/**
 * Генератор конфигурации MikroTik для интерфейсов и маршрутов
 * Поддерживает два формата вывода: 'text' (как раньше) и 'json' (структурированные операции для API)
 */

/**
 * @param {string} serverId
 * @param {Array} servers
 * @returns {object|null}
 */
function getServerInfo(serverId, servers) {
  if (!serverId || !Array.isArray(servers)) return null;
  return servers.find(s => s.id === serverId || s.ip === serverId || s.dns === serverId) || null;
}

/**
 * @param {string} parentId
 * @param {object} config
 * @param {Array} templateGateways
 * @returns {object|null}
 */
function getParentGateway(parentId, config, templateGateways = null) {
  if (!parentId || !config) return null;

  if (Array.isArray(templateGateways)) {
    const g = templateGateways.find(x => x.id === parentId);
    if (g) return { parentType: 'gateway', ...g, ip: g.ip };
  }

  const gateway = config.gateways?.find(g => g.id === parentId);
  if (gateway) return { parentType: 'gateway', ...gateway, ip: gateway.ip };

  const iface = config.tunnelInterfaces?.find(i => i.id === parentId);
  if (iface) {
    return {
      parentType: 'interface',
      ...iface,
      remoteIp: iface.remoteIp,
      localIp: iface.localIp,
      name: iface.name,
      interfaceType: iface.type,
    };
  }
  return null;
}

/**
 * Сериализация одной операции в строку RouterOS
 * @param {object} op - { path, action, params }
 * @returns {string}
 */
function operationToRouterOSLine(op) {
  const { path, action, params } = op;
  if (!path || !action) return '';
  const pathStr = path.replace(/^\//, '').replace(/\//g, ' ');
  const fullPath = pathStr ? `/${pathStr}` : '';
  const parts = (params && typeof params === 'object')
    ? Object.entries(params)
        .filter(([, v]) => v != null && v !== '')
        .map(([k, v]) => {
          const val = String(v);
          if (val.includes(' ') || val.includes('"')) return `${k}="${val}"`;
          return `${k}=${val}`;
        })
    : [];
  return `${fullPath} ${action} ${parts.join(' ')}`.trim();
}

/**
 * Сериализация массива операций в текст
 * @param {Array} operations
 * @returns {string}
 */
function serializeOperationsToText(operations) {
  if (!Array.isArray(operations)) return '';
  return operations.map(op => operationToRouterOSLine(op)).filter(Boolean).join('\n');
}

/**
 * Построение блоков MikroTik для интерфейсов
 * @param {object} config - { tunnelInterfaces, gateways }
 * @param {Array} servers
 * @param {object} passwordMap - { [ipsecPasswordId]: decryptedPassword }
 * @param {object} options - { format: 'text'|'json', serverId?: string }
 * @returns {Promise<Array>}
 */
async function buildMikrotikInterfaceBlocks(config, servers, passwordMap, options = {}) {
  const { format = 'text', serverId: filterServerId } = options;
  const interfaces = (config.tunnelInterfaces || []).filter(
    i => i.serverId && i.serverId2 && i.localIp && i.remoteIp
  );

  if (interfaces.length === 0) return [];

  const interfacesByServer = {};
  for (const iface of interfaces) {
    const server1 = getServerInfo(iface.serverId, servers);
    const server2 = getServerInfo(iface.serverId2, servers);
    if (!server1 || !server2) continue;

    const server1Name = server1.dns || server1.ip || iface.serverId;
    const server2Name = server2.dns || server2.ip || iface.serverId2;
    const interfaceName1 = iface.name || `${iface.type}-tunnel`;
    const interfaceName2 = iface.name2 || iface.name || `${iface.type}-tunnel`;

    const ipsecPassword = (iface.ipsecPasswordId && passwordMap[iface.ipsecPasswordId]) || null;

    if (!interfacesByServer[server1Name]) {
      interfacesByServer[server1Name] = { serverInfo: server1, interfaces: [] };
    }
    interfacesByServer[server1Name].interfaces.push({
      interfaceName: interfaceName1,
      localIp: iface.localIp,
      remoteIp: iface.remoteIp,
      type: iface.type,
      server2Name,
      server2Info: server2,
      ipsecPassword,
      mtu: iface.mtu || null,
    });

    if (!interfacesByServer[server2Name]) {
      interfacesByServer[server2Name] = { serverInfo: server2, interfaces: [] };
    }
    interfacesByServer[server2Name].interfaces.push({
      interfaceName: interfaceName2,
      localIp: iface.remoteIp,
      remoteIp: iface.localIp,
      type: iface.type,
      server2Name: server1Name,
      server2Info: server1,
      ipsecPassword,
      mtu: iface.mtu || null,
    });
  }

