// core-node.js
// Copyright (C) 2022 DTP Technologies, LLC
// License: Apache-2.0

'use strict';

const uuidv4 = require('uuid').v4;

const mongoose = require('mongoose');
const fetch = require('node-fetch'); // jshint ignore:line

const CoreNode = mongoose.model('CoreNode');
const CoreNodeRequest = mongoose.model('CoreNodeRequest');

const { SiteService, SiteError } = require('../../lib/site-lib');

class CoreAddress {

  constructor (host, port) {
    this.host = host;
    this.port = port;
  }

  parse (host) {
    const tokens = host.split(':');
    this.host = tokens[0];
    if (tokens[1]) {
      this.port = parseInt(tokens[1], 10);
    } else {
      this.port = 443;
    }
    return this;
  }
}

class CoreNodeService extends SiteService {

  constructor (dtp) {
    super(dtp, module.exports);
  }

  parseCoreAddress (host) {
    const address = new CoreAddress();
    return address.parse(host);
  }

  async getCoreByAddress (address) {
    const core = await CoreNode
      .findOne({
        'address.host': address.host,
        'address.port': address.port,
      })
      .lean();
    return core;
  }

  /**
   * First ensures that a record exists in the local database for the Core node.
   * Then, calls the node's info services to resolve more metadata about the
   * node, it's operation, policies, and available services.
   *
   * @param {String} host hostname and optional port number of Core node to be
   * resolved.
   * @returns CoreNode document describing the Core node.
   */
  async resolveCore (host) {
    const NOW = new Date();
    this.log.info('resolving Core node', { host });

    const address = this.parseCoreAddress(host);
    let core = await this.getCoreByAddress(address);
    if (!core) {
      core = new CoreNode();
      core.created = NOW;
      core.address.host = address.host;
      core.address.port = address.port;
      await core.save();
      core = core.toObject();
    }

    const txSite = await this.sendRequest(core, {
      method: 'GET',
      url: '/core/info/site',
    });
    const txPackage = await this.sendRequest(core, {
      method: 'GET',
      url: '/core/info/package',
    });

    await CoreNode.updateOne(
      { _id: core._id },
      {
        $set: {
          updated: NOW,
          'meta.name': txSite.response.site.name,
          'meta.description': txSite.response.site.description,
          'meta.domain': txSite.response.site.domain,
          'meta.domainKey': txSite.response.site.domainKey,
          'meta.version': txPackage.response.package.version,
          'meta.admin': txSite.response.site.admin,
          'meta.supportEmail': txSite.response.site.supportEmail,
        },
      },
    );

    core = await CoreNode.findOne({ _id: core._id }).lean();
    this.log.info('resolved Core node', { core });
    return core;
  }

  async broadcast (request) {
    const results = [ ];
    await CoreNode
      .find()
      .cursor()
      .eachAsync(async (core) => {
        try {
          const response = await this.sendRequest(core, request);
          results.push({ coreId: core._id, request, response });
        } catch (error) {
          this.log.error('failed to send Core Node request', { core: core._id, request: request.url, error });
        }
      });
    return results;
  }

  async sendRequest (core, request) {
    const coreScheme = process.env.DTP_CORE_AUTH_SCHEME || 'https';
    const requestUrl = `${coreScheme}://${core.address.host}:${core.address.port}${request.url}`;

    try {
      const req = new CoreNodeRequest();
      req.created = new Date();
      req.core = core._id;
      req.token = {
        value: uuidv4(),
        claimed: false,
      };
      req.method = request.method || 'GET';
      req.url = request.url;
      await req.save();

      this.log.info('sending Core node request', { request: req });
      const response = await fetch(requestUrl, {
        method: req.method,
        body: request.body,
      });
      const json = await response.json();

      /*
       * capture a little inline health monitoring data, which can be used to
       * generate health alerts.
       */
      const DONE = new Date();
      const ELAPSED = DONE.valueOf() - req.created.valueOf();
      await CoreNodeRequest.updateOne(
        { _id: req._id },
        {
          $set: {
            'response.received': DONE,
            'response.elapsed': ELAPSED,
            'response.success': json.success,
          },
        },
      );

      this.log.info('Core node request complete', { request: req });
      return { request: req.toObject(), response: json };
    } catch (error) {
      this.log.error('failed to send Core Node request', { core: core._id, request: request.url, error });
      throw error;
    }
  }
}

module.exports = {
  slug: 'core-node',
  name: 'coreNode',
  create: (dtp) => { return new CoreNodeService(dtp); },
};