import {AfterViewInit, Component, ElementRef, OnInit, OnDestroy, ViewChild} from '@angular/core';
import {FormBuilder, FormGroup} from '@angular/forms';
import { MatAutocompleteSelectedEvent } from '@angular/material/autocomplete';
import { MatDialog } from '@angular/material/dialog';
import {ActivatedRoute, Router} from '@angular/router';
import {BehaviorSubject, fromEvent, Observable, of, of as observableOf, zip} from 'rxjs';
import {ReceiptDataSource} from './receipt-datasource';
import {Account} from '../core/account';
import {VoucherService} from '../core/voucher.service';
import {AccountService} from '../core/account.service';
import {DbFile, Journal, Voucher} from '../core/voucher';
import * as moment from 'moment';
import * as math from 'mathjs';
import {AuthService} from '../auth/auth.service';
import {ConfirmDialogComponent} from '../shared/confirm-dialog/confirm-dialog.component';
import {ToasterService} from '../core/toaster.service';
import {debounceTime, distinctUntilChanged, map, startWith, switchMap} from 'rxjs/operators';
import {ReceiptDialogComponent} from './receipt-dialog.component';
import {ImageDialogComponent} from '../shared/image-dialog/image-dialog.component';
import {Hotkey, HotkeysService} from "angular2-hotkeys";

@Component({
  selector: 'app-receipt',
  templateUrl: './receipt.component.html',
  styleUrls: ['./receipt.component.css']
})
export class ReceiptComponent implements OnInit, AfterViewInit, OnDestroy {
  @ViewChild('accountElement', { static: true }) accountElement: ElementRef;
  @ViewChild('dateElement', { static: true }) dateElement: ElementRef;
  public journalObservable = new BehaviorSubject<Journal[]>([]);
  dataSource: ReceiptDataSource;
  form: FormGroup;
  receiptAccounts: Account[];
  receiptJournal: Journal;
  voucher: Voucher;
  account: Account;
  accBal: any;

  displayedColumns = ['account', 'amount', 'action'];

  accounts: Observable<Account[]>;

  constructor(
    private route: ActivatedRoute,
    private router: Router,
    private fb: FormBuilder,
    private dialog: MatDialog,
    private hotkeys: HotkeysService,
    private toaster: ToasterService,
    private auth: AuthService,
    private ser: VoucherService,
    private accountSer: AccountService
  ) {
    this.account = null;
    this.createForm();
    this.listenToAccountAutocompleteChange();
    this.listenToReceiptAccountChange();
  }

  ngOnInit() {
    this.route.data
      .subscribe((data: { voucher: Voucher, receiptAccounts: Account[] }) => {
        this.receiptAccounts = data.receiptAccounts;
        this.loadVoucher(data.voucher);
      });
    this.hotkeys.add(new Hotkey('f2', (event: KeyboardEvent): boolean => {
      setTimeout(() => {
        this.dateElement.nativeElement.focus();
      }, 0);
      return false; // Prevent bubbling
    }, ['INPUT', 'SELECT', 'TEXTAREA']));
    this.hotkeys.add(new Hotkey('ctrl+s', (event: KeyboardEvent): boolean => {
      if (this.canSave())
        this.save();
      return false; // Prevent bubbling
    }, ['INPUT', 'SELECT', 'TEXTAREA']));
    this.hotkeys.add(new Hotkey('ctrl+p', (event: KeyboardEvent): boolean => {
      if (this.voucher.id && !this.voucher.posted && this.auth.user.perms.indexOf('Post Vouchers') !== -1)
        this.post();
      return false; // Prevent bubbling
    }, ['INPUT', 'SELECT', 'TEXTAREA']));
  }

  ngAfterViewInit() {
    this.focusAccount();
  }

  ngOnDestroy() {
    this.hotkeys.reset();
  }

  loadVoucher(voucher: Voucher) {
    this.voucher = voucher;
    this.receiptJournal = this.voucher.journals.filter(x => x.debit === 1)[0];
    this.form.setValue({
      date: moment(this.voucher.date, 'DD-MMM-YYYY').toDate(),
      receiptAccount: this.receiptJournal.account.id,
      receiptAmount: this.receiptJournal.amount,
      addRow: {
        account: '',
        amount: 0
      },
      narration: this.voucher.narration
    });
    this.dataSource = new ReceiptDataSource(this.journalObservable);
    this.updateView();
  }

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

  addRow() {
    const amount = this.rowAmount(this.form.get('addRow').value.amount);
    const debit = -1;
    if (this.account === null || amount <= 0) {
      return;
    }
    const oldFiltered = this.voucher.journals.filter((x) => x.account.id === this.account.id);
    const old = oldFiltered.length ? oldFiltered[0] : null;
    if (old && (old.debit === 1 || old.id === this.receiptJournal.id)) {
      return;
    }
    if (old) {
      old.amount += amount;
    } else {
      this.voucher.journals.push({
        id: null,
        debit: debit,
        amount: amount,
        account: this.account,
        costCentre: null
      });
    }
    this.resetAddRow();
    this.updateView();
  }

  rowAmount(amount: string = ''): number {
    try {
      return math.eval(amount.trim().replace(',', ''));
    } catch {
      return 0;
    }
  }

  resetAddRow() {
    this.form.get('addRow').reset({
      account: null,
      amount: null
    });
    this.account = null;
    this.accBal = null;
    setTimeout(() => {
      this.accountElement.nativeElement.focus();
    }, 0);
  }

