'use strict';

const express = require('express');
const fetch = require('node-fetch');
const redirectToHTTPS = require('express-http-to-https').redirectToHTTPS;

// Change this to add a delay (ms) before the server responds.
const FORECAST_DELAY = 0;

// If running locally, set your Dark Sky API key here
const API_KEY = process.env.DARKSKY_API_KEY;
const BASE_URL = `https://api.darksky.net/forecast`;

/**
 * Generates a fake forecast in case the weather API is not available.
 *
 * @param {String} location GPS location to use.
 * @return {Object} forecast object.
 */
function generateFakeForecast(location) {
  location = location || '40.7720232,-73.9732319';
  const commaAt = location.indexOf(',');

  // Create a new copy of the forecast
  const result = Object.assign({}, fakeForecast);
  result.latitude = parseFloat(location.substr(0, commaAt));
  result.longitude = parseFloat(location.substr(commaAt + 1));
  return result;
}


/**
 * Gets the weather forecast from the Dark Sky API for the given location.
 *
 * @param {Request} req request object from Express.
 * @param {Response} resp response object from Express.
 */
function getForecast(req, resp) {
  const location = req.params.location || '40.7720232,-73.9732319';
  const url = `${BASE_URL}/${API_KEY}/${location}`;
  fetch(url).then((resp) => {
    if (resp.status !== 200) {
      throw new Error(resp.statusText);
    }
    return resp.json();
  }).then((data) => {
    setTimeout(() => {
      resp.json(data);
    }, FORECAST_DELAY);
  }).catch((err) => {
    console.error('Dark Sky API Error:', err.message);
    resp.json(generateFakeForecast(location));
  });
}

/**
 * Starts the Express server.
 *
 * @return {ExpressServer} instance of the Express server.
 */
function startServer() {
  const app = express();

  // Redirect HTTP to HTTPS,
  app.use(redirectToHTTPS([/localhost:(\d{4})/], [], 301));

  // Logging for each request
  app.use((req, resp, next) => {
    const now = new Date();
    const time = `${now.toLocaleDateString()} - ${now.toLocaleTimeString()}`;
    const path = `"${req.method} ${req.path}"`;
    const m = `${req.ip} - ${time} - ${path}`;
    // eslint-disable-next-line no-console
    console.log(m);
    next();
  });

  // Handle requests for static files
  app.use(express.static('public'));

  // Start the server
  return app.listen('8000', () => {
    // eslint-disable-next-line no-console
    console.log('Local DevServer Started on port 8000...');
  });
}

startServer();