/**
 @module ember
*/
/**
  A Glimmer2 AST transformation that replaces all instances of

  ```handlebars
 {{attrs.foo.bar}}
  ```

  to

  ```handlebars
 {{@foo.bar}}
  ```

  as well as `{{#if attrs.foo}}`, `{{deeply (nested attrs.foobar.baz)}}`,
  `{{this.attrs.foo}}` etc

  @private
  @class TransformAttrsToProps
*/
export default function transformAttrsIntoArgs(env) {
    let { builders: b } = env.syntax;
    let stack = [[]];
    return {
        name: 'transform-attrs-into-args',
        visitor: {
            Program: {
                enter(node) {
                    let parent = stack[stack.length - 1];
                    stack.push(parent.concat(node.blockParams));
                },
                exit() {
                    stack.pop();
                },
            },
            PathExpression(node) {
                if (isAttrs(node, stack[stack.length - 1])) {
                    let path = b.path(node.original.substr(6));
                    path.original = `@${path.original}`;
                    path.data = true;
                    return path;
                }
            },
        },
    };
}
function isAttrs(node, symbols) {
    let name = node.parts[0];
    if (symbols.indexOf(name) !== -1) {
        return false;
    }
    if (name === 'attrs') {
        if (node.this === true) {
            node.parts.shift();
            node.original = node.original.slice(5);
        }
        return true;
    }
    return false;
}