'use strict';

const fs = require('fs');
const path = require('path');
const paths = require('./paths');

// Make sure that including paths.js after env.js will read .env variables.
delete require.cache[require.resolve('./paths')];

const NODE_ENV = process.env.NODE_ENV;
if (!NODE_ENV) {
    throw new Error(
        'The NODE_ENV environment variable is required but was not specified.'
    );
}

// https://github.com/bkeepers/dotenv#what-other-env-files-can-i-use
const dotenvFiles = [
  `${paths.dotenv}.${NODE_ENV}.local`,
  // Don't include `.env.local` for `test` environment
  // since normally you expect tests to produce the same
  // results for everyone
  NODE_ENV !== 'test' && `${paths.dotenv}.local`,
  `${paths.dotenv}.${NODE_ENV}`,
  paths.dotenv,
].filter(Boolean);

// Load environment variables from .env* files. Suppress warnings using silent
// if this file is missing. dotenv will never modify any environment variables
// that have already been set.  Variable expansion is supported in .env files.
// https://github.com/motdotla/dotenv
// https://github.com/motdotla/dotenv-expand
dotenvFiles.forEach(dotenvFile => {
  if (fs.existsSync(dotenvFile)) {
    require('dotenv-expand')(
      require('dotenv').config({
        path: dotenvFile,
      })
    );
  }
});

// Grab NODE_ENV and WE_CHAT_MP_* environment variables and prepare them to be
// injected into the application via DefinePlugin in webpack configuration.
const WE_CHAT_MP = /^WE_CHAT_MP_/i;

function getClientEnvironment() {
    const raw = Object.keys(process.env)
        .filter((key) => WE_CHAT_MP.test(key))
        .reduce(
            (env, key) => {
                env[key] = process.env[key];
                return env;
            },
            {
                // Useful for determining whether we’re running in production mode.
                // Most importantly, it switches React into the correct mode.
                NODE_ENV: process.env.NODE_ENV || 'development',
                // process.env.OAK_PLATFORM: wechatMp | web | node
                OAK_PLATFORM: 'wechatMp',
                OAK_DEV_MODE: process.env.OAK_DEV_MODE || 'server',
                SUB_DIR_NAME: process.env.SUB_DIR_NAME || 'wechatMp',
            }
        );
    // Stringify all values so we can feed into webpack DefinePlugin
    const stringified = {
        'process.env': Object.keys(raw).reduce((env, key) => {
            env[key] = JSON.stringify(raw[key]);
            return env;
        }, {}),
    };

    return { raw, stringified };
}

module.exports = getClientEnvironment;