/**
 * Роуты для сбора статистики ресурсов (RAM, CPU, HDD) с MikroTik RouterOS.
 * GET /api/resources/stats — system/resource по каждому jumphost/home с учётами MikroTik.
 */

const { sendError } = require('../middleware/errorHandler');
const { decrypt } = require('../utils/encryption');
const { readServersFromS3 } = require('./serversRoutes');
const { createRosClient } = require('../services/mikrotikApplyService');

function getMikrotikCredentials(server) {
  if (!server || (server.type !== 'jumphost' && server.type !== 'home')) return null;
  const host = server.mikrotikHost || server.ip || server.dns;
  if (!host) return null;
  const port = server.mikrotikPort;
  const restPort = (port === 80 || port === 443 || port === 8443) ? port : 80;
  const user = server.mikrotikUser || 'admin';
  let password = '';
  if (server.encryptedMikrotikPassword) {
    try {
      password = decrypt(server.encryptedMikrotikPassword);
    } catch (_) {
      return null;
    }
  }
  return { host, port: restPort, user, password, secure: false };
}

/**
 * Парсинг system/resource в нормализованный объект для UI.
 * MikroTik REST возвращает: total-memory, free-memory (bytes), cpu-load (%),
 * total-hdd-space, free-hdd-space (bytes), uptime, version, board-name и др.
 */
function parseResource(raw) {
  if (!raw || typeof raw !== 'object') return null;
  const num = (v) => (v != null && v !== '' ? parseInt(String(v), 10) : null);
  const totalMemory = num(raw['total-memory']);
  const freeMemory = num(raw['free-memory']);
  const usedMemory = totalMemory != null && freeMemory != null ? totalMemory - freeMemory : null;
  const totalHdd = num(raw['total-hdd-space']);
  const freeHdd = num(raw['free-hdd-space']);
  const usedHdd = totalHdd != null && freeHdd != null ? totalHdd - freeHdd : null;
  const cpuLoad = raw['cpu-load'] != null ? parseFloat(String(raw['cpu-load'])) : null;

  return {
    // RAM (bytes и проценты)
    totalMemory: totalMemory,
    freeMemory: freeMemory,
    usedMemory: usedMemory,
    memoryUsagePercent:
      totalMemory != null && totalMemory > 0 && usedMemory != null
        ? Math.round((usedMemory / totalMemory) * 100)
        : null,
    // CPU (%)
    cpuLoad: cpuLoad != null ? Math.round(cpuLoad) : null,
    cpuCount: num(raw['cpu-count']) ?? null,
    cpuFrequency: raw['cpu-frequency'] != null ? String(raw['cpu-frequency']) : null,
    cpu: raw.cpu != null ? String(raw.cpu) : null,
    // HDD (bytes и проценты)
    totalHddSpace: totalHdd,
    freeHddSpace: freeHdd,
    usedHddSpace: usedHdd,
    hddUsagePercent:
      totalHdd != null && totalHdd > 0 && usedHdd != null
        ? Math.round((usedHdd / totalHdd) * 100)
        : null,
    // прочее
    uptime: raw.uptime != null ? String(raw.uptime) : null,
    version: raw.version != null ? String(raw.version) : null,
    boardName: raw['board-name'] != null ? String(raw['board-name']) : null,
    architectureName: raw['architecture-name'] != null ? String(raw['architecture-name']) : null,
    platform: raw.platform != null ? String(raw.platform) : null,
  };
}

/**
 * GET /api/resources/stats
 * По каждому jumphost/home с MikroTik — запрос system/resource, ответ с группировкой по роутерам.
 */
async function getResourceStats(req, res) {
  try {
    const servers = await readServersFromS3();
    const routers = (Array.isArray(servers) ? servers : []).filter(
      (s) =>
        s &&
        (String(s.type || '').toLowerCase() === 'jumphost' ||
          String(s.type || '').toLowerCase() === 'home')
    );

    const results = await Promise.all(
      routers.map(async (server) => {
        const serverId = server.id || server.dns || server.ip;
        const name = server.name || server.dns || server.ip || serverId;
        const host = server.mikrotikHost || server.ip || server.dns;

        const creds = getMikrotikCredentials(server);
        if (!creds) {
          return {
            serverId,
            name,
            host,
            groupKey: server.groupKey || null,
            error: 'MikroTik API не настроен или нет пароля',
            resource: null,
          };
        }
        try {
          const client = createRosClient(creds);
          const apiRes = await client.print('system/resource');
          const raw = apiRes?.data;
          const single = Array.isArray(raw) ? raw[0] : raw;
          const resource = parseResource(single);
          return {
            serverId,
            name,
            host,
            groupKey: server.groupKey || null,
            error: null,
            resource,
          };
        } catch (err) {
          const msg = err.response?.data?.message || err.message || 'Ошибка запроса к RouterOS';
          return {
            serverId,
            name,
            host,
            groupKey: server.groupKey || null,
            error: msg,
            resource: null,
          };
        }
      })
    );

    return res.json({ routers: results });
  } catch (error) {
    console.error('getResourceStats:', error);
    return sendError(
      res,
      500,
      error.message || 'Ошибка сбора статистики ресурсов',
      'E_RESOURCE_STATS'
    );
  }
}

module.exports = {
  getResourceStats,
};