import {
  Injector,
  Inject,
  Provider,
  Injectable,
  ResolvedProvider,
  forwardRef
} from 'angular2/src/core/di';
import {isPresent, isBlank} from 'angular2/src/facade/lang';
import {BaseException} from 'angular2/src/facade/exceptions';
import * as viewModule from './view';
import {ElementRef, ElementRef_} from './element_ref';
import {ProtoViewRef, ViewRef, HostViewRef, internalView, internalProtoView} from './view_ref';
import {ViewContainerRef} from './view_container_ref';
import {TemplateRef, TemplateRef_} from './template_ref';
import {
  Renderer,
  RenderViewRef,
  RenderFragmentRef,
  RenderViewWithFragments
} from 'angular2/src/core/render/api';
import {AppViewManagerUtils} from './view_manager_utils';
import {AppViewPool} from './view_pool';
import {AppViewListener} from './view_listener';
import {wtfCreateScope, wtfLeave, WtfScopeFn} from '../profile/profile';
import {ProtoViewFactory} from './proto_view_factory';

/**
 * Service exposing low level API for creating, moving and destroying Views.
 *
 * Most applications should use higher-level abstractions like {@link DynamicComponentLoader} and
 * {@link ViewContainerRef} instead.
 */
export abstract class AppViewManager {
  /**
   * Returns a {@link ViewContainerRef} of the View Container at the specified location.
   */
  abstract getViewContainer(location: ElementRef): ViewContainerRef;

  /**
   * Returns the {@link ElementRef} that makes up the specified Host View.
   */
  getHostElement(hostViewRef: HostViewRef): ElementRef {
    var hostView = internalView(<ViewRef>hostViewRef);
    if (hostView.proto.type !== viewModule.ViewType.HOST) {
      throw new BaseException('This operation is only allowed on host views');
    }
    return hostView.elementRefs[hostView.elementOffset];
  }

  /**
   * Searches the Component View of the Component specified via `hostLocation` and returns the
   * {@link ElementRef} for the Element identified via a Variable Name `variableName`.
   *
   * Throws an exception if the specified `hostLocation` is not a Host Element of a Component, or if
   * variable `variableName` couldn't be found in the Component View of this Component.
   */
  abstract getNamedElementInComponentView(hostLocation: ElementRef,
                                          variableName: string): ElementRef;

  /**
   * Returns the component instance for the provided Host Element.
   */
  abstract getComponent(hostLocation: ElementRef): any;

  /**
   * Creates an instance of a Component and attaches it to the first element in the global View
   * (usually DOM Document) that matches the component's selector or `overrideSelector`.
   *
   * This as a low-level way to bootstrap an application and upgrade an existing Element to a
   * Host Element. Most applications should use {@link DynamicComponentLoader#loadAsRoot} instead.
   *
   * The Component and its View are created based on the `hostProtoViewRef` which can be obtained
   * by compiling the component with {@link Compiler#compileInHost}.
   *
   * Use {@link AppViewManager#destroyRootHostView} to destroy the created Component and it's Host
   * View.
   *
   * ### Example
   *
   * ```
   * @ng.Component({
   *   selector: 'child-component'
   * })
   * @ng.View({
   *   template: 'Child'
   * })
   * class ChildComponent {
   *
   * }
   *
   * @ng.Component({
   *   selector: 'my-app'
   * })
   * @ng.View({
   *   template: `
   *     Parent (<some-component></some-component>)
   *   `
   * })
   * class MyApp implements OnDestroy {
   *   viewRef: ng.ViewRef;
   *
   *   constructor(public appViewManager: ng.AppViewManager, compiler: ng.Compiler) {
   *     compiler.compileInHost(ChildComponent).then((protoView: ng.ProtoViewRef) => {
   *       this.viewRef = appViewManager.createRootHostView(protoView, 'some-component', null);
   *     })
   *   }
   *
   *   ngOnDestroy() {
   *     this.appViewManager.destroyRootHostView(this.viewRef);
   *     this.viewRef = null;
   *   }
   * }
   *
   * ng.bootstrap(MyApp);
   * ```
   */
  abstract createRootHostView(hostProtoViewRef: ProtoViewRef, overrideSelector: string,
                              injector: Injector): HostViewRef;

