'use strict';

/**
 * @ngdoc function
 * @name angular.injector
 * @function
 *
 * @description
 * Creates an injector function that can be used for retrieving services as well as for
 * dependency injection (see {@link guide/di dependency injection}).
 *

 * @param {Array.<string|Function>} modules A list of module functions or their aliases. See
 *        {@link angular.module}. The `ng` module must be explicitly added.
 * @returns {function()} Injector function. See {@link AUTO.$injector $injector}.
 *
 * @example
 * Typical usage
 * <pre>
 *   // create an injector
 *   var $injector = angular.injector(['ng']);
 *
 *   // use the injector to kick off your application
 *   // use the type inference to auto inject arguments, or use implicit injection
 *   $injector.invoke(function($rootScope, $compile, $document){
 *     $compile($document)($rootScope);
 *     $rootScope.$digest();
 *   });
 * </pre>
 */


/**
 * @ngdoc overview
 * @name AUTO
 * @description
 *
 * Implicit module which gets automatically added to each {@link AUTO.$injector $injector}.
 */

var FN_ARGS = /^function\s*[^\(]*\(\s*([^\)]*)\)/m;
var FN_ARG_SPLIT = /,/;
var FN_ARG = /^\s*(_?)(\S+?)\1\s*$/;
var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
function annotate(fn) {
  var $inject,
      fnText,
      argDecl,
      last;

  if (typeof fn == 'function') {
    if (!($inject = fn.$inject)) {
      $inject = [];
      fnText = fn.toString().replace(STRIP_COMMENTS, '');
      argDecl = fnText.match(FN_ARGS);
      forEach(argDecl[1].split(FN_ARG_SPLIT), function(arg){
        arg.replace(FN_ARG, function(all, underscore, name){
          $inject.push(name);
        });
      });
      fn.$inject = $inject;
    }
  } else if (isArray(fn)) {
    last = fn.length - 1;
    assertArgFn(fn[last], 'fn');
    $inject = fn.slice(0, last);
  } else {
    assertArgFn(fn, 'fn', true);
  }
  return $inject;
}

///////////////////////////////////////

/**
 * @ngdoc object
 * @name AUTO.$injector
 * @function
 *
 * @description
 *
 * `$injector` is used to retrieve object instances as defined by
 * {@link AUTO.$provide provider}, instantiate types, invoke methods,
 * and load modules.
 *
 * The following always holds true:
 *
 * <pre>
 *   var $injector = angular.injector();
 *   expect($injector.get('$injector')).toBe($injector);
 *   expect($injector.invoke(function($injector){
 *     return $injector;
 *   }).toBe($injector);
 * </pre>
 *
 * # Injection Function Annotation
 *
 * JavaScript does not have annotations, and annotations are needed for dependency injection. The
 * following are all valid ways of annotating function with injection arguments and are equivalent.
 *
 * <pre>
 *   // inferred (only works if code not minified/obfuscated)
 *   $injector.invoke(function(serviceA){});
 *
 *   // annotated
 *   function explicit(serviceA) {};
 *   explicit.$inject = ['serviceA'];
 *   $injector.invoke(explicit);
 *
 *   // inline
 *   $injector.invoke(['serviceA', function(serviceA){}]);
 * </pre>
 *
 * ## Inference
 *
 * In JavaScript calling `toString()` on a function returns the function definition. The definition can then be
 * parsed and the function arguments can be extracted. *NOTE:* This does not work with minification, and obfuscation
 * tools since these tools change the argument names.
 *
 * ## `$inject` Annotation
 * By adding a `$inject` property onto a function the injection parameters can be specified.
 *
 * ## Inline
 * As an array of injection names, where the last item in the array is the function to call.
 */

/**
 * @ngdoc method
 * @name AUTO.$injector#get
 * @methodOf AUTO.$injector
 *
 * @description
 * Return an instance of the service.
 *
 * @param {string} name The name of the instance to retrieve.
 * @return {*} The instance.
 */

