/*-----------------------------------------------------------------------------
| Copyright (c) Jupyter Development Team.
| Distributed under the terms of the Modified BSD License.
|----------------------------------------------------------------------------*/

var path = require('path');
var fs = require('fs-extra');
var Handlebars = require('handlebars');
var HtmlWebpackPlugin = require('html-webpack-plugin');
var webpack = require('webpack');
var DuplicatePackageCheckerPlugin = require('duplicate-package-checker-webpack-plugin');
var Visualizer = require('webpack-visualizer-plugin');

var Build = require('@jupyterlab/buildutils').Build;
var package_data = require('./package.json');

// Handle the extensions.
var jlab = package_data.jupyterlab;
var extensions = jlab.extensions;
var mimeExtensions = jlab.mimeExtensions;

var extraConfig = Build.ensureAssets({
  packageNames: Object.keys(mimeExtensions).concat(Object.keys(extensions)),
  output: jlab.outputDir
});

// Create the entry point file.
var source = fs.readFileSync('index.js').toString();
var template = Handlebars.compile(source);
var data = {
  jupyterlab_extensions: extensions,
  jupyterlab_mime_extensions: mimeExtensions
};
var result = template(data);

// Ensure a clear build directory.
var buildDir = path.resolve(jlab.buildDir);
if (fs.existsSync(buildDir)) {
  fs.removeSync(buildDir);
}
fs.ensureDirSync(buildDir);

fs.writeFileSync(path.join(buildDir, 'index.out.js'), result);
fs.copySync('./package.json', path.join(buildDir, 'package.json'));

// Set up variables for watch mode.
var localLinked = {};
var ignoreCache = Object.create(null);
Object.keys(jlab.linkedPackages).forEach(function(name) {
  var localPath = require.resolve(path.join(name, 'package.json'));
  localLinked[name] = path.dirname(localPath);
});
var ignorePatterns = [/^\.\#/]; // eslint-disable-line

/**
 * Sync a local path to a linked package path if they are files and differ.
 */
function maybeSync(localPath, name, rest) {
  var stats = fs.statSync(localPath);
  if (!stats.isFile(localPath)) {
    return;
  }
  var source = fs.realpathSync(path.join(jlab.linkedPackages[name], rest));
  if (source === fs.realpathSync(localPath)) {
    return;
  }
  fs.watchFile(source, { interval: 500 }, function(curr) {
    if (!curr || curr.nlink === 0) {
      return;
    }
    try {
      fs.copySync(source, localPath);
    } catch (err) {
      console.error(err);
    }
  });
}

/**
 * A WebPack Plugin that copies the assets to the static directory and
 * fixes the output of the HTMLWebpackPlugin
 */
function JupyterFrontEndPlugin() {}

JupyterFrontEndPlugin.prototype.apply = function(compiler) {
  compiler.hooks.afterEmit.tap(
    'JupyterFrontEndPlugin',
    function() {
      // Fix the template output.
      var indexPath = path.join(buildDir, 'index.html');
      var indexData = fs.readFileSync(indexPath, 'utf8');
      indexData = indexData
        .split('{{page_config.frontendUrl}}/')
        .join('{{page_config.frontendUrl}}');
      fs.writeFileSync(indexPath, indexData, 'utf8');

      // Copy the static assets.
      var staticDir = jlab.staticDir;
      if (!staticDir) {
        return;
      }
      // Ensure a clean static directory on the first emit.
      if (this._first && fs.existsSync(staticDir)) {
        fs.removeSync(staticDir);
      }
      this._first = false;
      fs.copySync(buildDir, staticDir);
    }.bind(this)
  );
};

JupyterFrontEndPlugin.prototype._first = true;

const plugins = [
  new DuplicatePackageCheckerPlugin({
    verbose: true,
    exclude(instance) {
      // ignore known duplicates
      return ['domelementtype', 'hash-base', 'inherits'].includes(
        instance.name
      );
    }
  }),
  new HtmlWebpackPlugin({
    template: path.join('templates', 'template.html'),
    title: jlab.name || 'JupyterLab'
  }),
  new webpack.HashedModuleIdsPlugin(),
  new JupyterFrontEndPlugin({})
];

if (process.argv.includes('--analyze')) {
  plugins.push(new Visualizer());
}

module.exports = [
  {
    mode: 'development',
    entry: {
      main: ['whatwg-fetch', path.resolve(buildDir, 'index.out.js')]
    },
    output: {
      path: path.resolve(buildDir),
      publicPath: '{{page_config.frontendUrl}}',
      filename: '[name].[chunkhash].js'
    },
    optimization: {
      splitChunks: {
        chunks: 'all'
      }
    },
    module: {
      rules: [
        { test: /\.css$/, use: ['style-loader', 'css-loader'] },
        { test: /\.md$/, use: 'raw-loader' },
        { test: /\.txt$/, use: 'raw-loader' },
        {
          test: /\.js$/,
          use: ['source-map-loader'],
          enforce: 'pre',
          // eslint-disable-next-line no-undef
          exclude: /node_modules/
        },
        { test: /\.(jpg|png|gif)$/, use: 'file-loader' },
        { test: /\.js.map$/, use: 'file-loader' },
        {
          test: /\.woff2(\?v=\d+\.\d+\.\d+)?$/,
          use: 'url-loader?limit=10000&mimetype=application/font-woff'
        },
        {
          test: /\.woff(\?v=\d+\.\d+\.\d+)?$/,
          use: 'url-loader?limit=10000&mimetype=application/font-woff'
        },
        {
          test: /\.ttf(\?v=\d+\.\d+\.\d+)?$/,
          use: 'url-loader?limit=10000&mimetype=application/octet-stream'
        },
        {
          test: /\.otf(\?v=\d+\.\d+\.\d+)?$/,
          use: 'url-loader?limit=10000&mimetype=application/octet-stream'
        },
        { test: /\.eot(\?v=\d+\.\d+\.\d+)?$/, use: 'file-loader' },
        {
          test: /\.svg(\?v=\d+\.\d+\.\d+)?$/,
          use: 'url-loader?limit=10000&mimetype=image/svg+xml'
        }
      ]
    },
    watchOptions: {
      ignored: function(localPath) {
        localPath = path.resolve(localPath);
        if (localPath in ignoreCache) {
          return ignoreCache[localPath];
        }

        // Ignore files with certain patterns
        var baseName = localPath.replace(/^.*[\\\/]/, ''); // eslint-disable-line
        if (
          ignorePatterns.some(function(rexp) {
            return baseName.match(rexp);
          })
        ) {
          return true;
        }

        // Limit the watched files to those in our local linked package dirs.
        var ignore = true;
        Object.keys(localLinked).some(function(name) {
          // Bail if already found.
          var rootPath = localLinked[name];
          var contained = localPath.indexOf(rootPath + path.sep) !== -1;
          if (localPath !== rootPath && !contained) {
            return false;
          }
          var rest = localPath.slice(rootPath.length);
          if (rest.indexOf('node_modules') === -1) {
            ignore = false;
            maybeSync(localPath, name, rest);
          }
          return true;
        });
        ignoreCache[localPath] = ignore;
        return ignore;
      }
    },
    node: {
      fs: 'empty'
    },
    bail: true,
    devtool: 'source-map',
    externals: ['node-fetch', 'ws'],
    plugins,
    stats: {
      chunkModules: true
    }
  }
].concat(extraConfig);