const express = require('express');

const upload = require('./lib/upload');
const serve = require('./lib/serve');
const errorHandler = require('./lib/errorHandler');

const PRODUCTION = process.env.NODE_ENV === 'production';

/**
 * Create a storage server instance
 * @param {Object} [options]
 * @param {string} [options.storageDir] Folder to store files (relative to `cwd()`),
 *    defaults to `./storage`
 * @param {string} [options.tmpDir] Temp folder used for uploading files,
 *    defaults to `require('os').tmpdir` in production and `./temp` relative to `cwd()` in development
 * @param {number} [options.maxUploadSize] Maximum upload file size in bytes, defaults to `1024 * 1024 * 20` (20MB)
 * @param {number} [options.pictureQuality] Picture quality (in percents) for stored files,
 *    defaults to `25` (25%)
 * @param {number} [options.maxPicturePixels] Maximum stored file size in pixels,
 *    defaults to `1920 * 1080` (FullHD ~ 2 megapixels)
 * @param {number} [options.maxUrlCacheItems] Maximum number of entries to keep in the file info cache,
 *    defaults to `10000000` (one million items)
 * @param {number|string} [options.maxAge] maxAge of served files,
 *    a number representing milliseconds or a string in [ms format](https://www.npmjs.com/package/ms);
 *    defaults to `365 days` in production and `0` in development;
 * @returns {import('express')} Express instance
 */
module.exports = (
  { storageDir, tmpDir, maxUploadSize, pictureQuality, maxPicturePixels, maxUrlCacheItems, maxAge } = {
    storageDir: './storage',
    tmpDir: PRODUCTION ? require('os').tmpdir : './temp',
    maxUploadSize: 1024 * 1024 * 20, // 20 megabytes
    pictureQuality: 85, // 85%
    maxPicturePixels: 1920 * 1080, // FullHD ~ 2 megapixels
    maxUrlCacheEntries: 10000000, // one million items
    maxAge: PRODUCTION ? '365 days' : 0 // one year for production, none for development
  }
) => {
  const app = express();

  app.use(express.json());
  app.use(
    upload({
      storageDir,
      tmpDir,
      maxUploadSize,
      pictureQuality,
      maxPicturePixels
    })
  );
  app.use(
    serve({
      storageDir,
      maxUrlCacheItems,
      maxAge
    })
  );
  app.use(errorHandler);

  return app;
};