import * as fs from 'fs';
import { join, dirname, isAbsolute, resolve, sep } from 'path';
import { fileURLToPath } from 'url';
import * as crypto from 'crypto';
import request from './request.js';
import { Logger, LoggerService } from './logger.js';
import { ApplicationConfig, SelectedNode } from '../models/config.model.js';

export class CommonService {

  public logger: LoggerService = Logger;
  public nodes: SelectedNode[] = [];
  public selectedNode: SelectedNode = null;
  public ssoInit = { rtlSSO: 0, rtlCookiePath: '', logoutRedirectLink: '', cookieValue: '' };
  public appConfig: ApplicationConfig = { defaultNodeIndex: 0, selectedNodeIndex: 0, rtlConfFilePath: '', dbDirectoryPath: join(dirname(fileURLToPath(import.meta.url)), '..', '..'), rtlPass: '', allowPasswordUpdate: true, enable2FA: false, secret2FA: '', SSO: this.ssoInit, nodes: [] };
  public port = 3000;
  public host = '';
  public secret_key = crypto.randomBytes(64).toString('hex');
  public read_dummy_data = false;
  public baseHref = '/rtl';
  private dummy_data_array_from_file = [];
  private MONTHS = [
    { name: 'JAN', days: 31 }, { name: 'FEB', days: 28 }, { name: 'MAR', days: 31 }, { name: 'APR', days: 30 }, { name: 'MAY', days: 31 }, { name: 'JUN', days: 30 },
    { name: 'JUL', days: 31 }, { name: 'AUG', days: 31 }, { name: 'SEP', days: 30 }, { name: 'OCT', days: 31 }, { name: 'NOV', days: 30 }, { name: 'DEC', days: 31 }
  ];

  constructor() {}

  public maskPasswords = (obj) => {
    // Clone up front: masking a live config object must not blank the credentials LN
    // requests authenticate with (mirrors removeSecureData).
    const masked = JSON.parse(JSON.stringify(obj));
    const maskRecursive = (current) => {
      const keys = Object.keys(current);
      const length = keys.length;
      if (length !== 0) {
        for (let i = 0; i < length; i++) {
          // Header maps always carry credentials in this codebase (macaroon, rune, basic
          // auth). Key-substring matching cannot catch them without also hiding the *Path
          // fields the settings UI legitimately shows, so mask the whole map.
          if (keys[i] === 'headers' && current[keys[i]] && typeof current[keys[i]] === 'object') {
            Object.keys(current[keys[i]]).forEach((headerKey) => { current[keys[i]][headerKey] = '*'.repeat(20); });
          } else if (current[keys[i]] && typeof current[keys[i]] === 'object') {
            // Truthiness guard: null is 'object' too and must not reach Object.keys.
            maskRecursive(current[keys[i]]);
          }
          if (typeof keys[i] === 'string' &&
            ((keys[i].toLowerCase().includes('password') && keys[i] !== 'allowPasswordUpdate') || keys[i].toLowerCase().includes('multipass') ||
              keys[i].toLowerCase().includes('rpcpass') || keys[i].toLowerCase().includes('rpcpassword') ||
              keys[i].toLowerCase().includes('rpcuser') || keys[i].toLowerCase().includes('rpcauth') ||
              keys[i].toLowerCase().includes('secret2fa') || keys[i].toLowerCase().includes('cookievalue') ||
              keys[i].toLowerCase().includes('rtlpass') || keys[i].toLowerCase().includes('runevalue'))
          ) {
            current[keys[i]] = '*'.repeat(20);
          }
        }
      }
      return current;
    };
    return maskRecursive(masked);
  };

  public removeAuthSecureData = (node: SelectedNode) => {
    if (node.authentication) {
      delete node.authentication.macaroonPath;
      delete node.authentication.runePath;
      delete node.authentication.runeValue;
      delete node.authentication.lnApiPassword;
      delete node.authentication.options;
    }
    return node;
  };

