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 {ProductLedgerDataSource} from './product-ledger-datasource';
import {ProductLedger} from './product-ledger';
import {ProductLedgerService} from './product-ledger.service';
import {Product} from '../core/product';
import {ProductService} from '../product/product.service';
import {ToCsvService} from '../shared/to-csv.service';

@Component({
  selector: 'app-product-ledger',
  templateUrl: './product-ledger.component.html',
  styleUrls: ['./product-ledger.component.css']
})
export class ProductLedgerComponent implements OnInit, AfterViewInit {
  @ViewChild('productElement', { static: true }) productElement: ElementRef;
  @ViewChild(MatPaginator, { static: true }) paginator: MatPaginator;
  @ViewChild(MatSort, { static: true }) sort: MatSort;
  dataSource: ProductLedgerDataSource;
  form: FormGroup;
  info: ProductLedger;
  selectedRowId: string;
  debitQuantity: number;
  debitAmount: number;
  creditQuantity: number;
  creditAmount: number;
  runningQuantity: number;
  runningAmount: number;
  /** Columns displayed in the table. Columns IDs can be added, removed, or reordered. */
  displayedColumns = [
    'date', 'particulars', 'type', 'narration',
    'debitQuantity', 'debitAmount',
    'creditQuantity', 'creditAmount',
    'runningQuantity', 'runningAmount'
  ];

  products: Observable<Product[]>;

  constructor(
    private route: ActivatedRoute,
    private router: Router,
    private fb: FormBuilder,
    private toCsv: ToCsvService,
    private ser: ProductLedgerService,
    private productSer: ProductService
  ) {
    this.createForm();

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

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

      });
  }

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

  displayFn(product?: Product): string | undefined {
    return product ? product.name : undefined;
  }

  calculateTotals() {
    this.debitQuantity = 0;
    this.debitAmount = 0;
    this.creditQuantity = 0;
    this.creditAmount = 0;
    this.runningQuantity = 0;
    this.runningAmount = 0;
    this.info.body.forEach((item) => {
      if (item.type !== 'Opening Balance') {
        this.debitAmount += item.debitAmount;
        this.creditQuantity += item.creditQuantity;
        this.creditAmount += item.creditAmount;
      }
      this.runningQuantity += item.debitQuantity - item.creditQuantity;
      this.runningAmount += item.debitAmount - item.creditAmount;
      item.runningQuantity = this.runningQuantity;
      item.runningAmount = this.runningAmount;
    });
  }

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

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

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

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

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

    return {
      product: formModel.product,
      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);
  }
}