import express from 'express';
import cors from 'cors';
import helmet from 'helmet';
import dotenv from 'dotenv';
import { fileURLToPath } from 'url';
import path from 'path';
import bodyParser from 'body-parser';
import bcrypt from 'bcrypt';
import jwt from 'jsonwebtoken'; // For token-based authentication
import { initEncryption, encrypt, decrypt, verifyCanary, SENTINEL } from './shared/crypto/encryption.js';

import pool from './config/mysqlPool.js'; // adjust path if needed

import sqlite3 from 'sqlite3';


const CANARY_SQL = `
  CREATE TABLE IF NOT EXISTS encryption_canary (
    id    TINYINT  NOT NULL PRIMARY KEY,
    value TEXT     NOT NULL
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;`;

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const rootPath = path.resolve(__dirname, '..'); // Up one level
const env          = process.env.NODE_ENV?.trim() || 'development';
const envPath = path.resolve(rootPath, `.env.${env}`);
dotenv.config({ path: envPath }); // Load .env file

// Grab secrets and config from ENV
const {
  JWT_SECRET,
  CORS_ALLOWED_ORIGINS,
  SERVER1_PORT = 5000
} = process.env;

if (!JWT_SECRET) {
  console.error('FATAL: JWT_SECRET missing – aborting startup');
  process.exit(1);          // container exits, Docker marks it unhealthy
}

if (!CORS_ALLOWED_ORIGINS) {
  console.error('FATAL: CORS_ALLOWED_ORIGINS missing – aborting startup');
  process.exit(1);
}

/* ─── unwrap / verify DEK before we serve requests ────────────── */
await initEncryption();

try {
  /* quick connectivity smoke‑test (optional) */
  await pool.query('SELECT 1');

  /* ① ensure table exists */
  await pool.query(CANARY_SQL);

  /* ② insert sentinel on first run */
  await pool.query(
    'INSERT IGNORE INTO encryption_canary (id, value) VALUES (1, ?)',
    [encrypt(SENTINEL)]
  );

  /* ③ read back & verify */
  const [rows] = await pool.query(
    'SELECT value FROM encryption_canary WHERE id = 1 LIMIT 1'
  );

  const plaintext = decrypt(rows[0]?.value || '');
  if (plaintext !== SENTINEL) {
    throw new Error('DEK mismatch with database sentinel');
  }

  console.log('[ENCRYPT] DEK verified against canary – proceeding');
} catch (err) {
  console.error('FATAL:', err.message || err);
  process.exit(1);                         // container restarts → alert
}

/* ────────────────────────────────────────────────────────────────
   Express app & middleware
   ---------------------------------------------------------------- */
const app = express();
const PORT = process.env.SERVER1_PORT || 5000;

/* ─── Allowed origins for CORS (comma-separated in env) ──────── */
const allowedOrigins = process.env.CORS_ALLOWED_ORIGINS
  .split(',')
  .map(o => o.trim())
  .filter(Boolean);


app.disable('x-powered-by');
app.use(bodyParser.json());
app.use(express.json());
app.use(
  helmet({
    contentSecurityPolicy: false,
    crossOriginEmbedderPolicy: false,
  })
);

function fprPathFromEnv() {
  const p = (process.env.DEK_PATH || '').trim();
  return p ? path.join(path.dirname(p), 'dek.fpr') : null;
}

// 1) Liveness: process is up and event loop responsive
app.get('/livez', (_req, res) => res.type('text').send('OK'));

// 2) Readiness: crypto + canary are good
app.get('/readyz', async (_req, res) => {
  try {
    await initEncryption();      // load/unlock DEK
    await verifyCanary(pool);    // DB + decrypt sentinel
    return res.type('text').send('OK');
  } catch (e) {
    console.error('[READYZ]', e.message);
    return res.status(500).type('text').send('FAIL');
  }
});

// 3) Health: detailed JSON (you can curl this to “see everything”)
app.get('/healthz', async (_req, res) => {
  const out = {
    service: process.env.npm_package_name || 'server',
    version: process.env.IMG_TAG || null,
    uptime_s: Math.floor(process.uptime()),
    now: new Date().toISOString(),
    checks: {
      live: { ok: true },           // if we reached here, process is up
      crypto: { ok: false, fp: null },
      db: { ok: false, ping_ms: null },
      canary: { ok: false }
    }
  };

  // crypto / DEK
  try {
    await initEncryption();
    out.checks.crypto.ok = true;
    const p = fprPathFromEnv();
    if (p) {
      try { out.checks.crypto.fp = (await readFile(p, 'utf8')).trim(); }
      catch { /* fp optional */ }
    }
  } catch (e) {
    out.checks.crypto.error = e.message;
  }