  public removeSecureData = (config: ApplicationConfig) => {
    // Clone before deleting: cookieValue is runtime-only, so mutating a caller's live
    // appConfig would destroy SSO state with no way to restore it.
    const sanitized = JSON.parse(JSON.stringify(config));
    delete sanitized.rtlConfFilePath;
    delete sanitized.rtlPass;
    delete sanitized.multiPass;
    delete sanitized.multiPassHashed;
    delete sanitized.secret2FA;
    // The SSO cookie is a live bearer credential; it must never leave the server.
    if (sanitized.SSO) { delete sanitized.SSO.cookieValue; }
    sanitized.nodes?.forEach((node) => this.removeAuthSecureData(node));
    return sanitized;
  };

  public addSecureData = (config: ApplicationConfig) => {
    config.rtlConfFilePath = this.appConfig.rtlConfFilePath;
    config.rtlPass = this.appConfig.rtlPass;
    // Pin the hash only when the server holds one: on a default install's first boot the
    // file already has multiPassHashed but the in-memory config does not, and pinning
    // undefined would erase the only password from the file on save, bricking the boot.
    if (this.appConfig.multiPassHashed) {
      config.multiPassHashed = this.appConfig.multiPassHashed;
    } else {
      delete config.multiPassHashed;
    }
    // Deployment-level switches are pinned to server-held values: the settings API must
    // not flip the authentication mode (disableAuth, SSO) or move SSO fields, the
    // password policy, or the database location; no UI flow writes them. Pinning the
    // whole SSO object also means a trimmed or missing SSO object can never wipe server
    // state.
    config.disableAuth = this.appConfig.disableAuth;
    config.allowPasswordUpdate = this.appConfig.allowPasswordUpdate;
    config.dbDirectoryPath = this.appConfig.dbDirectoryPath;
    config.SSO = JSON.parse(JSON.stringify(this.appConfig.SSO || {}));
    if (this.appConfig.multiPass) {
      config.multiPass = this.appConfig.multiPass;
    }
    // Restore the TOTP seed when the client omits it — and when it sends an empty seed
    // while still claiming 2FA is on (an inconsistent pair no honest flow produces).
    // The settings UI's enable flow sends a non-empty seed; its disable flow sends an
    // empty seed with enable2FA false. Both are honored.
    if (config.secret2FA === undefined || (config.secret2FA === '' && config.enable2FA)) {
      config.secret2FA = this.appConfig.secret2FA;
    }
    // enable2FA derives from the seed, matching the boot-time derivation in config.ts,
    // so the two fields can never diverge after a save.
    config.enable2FA = !!config.secret2FA;
    const appConfigNodes = new Map(this.appConfig.nodes?.map((node) => [node.index, node]) || []);
    config.nodes?.forEach((node) => {
      const appConfigNode = appConfigNodes.get(node.index);
      if (appConfigNode?.authentication) {
        node.authentication = node.authentication || {};
        if (appConfigNode.authentication.macaroonPath) {
          node.authentication.macaroonPath = appConfigNode.authentication.macaroonPath;
        }
        if (appConfigNode.authentication.runePath) {
          node.authentication.runePath = appConfigNode.authentication.runePath;
        }
        if (appConfigNode.authentication.lnApiPassword) {
          node.authentication.lnApiPassword = appConfigNode.authentication.lnApiPassword;
        }
      }
    });
    return config;
  };

  public setSwapServerOptions = (req) => {
    const swapOptions = {
      baseUrl: req.session.selectedNode.settings.swapServerUrl,
      uri: '',
      rejectUnauthorized: false,
      json: true,
      headers: { 'Grpc-Metadata-macaroon': '' }
    };
    if (req.session.selectedNode.authentication.swapMacaroonPath) {
      try {
        swapOptions.headers = { 'Grpc-Metadata-macaroon': fs.readFileSync(join(req.session.selectedNode.authentication.swapMacaroonPath, 'loop.macaroon')).toString('hex') };
      } catch (err) {
        this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Loop macaroon Error', error: err });
      }
    }
    this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Swap Options Set' });
    return swapOptions;
  };

