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

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

/** Custom Services */
import { GroupsService } from './groups.service';

/** Custom Data Source */
import { GroupsDataSource } from './groups.datasource';

/**
 * Groups component.
 */
@Component({
  selector: 'mifosx-app-groups',
  templateUrl: './groups.component.html',
  styleUrls: ['./groups.component.scss']
})
export class GroupsComponent implements OnInit, AfterViewInit {
  @ViewChild('showClosedGroups', { static: true }) showClosedGroups: MatCheckbox;

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

  /** Paginator for groups table. */
  @ViewChild(MatPaginator, { static: true }) paginator: MatPaginator;
  /** Sorter for groups table. */
  @ViewChild(MatSort, { static: true }) sort: MatSort;

  /**
   * @param {GroupsService} groupsService Groups Service
   */
  constructor(private groupsService: GroupsService) { }

  ngOnInit() {
    this.getGroups();
  }

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

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

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

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

  changeShowClosedGroups() {
    this.loadGroupsPage();
  }

  /**
   * Loads a page of groups.
   */
  loadGroupsPage() {
    if (!this.sort.direction) {
      delete this.sort.active;
    }
    this.dataSource.getGroups(this.filterGroupsBy, this.sort.active, this.sort.direction, this.paginator.pageIndex, this.paginator.pageSize, !this.showClosedGroups.checked);
  }

  /**
   * Filters data in groups 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.filterGroupsBy.findIndex(filter => filter.type === property);
    this.filterGroupsBy[findIndex].value = filterValue;
    this.loadGroupsPage();
  }

  /**
   * Initializes the data source for groups table and loads the first page.
   */
  getGroups() {
    this.dataSource = new GroupsDataSource(this.groupsService);
    this.dataSource.getGroups(this.filterGroupsBy, this.sort.active, this.sort.direction, this.paginator.pageIndex, this.paginator.pageSize);
  }

}