import {AfterViewInit, Component, ElementRef, OnInit, ViewChild} from '@angular/core';
import {FormBuilder, FormGroup} from '@angular/forms';
import { MatAutocompleteSelectedEvent } from '@angular/material/autocomplete';
import { MatPaginator } from '@angular/material/paginator';
import { MatSort } from '@angular/material/sort';
import {ActivatedRoute, Router} from '@angular/router';
import {Observable, of as observableOf} from 'rxjs';
import {debounceTime, distinctUntilChanged, map, startWith, switchMap} from 'rxjs/operators';
import * as moment from 'moment';
import {LedgerDataSource} from './ledger-datasource';
import {Ledger} from './ledger';
import {Account} from '../account/account';
import {LedgerService} from './ledger.service';
import {AccountService} from '../account/account.service';
import {ToCsvService} from '../shared/to-csv.service';

@Component({
  selector: 'app-ledger',
  templateUrl: './ledger.component.html',
  styleUrls: ['./ledger.component.css']
})
export class LedgerComponent implements OnInit, AfterViewInit {
  @ViewChild('accountElement', { static: true }) accountElement: ElementRef;
  @ViewChild(MatPaginator, { static: true }) paginator: MatPaginator;
  @ViewChild(MatSort, { static: true }) sort: MatSort;
  dataSource: LedgerDataSource;
  form: FormGroup;
  info: Ledger;
  selectedRowId: string;
  debit: number;
  credit: number;
  running: number;
  /** Columns displayed in the table. Columns IDs can be added, removed, or reordered. */
  displayedColumns = ['date', 'particulars', 'type', 'narration', 'debit', 'credit', 'running'];

  accounts: Observable<Account[]>;

  constructor(
    private route: ActivatedRoute,
    private router: Router,
    private fb: FormBuilder,
    private toCsv: ToCsvService,
    private ser: LedgerService,
    private accountSer: AccountService
  ) {
    this.createForm();

    this.accounts = this.form.get('account').valueChanges
      .pipe(
        startWith(null),
        map(x => (x !== null && x.length >= 1) ? x : null),
        debounceTime(150),
        distinctUntilChanged(),
        switchMap(x => (x === null) ? observableOf([]) : this.accountSer.autocomplete(x))
      );
  }

  ngOnInit() {
    this.route.data
      .subscribe((data: { info: Ledger }) => {
        this.info = data.info;
        this.calculateTotals();
        this.form.setValue({
          account: this.info.account,
          startDate: moment(this.info.startDate, 'DD-MMM-YYYY').toDate(),
          finishDate: moment(this.info.finishDate, 'DD-MMM-YYYY').toDate()
        });
        this.dataSource = new LedgerDataSource(this.paginator, this.sort, this.info.body);
      });
  }

  ngAfterViewInit() {
    setTimeout(() => {
      this.accountElement.nativeElement.focus();
    }, 0);
  }

  displayFn(account?: Account): string | undefined {
    return account ? account.name : undefined;
  }

  calculateTotals() {
    this.debit = 0;
    this.credit = 0;
    this.running = 0;
    this.info.body.forEach((item) => {
      if (item.type !== 'Opening Balance') {
        this.debit += item.debit;
        this.credit += item.credit;
        if (item.posted) {
          this.running += item.debit - item.credit;
        }
      } else {
        this.running += item.debit - item.credit;
      }
      item.running = this.running;
    });
  }

  selected(event: MatAutocompleteSelectedEvent): void {
    this.info.account = event.option.value;
  }

  selectRow(id: string): void {
    this.selectedRowId = id;
  }

  getRowClass(id: string, posted: boolean): string {
    if (this.selectedRowId === id) {
      return 'selected';
    } else if (!posted) {
      return 'unposted';
    } else {
      return '';
    }
  }

  show() {
    const info = this.getInfo();
    this.router.navigate(['Ledger', info.account.id], {
      queryParams: {
        startDate: info.startDate,
        finishDate: info.finishDate
      }
    });
  }

  createForm() {
    this.form = this.fb.group({
      startDate: '',
      finishDate: '',
      account: ''
    });
  }

  getInfo(): Ledger {
    const formModel = this.form.value;

    return {
      account: formModel.account,
      startDate: moment(formModel.startDate).format('DD-MMM-YYYY'),
      finishDate: moment(formModel.finishDate).format('DD-MMM-YYYY')
    };
  }

  exportCsv() {
    const headers = {
      Date: 'date',
      Name: 'name',
      Type: 'type',
      Narration: 'narration',
      Debit: 'debit',
      Credit: 'credit',
      Running: 'running',
      Posted: 'posted'
    };
    const csvData = new Blob([this.toCsv.toCsv(headers, this.dataSource.data)], {type: 'text/csv;charset=utf-8;'});
    const link = document.createElement('a');
    link.href = window.URL.createObjectURL(csvData);
    link.setAttribute('download', 'ledger.csv');
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
  }
}