnjs.cloudflare.com'],
      imgSrc: ["'self'", 'data:', 'blob:'],
      mediaSrc: ["'self'", 'blob:'],
      connectSrc: ["'self'", 'https://cdnjs.cloudflare.com', 'https://fonts.googleapis.com', 'https://fonts.gstatic.com', 'https://www.google.com', 'wss://www.google.com', 'https://clinicaltables.nlm.nih.gov'],
      workerSrc: ["'self'"],
      frameSrc: ["'none'"],
      objectSrc: ["'none'"],
    }
  }
}));

// ============================================================
// CORS — restrict to APP_URL origin in production
// ============================================================
var allowedOrigin = process.env.APP_URL ? process.env.APP_URL.replace(/\/$/, '') : null;
app.use(cors({
  origin: function(origin, callback) {
    // Allow requests with no origin (mobile apps, curl, server-to-server)
    if (!origin) return callback(null, true);
    // In development (no APP_URL set) allow all
    if (!allowedOrigin) return callback(null, true);
    if (origin === allowedOrigin) return callback(null, true);
    callback(new Error('CORS: origin not allowed'));
  },
  credentials: true
}));

app.use(cookieParser());

// ============================================================
// BODY LIMITS — 1mb for JSON, transcribe uses multipart (no limit here)
// ============================================================
app.use(express.json({ limit: '1mb' }));

// ============================================================
// RATE LIMITING
// ============================================================
// General API: 60 req/min
app.use('/api/', rateLimit({
  windowMs: 60000, max: 60,
  message: { error: 'Too many requests' },
  standardHeaders: true, legacyHeaders: false
}));

// Auth routes: 10 attempts/15min per IP (brute-force protection)
app.use('/api/auth/login', rateLimit({
  windowMs: 15 * 60 * 1000, max: 10,
  message: { error: 'Too many login attempts. Try again in 15 minutes.' },
  standardHeaders: true, legacyHeaders: false
}));
app.use('/api/auth/register', rateLimit({
  windowMs: 60 * 60 * 1000, max: 5,
  message: { error: 'Too many registration attempts.' },
  standardHeaders: true, legacyHeaders: false
}));
app.use('/api/auth/forgot-password', rateLimit({
  windowMs: 60 * 60 * 1000, max: 5,
  message: { error: 'Too many password reset attempts.' },
  standardHeaders: true, legacyHeaders: false
}));

app.use(loggingMiddleware);
app.use(express.static(path.join(__dirname, 'public'), {
  setHeaders: (res, filePath) => {
    if (filePath.endsWith('.html')) {
      // Never cache HTML — ensures new deployments are picked up immediately
      res.setHeader('Cache-Control', 'no-cache, no-store, must-revalidate');
      res.setHeader('Pragma', 'no-cache');
      res.setHeader('Expires', '0');
    } else if (filePath.match(/\.(js|css)$/)) {
      // Short cache for JS/CSS — 1 hour
      res.setHeader('Cache-Control', 'public, max-age=3600');
    } else if (filePath.indexOf('/components/') !== -1) {
      // Component HTML — 1 hour cache
      res.setHeader('Cache-Control', 'public, max-age=3600');
    }
  }
}));

// Routes
app.use('/api/auth', require('./src/routes/auth'));

// Learning Hub CMS — must come BEFORE general /api/admin to avoid adminMiddleware conflict
// (moderators need access to /api/admin/learning but not other /api/admin routes)
app.use('/api/admin/learning', require('./src/routes/learningAdmin'));

app.use('/api/admin', require('./src/routes/admin'));
app.use('/api/admin', require('./src/routes/adminConfig'));

// Public endpoints — must come BEFORE any router that applies authMiddleware to /api/*
const { getAvailableModels, activeProvider: modelsProvider } = require('./src/utils/models');
app.get('/api/models', async (req, res) => {
  try {
    var { getAvailableModelsWithOverrides } = require('./src/utils/models');
    var db = require('./src/db/database');
    var models = await getAvailableModelsWithOverrides(db);
    res.json({ models: models, provider: modelsProvider });
  } catch(e) {
    res.json({ models: getAvailableModels(), provider: modelsProvider });
  }
});

const { activeProvider } = require('./src/utils/ai');
app.get('/api/health', (req, res) => {
  res.json({
    status: 'running', version: '3.1.0', provider: activeProvider,
    timestamp: new Date().toISOString(),
    openrouter: process.env.OPENROUTER_API_KEY ? 'configured' : 'missing',
    bedrock: process.env.AWS_BEDROCK_REGION ? 'configured' : 'not configured',
    azure: process.env.AZURE_OPENAI_ENDPOINT ? 'configured' : 'not configured',
    whisper: process.env.OPENAI_API_KEY ? 'configured' : 'missing'
  });
});

// Learning Hub routes (all authenticated users can read content & take quizzes)
app.use('/api/learning', require('./src/routes/learningHub'));

// Authenticated feature routes
app.use('/api', require('./src/routes/transcribe'));
app.use('/api', require('./src/routes/hpi'));
app.use('/api', require('./src/routes/hospitalCourse'));
app.use('/api', require('./src/routes/chartReview'));
app.use('/api', require('./src/routes/milestones'));
app.use('/api', require('./src/routes/soap'));
app.use('/api', require('./src/routes/tts'));
app.use('/api', require('./src/routes/nextcloud'));
app.use('/api', require('./src/routes/refine'));
app.use('/api', require('./src/routes/logs'));
app.use('/api', require('./src/routes/encounters'));
app.use('/api', require('./src/routes/memories'));
app.use('/api', require('./src/routes/wellVisit'));
app.use('/api', require('./src/routes/sickVisit'));
app.use('/api/admin/learning', require('./src/routes/learningAI'));

// User-level preference: save WebDAV learning path (auth only, not moderator-only)
(function() {
  var { authMiddleware } = require('./src/middleware/auth');
  var db = require('./src/db/database');
  app.post('/api/user/webdav-path', authMiddleware, async function(req, res) {
    try {
      await db.run('UPDATE users SET webdav_learning_path = ? WHERE id = ?', [req.body.path || null, req.user.id]);
      res.json({ success: true });
    } catch(e) { res.status(500).json({ error: e.message }); }
  });
})();

app.get('/', (req, res) => {
  res.setHeader('Cache-Control', 'no-cache, no-store, must-revalidate');
  res.setHeader('Pragma', 'no-cache');
  res.setHeader('Expires', '0');
  res.sendFile(path.join(__dirname, 'public', 'index.html'));
});

// 404 handler — must be last
app.use((req, res) => {
  res.status(404).sendFile(path.join(__dirname, 'public', '404.html'));
});

// Load prompt DB overrides after DB is ready (3s grace period)
const PROMPTS = require('./src/utils/prompts');
const db = require('./src/db/database');
setTimeout(() => { PROMPTS.loadFromDb(db); }, 3000);

const PORT = process.env.PORT || 3000;
server.listen(PORT, () => {
  console.log('');
  console.log('==========================================');
  console.log('🏥 PEDIATRIC AI SCRIBE v3.1');
  console.log('==========================================');
  console.log('🌐 http://localhost:' + PORT);
  console.log('🤖 Provider: ' + activeProvider);
  console.log('==========================================');
});