  updateView() {
    const journals = this.voucher.journals.filter(x => x.debit === -1);
    this.journalObservable.next(journals);
    this.receiptJournal.amount = Math.abs(journals.map((x) => x.amount).reduce((p, c) => p + c, 0));
    this.form.get('receiptAmount').setValue(this.receiptJournal.amount);
  }

  editRow(row: Journal) {
    const dialogRef = this.dialog.open(ReceiptDialogComponent, {
      width: '750px',
      data: {journal: Object.assign({}, row), date: moment(this.form.get('date').value).format('DD-MMM-YYYY')}
    });

    dialogRef.afterClosed().subscribe((result: boolean | Journal) => {
      if (!result) {
        return;
      }
      const j = result as Journal;
      if (j.account.id !== row.account.id && this.voucher.journals.filter((x) => x.account.id === j.account.id).length) {
        return;
      }
      Object.assign(row, j);
      this.updateView();
    });
  }

  deleteRow(row: Journal) {
    this.voucher.journals.splice(this.voucher.journals.indexOf(row), 1);
    this.updateView();
  }

  createForm() {
    this.form = this.fb.group({
      date: '',
      receiptAccount: '',
      receiptAmount: {value: '', disabled: true},
      addRow: this.fb.group({
        account: '',
        amount: ''
      }),
      narration: ''
    });
    this.accBal = null;
  }

  canSave() {
    if (!this.voucher.id) {
      return true;
    } else if (this.voucher.posted && this.auth.user.perms.indexOf('Edit Posted Vouchers') !== -1) {
      return true;
    } else {
      return this.voucher.user.id === this.auth.user.id || this.auth.user.perms.indexOf('Edit Other User\'s Vouchers') !== -1;
    }
  }

  post() {
    this.ser.post(this.voucher.id)
      .subscribe(
        (result) => {
          this.loadVoucher(result);
          this.toaster.show('Success', 'Voucher Posted');
        },
        (error) => {
          this.toaster.show('Danger', error.error);
        }
      );
  }

  save() {
    this.ser.saveOrUpdate(this.getVoucher())
      .subscribe(
        (result) => {
          this.loadVoucher(result);
          this.toaster.show('Success', '');
          this.router.navigate(['/receipt', result.id]);
        },
        (error) => {
          this.toaster.show('Danger', error.error);
        }
      );
  }

  getVoucher(): Voucher {
    const formModel = this.form.value;
    this.voucher.date = moment(formModel.date).format('DD-MMM-YYYY');
    this.receiptJournal.account.id = formModel.receiptAccount;
    this.voucher.narration = formModel.narration;
    return this.voucher;
  }

  delete() {
    this.ser.delete(this.voucher.id)
      .subscribe(
        (result) => {
          this.toaster.show('Success', '');
          this.router.navigate(['/receipt'], {replaceUrl: true});
        },
        (error) => {
          this.toaster.show('Danger', error.error);
        }
      );
  }

  confirmDelete(): void {
    const dialogRef = this.dialog.open(ConfirmDialogComponent, {
      width: '250px',
      data: {title: 'Delete Voucher?', content: 'Are you sure? This cannot be undone.'}
    });

    dialogRef.afterClosed().subscribe((result: boolean) => {
      if (result) {
        this.delete();
      }
    });
  }

  listenToAccountAutocompleteChange(): void {
    const control = this.form.get('addRow').get('account');
    this.accounts = control.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))
      );
  }

  listenToReceiptAccountChange(): void {
    this.form.get('receiptAccount').valueChanges
      .subscribe(x => this.router.navigate([], {
          relativeTo: this.route,
          queryParams: {a: x},
          replaceUrl: true
        })
      );
  }

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

  accountSelected(event: MatAutocompleteSelectedEvent): void {
    this.account = event.option.value;
    const date = moment(this.form.get('date').value).format('DD-MMM-YYYY');
    this.accountSer.balance(this.account.id, date).subscribe((v) => {
      this.accBal = v;
    });
  }

  zoomImage(file: DbFile) {
    this.dialog.open(ImageDialogComponent, {
      width: '750px',
      data: file.resized
    });
  }

  deleteImage(file: DbFile) {
    const index = this.voucher.files.indexOf(file);
    this.voucher.files.splice(index, 1);
  }

  detectFiles(event) {
    const files = event.target.files;
    if (files) {
      for (const file of files) {
        const reader = new FileReader();
        reader.onload = (e: any) => {
          zip(of(e.target.result),
            this.resizeImage(e.target.result, 100, 150),
            this.resizeImage(e.target.result, 825, 1170)
          ).subscribe(
            val => this.voucher.files.push({id: null, thumbnail: val[1], resized: val[2]})
          );
        };
        reader.readAsDataURL(file);
      }
    }
  }

  resizeImage(image, MAX_WIDTH, MAX_HEIGHT) {
    const canvas = document.createElement('canvas');
    const ctx = canvas.getContext('2d');
    const img = new Image();
    const ex = fromEvent(img, 'load').pipe(
      map((e) => {
        let width = img.naturalWidth,
          height = img.naturalHeight;
        const ratio = Math.min(1, MAX_WIDTH / width, MAX_HEIGHT / height);

        if (ratio === 1) {
          return image;
        }

        width *= ratio;
        height *= ratio;

        canvas.width = width;
        canvas.height = height;
        ctx.drawImage(img, 0, 0, width, height);
        return canvas.toDataURL('image/jpeg', 0.95);
      })
    );
    img.src = image;
    return ex;
  }
}