/**
 * @ngdoc method
 * @name AUTO.$injector#invoke
 * @methodOf AUTO.$injector
 *
 * @description
 * Invoke the method and supply the method arguments from the `$injector`.
 *
 * @param {!function} fn The function to invoke. The function arguments come form the function annotation.
 * @param {Object=} self The `this` for the invoked method.
 * @param {Object=} locals Optional object. If preset then any argument names are read from this object first, before
 *   the `$injector` is consulted.
 * @returns {*} the value returned by the invoked `fn` function.
 */

/**
 * @ngdoc method
 * @name AUTO.$injector#instantiate
 * @methodOf AUTO.$injector
 * @description
 * Create a new instance of JS type. The method takes a constructor function invokes the new operator and supplies
 * all of the arguments to the constructor function as specified by the constructor annotation.
 *
 * @param {function} Type Annotated constructor function.
 * @param {Object=} locals Optional object. If preset then any argument names are read from this object first, before
 *   the `$injector` is consulted.
 * @returns {Object} new instance of `Type`.
 */

/**
 * @ngdoc method
 * @name AUTO.$injector#annotate
 * @methodOf AUTO.$injector
 *
 * @description
 * Returns an array of service names which the function is requesting for injection. This API is used by the injector
 * to determine which services need to be injected into the function when the function is invoked. There are three
 * ways in which the function can be annotated with the needed dependencies.
 *
 * # Argument names
 *
 * The simplest form is to extract the dependencies from the arguments of the function. This is done by converting
 * the function into a string using `toString()` method and extracting the argument names.
 * <pre>
 *   // Given
 *   function MyController($scope, $route) {
 *     // ...
 *   }
 *
 *   // Then
 *   expect(injector.annotate(MyController)).toEqual(['$scope', '$route']);
 * </pre>
 *
 * This method does not work with code minfication / obfuscation. For this reason the following annotation strategies
 * are supported.
 *
 * # The `$inject` property
 *
 * If a function has an `$inject` property and its value is an array of strings, then the strings represent names of
 * services to be injected into the function.
 * <pre>
 *   // Given
 *   var MyController = function(obfuscatedScope, obfuscatedRoute) {
 *     // ...
 *   }
 *   // Define function dependencies
 *   MyController.$inject = ['$scope', '$route'];
 *
 *   // Then
 *   expect(injector.annotate(MyController)).toEqual(['$scope', '$route']);
 * </pre>
 *
 * # The array notation
 *
 * It is often desirable to inline Injected functions and that's when setting the `$inject` property is very
 * inconvenient. In these situations using the array notation to specify the dependencies in a way that survives
 * minification is a better choice:
 *
 * <pre>
 *   // We wish to write this (not minification / obfuscation safe)
 *   injector.invoke(function($compile, $rootScope) {
 *     // ...
 *   });
 *
 *   // We are forced to write break inlining
 *   var tmpFn = function(obfuscatedCompile, obfuscatedRootScope) {
 *     // ...
 *   };
 *   tmpFn.$inject = ['$compile', '$rootScope'];
 *   injector.invoke(tmpFn);
 *
 *   // To better support inline function the inline annotation is supported
 *   injector.invoke(['$compile', '$rootScope', function(obfCompile, obfRootScope) {
 *     // ...
 *   }]);
 *
 *   // Therefore
 *   expect(injector.annotate(
 *      ['$compile', '$rootScope', function(obfus_$compile, obfus_$rootScope) {}])
 *    ).toEqual(['$compile', '$rootScope']);
 * </pre>
 *
 * @param {function|Array.<string|Function>} fn Function for which dependent service names need to be retrieved as described
 *   above.
 *
 * @returns {Array.<string>} The names of the services which the function requires.
 */




