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

'use strict';

import 'dotenv/config';

import path, { dirname } from 'path';
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 * as glob from 'glob';
import * as rfs from 'rotating-file-stream';

import webpack from 'webpack';
import webpackDevMiddleware from 'webpack-dev-middleware';

import WEBPACK_CONFIG from './webpack.config.js';

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

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

import express from 'express';
import morgan from 'morgan';

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

const APP_CONFIG = {
  pkg: require('./package.json'),
};

class Harness {

  constructor ( ) {
    this.config = {
      root: __dirname,
    };
    this.log = new SiteLog(this, 'Harness');
    this.models = [ ];
  }

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

    await this.startMongoDB();
    await this.loadModels();

    await this.connectRedis();

    await this.startExpressJS();
  }

  async startMongoDB ( ) {
    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 modelScripts = glob.sync(path.join(this.config.root, 'app', 'models', '*.js'));
    this.log.info('loading models', { count: modelScripts.length });
    for (const modelScript of modelScripts) {
      const model = (await import(modelScript)).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.DTP_REDIS_HOST,
        port: parseInt(process.env.DTP_REDIS_PORT || '6379', 10),
        password: process.env.DTP_REDIS_PASSWORD,
        keyPrefix: process.env.DTP_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 startExpressJS ( ) {
    this.app = express();

    this.app.locals.config = APP_CONFIG;
    this.app.locals.pkg = APP_CONFIG.pkg; // convenience
    this.app.locals.site = (await import(path.join(this.config.root, 'config', 'site.js'))).default;
  
    this.app.set('view engine', 'pug');
    this.app.set('views', path.join(__dirname, 'app', 'views'));
    this.app.set('x-powered-by', false);

    this.app.use(this.tripwire.guard.bind(this.tripwire));

    /*
     * HTTP request logging
     */
    if (process.env.DTP_LOG_FILE === 'enabled') {
      const httpLogStream = rfs.createStream(process.env.DTP_LOG_FILE_NAME_HTTP || 'dtp-sites-access.log', {
        interval: '1d',
        path: process.env.DTP_LOG_FILE_PATH || '/tmp',
        compress: 'gzip',
      });
      this.app.use(morgan(process.env.DTP_LOG_HTTP_FORMAT || 'combined', { stream: httpLogStream }));
    }

    function cacheOneDay (req, res, next) {
      res.set('Cache-Control', 'public, maxage=86400, s-maxage=86400, immutable');
      return next();
    }
    function serviceWorkerAllowed (req, res, next) {
      res.set('Service-Worker-Allowed', '/');
      return next();
    }

    /*
     * Static content and file services
     */
    const staticOptions = {
      cacheControl: true,
      immutable: true,
      maxAge: '4h',
      dotfiles: 'ignore',
    };

    this.app.use('/fontawesome', cacheOneDay, express.static(path.join(__dirname, 'node_modules', '@fortawesome', 'fontawesome-free')));
    this.app.use('/uikit', cacheOneDay, express.static(path.join(__dirname, 'node_modules', 'uikit')));
    this.app.use('/pretty-checkbox', cacheOneDay, express.static(path.join(__dirname, 'node_modules', 'pretty-checkbox', 'dist')));

    this.app.use('/dist', cacheOneDay, serviceWorkerAllowed, express.static(path.join(__dirname, 'dist')));
    this.app.use('/static', cacheOneDay, serviceWorkerAllowed, express.static(path.join(__dirname, 'client', 'static'), staticOptions));

    /*
     * Webpack integration
     */
    if (process.env.NODE_ENV !== 'production') {
      this.compiler = webpack(WEBPACK_CONFIG);
      this.webpackDevMiddleware = webpackDevMiddleware(this.compiler, {
        publicPath: WEBPACK_CONFIG.output.publicPath,
        writeToDisk: true,
      });
      this.app.use(this.webpackDevMiddleware);
    }

    this.app.use((req, res, next) => {
      res.locals.dtp = {
        request: req,
      };
      return next();
    });

    await this.loadControllers();

    /*
     * Start the ExpressJS server
     */
    const host = process.env.DTP_HTTP_HOST || '127.0.0.1';
    const port = parseInt(process.env.DTP_HTTP_PORT || '3000', 10);
    this.log.info('Starting application server', { host, port });
    this.app.listen(port, host, ( ) => {
      this.log.info(`${APP_CONFIG.pkg.name} online.`);
    });
  }

  async loadControllers ( ) {
    const scripts = glob.sync(path.join(this.config.root, 'app', 'controllers', '*.js'));
    const inits = [ ];
  
    this.controllers = { };
  
    for await (const script of scripts) {
      try {
        const file = path.parse(script);
        this.log.info('loading controller', { name: file.base });
  
        let controller = await import(script);
        controller = controller.default;
        controller.instance = controller.create(this);

        this.controllers[controller.slug] = controller;
        inits.push(controller);
      } catch (error) {
        this.log.error('failed to load controller', { error });
        throw new Error('failed to load controller', { cause: error });
      }
    }

    for await (const controller of inits) {
      if (controller.isHome) {
        continue;
      }
      await controller.instance.start();
    }
  
    /*
     * Start the Home controller
     */
    await this.controllers.home.instance.start();
  }

}

(async ( ) => {

  try {
    const harness = new Harness();
    await harness.start();
  } catch (error) {
    console.error('failed to start application harness', error);
  }

})();