  /**
   * Destroys the Host View created via {@link AppViewManager#createRootHostView}.
   *
   * Along with the Host View, the Component Instance as well as all nested View and Components are
   * destroyed as well.
   */
  abstract destroyRootHostView(hostViewRef: HostViewRef);

  /**
   * Instantiates an Embedded View based on the {@link TemplateRef `templateRef`} and inserts it
   * into the View Container specified via `viewContainerLocation` at the specified `index`.
   *
   * Returns the {@link ViewRef} for the newly created View.
   *
   * This as a low-level way to create and attach an Embedded via to a View Container. Most
   * applications should used {@link ViewContainerRef#createEmbeddedView} instead.
   *
   * Use {@link AppViewManager#destroyViewInContainer} to destroy the created Embedded View.
   */
  // TODO(i): this low-level version of ViewContainerRef#createEmbeddedView doesn't add anything new
  //    we should make it private, otherwise we have two apis to do the same thing.
  abstract createEmbeddedViewInContainer(viewContainerLocation: ElementRef, index: number,
                                         templateRef: TemplateRef): ViewRef;

  /**
   * Instantiates a single {@link Component} and inserts its Host View into the View Container
   * found at `viewContainerLocation`. Within the container, the view will be inserted at position
   * specified via `index`.
   *
   * The component is instantiated using its {@link ProtoViewRef `protoViewRef`} which can be
   * obtained via {@link Compiler#compileInHost}.
   *
   * You can optionally specify `imperativelyCreatedInjector`, which configure the {@link Injector}
   * that will be created for the Host View.
   *
   * Returns the {@link HostViewRef} of the Host View created for the newly instantiated Component.
   *
   * Use {@link AppViewManager#destroyViewInContainer} to destroy the created Host View.
   */
  abstract createHostViewInContainer(viewContainerLocation: ElementRef, index: number,
                                     protoViewRef: ProtoViewRef,
                                     imperativelyCreatedInjector: ResolvedProvider[]): HostViewRef;

  /**
   * Destroys an Embedded or Host View attached to a View Container at the specified `index`.
   *
   * The View Container is located via `viewContainerLocation`.
   */
  abstract destroyViewInContainer(viewContainerLocation: ElementRef, index: number);

  /**
   *
   * See {@link AppViewManager#detachViewInContainer}.
   */
  // TODO(i): refactor detachViewInContainer+attachViewInContainer to moveViewInContainer
  abstract attachViewInContainer(viewContainerLocation: ElementRef, index: number,
                                 viewRef: ViewRef): ViewRef;

  /**
   * See {@link AppViewManager#attachViewInContainer}.
   */
  abstract detachViewInContainer(viewContainerLocation: ElementRef, index: number): ViewRef;
}

@Injectable()
export class AppViewManager_ extends AppViewManager {
  private _protoViewFactory: ProtoViewFactory;

  constructor(private _viewPool: AppViewPool, private _viewListener: AppViewListener,
              private _utils: AppViewManagerUtils, private _renderer: Renderer,
              @Inject(forwardRef(() => ProtoViewFactory)) _protoViewFactory) {
    super();
    this._protoViewFactory = _protoViewFactory;
  }

  getViewContainer(location: ElementRef): ViewContainerRef {
    var hostView = internalView((<ElementRef_>location).parentView);
    return hostView.elementInjectors[(<ElementRef_>location).boundElementIndex]
        .getViewContainerRef();
  }