  // DB ping
  const t0 = Date.now();
  try {
    await pool.query('SELECT 1');
    out.checks.db.ok = true;
    out.checks.db.ping_ms = Date.now() - t0;
  } catch (e) {
    out.checks.db.error = e.message;
  }

  // canary
  try {
    await verifyCanary(pool);
    out.checks.canary.ok = true;
  } catch (e) {
    out.checks.canary.error = e.message;
  }

  const ready = out.checks.crypto.ok && out.checks.db.ok && out.checks.canary.ok;
  return res.status(ready ? 200 : 503).json(out);
});

// Enable CORS with dynamic origin checking
app.use(
  cors({
    origin: (origin, callback) => {
      if (!origin || allowedOrigins.includes(origin)) {
        callback(null, true);
      } else {
        console.error('Blocked by CORS:', origin);
        callback(new Error('Not allowed by CORS'));
      }
    },
    methods: ['GET', 'POST', 'OPTIONS'],
    allowedHeaders: [
      'Authorization',
      'Content-Type',
      'Accept',
      'Origin',
      'X-Requested-With',
    ],
    credentials: true,
  })
);

// Handle preflight requests explicitly
app.options('*', (req, res) => {
  res.setHeader('Access-Control-Allow-Origin', req.headers.origin || '');
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
  res.setHeader(
    'Access-Control-Allow-Headers',
    'Authorization, Content-Type, Accept, Origin, X-Requested-With'
  );
  res.status(200).end();
});

// Add HTTP headers for security
app.use((req, res, next) => {
  res.setHeader('X-Content-Type-Options', 'nosniff');
  res.setHeader('X-Frame-Options', 'DENY');
  res.setHeader(
    'Strict-Transport-Security',
    'max-age=31536000; includeSubDomains'
  );
  res.setHeader('Content-Security-Policy', "default-src 'self';");
  res.removeHeader('X-Powered-By');
  next();
});

// Force Content-Type to application/json on all responses
app.use((req, res, next) => {
  res.setHeader('Content-Type', 'application/json');
  next();
});

/* ------------------------------------------------------------------
   USER REGISTRATION (MySQL)
   ------------------------------------------------------------------ */
/**
 * POST /api/register
 * Body:
 *   username, password, firstname, lastname, email, zipcode, state, area, career_situation
 */
app.post('/api/register', async (req, res) => {
  const {
    username, password, firstname, lastname, email,
    zipcode, state, area, career_situation, phone_e164, sms_opt_in
  } = req.body;

  if (!username || !password || !firstname || !lastname || !email || !zipcode || !state || !area) {
    return res.status(400).json({ error: 'Missing required fields.' });
  }

  if (sms_opt_in && !/^\+\d{8,15}$/.test(phone_e164 || '')) {
    return res.status(400).json({ error: 'Phone must be +E.164 format.' });
  }

  try {
    const hashedPassword = await bcrypt.hash(password, 10);

    const profileQuery = `
      INSERT INTO user_profile
        (username, firstname, lastname, email, zipcode, state, area, career_situation, phone_e164, sms_opt_in)
      VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
    `;
    const [resultProfile] = await pool.query(profileQuery, [
      username, firstname, lastname, email, zipcode, state, area,
      career_situation, phone_e164 || null, sms_opt_in ? 1 : 0
    ]);

    const newProfileId = resultProfile.insertId;

    const authQuery = `
      INSERT INTO user_auth (user_id, username, hashed_password)
      VALUES (?, ?, ?)
    `;
    await pool.query(authQuery, [newProfileId, username, hashedPassword]);

    const token = jwt.sign({ id: newProfileId }, JWT_SECRET, { expiresIn: '2h' });

    const userPayload = {
      username, firstname, lastname, email, zipcode, state, area,
      career_situation, phone_e164, sms_opt_in: !!sms_opt_in
    };

    return res.status(201).json({
      message: 'User registered successfully',
      profileId: newProfileId,
      token,
      user: userPayload
    });
  } catch (err) {
    console.error('Error during registration:', err.message);
    return res.status(500).json({ error: 'Internal server error' });
  }
});


/* ------------------------------------------------------------------
   SIGN-IN (MySQL)
   ------------------------------------------------------------------ */
/**
 * POST /api/signin
 * Body: { username, password }
 * Returns JWT signed with user_profile.id
 */
app.post('/api/signin', async (req, res) => {
  const { username, password } = req.body;
  if (!username || !password) {
    return res
      .status(400)
      .json({ error: 'Both username and password are required' });
  }

