import {Component, Directive, View, ElementRef, Host, Optional, forwardRef, Inject, Injector, NgZone, Renderer} from 'angular2/angular2';
import {ViewContainerRef} from 'angular2/src/core/compiler/view_container_ref';

import {IonicComponent} from '../../config/decorators';
import {NavController} from './nav-controller';

/**
 * TODO
 */
@IonicComponent({
  selector: 'ion-nav',
  properties: [
    'root'
  ],
  defaultProperties: {
    'swipeBackEnabled': true
  }
})
@View({
  template: '<template pane-anchor></template>',
  directives: [forwardRef(() => NavPaneAnchor)]
})
export class Nav extends NavController {

  /**
   * TODO
   * @param {NavController} hostNavCtrl  TODO
   * @param {Injector} injector  TODO
   * @param {ElementRef} elementRef  TODO
   * @param {NgZone} zone  TODO
   */
  constructor(
    @Optional() hostNavCtrl: NavController,
    injector: Injector,
    elementRef: ElementRef,
    zone: NgZone
  ) {
    super(hostNavCtrl, injector, elementRef, zone);
    this.panes = [];
  }

  /**
   * TODO
   */
  onInit() {
    super.onInit();

    if (this.root) {
      if (typeof this.root !== 'function') {
        throw 'The [root] property in <ion-nav> must be given a reference to a component class from within the constructor.';
      }
      this.push(this.root);
    }

    // default the swipe back to be enabled
    let isSwipeBackEnabled = (this.swipeBackEnabled || '').toString() !== 'false';
    this.isSwipeBackEnabled( isSwipeBackEnabled );
  }

  loadContainer(hostProtoViewRef, componentType, viewCtrl, done) {
    // this gets or creates the Pane which similar nav items live in
    // Nav items with just a navbar/content would all use the same Pane
    // Tabs and view's without a navbar would get a different Panes
    let structure = this.inspectStructure(hostProtoViewRef);

    if (structure.tabs) {
      // the component being loaded is an <ion-tabs>
      // Tabs is essentially a pane, cuz it has its own navbar and content containers
      let contentContainerRef = this.viewMngr.getViewContainer(this.anchorElementRef());
      let viewComponetRef = this.createViewComponetRef(hostProtoViewRef, contentContainerRef, this.getBindings(viewCtrl));
      viewComponetRef.instance._paneView = true;

      viewCtrl.disposals.push(() => {
        viewComponetRef.dispose();
      });

      viewCtrl.onReady().then(() => {
        done();
      });

    } else {
      // normal ion-view going into pane
      this.getPane(structure, viewCtrl, (pane) => {
        // add the content of the view into the pane's content area
        let viewComponetRef = this.createViewComponetRef(hostProtoViewRef, pane.contentContainerRef, this.getBindings(viewCtrl));
        viewCtrl.disposals.push(() => {
          viewComponetRef.dispose();

          // remove the pane if there are no view items left
          pane.totalViews--;
          if (pane.totalViews === 0) {
            pane.dispose && pane.dispose();
          }
        });

        // count how many ViewControllers are in this pane
        pane.totalViews++;

        // a new ComponentRef has been created
        // set the ComponentRef's instance to this ViewController
        viewCtrl.setInstance(viewComponetRef.instance);

        // remember the ElementRef to the content that was just created
        viewCtrl.viewElementRef(viewComponetRef.location);

        // get the NavController's container for navbars, which is
        // the place this NavController will add each ViewController's navbar
        let navbarContainerRef = pane.navbarContainerRef;

        // get this ViewController's navbar TemplateRef, which may not
        // exist if the ViewController's template didn't have an <ion-navbar *navbar>
        let navbarTemplateRef = viewCtrl.getNavbarTemplateRef();