  getNamedElementInComponentView(hostLocation: ElementRef, variableName: string): ElementRef {
    var hostView = internalView((<ElementRef_>hostLocation).parentView);
    var boundElementIndex = (<ElementRef_>hostLocation).boundElementIndex;
    var componentView = hostView.getNestedView(boundElementIndex);
    if (isBlank(componentView)) {
      throw new BaseException(`There is no component directive at element ${boundElementIndex}`);
    }
    var binderIdx = componentView.proto.variableLocations.get(variableName);
    if (isBlank(binderIdx)) {
      throw new BaseException(`Could not find variable ${variableName}`);
    }
    return componentView.elementRefs[componentView.elementOffset + binderIdx];
  }

  getComponent(hostLocation: ElementRef): any {
    var hostView = internalView((<ElementRef_>hostLocation).parentView);
    var boundElementIndex = (<ElementRef_>hostLocation).boundElementIndex;
    return this._utils.getComponentInstance(hostView, boundElementIndex);
  }

  /** @internal */
  _createRootHostViewScope: WtfScopeFn = wtfCreateScope('AppViewManager#createRootHostView()');

  createRootHostView(hostProtoViewRef: ProtoViewRef, overrideSelector: string,
                     injector: Injector): HostViewRef {
    var s = this._createRootHostViewScope();
    var hostProtoView: viewModule.AppProtoView = internalProtoView(hostProtoViewRef);
    this._protoViewFactory.initializeProtoViewIfNeeded(hostProtoView);
    var hostElementSelector = overrideSelector;
    if (isBlank(hostElementSelector)) {
      hostElementSelector = hostProtoView.elementBinders[0].componentDirective.metadata.selector;
    }
    var renderViewWithFragments = this._renderer.createRootHostView(
        hostProtoView.render, hostProtoView.mergeInfo.embeddedViewCount + 1, hostElementSelector);
    var hostView = this._createMainView(hostProtoView, renderViewWithFragments);

    this._renderer.hydrateView(hostView.render);
    this._utils.hydrateRootHostView(hostView, injector);
    return wtfLeave(s, hostView.ref);
  }

  /** @internal */
  _destroyRootHostViewScope: WtfScopeFn = wtfCreateScope('AppViewManager#destroyRootHostView()');

  destroyRootHostView(hostViewRef: HostViewRef) {
    // Note: Don't put the hostView into the view pool
    // as it is depending on the element for which it was created.
    var s = this._destroyRootHostViewScope();
    var hostView = internalView(<ViewRef>hostViewRef);
    this._renderer.detachFragment(hostView.renderFragment);
    this._renderer.dehydrateView(hostView.render);
    this._viewDehydrateRecurse(hostView);
    this._viewListener.onViewDestroyed(hostView);
    this._renderer.destroyView(hostView.render);
    wtfLeave(s);
  }

  /** @internal */
  _createEmbeddedViewInContainerScope: WtfScopeFn =
      wtfCreateScope('AppViewManager#createEmbeddedViewInContainer()');

  createEmbeddedViewInContainer(viewContainerLocation: ElementRef, index: number,
                                templateRef: TemplateRef): ViewRef {
    var s = this._createEmbeddedViewInContainerScope();
    var protoView = internalProtoView((<TemplateRef_>templateRef).protoViewRef);
    if (protoView.type !== viewModule.ViewType.EMBEDDED) {
      throw new BaseException('This method can only be called with embedded ProtoViews!');
    }
    this._protoViewFactory.initializeProtoViewIfNeeded(protoView);
    return wtfLeave(s, this._createViewInContainer(viewContainerLocation, index, protoView,
                                                   templateRef.elementRef, null));
  }

  /** @internal */
  _createHostViewInContainerScope: WtfScopeFn =
      wtfCreateScope('AppViewManager#createHostViewInContainer()');

  createHostViewInContainer(viewContainerLocation: ElementRef, index: number,
                            protoViewRef: ProtoViewRef,
                            imperativelyCreatedInjector: ResolvedProvider[]): HostViewRef {
    var s = this._createHostViewInContainerScope();
    var protoView = internalProtoView(protoViewRef);
    if (protoView.type !== viewModule.ViewType.HOST) {
      throw new BaseException('This method can only be called with host ProtoViews!');
    }
    this._protoViewFactory.initializeProtoViewIfNeeded(protoView);
    return wtfLeave(
        s, this._createViewInContainer(viewContainerLocation, index, protoView,
                                       viewContainerLocation, imperativelyCreatedInjector));
  }