  public getBoltzServerOptions = (req) => {
    const boltzOptions = {
      url: req.session.selectedNode.settings.boltzServerUrl,
      rejectUnauthorized: false,
      json: true,
      headers: { 'Grpc-Metadata-macaroon': '' }
    };
    if (req.session.selectedNode.authentication.boltzMacaroonPath) {
      try {
        boltzOptions.headers = { 'Grpc-Metadata-macaroon': fs.readFileSync(join(req.session.selectedNode.authentication.boltzMacaroonPath, 'admin.macaroon')).toString('hex') };
      } catch (err) {
        this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Boltz macaroon Error', error: err });
      }
    }
    this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Boltz Options Set' });
    return boltzOptions;
  };

  public getOptions = (req) => {
    if (req.session.selectedNode && req.session.selectedNode.authentication.options) {
      req.session.selectedNode.authentication.options.method = (req.session.selectedNode.lnImplementation && req.session.selectedNode.lnImplementation.toUpperCase() === 'LND') ? 'GET' : 'POST';
      delete req.session.selectedNode.authentication.options.form;
      delete req.session.selectedNode.authentication.options.body;
      req.session.selectedNode.authentication.options.qs = {};
      return req.session.selectedNode.authentication.options;
    }
    return this.handleError({ statusCode: 401, message: 'Session expired after a day\'s inactivity' }, 'Session Expired', 'Session Expiry Error', this.selectedNode);
  };

  public updateSelectedNodeOptions = (req) => {
    if (!req.session.selectedNode) {
      req.session.selectedNode = {};
    }
    req.session.selectedNode.authentication.options = {
      url: '',
      rejectUnauthorized: false,
      json: true,
      form: null
    };
    try {
      if (req.session.selectedNode && req.session.selectedNode.lnImplementation) {
        switch (req.session.selectedNode.lnImplementation.toUpperCase()) {
          case 'CLN':
            try {
              if (!req.session.selectedNode.authentication.runeValue) {
                req.session.selectedNode.authentication.runeValue = this.getRuneValue(req.session.selectedNode.authentication.runePath);
              }
              req.session.selectedNode.authentication.options.headers = { rune: req.session.selectedNode.authentication.runeValue };
            } catch (err) {
              throw new Error(err);
            }
            break;

          case 'ECL':
            req.session.selectedNode.authentication.options.headers = { authorization: 'Basic ' + Buffer.from(':' + req.session.selectedNode.authentication.lnApiPassword).toString('base64') };
            break;

          default:
            req.session.selectedNode.authentication.options.headers = { 'Grpc-Metadata-macaroon': fs.readFileSync(join(req.session.selectedNode.authentication.macaroonPath, 'admin.macaroon')).toString('hex') };
            break;
        }
      }
      if (req.session.selectedNode) {
        this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Updated Node Options for ' + req.session.selectedNode.lnNode });
      }
      return { status: 200, message: 'Updated Successfully' };
    } catch (err) {
      req.session.selectedNode.authentication.options = {
        url: '',
        rejectUnauthorized: false,
        json: true,
        form: null
      };
      this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Update Selected Node Options Error', error: err });
      return { status: 502, message: err };
    }
  };

  public getRuneValue = (rune_path) => {
    const data = fs.readFileSync(rune_path, 'utf8');
    const pattern = /LIGHTNING_RUNE="(?<runeValue>[^"]+)"/;
    const match = data.match(pattern);
    if (match.groups.runeValue) {
      return match.groups.runeValue;
    } else {
      throw new Error('Rune not found in the file.');
    }
  };

