// site-runtime.js
// Copyright (C) 2024 DTP Technologies, LLC
// All Rights Reserved

'use strict';

import 'dotenv/config';

import path, { dirname } from 'path';
import fs from 'fs';
import { fileURLToPath } from 'url';
const __dirname = dirname(fileURLToPath(import.meta.url)); // jshint ignore:line

import { createRequire } from 'module';
const require = createRequire(import.meta.url); // jshint ignore:line

import numeral from 'numeral';

import dayjs from 'dayjs';
import relativeTime from 'dayjs/plugin/relativeTime.js';
dayjs.extend(relativeTime);

import * as Marked from 'marked';
import hljs from 'highlight.js';

import mongoose from 'mongoose';
import { Redis } from 'ioredis';

import { SiteLog } from './site-log.js';
import { SiteTripwire } from './site-tripwire.js';

import { Emitter } from '@socket.io/redis-emitter';

export class SiteRuntime {

  static get name ( ) { return 'SiteRuntime'; }
  static get slug ( ) { return 'runtime'; }

  constructor (RuntimeClass, rootDir) {
    this.config = { root: rootDir };
    this.models = [ ];
    this.log = new SiteLog(this, RuntimeClass);
  }

  async start ( ) {
    await this.loadConfig();

    this.log.info('loading SiteTripwire (known-malicious request protection)');
    this.tripwire = new SiteTripwire(this);
    await this.tripwire.start();

    await this.connectMongoDB();
    await this.connectRedis();

    await this.loadModels();
    await this.loadServices();

    process.on('unhandledRejection', async (error, p) => {
      this.log.error('Unhandled rejection', {
        error: error,
        promise: p,
        stack: error.stack
      });
      const exitCode = await this.shutdown();
      await this.terminate(exitCode);
    });

    process.on('warning', (error) => {
      this.log.alert('warning', { error });
    });

    process.once('SIGINT', async ( ) => {
      this.log.info('SIGINT received (requesting shutdown)');
      const exitCode = await this.shutdown();
      this.terminate(exitCode);
    });
  }

  async shutdown ( ) {
    this.log.alert('System runtime shutting down');
  }

  terminate (exitCode = 0) {
    process.nextTick(( ) => {
      process.exit(exitCode);
    });
  }

  async loadConfig ( ) {
    this.log.debug('loading config', { root: this.config.root });
    this.config.pkg = require(path.join(this.config.root, 'package.json'));
    this.config.site = (await import(path.join(this.config.root, 'config', 'site.js'))).default;
    this.config.limiter = (await import(path.join(this.config.root, 'config', 'limiter.js'))).default;
    this.config.jobQueues = (await import(path.join(this.config.root, 'config', 'job-queues.js'))).default;
  }

  async connectMongoDB ( ) {
    try {
      this.log.info('starting MongoDB');

      /*
       * For some time, strictQuery=true was the Mongoose default. It's being
       * changed. The option has to be set manually now.
       */
      mongoose.set('strictQuery', true);
  
      this.log.info('connecting to MongoDB database', {
        pid: process.pid,
        host: process.env.MONGODB_HOST,
        database: process.env.MONGODB_DATABASE,
      });
      const mongoConnectUri = `mongodb://${process.env.DTP_MONGODB_HOST}/${process.env.DTP_MONGODB_DATABASE}`;
      await mongoose.connect(mongoConnectUri, {
        socketTimeoutMS: 0,
        dbName: process.env.MONGODB_DATABASE,
      });
      this.db = mongoose.connection;
      this.log.info('connected to MongoDB');
    } catch (error) {
      this.log.error('failed to connect to database', { error });
      throw error;
    }
  }

  async loadModels ( ) {
    const basePath = path.join(this.config.root, 'app', 'models');
    const entries = await fs.promises.readdir(basePath, { withFileTypes: true });

    this.log.info('loading models', { count: entries.length });
    for (const entry of entries) {
      if (!entry.isFile()) {
        continue;
      }
      const filename = path.join(basePath, entry.name);
      const model = (await import(filename)).default;
      if (this.models[model.modelName]) {
        this.log.error('model name collision', { name: model.modelName });
        process.exit(-1);
      }
      this.models.push(model);
      this.log.info('model loaded', { name: model.modelName});
    }
  }
  
  async resetIndexes (target) {
    if (target === 'all') {
      for (const model of this.models) {
        await this.resetIndex(model);
      }
      return;
    }
  
    const model = this.models.find((model) => model.modelName === target);
    if (!model) {
      throw new Error(`requested Mongoose model does not exist: ${target}`);
    }