/**
 * @ngdoc object
 * @name AUTO.$provide
 *
 * @description
 *
 * The {@link AUTO.$provide $provide} service has a number of methods for registering components with
 * the {@link AUTO.$injector $injector}. Many of these functions are also exposed on {@link angular.Module}.
 *
 * An Angular **service** is a singleton object created by a **service factory**.  These **service
 * factories** are functions which, in turn, are created by a **service provider**.
 * The **service providers** are constructor functions. When instantiated they must contain a property
 * called `$get`, which holds the **service factory** function.
 * 
 * When you request a service, the {@link AUTO.$injector $injector} is responsible for finding the
 * correct **service provider**, instantiating it and then calling its `$get` **service factory**
 * function to get the instance of the **service**.
 * 
 * Often services have no configuration options and there is no need to add methods to the service
 * provider.  The provider will be no more than a constructor function with a `$get` property. For
 * these cases the {@link AUTO.$provide $provide} service has additional helper methods to register
 * services without specifying a provider.
 *
 * * {@link AUTO.$provide#provider provider(provider)} - registers a **service provider** with the
 *     {@link AUTO.$injector $injector}
 * * {@link AUTO.$provide#constant constant(obj)} - registers a value/object that can be accessed by
 *     providers and services.
 * * {@link AUTO.$provide#value value(obj)} - registers a value/object that can only be accessed by
 *     services, not providers.
 * * {@link AUTO.$provide#factory factory(fn)} - registers a service **factory function**, `fn`, that
 *     will be wrapped in a **service provider** object, whose `$get` property will contain the given
 *     factory function.
 * * {@link AUTO.$provide#service service(class)} - registers a **constructor function**, `class` that
 *     will be wrapped in a **service provider** object, whose `$get` property will instantiate a new
 *     object using the given constructor function.
 *
 * See the individual methods for more information and examples.
 */

/**
 * @ngdoc method
 * @name AUTO.$provide#provider
 * @methodOf AUTO.$provide
 * @description
 *
 * Register a **provider function** with the {@link AUTO.$injector $injector}. Provider functions are
 * constructor functions, whose instances are responsible for "providing" a factory for a service.
 * 
 * Service provider names start with the name of the service they provide followed by `Provider`.
 * For example, the {@link ng.$log $log} service has a provider called {@link ng.$logProvider $logProvider}.
 *
 * Service provider objects can have additional methods which allow configuration of the provider and
 * its service. Importantly, you can configure what kind of service is created by the `$get` method,
 * or how that service will act. For example, the {@link ng.$logProvider $logProvider} has a method
 * {@link ng.$logProvider#debugEnabled debugEnabled}
 * which lets you specify whether the {@link ng.$log $log} service will log debug messages to the
 * console or not.
 *
 * @param {string} name The name of the instance. NOTE: the provider will be available under `name + 'Provider'` key.
 * @param {(Object|function())} provider If the provider is:
 *
 *   - `Object`: then it should have a `$get` method. The `$get` method will be invoked using
 *               {@link AUTO.$injector#invoke $injector.invoke()} when an instance needs to be created.
 *   - `Constructor`: a new instance of the provider will be created using
 *               {@link AUTO.$injector#instantiate $injector.instantiate()}, then treated as `object`.
 *
 * @returns {Object} registered provider instance

 * @example
 *
 * The following example shows how to create a simple event tracking service and register it using
 * {@link AUTO.$provide#provider $provide.provider()}.
 *
 * <pre>
 *  // Define the eventTracker provider
 *  function EventTrackerProvider() {
 *    var trackingUrl = '/track';
 *
 *    // A provider method for configuring where the tracked events should been saved
 *    this.setTrackingUrl = function(url) {
 *      trackingUrl = url;
 *    };
 *
 *    // The service factory function
 *    this.$get = ['$http', function($http) {
 *      var trackedEvents = {};
 *      return {
 *        // Call this to track an event
 *        event: function(event) {
 *          var count = trackedEvents[event] || 0;
 *          count += 1;
 *          trackedEvents[event] = count;
 *          return count;
 *        },
 *        // Call this to save the tracked events to the trackingUrl
 *        save: function() {
 *          $http.post(trackingUrl, trackedEvents);
 *        }
 *      };
 *    }];
 *  }
 *
 *  describe('eventTracker', function() {
 *    var postSpy;
 *
 *    beforeEach(module(function($provide) {
 *      // Register the eventTracker provider
 *      $provide.provider('eventTracker', EventTrackerProvider);
 *    }));
 *
 *    beforeEach(module(function(eventTrackerProvider) {
 *      // Configure eventTracker provider
 *      eventTrackerProvider.setTrackingUrl('/custom-track');
 *    }));
 *
 *    it('tracks events', inject(function(eventTracker) {
 *      expect(eventTracker.event('login')).toEqual(1);
 *      expect(eventTracker.event('login')).toEqual(2);
 *    }));
 *
 *    it('saves to the tracking url', inject(function(eventTracker, $http) {
 *      postSpy = spyOn($http, 'post');
 *      eventTracker.event('login');
 *      eventTracker.save();
 *      expect(postSpy).toHaveBeenCalled();
 *      expect(postSpy.mostRecentCall.args[0]).not.toEqual('/track');
 *      expect(postSpy.mostRecentCall.args[0]).toEqual('/custom-track');
 *      expect(postSpy.mostRecentCall.args[1]).toEqual({ 'login': 1 });
 *    }));
 *  });
 * </pre>
 */

