'use strict';

const express = require('express');
const ldapClient = require('./ldapClient');
const config = require('./config');
const sessions = require('./sessions');
const adminSettings = require('./adminSettings');
const requests = require('./requests');
const mailer = require('./mailer');

const router = express.Router();

function errorResponse(res, err) {
  const status = err.status || 500;
  res.status(status).json({ success: false, error: err.message || 'Внутренняя ошибка сервера' });
}

function getToken(req) {
  const header = req.headers.authorization || '';
  if (header.startsWith('Bearer ')) return header.slice(7);
  return null;
}

function requireAuth(req, res, next) {
  const session = sessions.getSession(getToken(req));
  if (!session) {
    return res.status(401).json({ success: false, error: 'Требуется авторизация' });
  }
  req.session = session;
  next();
}

router.post('/login', async (req, res) => {
  const { username, password } = req.body || {};
  if (!username || !password) {
    return res.status(400).json({ success: false, error: 'Логин и пароль обязательны' });
  }
  if (!config.adminLogin || !config.adminPassword) {
    return res.status(500).json({ success: false, error: 'Учётные данные администратора не заданы в .env (ADMIN_LOGIN/ADMIN_PASSWORD)' });
  }
  const adminAliases = new Set(
    ldapClient.buildBindNames(config.adminLogin).map((n) => n.toLowerCase())
  );
  adminAliases.add(config.adminLogin.split('@')[0].split('\\').pop().toLowerCase());
  if (!adminAliases.has(String(username).toLowerCase())) {
    return res.status(401).json({ success: false, error: 'Доступ разрешён только администратору' });
  }
  try {
    const info = await ldapClient.authenticate(username, password, 'basic');
    const token = sessions.createSession({
      username: info.username,
      full_name: info.full_name,
      groups: info.groups
    });
    res.json({ success: true, token, user: { username: info.username, full_name: info.full_name } });
  } catch (err) {
    return errorResponse(res, err);
  }
});

router.post('/logout', (req, res) => {
  sessions.destroySession(getToken(req));
  res.json({ success: true });
});

router.get('/me', requireAuth, (req, res) => {
  res.json({ success: true, user: req.session.user });
});

router.get('/ous', requireAuth, async (req, res) => {
  try {
    const ous = await ldapClient.listOUs();
    res.json({ success: true, ous });
  } catch (err) {
    errorResponse(res, err);
  }
});

router.get('/groups', requireAuth, async (req, res) => {
  try {
    const groups = await ldapClient.listGroups();
    res.json({ success: true, groups });
  } catch (err) {
    errorResponse(res, err);
  }
});

router.get('/settings', requireAuth, (req, res) => {
  res.json({ success: true, settings: adminSettings.getSettings() });
});

router.put('/settings', requireAuth, (req, res) => {
  const body = req.body || {};
  const patch = {};
  if (typeof body.ouDn === 'string') patch.ouDn = body.ouDn;
  if (Array.isArray(body.defaultGroups)) {
    patch.defaultGroups = body.defaultGroups.filter((g) => typeof g === 'string');
  }
  if (Object.keys(patch).length === 0) {
    return res.status(400).json({ success: false, error: 'Нет данных для сохранения' });
  }
  try {
    const settings = adminSettings.updateSettings(patch);
    res.json({ success: true, settings });
  } catch (err) {
    errorResponse(res, err);
  }
});

router.get('/users', requireAuth, async (req, res) => {
  try {
    const users = await ldapClient.listUsers();
    res.json({ success: true, users });
  } catch (err) {
    errorResponse(res, err);
  }
});

router.get('/users/:login', requireAuth, async (req, res) => {
  try {
    const user = await ldapClient.getUser(req.params.login);
    res.json({ success: true, user });
  } catch (err) {
    errorResponse(res, err);
  }
});

router.post('/users', requireAuth, async (req, res) => {
  const { ouDn, fio, login, password, email, phone, groupCNs } = req.body || {};
  if (!login || !fio) {
    return res.status(400).json({ success: false, error: 'ФИО и логин обязательны' });
  }
  try {
    const result = await ldapClient.createUser({ ouDn, fio, login, password, email, phone, groupCNs });
    res.json(result);
  } catch (err) {
    errorResponse(res, err);
  }
});

router.put('/users/:login', requireAuth, async (req, res) => {
  const { fio, email, phone, password, groupCNs } = req.body || {};
  try {
    const result = await ldapClient.updateUser(req.params.login, { fio, email, phone, password, groupCNs });
    res.json(result);
  } catch (err) {
    errorResponse(res, err);
  }
});

router.post('/users/:login/disable', requireAuth, async (req, res) => {
  try {
    const result = await ldapClient.setUserEnabled(req.params.login, false);
    res.json(result);
  } catch (err) {
    errorResponse(res, err);
  }
});

router.post('/users/:login/enable', requireAuth, async (req, res) => {
  try {
    const result = await ldapClient.setUserEnabled(req.params.login, true);
    res.json(result);
  } catch (err) {
    errorResponse(res, err);
  }
});

