/**
 * Module to add labels to breaks and continues according to tagged AST nodes
 * generated by desugarLoop.
 *
 */

import { NodePath, Visitor } from 'babel-traverse';
import * as t from 'babel-types';
import { While, Break } from '@stopify/util';

const labelVisitor : Visitor = {
  ContinueStatement: function (path: NodePath<t.ContinueStatement>): void {
    const { label } = path.node;
    if (label) {
      const breakStatement = t.breakStatement(label);
      path.replaceWith(breakStatement);
    } else {
      const loopParent : NodePath<While<t.Node>> =
        path.findParent(p => p.isWhileStatement());
      const continueLabel = loopParent.node.continue_label;

      const breakStatement = t.breakStatement(continueLabel);
      path.replaceWith(breakStatement);
    }
  },

  BreakStatement: function (path: NodePath<Break<t.BreakStatement>>): void {
    const label = path.node.label;
    if (label === null) {
      const labeledParent : NodePath<Break<t.Node>> =
        path.findParent(p => p.isLoop() || p.isSwitchStatement());

      if (labeledParent === null) {
        return;
      }

      path.node.label = <t.Identifier>labeledParent.node.break_label;
    }
  },
};

module.exports = function() {
  return { visitor: labelVisitor };
};