  // SELECT only the columns you actually have:
  // 'ua.id' is user_auth's primary key,
  // 'ua.user_id' references user_profile.id,
  // and we alias user_profile.id as profileId for clarity.
  const query = `
    SELECT
      ua.id AS authId,
      ua.user_id AS userProfileId,
      ua.hashed_password,
      up.firstname,
      up.lastname,
      up.email,
      up.zipcode,
      up.state,
      up.area,
      up.career_situation
    FROM user_auth ua
    LEFT JOIN user_profile up ON ua.user_id = up.id
    WHERE ua.username = ?
  `;

  try {
    const [results] = await pool.query(query, [username]);

    if (!results || results.length === 0) {
      return res.status(401).json({ error: 'Invalid username or password' });
    }

    const row = results[0];

    // Compare password with bcrypt
    const isMatch = await bcrypt.compare(password, row.hashed_password);
    if (!isMatch) {
      return res.status(401).json({ error: 'Invalid username or password' });
    }

    // Return user info + token
    // 'authId' is user_auth's PK, but typically you won't need it on the client
    // 'row.userProfileId' is the actual user_profile.id
    const [profileRows] = await pool.query(
   'SELECT firstname, lastname, email, zipcode, state, area, career_situation \
      FROM user_profile WHERE id = ?',
   [row.userProfileId]
 );
 const profile = profileRows[0];          // ← already decrypted

 const token = jwt.sign({ id: row.userProfileId }, JWT_SECRET, { expiresIn: '2h' });

 res.status(200).json({
   message: 'Login successful',
   token,
   id: row.userProfileId,
   user: profile
 });
  } catch (err) {
    console.error('Error querying user_auth:', err.message);
    return res
      .status(500)
      .json({ error: 'Failed to query user authentication data' });
  }
});



/* ------------------------------------------------------------------
   CHECK USERNAME (MySQL)
   ------------------------------------------------------------------ */
app.get('/api/check-username/:username', async (req, res) => {
  const { username } = req.params;
  try {
    const [results] = await pool.query(`SELECT username FROM user_auth WHERE username = ?`, [username]);
    res.status(200).json({ exists: results.length > 0 });
  } catch (err) {
    console.error('Error checking username:', err.message);
    res.status(500).json({ error: 'Database error' });
  }
});


/* ------------------------------------------------------------------
   UPSERT USER PROFILE (MySQL)
   ------------------------------------------------------------------ */
/**
 * POST /api/user-profile
 * Headers: { Authorization: Bearer <token> }
 * Body: { userName, firstName, lastName, email, zipCode, state, area, ... }
 *
 * If user_profile row exists (id = token.id), update
 * else insert
 */
app.post('/api/user-profile', async (req, res) => {
  const token = req.headers.authorization?.split(' ')[1];
  if (!token) {
    return res.status(401).json({ error: 'Authorization token is required' });
  }

  let profileId;
  try {
    const decoded = jwt.verify(token, JWT_SECRET);
    profileId = decoded.id;
  } catch (error) {
    console.error('JWT verification failed:', error);
    return res.status(401).json({ error: 'Invalid or expired token' });
  }

  const {
    userName,
    firstName,
    lastName,
    email,
    zipCode,
    state,
    area,
    careerSituation,
    interest_inventory_answers,
    riasec: riasec_scores,
    career_priorities,
    career_list,
  } = req.body;

  try {
    const [results] = await pool.query(
      `SELECT * FROM user_profile WHERE id = ?`,
      [profileId]
    );
    const existingRow = results.length > 0 ? results[0] : null;

    if (
      !existingRow &&
      (!firstName || !lastName || !email || !zipCode || !state || !area)
    ) {
      return res.status(400).json({
        error: 'All fields are required for initial profile creation.',
      });
    }

    const finalAnswers =
      interest_inventory_answers !== undefined
        ? interest_inventory_answers
        : existingRow?.interest_inventory_answers || null;

    const finalCareerPriorities =
      career_priorities !== undefined
        ? career_priorities
        : existingRow?.career_priorities || null;

    const finalCareerList =
      career_list !== undefined
        ? career_list
        : existingRow?.career_list || null;

    const finalUserName =
      userName !== undefined ? userName : existingRow?.username || null;

    const finalRiasec = riasec_scores
      ? JSON.stringify(riasec_scores)
      : existingRow?.riasec_scores || null;