  /**
   *
   * See {@link AppViewManager#destroyViewInContainer}.
   * @internal
   */
  _createViewInContainer(viewContainerLocation: ElementRef, index: number,
                         protoView: viewModule.AppProtoView, context: ElementRef,
                         imperativelyCreatedInjector: ResolvedProvider[]): ViewRef {
    var parentView = internalView((<ElementRef_>viewContainerLocation).parentView);
    var boundElementIndex = (<ElementRef_>viewContainerLocation).boundElementIndex;
    var contextView = internalView((<ElementRef_>context).parentView);
    var contextBoundElementIndex = (<ElementRef_>context).boundElementIndex;
    var embeddedFragmentView = contextView.getNestedView(contextBoundElementIndex);
    var view;
    if (protoView.type === viewModule.ViewType.EMBEDDED && isPresent(embeddedFragmentView) &&
        !embeddedFragmentView.hydrated()) {
      // Case 1: instantiate the first view of a template that has been merged into a parent
      view = embeddedFragmentView;
      this._attachRenderView(parentView, boundElementIndex, index, view);
    } else {
      // Case 2: instantiate another copy of the template or a host ProtoView.
      // This is a separate case
      // as we only inline one copy of the template into the parent view.
      view = this._createPooledView(protoView);
      this._attachRenderView(parentView, boundElementIndex, index, view);
      this._renderer.hydrateView(view.render);
    }
    this._utils.attachViewInContainer(parentView, boundElementIndex, contextView,
                                      contextBoundElementIndex, index, view);
    this._utils.hydrateViewInContainer(parentView, boundElementIndex, contextView,
                                       contextBoundElementIndex, index,
                                       imperativelyCreatedInjector);
    return view.ref;
  }

  /** @internal */
  _attachRenderView(parentView: viewModule.AppView, boundElementIndex: number, index: number,
                    view: viewModule.AppView) {
    var elementRef = parentView.elementRefs[boundElementIndex];
    if (index === 0) {
      this._renderer.attachFragmentAfterElement(elementRef, view.renderFragment);
    } else {
      var prevView = parentView.viewContainers[boundElementIndex].views[index - 1];
      this._renderer.attachFragmentAfterFragment(prevView.renderFragment, view.renderFragment);
    }
  }

  /** @internal */
  _destroyViewInContainerScope = wtfCreateScope('AppViewMananger#destroyViewInContainer()');

  destroyViewInContainer(viewContainerLocation: ElementRef, index: number) {
    var s = this._destroyViewInContainerScope();
    var parentView = internalView((<ElementRef_>viewContainerLocation).parentView);
    var boundElementIndex = (<ElementRef_>viewContainerLocation).boundElementIndex;
    this._destroyViewInContainer(parentView, boundElementIndex, index);
    wtfLeave(s);
  }

  /** @internal */
  _attachViewInContainerScope = wtfCreateScope('AppViewMananger#attachViewInContainer()');

  // TODO(i): refactor detachViewInContainer+attachViewInContainer to moveViewInContainer
  attachViewInContainer(viewContainerLocation: ElementRef, index: number,
                        viewRef: ViewRef): ViewRef {
    var s = this._attachViewInContainerScope();
    var view = internalView(viewRef);
    var parentView = internalView((<ElementRef_>viewContainerLocation).parentView);
    var boundElementIndex = (<ElementRef_>viewContainerLocation).boundElementIndex;
    // TODO(tbosch): the public methods attachViewInContainer/detachViewInContainer
    // are used for moving elements without the same container.
    // We will change this into an atomic `move` operation, which should preserve the
    // previous parent injector (see https://github.com/angular/angular/issues/1377).
    // Right now we are destroying any special
    // context view that might have been used.
    this._utils.attachViewInContainer(parentView, boundElementIndex, null, null, index, view);
    this._attachRenderView(parentView, boundElementIndex, index, view);
    return wtfLeave(s, viewRef);
  }

