var path = require("path")

var webpack = require("webpack")
var ExtractTextPlugin = require("extract-text-webpack-plugin")
var UglifyJsPlugin = require("uglifyjs-webpack-plugin")
var deepExtend = require("deep-extend")
var autoprefixer = require("autoprefixer")
const {gitDescribeSync} = require("git-describe")

var pkg = require("./package.json")

let gitInfo

try {
  gitInfo = gitDescribeSync(__dirname)
} catch(e) {
  gitInfo = {
    hash: "noGit",
    dirty: false
  }
}

var loadersByExtension = require("./build-tools/loadersByExtension")

module.exports = function(options) {

  // Special options, that have logic in this file
  // ...with defaults
  var specialOptions = deepExtend({}, {
    hot: false,
    separateStylesheets: true,
    minimize: false,
    html: false,
    longTermCaching: false,
    sourcemaps: false,
  }, options._special)

  var loadersMap = {
    "js(x)?": {
      loader: "babel?retainLines=true",
      include: [
        path.join(__dirname, "src"),
        /(object\-assign\-deep)/
      ],
    },
    "json": "json-loader",
    "txt|yaml": "raw-loader",
    "png|jpg|jpeg|gif|svg": specialOptions.disableAssets ? "null-loader" : "url-loader",
    "woff|woff2": specialOptions.disableAssets ? "null-loader" : "url-loader?limit=100000",
    "ttf|eot":  specialOptions.disableAssets ? "null-loader" : "file-loader" ,
    "worker.js": ["worker-loader?inline=true", "babel"]
  }

  var plugins = []

  if( specialOptions.separateStylesheets ) {
    plugins.push(new ExtractTextPlugin("[name].css" + (specialOptions.longTermCaching ? "?[contenthash]" : ""), {
      allChunks: true
    }))
  }

  if( specialOptions.minimize ) {

    plugins.push(
      new UglifyJsPlugin({
        sourceMap: true,
        uglifyOptions: {
          keep_fnames: true
        }
      }),
      new webpack.optimize.DedupePlugin()
    )

    if(specialOptions.html) {
      var HtmlWebpackPlugin = require("html-webpack-plugin")
      plugins.push(new HtmlWebpackPlugin())
    }

    plugins.push( new webpack.NoErrorsPlugin())
  }

  plugins.push(
    new webpack.DefinePlugin({
      "process.env": {
        NODE_ENV:  specialOptions.minimize ? JSON.stringify("production") : null,
        WEBPACK_INLINE_STYLES: !Boolean(specialOptions.separateStylesheets)
      },
      "buildInfo": JSON.stringify({
        PACKAGE_VERSION: pkg.version,
        GIT_COMMIT: gitInfo.hash,
        GIT_DIRTY: gitInfo.dirty
      })
    }))

  var cssLoader = "css-loader!postcss-loader"

  var completeStylesheetLoaders = deepExtend({
    "css": cssLoader,
    "less": cssLoader + "!" + "less-loader",
  }, specialOptions.stylesheetLoaders)

  if(specialOptions.cssModules) {
    cssLoader = cssLoader + "?module" + (specialOptions.minimize ? "" : "&localIdentName=[path][name]---[local]---[hash:base64:5]")
  }

  Object.keys(completeStylesheetLoaders).forEach(function(ext) {
    var ori = completeStylesheetLoaders[ext]
    if(specialOptions.separateStylesheets) {
      completeStylesheetLoaders[ext] = ExtractTextPlugin.extract("style-loader", ori)
    } else {
      completeStylesheetLoaders[ext] = "style-loader!" + ori
    }
  })

  var loaders = loadersByExtension(deepExtend({}, loadersMap, specialOptions.loaders, completeStylesheetLoaders))
  var extraLoaders = (options.module || {} ).loaders

  if(Array.isArray(extraLoaders)) {
    loaders = loaders.concat(extraLoaders)
    delete options.module.loaders
  }

  var completeConfig = deepExtend({
    entry: {},

    output:  {
      path: path.join(__dirname, "dist"),
      publicPath: "/",
      filename: "[name].js",
      chunkFilename: "[id].[chunkhash].js"
    },

    target: "web",

    // yaml-js has a reference to `fs`, this is a workaround
    node: {
      fs: "empty"
    },

    module: {
      loaders: loaders,
    },

    resolveLoader: {
      root: path.join(__dirname, "node_modules"),
    },

    externals: {
      "buffertools": true // json-react-schema/deeper depends on buffertools, which fails.
    },

    resolve: {
      root: path.join(__dirname, "./src"),
      modulesDirectories: ["node_modules"],
      extensions: ["", ".js", ".jsx", "json"],
      packageAlias: "browser",
      alias: {
        "react": path.resolve(__dirname, "node_modules", "react"),
        "swagger-jx": path.resolve(__dirname, "node_modules", "swagger-jx")
      }
    },

    postcss: function() {
      return [autoprefixer]
    },

    devtool: specialOptions.sourcemaps ? "nosource-source-map" : null,

  }, options)

  completeConfig.plugins = (plugins).concat(options.plugins || [])

  return completeConfig
}