// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.
const data = require('./package.json');
const Build = require('@jupyterlab/buildutils').Build;
const webpack = require('webpack');
const merge = require('webpack-merge');
const baseConfig = require('@jupyterlab/buildutils/lib/webpack.config.base');
const { ModuleFederationPlugin } = webpack.container;
const fs = require('fs-extra');
const path = require('path');
const Handlebars = require('handlebars');

const names = Object.keys(data.dependencies).filter(function(name) {
  const packageData = require(path.join(name, 'package.json'));
  return packageData.jupyterlab !== undefined;
});

const jlab = data.jupyterlab;

// Ensure a clear build directory.
const buildDir = path.resolve(__dirname, 'build');
if (fs.existsSync(buildDir)) {
  fs.removeSync(buildDir);
}
fs.ensureDirSync(buildDir);

const extras = Build.ensureAssets({
  packageNames: names,
  output: buildDir
});

const singletons = {};

data.jupyterlab.singletonPackages.forEach(element => {
  singletons[element] = { singleton: true };
});

// Handle the extensions.
const extensions = jlab.extensions || {};
const mimeExtensions = jlab.mimeExtensions || {};
const externalExtensions = jlab.externalExtensions || {};

// go through each external extension
// add to mapping of extension and mime extensions, of package name
// to path of the extension.
for (const key in externalExtensions) {
  const {
    jupyterlab: { extension, mimeExtension }
  } = require(`${key}/package.json`);
  if (extension !== undefined) {
    extensions[key] = extension === true ? '' : extension;
  }
  if (mimeExtension !== undefined) {
    mimeExtensions[key] = mimeExtension === true ? '' : mimeExtension;
  }
}

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

fs.writeFileSync(path.join(buildDir, 'index.out.js'), result);

// Make a bootstrap entrypoint
const entryPoint = path.join(buildDir, 'bootstrap.js');
const bootstrap = 'import("./index.out.js");';
fs.writeFileSync(entryPoint, bootstrap);

if (process.env.NODE_ENV === 'production') {
  baseConfig.mode = 'production';
}

module.exports = [
  merge(baseConfig, {
    entry: entryPoint,
    output: {
      path: buildDir,
      library: {
        type: 'var',
        name: ['_JUPYTERLAB', 'CORE_OUTPUT']
      },
      filename: 'bundle.js',
      // TODO: if this path changes we will also have to
      // change main.py (name property inside ExampleApp)
      publicPath: 'static/lab/'
    },
    module: {
      rules: [
        // Workaround for https://github.com/jupyterlab/jupyterlab/issues/8655
        {
          test: /vega-statistics\/src\/.*.js$/,
          use: {
            loader: 'babel-loader',
            options: {
              presets: ['@babel/preset-env']
            }
          }
        }
      ]
    },
    plugins: [
      new ModuleFederationPlugin({
        library: {
          type: 'var',
          name: ['_JUPYTERLAB', 'CORE_LIBRARY_FEDERATION']
        },
        name: 'CORE_FEDERATION',
        shared: {
          ...data.resolutions,
          ...singletons
        }
      })
    ]
  })
].concat(extras);