/**
 * @ngdoc method
 * @name AUTO.$provide#factory
 * @methodOf AUTO.$provide
 * @description
 *
 * Register a **service factory**, which will be called to return the service instance.
 * This is short for registering a service where its provider consists of only a `$get` property,
 * which is the given service factory function.
 * You should use {@link AUTO.$provide#factory $provide.factor(getFn)} if you do not need to configure
 * your service in a provider.
 *
 * @param {string} name The name of the instance.
 * @param {function()} $getFn The $getFn for the instance creation. Internally this is a short hand for
 * `$provide.provider(name, {$get: $getFn})`.
 * @returns {Object} registered provider instance
 *
 * @example
 * Here is an example of registering a service 
 * <pre>
 *   $provide.factory('ping', ['$http', function($http) {
 *     return function ping() {
 *       return $http.send('/ping');
 *     };
 *   }]);
 * </pre>
 * You would then inject and use this service like this:
 * <pre>
 *   someModule.controller('Ctrl', ['ping', function(ping) {
 *     ping();
 *   }]);
 * </pre>
 */


/**
 * @ngdoc method
 * @name AUTO.$provide#service
 * @methodOf AUTO.$provide
 * @description
 *
 * Register a **service constructor**, which will be invoked with `new` to create the service instance.
 * This is short for registering a service where its provider's `$get` property is the service
 * constructor function that will be used to instantiate the service instance.
 *
 * You should use {@link AUTO.$provide#service $provide.service(class)} if you define your service
 * as a type/class. This is common when using {@link http://coffeescript.org CoffeeScript}.
 *
 * @param {string} name The name of the instance.
 * @param {Function} constructor A class (constructor function) that will be instantiated.
 * @returns {Object} registered provider instance
 *
 * @example
 * Here is an example of registering a service using {@link AUTO.$provide#service $provide.service(class)}
 * that is defined as a CoffeeScript class.
 * <pre>
 *   class Ping
 *     constructor: (@$http)->
 *     send: ()=>
 *       @$http.get('/ping')
 *  
 *   $provide.service('ping', ['$http', Ping])
 * </pre>
 * You would then inject and use this service like this:
 * <pre>
 *   someModule.controller 'Ctrl', ['ping', (ping)->
 *     ping.send()
 *   ]
 * </pre>
 */


/**
 * @ngdoc method
 * @name AUTO.$provide#value
 * @methodOf AUTO.$provide
 * @description
 *
 * Register a **value service** with the {@link AUTO.$injector $injector}, such as a string, a number,
 * an array, an object or a function.  This is short for registering a service where its provider's
 * `$get` property is a factory function that takes no arguments and returns the **value service**.
 *
 * Value services are similar to constant services, except that they cannot be injected into a module
 * configuration function (see {@link angular.Module#config}) but they can be overridden by an Angular
 * {@link AUTO.$provide#decorator decorator}.
 * 
 * @param {string} name The name of the instance.
 * @param {*} value The value.
 * @returns {Object} registered provider instance
 *
 * @example
 * Here are some examples of creating value services.
 * <pre>
 *   $provide.constant('ADMIN_USER', 'admin');
 *   
 *   $provide.constant('RoleLookup', { admin: 0, writer: 1, reader: 2 });
 *   
 *   $provide.constant('halfOf', function(value) {
 *     return value / 2;
 *   });
 * </pre>
 */


