import { Component, ElementRef, EventEmitter, Input, OnDestroy, OnInit, Output, Renderer2, ViewChild, ViewEncapsulation } from '@angular/core';
import { FormControl } from '@angular/forms';
import { HttpClient } from '@angular/common/http';
import { MatFormField } from '@angular/material/form-field';
import { Subject } from 'rxjs';
import { debounceTime, filter, map, takeUntil } from 'rxjs/operators';
import { TreoAnimations } from '@treo/animations/public-api';
import { getBasePath } from 'app/app.routing';

@Component({
    selector     : 'search',
    templateUrl  : './search.component.html',
    styleUrls    : ['./search.component.scss'],
    encapsulation: ViewEncapsulation.None,
    exportAs     : 'treoSearch',
    animations   : TreoAnimations
})
export class SearchComponent implements OnInit, OnDestroy
{
    results: any[] | null;
    searchControl: FormControl;

    // Debounce
    @Input()
    debounce: number;

    // Min. length
    @Input()
    minLength: number;

    // Search
    @Output()
    search: EventEmitter<any>;

    // Private
    private _appearance: 'basic' | 'bar';
    private _opened: boolean;
    private _unsubscribeAll: Subject<void>;

    /**
     * Constructor
     *
     * @param {ElementRef} _elementRef
     * @param {HttpClient} _httpClient
     * @param {Renderer2} _renderer2
     */
    constructor(
        private _elementRef: ElementRef,
        private _httpClient: HttpClient,
        private _renderer2: Renderer2
    )
    {
        // Set the private defaults
        this._unsubscribeAll = new Subject();

        // Set the defaults
        this.appearance = 'basic';
        this.debounce = this.debounce || 300;
        this.minLength = this.minLength || 2;
        this.opened = false;
        this.results = null;
        this.searchControl = new FormControl();
    }

    // -----------------------------------------------------------------------------------------------------
    // @ Accessors
    // -----------------------------------------------------------------------------------------------------

    /**
     * Setter and getter for appearance
     *
     * @param value
     */
    @Input()
    set appearance(value: 'basic' | 'bar')
    {
        // If the value is the same, return...
        if ( this._appearance === value )
        {
            return;
        }

        // Make sure the search is closed, before
        // changing the appearance to prevent issues
        this.close();

        let appearanceClassName;

        // Remove the previous appearance class
        appearanceClassName = 'search-appearance-' + this.appearance;
        this._renderer2.removeClass(this._elementRef.nativeElement, appearanceClassName);

        // Store the appearance
        this._appearance = value;

        // Add the new appearance class
        appearanceClassName = 'search-appearance-' + this.appearance;
        this._renderer2.addClass(this._elementRef.nativeElement, appearanceClassName);
    }

    get appearance(): 'basic' | 'bar'
    {
        return this._appearance;
    }

    /**
     * Setter and getter for opened
     *
     * @param value
     */
    set opened(value: boolean)
    {
        // If the value is the same, return...
        if ( this._opened === value )
        {
            return;
        }

        // Store the opened status
        this._opened = value;

        // If opened...
        if ( value )
        {
            // Add opened class
            this._renderer2.addClass(this._elementRef.nativeElement, 'search-opened');
        }
        else
        {
            // Remove opened class
            this._renderer2.removeClass(this._elementRef.nativeElement, 'search-opened');
        }
    }

    get opened(): boolean
    {
        return this._opened;
    }

    /**
     * Setter and getter for search input
     *
     * @param value
     */
    @ViewChild('searchInput')
    set searchInput(value: MatFormField)
    {
        // Return if the appearance is basic, since we don't want
        // basic search to be focused as soon as the page loads
        if ( this.appearance === 'basic' )
        {
            return;
        }

        // If the value exists, it means that the search input
        // is now in the DOM and we can focus on the input..
        if ( value )
        {
            // Give Angular time to complete the change detection cycle
            setTimeout(() => {

                // Focus to the input element
                value._inputContainerRef.nativeElement.children[0].focus();
            });
        }
    }

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

    /**
     * On init
     */
    ngOnInit(): void
    {
        // Subscribe to the search field value changes
        this.searchControl.valueChanges
            .pipe(
                debounceTime(this.debounce),
                takeUntil(this._unsubscribeAll),
                map((value) => {

                    // Set the search results to null if there is no value or
                    // the length of the value is smaller than the minLength
                    // so the autocomplete panel can be closed
                    if ( !value || value.length < this.minLength )
                    {
                        this.results = null;
                    }

                    // Continue
                    return value;
                }),
                filter((value) => {

                    // Filter out undefined/null/false statements and also
                    // filter out the values that are smaller than minLength
                    return value && value.length >= this.minLength;
                })
            )
            .subscribe((value) => {
                this._httpClient.post(getBasePath() + '/api/common/search', {query: value})
                    .subscribe((response: any) => {
                        this.results = response.results;
                    });
            });
    }

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

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

    /**
     * On keydown of the search input
     *
     * @param event
     */
    onKeydown(event): void
    {
        // Listen for escape to close the search
        // if the appearance is 'bar'
        if ( this.appearance === 'bar' )
        {
            // Escape
            if ( event.keyCode === 27 )
            {
                // Close the search
                this.close();
            }
        }
    }

    /**
     * Open the search
     * Used in 'bar'
     */
    open(): void
    {
        // Return, if it's already opened
        if ( this.opened )
        {
            return;
        }

        // Open the search
        this.opened = true;
    }

    /**
     * Close the search
     * * Used in 'bar'
     */
    close(): void
    {
        // Return, if it's already closed
        if ( !this.opened )
        {
            return;
        }

        // Clear the search input
        this.searchControl.setValue('');

        // Close the search
        this.opened = false;
    }
}