    if (existingRow) {
      const updateQuery = `
        UPDATE user_profile
        SET 
          username = ?,
          firstname = ?,
          lastname = ?,
          email = ?,
          zipcode = ?,
          state = ?,
          area = ?,
          career_situation = ?,
          interest_inventory_answers = ?,
          riasec_scores = ?,
          career_priorities = ?,
          career_list = ?
        WHERE id = ?
      `;
      const params = [
        finalUserName,
        firstName || existingRow.firstname,
        lastName || existingRow.lastname,
        email || existingRow.email,
        zipCode || existingRow.zipcode,
        state || existingRow.state,
        area || existingRow.area,
        careerSituation || existingRow.career_situation,
        finalAnswers,
        finalRiasec,
        finalCareerPriorities,
        finalCareerList,
        profileId,
      ];

      await pool.query(updateQuery, params);
      return res
        .status(200)
        .json({ message: 'User profile updated successfully' });
    } else {
      const insertQuery = `
        INSERT INTO user_profile
          (id, username, firstname, lastname, email, zipcode, state, area,
           career_situation, interest_inventory_answers, riasec_scores,
           career_priorities, career_list)
        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
      `;
      const params = [
        profileId,
        finalUserName,
        firstName,
        lastName,
        email,
        zipCode,
        state,
        area,
        careerSituation || null,
        finalAnswers,
        finalRiasec,
        finalCareerPriorities,
        finalCareerList,
      ];

      await pool.query(insertQuery, params);
      return res
        .status(201)
        .json({ message: 'User profile created successfully', id: profileId });
    }
  } catch (err) {
    console.error('Error upserting user profile:', err.message);
    return res.status(500).json({ error: 'Internal server error' });
  }
});


/* ------------------------------------------------------------------
   FETCH USER PROFILE (MySQL)
   ------------------------------------------------------------------ */
app.get('/api/user-profile', async (req, res) => {
  const token = req.headers.authorization?.split(' ')[1];
  if (!token) return res.status(401).json({ error: 'Authorization token is required' });

  let profileId;
  try {
    const decoded = jwt.verify(token, JWT_SECRET);
    profileId = decoded.id;
  } catch (error) {
    return res.status(401).json({ error: 'Invalid or expired token' });
  }

  try {
    const [results] = await pool.query('SELECT * FROM user_profile WHERE id = ?', [profileId]);
    if (!results || results.length === 0) {
      return res.status(404).json({ error: 'User profile not found' });
    }
    res.status(200).json(results[0]);
  } catch (err) {
    console.error('Error fetching user profile:', err.message);
    res.status(500).json({ error: 'Internal server error' });
  }
});


/* ------------------------------------------------------------------
   SALARY_INFO REMAINS IN SQLITE
------------------------------------------------------------------ */
app.get('/api/areas', (req, res) => {
  const { state } = req.query;
  if (!state) {
    return res.status(400).json({ error: 'State parameter is required' });
  }

  // Use env when present (Docker), fall back for local dev
const salaryDbPath =
      process.env.SALARY_DB_PATH           // ← preferred
   || process.env.SALARY_DB               // ← legacy
   || '/app/salary_info.db';              // final fallback
   
  const salaryDb = new sqlite3.Database(
    salaryDbPath,
    sqlite3.OPEN_READONLY,
    (err) => {
      if (err) {
        console.error('DB connect error:', err.message);
        return res
          .status(500)
          .json({ error: 'Failed to connect to database' });
      }
    }
  );

  const query =
    `SELECT DISTINCT AREA_TITLE
       FROM salary_data
      WHERE PRIM_STATE = ?`;

  salaryDb.all(query, [state], (err, rows) => {
    if (err) {
      console.error('Query error:', err.message);
      return res
        .status(500)
        .json({ error: 'Failed to fetch areas' });
    }
    res.json({ areas: rows.map(r => r.AREA_TITLE) });
  });

  salaryDb.close();
});

/* ------------------------------------------------------------------
   PREMIUM UPGRADE ENDPOINT
   ------------------------------------------------------------------ */
app.post('/api/activate-premium', async (req, res) => {
  const token = req.headers.authorization?.split(' ')[1];
  if (!token) return res.status(401).json({ error: 'Authorization token is required' });

  let profileId;
  try {
    const decoded = jwt.verify(token, JWT_SECRET);
    profileId = decoded.id;
  } catch (error) {
    return res.status(401).json({ error: 'Invalid or expired token' });
  }

  try {
    await pool.query(`
      UPDATE user_profile
      SET is_premium = 1,
          is_pro_premium = 1
      WHERE id = ?
    `, [profileId]);

    res.status(200).json({ message: 'Premium activated successfully' });
  } catch (err) {
    console.error('Error updating premium status:', err.message);
    res.status(500).json({ error: 'Failed to activate premium' });
  }
});


/* ------------------------------------------------------------------
   START SERVER
   ------------------------------------------------------------------ */
app.listen(PORT, () => {
  console.log(`Server running on http://localhost:${PORT}`);
});