/**
 * Plugin for HtmlPlugin which inlines content for an extracted Webpack manifest
 * into the HTML in a <script> tag before other emitted asssets are injected by
 * HtmlPlugin itself.
 */
export default function injectManifestPlugin() {
  this.plugin('compilation', (compilation) => {
    compilation.plugin('html-webpack-plugin-before-html-processing', (data, cb) => {
      Object.keys(compilation.assets).forEach((key) => {
        if (!key.startsWith('manifest.')) { return; }
        const { children } = compilation.assets[key];
        if (children && children[0]) {
          // eslint-disable-next-line no-param-reassign
          data.html = data.html.replace(/^(\s*)<\/body>/m, `$1<script>${children[0]._value}</script>\n$1</body>`);
          // Remove the manifest from HtmlPlugin's assets to prevent a <script>
          // tag being created for it.
          const manifestIndex = data.assets.js.indexOf(data.assets.publicPath + key);
          data.assets.js.splice(manifestIndex, 1);
          // eslint-disable-next-line no-param-reassign
          delete data.assets.chunks.manifest;
        }
      });
      cb(null, data);
    });
  });
}