'use strict';

var MODULE_NAME = 'Controllers',
    CNTRL_REG = /^(\S+)(\s+as\s+(\w+))?$/,
    CATEGORY_CONTROLLER_NAME = 'Name controllers according to best practices',
    CATEGORY_GLOBAL_CONTROLLER = 'Using global functions as controllers is against Angular best practices and depricated in Angular 1.3 and up',
    SEVERITY_ERROR = 1,
    SEVERITY_WARNING = 2;

// local state
var nameToControllerMap = {};

/**
* Decorates $controller with a patching function to
* log a message if the controller is instantiated on the window
*/
angular.module('ngHintControllers', []).
  config(['$provide', '$controllerProvider', function ($provide, $controllerProvider) {
    $provide.decorator('$controller', ['$delegate', controllerDecorator]);

    var originalRegister = $controllerProvider.register;
    $controllerProvider.register = function(name, constructor) {
      stringOrObjectRegister(name);
      originalRegister.apply($controllerProvider, arguments);
    }
  }]);

function controllerDecorator($delegate) {
  return function(ctrl) {
    if (typeof ctrl === 'string') {
      var match = ctrl.match(CNTRL_REG);
      var ctrlName = (match && match[1]) || ctrl;

      if (!nameToControllerMap[ctrlName]) {
        sendMessageForControllerName(ctrlName);
      }

      if (!nameToControllerMap[ctrlName] && typeof window[ctrlName] === 'function') {
        sendMessageForGlobalController(ctrlName);
      }
    }
    return $delegate.apply(this, arguments);
  };
}

/**
* Save details of the controllers as they are instantiated
* for use in decoration.
* Hint about the best practices for naming controllers.
*/
var originalModule = angular.module;

function stringOrObjectRegister(controllerName) {
  if ((controllerName !== null) && (typeof controllerName === 'object')) {
    Object.keys(controllerName).forEach(processController);
  } else {
    processController(controllerName);
  }
}

function processController(ctrlName) {
  nameToControllerMap[ctrlName] = true;
  sendMessageForControllerName(ctrlName);
}

function sendMessageForGlobalController(name) {
  angular.hint.emit(MODULE_NAME + ':global',
    'add `' + name + '` to a module',
    angular.version.minor <= 2 ? SEVERITY_WARNING : SEVERITY_ERROR,
    CATEGORY_GLOBAL_CONTROLLER);
}

function sendMessageForControllerName(name) {
  var newName = name;
  if (!startsWithUpperCase(name)) {
    newName = title(newName);
  }
  if (!endsWithController(name)) {
    newName = addControllerSuffix(newName);
  }
  if (name !== newName) {
    angular.hint.emit(MODULE_NAME + ':rename',
      'Consider renaming `' + name + '` to `' + newName + '`.',
      SEVERITY_WARNING,
      CATEGORY_CONTROLLER_NAME);
  }
}

function startsWithUpperCase(name) {
  var firstChar = name.charAt(0);
  return firstChar === firstChar.toUpperCase() &&
         firstChar !== firstChar.toLowerCase();
}

function title (name) {
  return name[0].toUpperCase() + name.substr(1);
}

var CONTROLLER_RE = /Controller$/;
function endsWithController(name) {
  return CONTROLLER_RE.test(name);
}

var RE = /(Ctrl|Kontroller)?$/;
function addControllerSuffix(name) {
  return name.replace(RE, 'Controller');
}

/*
 * decorate angular module API
 */

angular.module = function() {
  var module = originalModule.apply(this, arguments),
      originalController = module.controller;

  module.controller = function(controllerName, controllerConstructor) {
    stringOrObjectRegister(controllerName);
    return originalController.apply(this, arguments);
  };

  return module;
};