import { ChangeDetectionStrategy, ChangeDetectorRef, Component, Input, OnChanges, OnDestroy, OnInit, SimpleChanges, TemplateRef, ViewChild, ViewContainerRef, ViewEncapsulation } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { Overlay, OverlayRef } from '@angular/cdk/overlay';
import { TemplatePortal } from '@angular/cdk/portal';
import { MatButton } from '@angular/material/button';
import { takeUntil } from 'rxjs/operators';
import { Subject } from 'rxjs';
import { Shortcut } from 'app/layout/common/shortcuts/shortcuts.types';
import { ShortcutsService } from 'app/layout/common/shortcuts/shortcuts.service';

@Component({
    selector       : 'shortcuts',
    templateUrl    : './shortcuts.component.html',
    encapsulation  : ViewEncapsulation.None,
    changeDetection: ChangeDetectionStrategy.OnPush,
    exportAs       : 'shortcuts'
})
export class ShortcutsComponent implements OnChanges, OnInit, OnDestroy
{
    @Input() shortcuts: Shortcut[];
    @ViewChild('shortcutsOrigin') private _shortcutsOrigin: MatButton;
    @ViewChild('shortcutsPanel') private _shortcutsPanel: TemplateRef<any>;

    mode: 'view' | 'modify' | 'add' | 'edit' = 'view';
    shortcutForm: FormGroup;
    private _overlayRef: OverlayRef;
    private _unsubscribeAll: Subject<any> = new Subject<any>();

    /**
     * Constructor
     */
    constructor(
        private _changeDetectorRef: ChangeDetectorRef,
        private _formBuilder: FormBuilder,
        private _shortcutsService: ShortcutsService,
        private _overlay: Overlay,
        private _viewContainerRef: ViewContainerRef
    )
    {
    }

    // -----------------------------------------------------------------------------------------------------
    // @ Lifecycle hooks
    // -----------------------------------------------------------------------------------------------------

    /**
     * On changes
     *
     * @param changes
     */
    ngOnChanges(changes: SimpleChanges): void
    {
        // Shortcuts
        if ( 'shortcuts' in changes )
        {
            // Store the shortcuts on the service
            this._shortcutsService.store(changes.shortcuts.currentValue);
        }
    }

    /**
     * On init
     */
    ngOnInit(): void
    {
        // Initialize the form
        this.shortcutForm = this._formBuilder.group({
            id         : [null],
            label      : ['', Validators.required],
            description: [''],
            icon       : ['', Validators.required],
            link       : ['', Validators.required],
            useRouter  : ['', Validators.required]
        });

        // Get the shortcuts
        this._shortcutsService.shortcuts$
            .pipe(takeUntil(this._unsubscribeAll))
            .subscribe((shortcuts: Shortcut[]) => {

                // Load the shortcuts
                this.shortcuts = shortcuts;

                // Mark for check
                this._changeDetectorRef.markForCheck();
            });
    }

    /**
     * On destroy
     */
    ngOnDestroy(): void
    {
        // Unsubscribe from all subscriptions
        this._unsubscribeAll.next();
        this._unsubscribeAll.complete();

        // Dispose the overlay
        if ( this._overlayRef )
        {
            this._overlayRef.dispose();
        }
    }

    // -----------------------------------------------------------------------------------------------------
    // @ Public methods
    // -----------------------------------------------------------------------------------------------------

    /**
     * Open the shortcuts panel
     */
    openPanel(): void
    {
        // Return if the shortcuts panel or its origin is not defined
        if ( !this._shortcutsPanel || !this._shortcutsOrigin )
        {
            return;
        }

        // Make sure to start in 'view' mode
        this.mode = 'view';

        // Create the overlay if it doesn't exist
        if ( !this._overlayRef )
        {
            this._createOverlay();
        }

        // Attach the portal to the overlay
        this._overlayRef.attach(new TemplatePortal(this._shortcutsPanel, this._viewContainerRef));
    }

    /**
     * Close the messages panel
     */
    closePanel(): void
    {
        this._overlayRef.detach();
    }

    /**
     * Change the mode
     */
    changeMode(mode: 'view' | 'modify' | 'add' | 'edit'): void
    {
        // Change the mode
        this.mode = mode;
    }

    /**
     * Prepare for a new shortcut
     */
    newShortcut(): void
    {
        // Reset the form
        this.shortcutForm.reset();

        // Enter the add mode
        this.mode = 'add';
    }

    /**
     * Edit a shortcut
     */
    editShortcut(shortcut: Shortcut): void
    {
        // Reset the form with the shortcut
        this.shortcutForm.reset(shortcut);

        // Enter the edit mode
        this.mode = 'edit';
    }

    /**
     * Save shortcut
     */
    save(): void
    {
        // Get the data from the form
        const shortcut = this.shortcutForm.value;

        // If there is an id, update it...
        if ( shortcut.id )
        {
            this._shortcutsService.update(shortcut.id, shortcut).subscribe();
        }
        // Otherwise, create a new shortcut...
        else
        {
            this._shortcutsService.create(shortcut).subscribe();
        }

        // Go back the modify mode
        this.mode = 'modify';
    }

    /**
     * Delete shortcut
     */
    delete(): void
    {
        // Get the data from the form
        const shortcut = this.shortcutForm.value;

        // Delete
        this._shortcutsService.delete(shortcut.id).subscribe();

        // Go back the modify mode
        this.mode = 'modify';
    }

    /**
     * Track by function for ngFor loops
     *
     * @param index
     * @param item
     */
    trackByFn(index: number, item: any): any
    {
        return item.id || index;
    }

    // -----------------------------------------------------------------------------------------------------
    // @ Private methods
    // -----------------------------------------------------------------------------------------------------

    /**
     * Create the overlay
     */
    private _createOverlay(): void
    {
        // Create the overlay
        this._overlayRef = this._overlay.create({
            hasBackdrop     : true,
            backdropClass   : 'fuse-backdrop-on-mobile',
            scrollStrategy  : this._overlay.scrollStrategies.block(),
            positionStrategy: this._overlay.position()
                                  .flexibleConnectedTo(this._shortcutsOrigin._elementRef.nativeElement)
                                  .withLockedPosition()
                                  .withPush(true)
                                  .withPositions([
                                      {
                                          originX : 'start',
                                          originY : 'bottom',
                                          overlayX: 'start',
                                          overlayY: 'top'
                                      },
                                      {
                                          originX : 'start',
                                          originY : 'top',
                                          overlayX: 'start',
                                          overlayY: 'bottom'
                                      },
                                      {
                                          originX : 'end',
                                          originY : 'bottom',
                                          overlayX: 'end',
                                          overlayY: 'top'
                                      },
                                      {
                                          originX : 'end',
                                          originY : 'top',
                                          overlayX: 'end',
                                          overlayY: 'bottom'
                                      }
                                  ])
        });

        // Detach the overlay from the portal on backdrop click
        this._overlayRef.backdropClick().subscribe(() => {
            this._overlayRef.detach();
        });
    }
}