  /** @internal */
  _detachViewInContainerScope = wtfCreateScope('AppViewMananger#detachViewInContainer()');

  // TODO(i): refactor detachViewInContainer+attachViewInContainer to moveViewInContainer
  detachViewInContainer(viewContainerLocation: ElementRef, index: number): ViewRef {
    var s = this._detachViewInContainerScope();
    var parentView = internalView((<ElementRef_>viewContainerLocation).parentView);
    var boundElementIndex = (<ElementRef_>viewContainerLocation).boundElementIndex;
    var viewContainer = parentView.viewContainers[boundElementIndex];
    var view = viewContainer.views[index];
    this._utils.detachViewInContainer(parentView, boundElementIndex, index);
    this._renderer.detachFragment(view.renderFragment);
    return wtfLeave(s, view.ref);
  }

  /** @internal */
  _createMainView(protoView: viewModule.AppProtoView,
                  renderViewWithFragments: RenderViewWithFragments): viewModule.AppView {
    var mergedParentView =
        this._utils.createView(protoView, renderViewWithFragments, this, this._renderer);
    this._renderer.setEventDispatcher(mergedParentView.render, mergedParentView);
    this._viewListener.onViewCreated(mergedParentView);
    return mergedParentView;
  }

  /** @internal */
  _createPooledView(protoView: viewModule.AppProtoView): viewModule.AppView {
    var view = this._viewPool.getView(protoView);
    if (isBlank(view)) {
      view = this._createMainView(
          protoView,
          this._renderer.createView(protoView.render, protoView.mergeInfo.embeddedViewCount + 1));
    }
    return view;
  }

  /** @internal */
  _destroyPooledView(view: viewModule.AppView) {
    var wasReturned = this._viewPool.returnView(view);
    if (!wasReturned) {
      this._viewListener.onViewDestroyed(view);
      this._renderer.destroyView(view.render);
    }
  }

  /** @internal */
  _destroyViewInContainer(parentView: viewModule.AppView, boundElementIndex: number,
                          index: number) {
    var viewContainer = parentView.viewContainers[boundElementIndex];
    var view = viewContainer.views[index];

    this._viewDehydrateRecurse(view);
    this._utils.detachViewInContainer(parentView, boundElementIndex, index);
    if (view.viewOffset > 0) {
      // Case 1: a view that is part of another view.
      // Just detach the fragment
      this._renderer.detachFragment(view.renderFragment);
    } else {
      // Case 2: a view that is not part of another view.
      // dehydrate and destroy it.
      this._renderer.dehydrateView(view.render);
      this._renderer.detachFragment(view.renderFragment);
      this._destroyPooledView(view);
    }
  }

  /** @internal */
  _viewDehydrateRecurse(view: viewModule.AppView) {
    if (view.hydrated()) {
      this._utils.dehydrateView(view);
    }
    var viewContainers = view.viewContainers;
    var startViewOffset = view.viewOffset;
    var endViewOffset = view.viewOffset + view.proto.mergeInfo.viewCount - 1;
    var elementOffset = view.elementOffset;
    for (var viewIdx = startViewOffset; viewIdx <= endViewOffset; viewIdx++) {
      var currView = view.views[viewIdx];
      for (var binderIdx = 0; binderIdx < currView.proto.elementBinders.length;
           binderIdx++, elementOffset++) {
        var vc = viewContainers[elementOffset];
        if (isPresent(vc)) {
          for (var j = vc.views.length - 1; j >= 0; j--) {
            this._destroyViewInContainer(currView, elementOffset, j);
          }
        }
      }
    }
  }
}