/* Angular Imports */
import { ComponentType, Overlay, OriginConnectionPosition, OverlayConnectionPosition, ConnectionPositionPair } from '@angular/cdk/overlay';
import { ComponentPortal, TemplatePortal } from '@angular/cdk/portal';
import { Injectable, InjectionToken, Injector, TemplateRef, ElementRef } from '@angular/core';

/* Custom Imports */
import { PopoverConfig } from './popover-config';
import { PopoverRef } from './popover-ref';
import { PopoverComponent } from './popover.component';

/**
 * Injection token that can be used to access the data that was passed in to a popover.
 *
 */
export const POPOVER_DATA = new InjectionToken('popover.data');

const defaultConfig: PopoverConfig = {
  backdropClass: '',
  disableClose: false,
  panelClass: '',
  arrowOffset: 30,
  arrowSize: 20
};

/**
 * Service to open modal and manage popovers.
 */
@Injectable({
  providedIn: 'root'
})
export class PopoverService {
  /**
   * @param {Injector} injector Injector.
   * @param {overlay} overlay Overlay.
   */
  constructor(private overlay: Overlay, private injector: Injector) { }

  /**
   * Opens the popover at target element
   * @param {ComponentType<any> | TemplateRef<any>} componentOrTemplate ComponentType<any> | TemplateRef<any>.
   * @param {ElementRef | HTMLElement} target ElementRef | HTMLElement.
   * @param {string} position String.
   * @param {Partial<PopoverConfig> = {}} config Partial<PopoverConfig> = {}.
   */
  open<D = any>(componentOrTemplate: ComponentType<any> | TemplateRef<any>,
      target: ElementRef | HTMLElement, position: string,
      backdrop: boolean,
      config: Partial<PopoverConfig> = {}): PopoverRef<D> {
    const popoverConfig: PopoverConfig = Object.assign({}, defaultConfig, config);

    const arrowSize = popoverConfig.arrowSize;
    const arrowOffset = popoverConfig.arrowOffset;
    const panelOffset = arrowSize / 2;
    let showbackdrop: boolean;
    let positions: ConnectionPositionPair[];
    // preferred positions, in order of priority
    if (position === 'bottom') {
        positions = [
        // bottom center
        {
          overlayX: 'center',
          overlayY: 'top',
          originX: 'center',
          originY: 'bottom',
          panelClass: ['top', 'center'],
          offsetY: panelOffset
        },
        // bottom left
        {
          overlayX: 'start',
          overlayY: 'top',
          originX: 'center',
          originY: 'bottom',
          panelClass: ['top', 'left'],
          offsetX: -1 * arrowOffset,
          offsetY: panelOffset
        },
        // bottom right
        {
          overlayX: 'end',
          overlayY: 'top',
          originX: 'center',
          originY: 'bottom',
          panelClass: ['top', 'right'],
          offsetX: arrowOffset,
          offsetY: panelOffset
        }
      ];
    } else if (position === 'top') {
      positions = [
        // top center
        {
          overlayX: 'center',
          overlayY: 'bottom',
          originX: 'center',
          originY: 'top',
          panelClass: ['bottom', 'center'],
          offsetY: -1 * panelOffset
        },
        // top left
        {
          overlayX: 'start',
          overlayY: 'bottom',
          originX: 'center',
          originY: 'top',
          panelClass: ['bottom', 'left'],
          offsetX: -1 * arrowOffset,
          offsetY: -1 * panelOffset
        },
        // top right
        {
          overlayX: 'end',
          overlayY: 'bottom',
          originX: 'center',
          originY: 'top',
          panelClass: ['bottom', 'right'],
          offsetX: arrowOffset,
          offsetY: -1 * panelOffset
        }
      ];
    } else if (position === 'right') {
      positions = [
        // right
        {
          originX : 'end',
          originY : 'center',
          overlayX: 'start',
          overlayY: 'center',
          panelClass: ['center', 'left'],
          offsetX: 0.5 * arrowOffset,
          offsetY: -1 * panelOffset
        },
      ];
    } else if (position === 'left') {
      positions = [
        // left
        {
          originX : 'start',
          originY : 'center',
          overlayX: 'end',
          overlayY: 'center',
          panelClass: ['center', 'right'],
          offsetX: -0.5 * arrowOffset,
          offsetY: -1 * panelOffset
        },
      ];
    }
    if (backdrop === true) {
      showbackdrop = true;
    } else {
      showbackdrop = false;
    }
    const positionStrategy = this.overlay
        .position()
        .flexibleConnectedTo(target)
        .withPush(false)
        .withFlexibleDimensions(false)
        .withPositions(positions);

    const overlayRef = this.overlay.create({
      hasBackdrop: showbackdrop,
      backdropClass: config.backdropClass,
      panelClass: config.panelClass,
      positionStrategy,
      scrollStrategy: this.overlay.scrollStrategies.reposition()
    });

    const popoverRef = new PopoverRef(overlayRef, positionStrategy, popoverConfig);

    const popover = overlayRef.attach(new ComponentPortal(
      PopoverComponent,
      null,
      Injector.create({
        parent: this.injector,
        providers: [
          { provide: PopoverRef, useValue: popoverRef }
        ]
      })
      // new PortalInjector(
      //   this.injector,
      //   new WeakMap<any, any>([
      //     [PopoverRef, popoverRef]
      //   ])
      // )
    )).instance;

    if (componentOrTemplate instanceof TemplateRef) {
      // rendering a provided template dynamically
      popover.attachTemplatePortal(
        new TemplatePortal(
          componentOrTemplate,
          null,
          {
            $implicit: config.data,
            popover: popoverRef
          }
        )
      );
    } else {
      // rendering a provided component dynamically
      popover.attachComponentPortal(
        new ComponentPortal(
          componentOrTemplate,
          null,
          Injector.create({
            parent: this.injector,
            providers: [
              { provide: POPOVER_DATA, useValue: config.data },
              { provide: PopoverRef, useValue: popoverRef },
            ]
          })
          // new PortalInjector(
          //   this.injector,
          //   new WeakMap<any, any>([
          //     [POPOVER_DATA, config.data],
          //     [PopoverRef, popoverRef]
          //   ])
          // )
        )
      );

    }

    return popoverRef;
  }
}