  public setOptions = (req) => {
    if (this.nodes && this.nodes.length > 0) {
      this.nodes.forEach((node) => {
        if (node.authentication.options && node.authentication.options.headers) { return; }
        node.authentication.options = {
          url: '',
          rejectUnauthorized: false,
          json: true,
          form: null
        };
        try {
          if (node.lnImplementation) {
            switch (node.lnImplementation.toUpperCase()) {
              case 'CLN':
                try {
                  if (!node.authentication.runeValue) {
                    node.authentication.runeValue = this.getRuneValue(node.authentication.runePath);
                  }
                  node.authentication.options.headers = { rune: node.authentication.runeValue };
                } catch (err) {
                  throw new Error(err);
                }
                break;

              case 'ECL':
                node.authentication.options.headers = { authorization: 'Basic ' + Buffer.from(':' + node.authentication.lnApiPassword).toString('base64') };
                break;

              default:
                node.authentication.options.headers = { 'Grpc-Metadata-macaroon': fs.readFileSync(join(node.authentication.macaroonPath, 'admin.macaroon')).toString('hex') };
                break;
            }
          }
        } catch (err) {
          this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Common Set Options Error', error: err });
          node.authentication.options = {
            url: '',
            rejectUnauthorized: false,
            json: true,
            form: ''
          };
        }
        this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Set Node Options for ' + node.lnNode });
      });
      this.updateSelectedNodeOptions(req);
    }
  };

  public findNode = (selNodeIndex) => this.nodes.find((node) => node.index === selNodeIndex);

  public replaceNode = (req, newNode) => {
    const foundIndex = this.nodes.findIndex((node) => node.index === req.session.selectedNode.index);
    this.nodes.splice(foundIndex, 1, newNode);
    req.session.selectedNode = this.findNode(req.session.selectedNode.index);
  };

  public convertTimeToEpoch = (timeToConvert: Date) => Math.floor(timeToConvert.getTime() / 1000);

  public convertTimestampToTime = (num) => {
    const myDate = new Date(+num * 1000);
    let days = myDate.getDate().toString();
    days = +days < 10 ? '0' + days : days;
    let hours = myDate.getHours().toString();
    hours = +hours < 10 ? '0' + hours : hours;
    let minutes = myDate.getMinutes().toString();
    minutes = +minutes < 10 ? '0' + minutes : minutes;
    let seconds = myDate.getSeconds().toString();
    seconds = +seconds < 10 ? '0' + seconds : seconds;
    return days + '/' + this.MONTHS[myDate.getMonth()].name + '/' + myDate.getFullYear() + ' ' + hours + ':' + minutes + ':' + seconds;
  };

  public sortAscByKey = (array, key) => array.sort((a, b) => {
    const x = +a[key];
    const y = +b[key];
    return ((x < y) ? -1 : ((x > y) ? 1 : 0));
  });

  public sortAscByStrKey = (array, key) => array.sort((a, b) => {
    const x = a[key] ? a[key].toUpperCase() : '';
    const y = b[key] ? b[key].toUpperCase() : '';
    return ((x < y) ? -1 : ((x > y) ? 1 : 0));
  });

  public sortDescByKey = (array, key) => {
    const temp = array.sort((a, b) => {
      const x = +a[key] ? +a[key] : 0;
      const y = +b[key] ? +b[key] : 0;
      return (x > y) ? -1 : ((x < y) ? 1 : 0);
    });
    return temp;
  };

  public sortDescByStrKey = (array, key) => {
    const temp = array.sort((a, b) => {
      const x = a[key] ? a[key].toUpperCase() : '';
      const y = b[key] ? b[key].toUpperCase() : '';
      return (x > y) ? -1 : ((x < y) ? 1 : 0);
    });
    return temp;
  };

  public newestOnTop = (array, key, value) => {
    const newlyAddedRecord = array.splice(array.findIndex((item) => item[key] === value), 1);
    array?.unshift(newlyAddedRecord[0]);
    return array;
  };

