/** Angular Imports */
import { Component, OnInit, ViewChild, AfterViewInit } from '@angular/core';
import { MatPaginator, MatSort, MatCheckbox } from '@angular/material';
import { FormControl } from '@angular/forms';
import { Router, ActivatedRoute } from '@angular/router';

/** rxjs Imports */
import { merge } from 'rxjs';
import { tap, startWith, map, distinctUntilChanged, debounceTime} from 'rxjs/operators';

/** Custom Services */
import { CentersService } from './centers.service';

/** Custom Data Source */
import { CentersDataSource } from './centers.datasource';

/**
 * Centers component.
 */
@Component({
  selector: 'mifosx-app-centers',
  templateUrl: './centers.component.html',
  styleUrls: ['./centers.component.scss'],
})
export class CentersComponent implements OnInit, AfterViewInit {
  @ViewChild('showClosedCenters') showClosedCenters: MatCheckbox;

  /** Name form control. */
  name = new FormControl();
  /** ExternalId form control. */
  externalId = new FormControl();
  /** Columns to be displayed in centers table. */
  displayedColumns =  ['name', 'accountNo', 'externalId', 'status', 'officeName'];
  /** Data source for centers table. */
  dataSource: CentersDataSource;
  /** Centers filter. */
  filterCentersBy = [
    {
      type: 'name',
      value: ''
    },
    {
      type: 'externalId',
      value: ''
    }
  ];

  /** Paginator for centers table. */
  @ViewChild(MatPaginator) paginator: MatPaginator;
  /** Sorter for centers table. */
  @ViewChild(MatSort) sort: MatSort;

  constructor(private centersService: CentersService) { }

  ngOnInit() {
    this.getCenters();
  }

  /**
   * Subscribes to all search filters:
   * Name, ExternalId
   * sort change and page change.
   */
  ngAfterViewInit() {

    this.name.valueChanges
      .pipe(
        debounceTime(500),
        distinctUntilChanged(),
        tap((filterValue) => {
          this.applyFilter(filterValue, 'name');
        })
      )
      .subscribe();

    this.externalId.valueChanges
    .pipe(
      debounceTime(500),
      distinctUntilChanged(),
      tap((filterValue) => {
        this.applyFilter(filterValue, 'externalId');
      })
    )
    .subscribe();

    this.sort.sortChange.subscribe(() => this.paginator.pageIndex = 0);

    merge(this.sort.sortChange, this.paginator.page)
      .pipe(
        tap(() => this.loadCentersPage())
      )
      .subscribe();
  }

  /**
   * Reloads page on changing show closed centers checkbox
   */
  changeShowClosedCenters() {
    this.loadCentersPage();
  }

  /**
   * Loads a page of centers.
   */
  loadCentersPage() {
    if (!this.sort.direction) {
      delete this.sort.active;
    }
    this.dataSource.getCenters(this.filterCentersBy, this.sort.active, this.sort.direction, this.paginator.pageIndex, this.paginator.pageSize, !this.showClosedCenters.checked);
  }

  /**
   * Filters data in centers table based on passed value and poperty.
   * @param {string} filterValue Value to filter data.
   * @param {string} property Property to filter data by.
   */
  applyFilter(filterValue: string, property: string) {
    this.paginator.pageIndex = 0;
    const findIndex = this.filterCentersBy.findIndex(filter => filter.type === property);
    this.filterCentersBy[findIndex].value = filterValue;
    this.loadCentersPage();
  }

  /**
   * Initializes the data source for centers table and loads the first page.
   */
  getCenters() {
    this.dataSource = new CentersDataSource(this.centersService);
    this.dataSource.getCenters(this.filterCentersBy, this.sort.active, this.sort.direction, this.paginator.pageIndex, this.paginator.pageSize);
  }

}