import syntaxExportExtensions from "babel-plugin-syntax-export-extensions";

export default function({ types: t }) {
  function build(node, nodes, scope) {
    const hasNoExportDefault = node.specifiers.every(
      specifier => !t.isExportDefaultSpecifier(specifier),
    );
    if (hasNoExportDefault) return;

    const specifier = node.specifiers.shift();
    const uid = scope.generateUidIdentifier(specifier.exported.name);

    let newSpecifier;
    if (t.isExportNamespaceSpecifier(specifier)) {
      newSpecifier = t.importNamespaceSpecifier(uid);
    } else {
      newSpecifier = t.importDefaultSpecifier(uid);
    }
    nodes.push(t.importDeclaration([newSpecifier], node.source));
    nodes.push(
      t.exportNamedDeclaration(null, [
        t.exportSpecifier(uid, specifier.exported),
      ]),
    );

    build(node, nodes, scope);
  }

  return {
    inherits: syntaxExportExtensions,

    visitor: {
      ExportNamedDeclaration(path) {
        const { node, scope } = path;
        const nodes = [];
        build(node, nodes, scope);
        if (!nodes.length) return;

        if (node.specifiers.length >= 1) {
          nodes.push(node);
        }
        path.replaceWithMultiple(nodes);
      },
    },
  };
}