  public camelCase = (str: string) => str?.replace(/(?:^\w|[A-Z]|\b\w)/g, (word, index) => (word.toUpperCase()))?.replace(/\s+/g, '')?.replace(/-/g, ' ');

  public titleCase = (str: string) => {
    if (str.indexOf('!\n') > 0 || str.indexOf('.\n') > 0) {
      return str.split('\n')?.reduce((accumulator, currentStr) => accumulator + currentStr.charAt(0).toUpperCase() + currentStr.substring(1).toLowerCase() + '\n', '');
    } else {
      if (str.indexOf(' ') > 0) {
        return str.split(' ')?.reduce((accumulator, currentStr) => accumulator + currentStr.charAt(0).toUpperCase() + currentStr.substring(1).toLowerCase() + ' ', '');
      } else {
        return str.charAt(0).toUpperCase() + str.substring(1).toLowerCase();
      }
    }
  };

  public handleError = (errRes, fileName, errMsg, selectedNode: SelectedNode) => {
    const err = JSON.parse(JSON.stringify(errRes));
    if (!selectedNode) { selectedNode = this.selectedNode; }
    switch (selectedNode.lnImplementation) {
      case 'LND':
        if (err.options && err.options.headers && err.options.headers['Grpc-Metadata-macaroon']) {
          delete err.options.headers['Grpc-Metadata-macaroon'];
        }
        if (err.response && err.response.request && err.response.request.headers && err.response.request.headers['Grpc-Metadata-macaroon']) {
          delete err.response.request.headers['Grpc-Metadata-macaroon'];
        }
        break;

      case 'CLN':
        if (err.options && err.options.headers && err.options.headers.rune) {
          delete err.options.headers.rune;
        }
        if (err.response && err.response.request && err.response.request.headers && err.response.request.headers.rune) {
          delete err.response.request.headers.rune;
        }
        break;

      case 'ECL':
        if (err.options && err.options.headers && err.options.headers.authorization) {
          delete err.options.headers.authorization;
        }
        if (err.response && err.response.request && err.response.request.headers && err.response.request.headers.authorization) {
          delete err.response.request.headers.authorization;
        }
        break;

      default:
        if (err.options && err.options.headers) { delete err.options.headers; }
        break;
    }
    this.logger.log({ selectedNode: selectedNode, level: 'ERROR', fileName: fileName, msg: errMsg, error: (typeof err === 'object' ? JSON.stringify(err) : err) });
    let newErrorObj = { statusCode: 500, message: '', error: '' };
    if (err.code && err.code === 'ENOENT') {
      // The absolute path stays in the server log above but is not echoed to clients.
      newErrorObj = {
        statusCode: 500,
        message: 'No such file or directory',
        error: 'No such file or directory'
      };
    } else {
      newErrorObj = {
        statusCode: err.statusCode ? err.statusCode : err.status ? err.status : (err.error && err.error.code && err.error.code === 'ECONNREFUSED') ? 503 : 500,
        message: (err.error && err.error.message) ? err.error.message : err.message ? err.message : errMsg,
        error: (
          (err.error && err.error.error && err.error.error.error && typeof err.error.error.error === 'string') ? err.error.error.error :
            (err.error && err.error.error && typeof err.error.error === 'string') ? err.error.error :
              (err.error && err.error.error && err.error.error.message && typeof err.error.error.message === 'string') ? err.error.error.message :
                (err.error && err.error.message && typeof err.error.message === 'string') ? err.error.message :
                  (err.error && typeof err.error === 'string') ? err.error :
                    (err.message && typeof err.message === 'string') ? err.message : (typeof err === 'string') ? err : 'Unknown Error'
        )
      };
    }
    if (selectedNode.lnImplementation === 'ECL' && err.message && err.message.indexOf('Authentication Error') < 0 && err.name && err.name === 'StatusCodeError') { newErrorObj.statusCode = 500; }
    return newErrorObj;
  };