/**
 * @ngdoc method
 * @name AUTO.$provide#constant
 * @methodOf AUTO.$provide
 * @description
 *
 * Register a **constant service**, such as a string, a number, an array, an object or a function, with
 * the {@link AUTO.$injector $injector}. Unlike {@link AUTO.$provide#value value} it can be injected
 * into a module configuration function (see {@link angular.Module#config}) and it cannot be
 * overridden by an Angular {@link AUTO.$provide#decorator decorator}.
 *
 * @param {string} name The name of the constant.
 * @param {*} value The constant value.
 * @returns {Object} registered instance
 *
 * @example
 * Here a some examples of creating constants:
 * <pre>
 *   $provide.constant('SHARD_HEIGHT', 306);
 *   
 *   $provide.constant('MY_COLOURS', ['red', 'blue', 'grey']);
 *   
 *   $provide.constant('double', function(value) {
 *     return value * 2;
 *   });
 * </pre>
 */


/**
 * @ngdoc method
 * @name AUTO.$provide#decorator
 * @methodOf AUTO.$provide
 * @description
 *
 * Register a **service decorator** with the {@link AUTO.$injector $injector}. A service decorator
 * intercepts the creation of a service, allowing it to override or modify the behaviour of the
 * service. The object returned by the decorator may be the original service, or a new service object
 * which replaces or wraps and delegates to the original service.
 *
 * @param {string} name The name of the service to decorate.
 * @param {function()} decorator This function will be invoked when the service needs to be
 *    instantiated and should return the decorated service instance. The function is called using
 *    the {@link AUTO.$injector#invoke injector.invoke} method and is therefore fully injectable.
 *    Local injection arguments:
 *
 *    * `$delegate` - The original service instance, which can be monkey patched, configured,
 *      decorated or delegated to.
 *
 * @example
 * Here we decorate the {@link ng.$log $log} service to convert warnings to errors by intercepting
 * calls to {@link ng.$log#error $log.warn()}.
 * <pre>
 *   $provider.decorator('$log', ['$delegate', function($delegate) {
 *     $delegate.warn = $delegate.error;
 *     return $delegate;
 *   }]);
 * </pre>
 */


function createInjector(modulesToLoad) {
  var INSTANTIATING = {},
      providerSuffix = 'Provider',
      path = [],
      loadedModules = new HashMap(),
      providerCache = {
        $provide: {
            provider: supportObject(provider),
            factory: supportObject(factory),
            service: supportObject(service),
            value: supportObject(value),
            constant: supportObject(constant),
            decorator: decorator
          }
      },
      providerInjector = createInternalInjector(providerCache, function() {
        throw Error("Unknown provider: " + path.join(' <- '));
      }),
      instanceCache = {},
      instanceInjector = (instanceCache.$injector =
          createInternalInjector(instanceCache, function(servicename) {
            var provider = providerInjector.get(servicename + providerSuffix);
            return instanceInjector.invoke(provider.$get, provider);
          }));


  forEach(loadModules(modulesToLoad), function(fn) { instanceInjector.invoke(fn || noop); });

  return instanceInjector;

  ////////////////////////////////////
  // $provider
  ////////////////////////////////////

  function supportObject(delegate) {
    return function(key, value) {
      if (isObject(key)) {
        forEach(key, reverseParams(delegate));
      } else {
        return delegate(key, value);
      }
    }
  }

  function provider(name, provider_) {
    if (isFunction(provider_) || isArray(provider_)) {
      provider_ = providerInjector.instantiate(provider_);
    }
    if (!provider_.$get) {
      throw Error('Provider ' + name + ' must define $get factory method.');
    }
    return providerCache[name + providerSuffix] = provider_;
  }

  function factory(name, factoryFn) { return provider(name, { $get: factoryFn }); }

  function service(name, constructor) {
    return factory(name, ['$injector', function($injector) {
      return $injector.instantiate(constructor);
    }]);
  }

  function value(name, value) { return factory(name, valueFn(value)); }

  function constant(name, value) {
    providerCache[name] = value;
    instanceCache[name] = value;
  }

  function decorator(serviceName, decorFn) {
    var origProvider = providerInjector.get(serviceName + providerSuffix),
        orig$get = origProvider.$get;

    origProvider.$get = function() {
      var origInstance = instanceInjector.invoke(orig$get, origProvider);
      return instanceInjector.invoke(decorFn, null, {$delegate: origInstance});
    };
  }

