var path = require('path')
var config = require('../config')
var ExtractTextPlugin = require('extract-text-webpack-plugin')
const packageConfig = require('../package.json')

exports.assetsPath = function (_path) {
    var assetsSubDirectory = process.env.NODE_ENV === 'production' ?
      config.build.assetsSubDirectory :
      config.dev.assetsSubDirectory
    return path.posix.join(assetsSubDirectory, _path)
  },

  exports.createNotifierCallback = () => {
    const notifier = require('node-notifier')

    return (severity, errors) => {
      if (severity !== 'error') return

      const error = errors[0]
      const filename = error.file && error.file.split('!').pop()

      notifier.notify({
        title: packageConfig.name,
        message: severity + ': ' + error.name,
        subtitle: filename || '',
        icon: path.join(__dirname, 'logo.png')
      })
    }
  }

exports.cssLoaders = function (options) {
  options = options || {}

  var cssLoader = {
    loader: 'css-loader',
    options: {
      minimize: process.env.NODE_ENV === 'production',
      sourceMap: options.sourceMap
    }
  }

  function generateLoaders(loader, loaderOptions) {
    var loaders = [cssLoader]
    if (loader) {
      loaders.push({
        loader: loader + '-loader',
        options: Object.assign({}, loaderOptions, {
          sourceMap: options.sourceMap
        })
      })
    }

    if (options.extract) {
      return ExtractTextPlugin.extract({
        use: loaders,
        fallback: 'vue-style-loader'
      })
    } else {
      return ['vue-style-loader'].concat(loaders)
    }
  }

  return {
    css: generateLoaders(),
    postcss: generateLoaders(),
    less: generateLoaders('less'),
    sass: generateLoaders('sass', {
      indentedSyntax: true
    }),
    scss: generateLoaders('sass'),
    stylus: generateLoaders('stylus'),
    styl: generateLoaders('stylus')
  }
}

exports.styleLoaders = function (options) {
  var output = []
  var loaders = exports.cssLoaders(options)
  for (var extension in loaders) {
    var loader = loaders[extension]
    output.push({
      test: new RegExp('\\.' + extension + '$'),
      use: loader
    })
  }
  return output
}