  public getRequestIP = (req) => ((typeof req.headers['x-forwarded-for'] === 'string' && req.headers['x-forwarded-for'].split(',').shift()) ||
    req.ip ||
    req.connection.remoteAddress ||
    req.socket.remoteAddress ||
    (req.connection.socket ? req.connection.socket.remoteAddress : null));

  public getDummyData = (dataKey, lnImplementation) => {
    const dummyDataFile = this.appConfig.rtlConfFilePath + sep + 'ECLDummyData.log';
    return new Promise((resolve, reject) => {
      if (this.dummy_data_array_from_file.length === 0) {
        fs.readFile(dummyDataFile, 'utf8', (err, data) => {
          if (err) {
            if (err.code === 'ENOENT') {
              this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Dummy data file does not exist' });
            } else {
              this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Getting dummy data failed' });
            }
          } else {
            this.dummy_data_array_from_file = data.split('\n');
            resolve(this.filterData(dataKey, lnImplementation));
          }
        });
      } else {
        resolve(this.filterData(dataKey, lnImplementation));
      }
    });
  };

  public readCookie = (config) => {
    this.appConfig.SSO = config.SSO;
    const exists = fs.existsSync(this.appConfig.SSO.rtlCookiePath);
    if (exists) {
      try {
        this.appConfig.SSO.cookieValue = fs.readFileSync(this.appConfig.SSO.rtlCookiePath, 'utf-8');
      } catch (err) {
        this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Something went wrong while reading cookie: \n' + err });
        throw new Error(err);
      }
    } else {
      try {
        const directoryName = dirname(this.appConfig.SSO.rtlCookiePath);
        this.createDirectory(directoryName);
        fs.writeFileSync(this.appConfig.SSO.rtlCookiePath, crypto.randomBytes(64).toString('hex'));
        this.appConfig.SSO.cookieValue = fs.readFileSync(this.appConfig.SSO.rtlCookiePath, 'utf-8');
      } catch (err) {
        this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Something went wrong while reading the cookie: \n' + err });
        throw new Error(err);
      }
    }
  };

  public refreshCookie = () => {
    try {
      fs.writeFileSync(this.appConfig.SSO.rtlCookiePath, crypto.randomBytes(64).toString('hex'));
      this.appConfig.SSO.cookieValue = fs.readFileSync(this.appConfig.SSO.rtlCookiePath, 'utf-8');
    } catch (err) {
      this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Something went wrong while refreshing cookie', error: err });
      throw new Error(err);
    }
  };

  public createDirectory = (directoryName) => {
    const initDir = isAbsolute(directoryName) ? sep : '';
    directoryName.split(sep)?.reduce((parentDir, childDir) => {
      const curDir = resolve(parentDir, childDir);
      try {
        if (!fs.existsSync(curDir)) {
          fs.mkdirSync(curDir);
        }
      } catch (err) {
        if (err.code !== 'EEXIST') {
          if (err.code === 'ENOENT') {
            throw new Error(`ENOENT: No such file or directory, mkdir '${directoryName}'. Ensure that the path separator is '${sep}'`);
          } else {
            throw err;
          }
        }
      }
      return curDir;
    }, initDir);
  };

  public replacePasswordWithHash = (multiPassHashed) => {
    this.appConfig.rtlConfFilePath = process.env.RTL_CONFIG_PATH ? process.env.RTL_CONFIG_PATH : join(dirname(fileURLToPath(import.meta.url)), '../..');
    try {
      const RTLConfFile = this.appConfig.rtlConfFilePath + sep + 'RTL-Config.json';
      const config = JSON.parse(fs.readFileSync(RTLConfFile, 'utf-8'));
      config.multiPassHashed = multiPassHashed;
      delete config.multiPass;
      fs.writeFileSync(RTLConfFile, JSON.stringify(config, null, 2), 'utf-8');
      this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Please note that, RTL has encrypted the plaintext password into its corresponding hash' });
      return config.multiPassHashed;
    } catch (err) {
      this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Password hashing failed', error: err });
    }
  };

