/**
 * Copyright 2013-2014, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */
/*global exports:true*/
"use strict";

var Syntax = require('jstransform').Syntax;
var utils = require('jstransform/src/utils');

function addDisplayName(displayName, object, state) {
  if (object &&
      object.type === Syntax.CallExpression &&
      object.callee.type === Syntax.MemberExpression &&
      object.callee.object.type === Syntax.Identifier &&
      object.callee.object.name === 'React' &&
      object.callee.property.type === Syntax.Identifier &&
      object.callee.property.name === 'createClass' &&
      object['arguments'].length === 1 &&
      object['arguments'][0].type === Syntax.ObjectExpression) {
    // Verify that the displayName property isn't already set
    var properties = object['arguments'][0].properties;
    var safe = properties.every(function(property) {
      var value = property.key.type === Syntax.Identifier ?
        property.key.name :
        property.key.value;
      return value !== 'displayName';
    });

    if (safe) {
      utils.catchup(object['arguments'][0].range[0] + 1, state);
      utils.append('displayName: "' + displayName + '",', state);
    }
  }
}

/**
 * Transforms the following:
 *
 * var MyComponent = React.createClass({
 *    render: ...
 * });
 *
 * into:
 *
 * var MyComponent = React.createClass({
 *    displayName: 'MyComponent',
 *    render: ...
 * });
 *
 * Also catches:
 *
 * MyComponent = React.createClass(...);
 * exports.MyComponent = React.createClass(...);
 * module.exports = {MyComponent: React.createClass(...)};
 */
function visitReactDisplayName(traverse, object, path, state) {
  var left, right;

  if (object.type === Syntax.AssignmentExpression) {
    left = object.left;
    right = object.right;
  } else if (object.type === Syntax.Property) {
    left = object.key;
    right = object.value;
  } else if (object.type === Syntax.VariableDeclarator) {
    left = object.id;
    right = object.init;
  }

  if (left && left.type === Syntax.MemberExpression) {
    left = left.property;
  }
  if (left && left.type === Syntax.Identifier) {
    addDisplayName(left.name, right, state);
  }
}

visitReactDisplayName.test = function(object, path, state) {
  return (
    object.type === Syntax.AssignmentExpression ||
    object.type === Syntax.Property ||
    object.type === Syntax.VariableDeclarator
  );
};

exports.visitorList = [
  visitReactDisplayName
];