  const sortedServers = Object.entries(interfacesByServer).sort(([a], [b]) => a.localeCompare(b));
  const blocks = [];

  for (const [serverName, serverData] of sortedServers) {
    if (filterServerId) {
      const s = getServerInfo(filterServerId, servers);
      const matchName = s ? (s.dns || s.ip || filterServerId) : filterServerId;
      if (serverName !== matchName && serverData.serverInfo?.id !== filterServerId) continue;
    }

    const server = serverData.serverInfo;
    const isHomeRouter = server.type === 'home';
    const hasGreInterfaces = serverData.interfaces.some(i => i.type === 'GRE');

    const operations = [];
    let code = '';

    if (format === 'text') {
      code += `# Настройка IP адресов интерфейсов для сервера: ${serverName}\n`;
      if (server.provider) code += `# Провайдер: ${server.provider}\n`;
      if (server.country) code += `# Страна: ${server.country}\n`;
      if (server.ip && server.ip !== serverName) code += `# IP: ${server.ip}\n`;
      code += '\n';
    }

    if (isHomeRouter && hasGreInterfaces) {
      if (format === 'text') {
        code += `# Создание interface list для GRE туннелей (если не существует)\n`;
        code += `:if ([/interface list find name=GREs] = "") do={ /interface list add name=GREs comment="GRE tunnels list" }\n\n`;
      } else {
        operations.push({
          path: '/interface/list',
          action: 'add',
          params: { name: 'GREs', comment: 'GRE tunnels list' },
          meta: { ensureExists: true },
        });
      }
    }

    for (let i = 0; i < serverData.interfaces.length; i++) {
      const iface = serverData.interfaces[i];
      const remoteAddress = iface.server2Info?.dns || iface.server2Info?.ip || iface.server2Name;
      const hasIpsecPassword = iface.ipsecPassword && String(iface.ipsecPassword).trim() !== '';
      const localAddressParam = isHomeRouter && server.ip ? server.ip : null;

      if (format === 'text') {
        code += `# Интерфейс ${i + 1}: ${iface.interfaceName} (${iface.type})\n`;
        code += `# Связь с сервером: ${iface.server2Name}\n`;
        code += `# Local IP: ${iface.localIp}\n`;
        code += `# Remote IP: ${iface.remoteIp}\n`;
      }

      if (iface.type === 'GRE') {
        const greParams = {
          name: iface.interfaceName,
          'remote-address': remoteAddress,
          'keepalive': '10s',
          'allow-fast-path': 'no',
        };
        if (localAddressParam) greParams['local-address'] = localAddressParam;
        if (iface.mtu) greParams.mtu = String(iface.mtu);
        if (hasIpsecPassword) greParams['ipsec-secret'] = iface.ipsecPassword;

        const op = { path: '/interface/gre', action: 'add', params: greParams };
        operations.push(op);

        if (format === 'text') {
          if (hasIpsecPassword) code += `# Создание GRE туннеля с IPSec\n`;
          else code += `# Создание GRE туннеля (без IPSec)\n`;
          code += operationToRouterOSLine(op) + '\n';
        }

        if (isHomeRouter) {
          const listOp = {
            path: '/interface/list/member',
            action: 'add',
            params: { list: 'GREs', interface: iface.interfaceName, comment: `GRE tunnel to ${iface.server2Name}` },
          };
          operations.push(listOp);
          if (format === 'text') code += operationToRouterOSLine(listOp) + '\n';
        }
      }

      const addrOp = {
        path: '/ip/address',
        action: 'add',
        params: {
          address: `${iface.localIp}/30`,
          interface: iface.interfaceName,
          comment: `Interface: ${iface.interfaceName} (${iface.type}) to ${iface.server2Name}`,
        },
      };
      operations.push(addrOp);
      if (format === 'text') code += operationToRouterOSLine(addrOp) + '\n';
    }

    if (format === 'text') {
      code += '# Проверка настроенных адресов:\n';
      code += '# /ip address print\n';
    }

    blocks.push({
      type: 'interface-addresses',
      serverName,
      server,
      ...(format === 'text' ? { code } : { operations }),
    });
  }

  return blocks;
}

/**
 * Построение блоков для рекурсивных маршрутов
 * @param {object} config
 * @param {Array} servers
 * @param {object} options - { format: 'text'|'json', serverId?: string }
 * @returns {Promise<Array>}
 */
async function buildMikrotikRecursiveRoutes(config, servers, options = {}) {
  const { format = 'text', serverId: filterServerId } = options;
  const recursiveGateways = (config.gateways || []).filter(g => g.type === 'recursive');
  const blocks = [];

  if (recursiveGateways.length === 0) return [];