  public getAllNodeAllChannelBackup = (node: SelectedNode) => {
    const channel_backup_file = node.settings.channelBackupPath + sep + 'channel-all.bak';
    const options = {
      url: node.settings.lnServerUrl + '/v1/channels/backup',
      rejectUnauthorized: false,
      json: true,
      headers: { 'Grpc-Metadata-macaroon': fs.readFileSync(node.authentication.macaroonPath + '/admin.macaroon').toString('hex') }
    };
    this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Getting Channel Backup for Node ' + node.lnNode + '..' });
    request(options).then((body) => {
      fs.writeFile(channel_backup_file, JSON.stringify(body), (err) => {
        if (err) {
          if (node.lnNode) {
            this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Error in Channel Backup for Node ' + node.lnNode, error: err });
          } else {
            this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Error in Channel Backup for File ' + channel_backup_file, error: err });
          }
        } else {
          if (node.lnNode) {
            this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Successful in Channel Backup for Node ' + node.lnNode, data: body });
          } else {
            this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Successful in Channel Backup for File ' + channel_backup_file, data: body });
          }
        }
      });
    }, (err) => {
      this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Error in Channel Backup for Node ' + node.lnNode, error: err });
      fs.writeFile(channel_backup_file, '', () => { });
    });
  };

  public isVersionCompatible = (currentVersion, checkVersion) => {
    if (currentVersion && currentVersion !== '') {
      // eslint-disable-next-line prefer-named-capture-group
      const pattern = /v?(\d+(\.\d+)*)/;
      const match = currentVersion.match(pattern);
      if (match && match.length && match.length > 1) {
        this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Global Version ' + match[1] });
        this.logger.log({ selectedNode: this.selectedNode, level: 'INFO', fileName: 'Common', msg: 'Checking Compatiblility with Version ' + checkVersion });
        const currentVersionArr = match[1].split('.') || [];
        currentVersionArr[1] = currentVersionArr[1].substring(0, 2);
        const checkVersionsArr = checkVersion.split('.');
        checkVersionsArr[1] = checkVersionsArr[1].substring(0, 2);
        return (+currentVersionArr[0] > +checkVersionsArr[0]) ||
        (+currentVersionArr[0] === +checkVersionsArr[0] && +currentVersionArr[1] > +checkVersionsArr[1]) ||
        (+currentVersionArr[0] === +checkVersionsArr[0] && +currentVersionArr[1] === +checkVersionsArr[1] && +currentVersionArr[2] >= +checkVersionsArr[2]);
      } else {
        this.logger.log({ selectedNode: this.selectedNode, level: 'ERROR', fileName: 'Common', msg: 'Invalid Version String ' + currentVersion });
        return false;
      }
    }
    return false;
  };

  public getMonthDays = (selMonth, selYear) => ((selMonth === 1 && selYear % 4 === 0) ? (this.MONTHS[selMonth].days + 1) : this.MONTHS[selMonth].days);

  public logEnvVariables = (req) => {
    const selNode = <SelectedNode>req.session.selectedNode;
    if (selNode && selNode.index) {
      this.logger.log({ selectedNode: selNode, level: 'INFO', fileName: 'Config Setup:', msg: JSON.stringify(this.removeSecureData(JSON.parse(JSON.stringify(this.appConfig)))) });
      this.logger.log({ selectedNode: selNode, level: 'INFO', fileName: 'Config Setup Variable', msg: 'SSO: ' + this.appConfig.SSO.rtlSSO });
    }
  };