  ////////////////////////////////////
  // Module Loading
  ////////////////////////////////////
  function loadModules(modulesToLoad){
    var runBlocks = [];
    forEach(modulesToLoad, function(module) {
      if (loadedModules.get(module)) return;
      loadedModules.put(module, true);
      if (isString(module)) {
        var moduleFn = angularModule(module);
        runBlocks = runBlocks.concat(loadModules(moduleFn.requires)).concat(moduleFn._runBlocks);

        try {
          for(var invokeQueue = moduleFn._invokeQueue, i = 0, ii = invokeQueue.length; i < ii; i++) {
            var invokeArgs = invokeQueue[i],
                provider = invokeArgs[0] == '$injector'
                    ? providerInjector
                    : providerInjector.get(invokeArgs[0]);

            provider[invokeArgs[1]].apply(provider, invokeArgs[2]);
          }
        } catch (e) {
          if (e.message) e.message += ' from ' + module;
          throw e;
        }
      } else if (isFunction(module)) {
        try {
          runBlocks.push(providerInjector.invoke(module));
        } catch (e) {
          if (e.message) e.message += ' from ' + module;
          throw e;
        }
      } else if (isArray(module)) {
        try {
          runBlocks.push(providerInjector.invoke(module));
        } catch (e) {
          if (e.message) e.message += ' from ' + String(module[module.length - 1]);
          throw e;
        }
      } else {
        assertArgFn(module, 'module');
      }
    });
    return runBlocks;
  }

  ////////////////////////////////////
  // internal Injector
  ////////////////////////////////////

  function createInternalInjector(cache, factory) {

    function getService(serviceName) {
      if (typeof serviceName !== 'string') {
        throw Error('Service name expected');
      }
      if (cache.hasOwnProperty(serviceName)) {
        if (cache[serviceName] === INSTANTIATING) {
          throw Error('Circular dependency: ' + path.join(' <- '));
        }
        return cache[serviceName];
      } else {
        try {
          path.unshift(serviceName);
          cache[serviceName] = INSTANTIATING;
          return cache[serviceName] = factory(serviceName);
        } finally {
          path.shift();
        }
      }
    }

    function invoke(fn, self, locals){
      var args = [],
          $inject = annotate(fn),
          length, i,
          key;

      for(i = 0, length = $inject.length; i < length; i++) {
        key = $inject[i];
        args.push(
          locals && locals.hasOwnProperty(key)
          ? locals[key]
          : getService(key)
        );
      }
      if (!fn.$inject) {
        // this means that we must be an array.
        fn = fn[length];
      }


      // Performance optimization: http://jsperf.com/apply-vs-call-vs-invoke
      switch (self ? -1 : args.length) {
        case  0: return fn();
        case  1: return fn(args[0]);
        case  2: return fn(args[0], args[1]);
        case  3: return fn(args[0], args[1], args[2]);
        case  4: return fn(args[0], args[1], args[2], args[3]);
        case  5: return fn(args[0], args[1], args[2], args[3], args[4]);
        case  6: return fn(args[0], args[1], args[2], args[3], args[4], args[5]);
        case  7: return fn(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
        case  8: return fn(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7]);
        case  9: return fn(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8]);
        case 10: return fn(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9]);
        default: return fn.apply(self, args);
      }
    }

    function instantiate(Type, locals) {
      var Constructor = function() {},
          instance, returnedValue;

      // Check if Type is annotated and use just the given function at n-1 as parameter
      // e.g. someModule.factory('greeter', ['$window', function(renamed$window) {}]);
      Constructor.prototype = (isArray(Type) ? Type[Type.length - 1] : Type).prototype;
      instance = new Constructor();
      returnedValue = invoke(Type, instance, locals);

      return isObject(returnedValue) ? returnedValue : instance;
    }

    return {
      invoke: invoke,
      instantiate: instantiate,
      get: getService,
      annotate: annotate
    };
  }
}