  const gatewaysByServer = {};
  for (const gw of recursiveGateways) {
    const sid = gw.serverId || '__unassigned__';
    if (!gatewaysByServer[sid]) gatewaysByServer[sid] = [];
    gatewaysByServer[sid].push(gw);
  }

  for (const [sid, gateways] of Object.entries(gatewaysByServer)) {
    const server = getServerInfo(sid, servers);
    const serverName = server?.dns || server?.ip || sid;

    if (filterServerId && sid !== filterServerId) continue;

    const operations = [];
    let code = '';

    if (format === 'text') {
      code += `# Рекурсивные маршруты для сервера: ${serverName}\n`;
      if (server?.provider) code += `# Провайдер: ${server.provider}\n`;
      if (server?.country) code += `# Страна: ${server.country}\n`;
      code += '\n';
      code += '# Удаление старых рекурсивных маршрутов (comment начинается с "Recursive: ")\n';
      code += '/ip route remove [find comment~"^Recursive: "] \n\n';
    } else {
      operations.push({
        path: '/ip/route',
        action: 'remove',
        params: {},
        meta: { findComment: '^Recursive: ' },
      });
    }

    let validCount = 0;

    for (const gw of gateways) {
      const parentGatewaysList = (gw.parentGateways && gw.parentGateways.length > 0)
        ? gw.parentGateways
        : (gw.parentGatewayId ? [{ id: gw.parentGatewayId, distance: undefined }] : []);

      if (parentGatewaysList.length === 0 || !gw.ip) continue;

      for (const parentRef of parentGatewaysList) {
        const parent = getParentGateway(parentRef.id, config);
        if (!parent) continue;

        const parentIp = parent.parentType === 'interface' ? parent.remoteIp : parent.ip;
        if (!parentIp) continue;

        validCount++;
        const gatewayValue = parent.parentType === 'interface'
          ? `${parentIp}%${parent.name || parent.interfaceType || 'interface'}`
          : parentIp;
        const distance = parentRef.distance;
        const comment = gw.description
          ? `Recursive: ${gw.description} -> ${parentIp}`
          : `Recursive: ${gw.ip} -> ${parentIp}`;

        const routeParams = {
          'dst-address': `${gw.ip}/32`,
          gateway: gatewayValue,
          comment,
        };
        if (distance != null) routeParams.distance = String(distance);

        const op = { path: '/ip/route', action: 'add', params: routeParams };
        operations.push(op);

        if (format === 'text') {
          code += `# Рекурсивный gateway: ${gw.ip}\n`;
          code += operationToRouterOSLine(op) + '\n';
        }

        if (gw.description && (gw.description.toLowerCase().includes('default') || gw.description.toLowerCase().includes('0.0.0.0'))) {
          const defaultParams = {
            'dst-address': '0.0.0.0/0',
            gateway: gatewayValue,
            comment: `Recursive: ${gw.description || gw.ip} (default)`,
          };
          if (distance != null) defaultParams.distance = String(distance);
          const defaultOp = { path: '/ip/route', action: 'add', params: defaultParams };
          operations.push(defaultOp);
          if (format === 'text') code += operationToRouterOSLine(defaultOp) + '\n';
        }
      }
    }

    if (validCount > 0) {
      if (format === 'text') {
        code += '# Проверка: /ip route print where comment~"Recursive"\n';
      }
      blocks.push({
        type: 'recursive-routes',
        serverName,
        server,
        ...(format === 'text' ? { code } : { operations }),
      });
    }
  }

  return blocks;
}

/**
 * Комбинированная генерация: интерфейсы + рекурсивные маршруты
 * @param {object} config
 * @param {Array} servers
 * @param {object} passwordMap
 * @param {object} options - { format: 'text'|'json', serverId?: string, includeInterfaces?: boolean, includeRecursive?: boolean }
 */
async function buildMikrotikConfig(config, servers, passwordMap, options = {}) {
  const {
    format = 'text',
    serverId,
    includeInterfaces = true,
    includeRecursive = true,
  } = options;

  const opts = { format, serverId };
  const blocks = [];

  if (includeInterfaces) {
    const ifBlocks = await buildMikrotikInterfaceBlocks(config, servers, passwordMap, opts);
    blocks.push(...ifBlocks);
  }

  if (includeRecursive) {
    const recBlocks = await buildMikrotikRecursiveRoutes(config, servers, opts);
    blocks.push(...recBlocks);
  }

  return blocks;
}

module.exports = {
  getServerInfo,
  getParentGateway,
  operationToRouterOSLine,
  serializeOperationsToText,
  buildMikrotikInterfaceBlocks,
  buildMikrotikRecursiveRoutes,
  buildMikrotikConfig,
};