  public filterData = (dataKey, lnImplementation) => {
    let search_string = '';
    if (lnImplementation === 'ECL') {
      switch (dataKey) {
        case 'GetInfo': search_string = 'INFO: GetInfo => Get Info Response: '; break;
        case 'Fees': search_string = 'INFO: Fees => Fee Response: '; break;
        case 'Payments': search_string = 'INFO: Fees => Payments Response: '; break;
        case 'Invoices': search_string = 'INFO: Invoice => Invoices List Received: '; break;
        case 'OnChainBalance': search_string = 'INFO: Onchain => Balance Received: '; break;
        case 'Peers': search_string = 'INFO: Peers => Peers with Alias: '; break;
        case 'Channels': search_string = 'INFO: Channels => Simplified Channels with Alias: '; break;
        default: search_string = 'Random Line'; break;
      }
    } else if (lnImplementation === 'CLN') {
      switch (dataKey) {
        case 'GetInfo': search_string = 'DEBUG: GetInfo => Node Information. '; break;
        case 'Fees': search_string = 'DEBUG: Fees => Fee Received. '; break;
        case 'Payments': search_string = 'DEBUG: Payments => Payment List Received: '; break;
        case 'Invoices': search_string = 'DEBUG: Invoice => Invoices List Received. '; break;
        case 'ChannelBalance': search_string = 'DEBUG: Channels => Local Remote Balance. '; break;
        case 'Peers': search_string = 'DEBUG: Peers => Peers with Alias: '; break;
        case 'Channels': search_string = 'DEBUG: Channels => List Channels: '; break;
        case 'Balance': search_string = 'DEBUG: Balance => Balance Received. '; break;
        case 'ForwardingHistory': search_string = 'DEBUG: Channels => Forwarding History Received: '; break;
        case 'UTXOs': search_string = 'DEBUG: OnChain => List Funds Received. '; break;
        case 'FeeRateperkb': search_string = 'DEBUG: Network => Network Fee Rates Received for perkb. '; break;
        case 'FeeRateperkw': search_string = 'DEBUG: Network => Network Fee Rates Received for perkw. '; break;
        default: search_string = 'Random Line'; break;
      }
    }
    const foundDataLine = this.dummy_data_array_from_file.find((dataItem) => dataItem.includes(search_string));
    const dataStr = foundDataLine ? foundDataLine.substring((foundDataLine.indexOf(search_string)) + search_string.length) : '{}';
    return JSON.parse(dataStr);
  };

  public runWithConcurrencyLimit = (tasks, limit, done) => {
    const results = new Array(tasks?.length || 0);
    // 'done' must fire exactly once. Guard it: multiple runNext() completions (e.g. several
    // non-function task elements draining synchronously) must not send the response twice.
    let finished = false;
    const finish = () => {
      if (finished) { return; }
      finished = true;
      done(results);
    };
    // No tasks: the start loop below never runs, so 'done' would never fire and the
    // response would hang. Resolve immediately for empty lists (e.g. a node with no peers).
    if (!tasks || tasks.length === 0) { return finish(); }
    let nextIndex = 0;
    let activeCount = 0;

    const runNext = () => {
      if (nextIndex >= tasks.length) {
        if (activeCount === 0) {
          finish(); // all tasks are finished
        }
        return;
      }

      const currentIndex = nextIndex++;
      activeCount++;

      const task = tasks[currentIndex];
      if (typeof task !== 'function') {
        results[currentIndex] = { error: new Error('Invalid task at index ' + currentIndex) };
        activeCount--;
        runNext();
        return;
      }

      Promise.resolve().then(() => task()).then((result) => {
        results[currentIndex] = result;
      }).catch((err) => {
        results[currentIndex] = { error: err };
      }).finally(() => {
        activeCount--;
        runNext();
      });
    };

    // Normalize to at least 1: a non-positive limit would start no tasks, so 'done' (only
    // reached from a task's finally) would never fire and the response would hang.
    const startCount = Math.max(1, limit);
    for (let i = 0; i < startCount && i < tasks.length; i++) {
      runNext();
    }
  };

}

export const Common = new CommonService();