    return this.resetIndex(model);
  }
  
  async resetIndex (model) {
    return new Promise(async (resolve, reject) => {
      this.log.info('dropping model indexes', { model: model.modelName });
      model.collection.dropIndexes((err) => {
        if (err) {
          return reject(err);
        }
        this.log.info('creating model indexes', { model: model.modelName });
        model.ensureIndexes((err) => {
          if (err) {
            return reject(err);
          }
          return resolve(model);
        });
      });
    });
  }

  async connectRedis ( ) {
    try {
      const options = {
        host: process.env.REDIS_HOST,
        port: parseInt(process.env.REDIS_PORT || '6379', 10),
        password: process.env.REDIS_PASSWORD,
        keyPrefix: process.env.REDIS_KEY_PREFIX,
        lazyConnect: false,
      };
      this.log.info('connecting to Redis', {
        host: options.host,
        port: options.port,
        prefix: options.keyPrefix || 'dtp',
      });
  
      this.redis = new Redis(options);
      this.redis.setMaxListeners(64); // prevents warnings/errors with Bull Queue
  
      this.log.info('creating Socket.io Emitter');
      this.emitter = new Emitter(this.redis);
  
      this.log.info('Redis connected');
    } catch (error) {
      this.log.error('failed to connect to Redis', error);
      throw new Error('failed to connect to Redis', { cause: error });
    }
  }
  
  async getRedisKeys (pattern) {
    return new Promise((resolve, reject) => {
      return this.redis.keys(pattern, (err, response) => {
        if (err) {
          return reject(err);
        }
        return resolve(response);
      });
    });
  }

  async loadServices ( ) {
    const basePath = path.join(this.config.root, 'app', 'services');
    const entries = await fs.promises.readdir(basePath, { withFileTypes: true });
    const inits = [ ];
  
    this.services = { };
  
    for await (const entry of entries) {
      if (!entry.isFile()) {
        continue;
      }
      try {
        const ServiceClass = (await import(path.join(basePath, entry.name))).default;
        this.log.info('loading service', {
          script: entry.name,
          name: ServiceClass.name,
          slug: ServiceClass.slug,
        });

        const service = new ServiceClass(this);

        this.services[ServiceClass.slug] = service;
        inits.push(service);
      } catch (error) {
        this.log.error('failed to load service', { script: entry, error });
        throw new Error('failed to load service', { cause: error });
      }
    }

    for await (const service of inits) {
      await service.start();
    }
  }

  async populateViewModel (viewModel) {
    viewModel.DTP_SCRIPT_DEBUG = (process.env.NODE_ENV !== 'production');
    viewModel.dtp = this;

    viewModel.pkg = this.config.pkg;
    viewModel.dayjs = dayjs;
    viewModel.numeral = numeral;
    viewModel.hljs = hljs;
    // viewModel.anchorme = require('anchorme').default;
    // viewModel.Color = require('color');
    // viewModel.numberToWords = require('number-to-words');
    viewModel.uuidv4 = (await import('uuid')).v4;
  
    /*
     * Set up the protected markdown renderer that will refuse to process links and images
     * for security reasons.
     */
  
    function safeImageRenderer (href, title, text) { return text; }
    function safeLinkRenderer (href, title, text) { return text; }
  
    function confirmedLinkRenderer (href, title, text) {
      return `<a href="${href}" uk-tooltip="${title || 'Visit link...'}" onclick="return dtp.app.confirmNavigation(event);">${text}</a>`;
    }
  
    viewModel.fullMarkedRenderer = new Marked.Renderer();
    viewModel.fullMarkedRenderer.image = safeImageRenderer;
    viewModel.fullMarkedRenderer.link = confirmedLinkRenderer;
  
    viewModel.safeMarkedRenderer = new Marked.Renderer();
    viewModel.safeMarkedRenderer.image = safeImageRenderer;
    viewModel.safeMarkedRenderer.link = safeLinkRenderer;
  
    viewModel.markedConfigChat = {
      renderer: this.safeMarkedRenderer,
      highlight: function(code, lang) {
        const language = hljs.getLanguage(lang) ? lang : 'plaintext';
        return hljs.highlight(code, { language }).value;
      },
      langPrefix: 'hljs language-',
      pedantic: false,
      gfm: true,
      breaks: true,
      sanitize: false,
      smartLists: true,
      smartypants: false,
      xhtml: false,
    };
    Marked.setOptions(viewModel.markedConfigChat);
    viewModel.marked = Marked;
  }
}