        // create the navbar view if the pane has a navbar container, and the
        // ViewController's instance has a navbar TemplateRef to go to inside of it
        if (navbarContainerRef && navbarTemplateRef) {
          let navbarView = navbarContainerRef.createEmbeddedView(navbarTemplateRef, -1);

          viewCtrl.disposals.push(() => {
            let index = navbarContainerRef.indexOf(navbarView);
            if (index > -1) {
              navbarContainerRef.remove(index);
            }
          });
        }

        done();
      });
    }
  }

  getPane(structure, viewCtrl, done) {
    let pane = this.panes[this.panes.length - 1];

    if (pane && pane.navbar === structure.navbar) {
      // the last pane's structure is the same as the one
      // this ViewController will need, so reuse it
      done(pane);

    } else {
      // create a new nav pane
      this.loader.loadNextToLocation(Pane, this.anchorElementRef(), this.getBindings(viewCtrl)).then(componentRef => {

        // get the pane reference
        pane = this.newPane;
        this.newPane = null;

        pane.showNavbar(structure.navbar);
        pane.dispose = () => {
          componentRef.dispose();
          this.panes.splice(this.panes.indexOf(pane), 1);
        };

        this.panes.push(pane);

        done(pane);

      }, loaderErr => {
        console.error(loaderErr);

      }).catch(err => {
        console.error(err);
      });

    }
  }

  addPane(pane) {
    this.newPane = pane;
  }

  inspectStructure(componentProtoViewRef) {
    let navbar = false;
    let tabs = false;
    //let key = '_';

    componentProtoViewRef._protoView.elementBinders.forEach(rootElementBinder => {
      if (!rootElementBinder.componentDirective || !rootElementBinder.nestedProtoView) return;

      rootElementBinder.nestedProtoView.elementBinders.forEach(nestedElementBinder => {
        if ( isComponent(nestedElementBinder, 'Tabs') ) {
          tabs = true;
        }
        if (!nestedElementBinder.componentDirective && nestedElementBinder.nestedProtoView) {
          nestedElementBinder.nestedProtoView.elementBinders.forEach(templatedElementBinder => {
            if ( isComponent(templatedElementBinder, 'Navbar') ) {
              navbar = true;
            }
          });
        }
      });
    });

    return {
      navbar,
      tabs
    };
  }

}

function isComponent(elementBinder, id) {
  return (elementBinder && elementBinder.componentDirective && elementBinder.componentDirective.metadata.id == id);
}

@Directive({selector: 'template[pane-anchor]'})
class NavPaneAnchor {
  constructor(@Host() nav: Nav, elementRef: ElementRef) {
    nav.anchorElementRef(elementRef);
  }
}


@Directive({selector: 'template[navbar-anchor]'})
class NavBarAnchor {
  constructor(
    @Host() @Inject(forwardRef(() => Pane)) pane: Pane,
    viewContainerRef: ViewContainerRef
  ) {
    pane.navbarContainerRef = viewContainerRef;
  }
}


@Directive({selector: 'template[content-anchor]'})
class ContentAnchor {
  constructor(
    @Host() @Inject(forwardRef(() => Pane)) pane: Pane,
    viewContainerRef: ViewContainerRef
  ) {
    pane.contentContainerRef = viewContainerRef;
  }
}


@Component({
  selector: 'ion-pane',
  host: {
    'class': 'nav'
  }
})
@View({
  template: '' +
    '<section class="navbar-container">' +
      '<template navbar-anchor></template>' +
    '</section>' +
    '<section class="content-container">' +
      '<template content-anchor></template>' +
    '</section>',
  directives: [NavBarAnchor, ContentAnchor]
})
class Pane {
  constructor(
    nav: Nav,
    elementRef: ElementRef,
    renderer: Renderer
  ) {
    this.zIndex = (nav.panes.length ? nav.panes[nav.panes.length - 1].zIndex + 1 : 0);
    renderer.setElementStyle(elementRef, 'zIndex', this.zIndex);

    nav.addPane(this);
    this.totalViews = 0;
    this.elementRef = elementRef;
    this.renderer = renderer;
  }

  showNavbar(hasNavbar) {
    this.navbar = hasNavbar;
    if (!hasNavbar) {
      this.renderer.setElementClass(this.elementRef, 'no-navbar', true);
    }
  }

}