// ================= Registration requests =================

async function getTakenLogins(excludeId) {
  const users = await ldapClient.listUsers();
  const taken = users.map((u) => u.login).filter(Boolean);
  const all = requests.listRequests();
  for (const r of [...all.pending, ...all.history]) {
    if (r.login && r.id !== excludeId) taken.push(r.login);
  }
  return taken;
}

async function getUsedEmails(excludeId) {
  const users = await ldapClient.listUsers();
  const emails = users.map((u) => u.email).filter(Boolean).map((e) => e.toLowerCase());
  const all = requests.listRequests();
  for (const r of [...all.pending, ...all.history]) {
    if (r.id === excludeId || r.phase === 'denied') continue;
    if (r.email) emails.push(r.email.toLowerCase());
  }
  return new Set(emails);
}

router.get('/requests', requireAuth, (req, res) => {
  res.json({ success: true, ...requests.listRequests() });
});

router.get('/requests/:id', requireAuth, (req, res) => {
  const record = requests.getRequest(req.params.id);
  if (!record) return res.status(404).json({ success: false, error: 'Заявка не найдена' });
  res.json({ success: true, request: record });
});

router.put('/requests/:id', requireAuth, async (req, res) => {
  const { surname, name, patronymic, email, password, groupCNs } = req.body || {};
  try {
    if (email !== undefined) {
      const used = await getUsedEmails(req.params.id);
      if (used.has(String(email).toLowerCase())) {
        return res.status(409).json({ success: false, error: 'Эта почта уже используется' });
      }
    }
    const taken = await getTakenLogins(req.params.id);
    const record = requests.updateRequest(req.params.id, { surname, name, patronymic, email, password, groupCNs }, taken);
    res.json({ success: true, request: record });
  } catch (err) {
    errorResponse(res, err);
  }
});

router.post('/requests/:id/approve', requireAuth, async (req, res) => {
  const record = requests.getRequest(req.params.id);
  if (!record) return res.status(404).json({ success: false, error: 'Заявка не найдена' });
  if (record.phase !== 'pending') {
    return res.status(409).json({ success: false, error: 'Заявка уже обработана' });
  }
  try {
    const settings = adminSettings.getSettings();
    if (!settings.ouDn) {
      return res.status(400).json({ success: false, error: 'Не задано подразделение — откройте Настройки' });
    }
    const groupCNs = record.groupsEdited ? record.groups : (settings.defaultGroups || []);
    await ldapClient.createUser({
      ouDn: settings.ouDn || undefined,
      fio: record.fio,
      login: record.login,
      password: record.password,
      email: record.email,
      groupCNs
    });
    let warning = null;
    try {
      await mailer.sendApproved(record.email, { login: record.login, password: record.password, fio: record.fio });
      requests.markProcessed(record.id, { phase: 'approved', emailSent: true });
    } catch (mailErr) {
      requests.markProcessed(record.id, { phase: 'approved', emailSent: false });
      warning = `Пользователь создан, но письмо не отправлено: ${mailErr.message}`;
    }
    res.json({ success: true, login: record.login, warning });
  } catch (err) {
    errorResponse(res, err);
  }
});

router.post('/requests/:id/deny', requireAuth, async (req, res) => {
  const reason = String((req.body || {}).reason || '').trim();
  if (!reason) return res.status(400).json({ success: false, error: 'Укажите причину отказа' });
  const record = requests.getRequest(req.params.id);
  if (!record) return res.status(404).json({ success: false, error: 'Заявка не найдена' });
  if (record.phase !== 'pending') {
    return res.status(409).json({ success: false, error: 'Заявка уже обработана' });
  }
  let warning = null;
  try {
    await mailer.sendDenied(record.email, { fio: record.fio, reason });
    requests.markProcessed(record.id, { phase: 'denied', reason, emailSent: true });
  } catch (mailErr) {
    requests.markProcessed(record.id, { phase: 'denied', reason, emailSent: false });
    warning = `Заявка отклонена, но письмо не отправлено: ${mailErr.message}`;
  }
  res.json({ success: true, warning });
});

router.post('/requests/:id/resend', requireAuth, async (req, res) => {
  const record = requests.getRequest(req.params.id);
  if (!record) return res.status(404).json({ success: false, error: 'Заявка не найдена' });
  if (record.phase !== 'approved' && record.phase !== 'denied') {
    return res.status(409).json({ success: false, error: 'Письмо можно отправить только по обработанной заявке' });
  }
  try {
    if (record.phase === 'approved') {
      await mailer.sendApproved(record.email, { login: record.login, password: record.password, fio: record.fio });
    } else {
      await mailer.sendDenied(record.email, { fio: record.fio, reason: record.reason });
    }
    requests.markProcessed(record.id, { emailSent: true });
    res.json({ success: true });
  } catch (err) {
    errorResponse(res, err);
  }
});

module.exports = router;