import { SelectionModel } from '@angular/cdk/collections';
import { Injectable } from '@angular/core';
import { MatDialog } from '@angular/material/dialog';
import * as math from 'mathjs';
import { BehaviorSubject } from 'rxjs';
import { Observable } from 'rxjs/internal/Observable';

import { BillViewItem } from '../core/bill-view-item';
import { ModifierCategory } from '../core/modifier-category';
import { Product } from '../core/product';
import { Table } from '../core/table';
import { ToasterService } from '../core/toaster.service';
import { ModifierCategoryService } from '../modifier-categories/modifier-category.service';

import { Bill } from './bills/bill';
import { Inventory } from './bills/inventory';
import { Kot } from './bills/kot';
import { VoucherType } from './bills/voucher-type';
import { VoucherService } from './bills/voucher.service';
import { ModifiersComponent } from './modifiers/modifiers.component';

@Injectable()
export class BillService {
  public dataObs: BehaviorSubject<BillViewItem[]>;
  public data: BillViewItem[];
  public bill: Bill = new Bill();
  public netAmount: BehaviorSubject<number>;
  public discountAmount: BehaviorSubject<number>;
  public taxAmount: BehaviorSubject<number>;
  public amount: BehaviorSubject<number>;
  public selection = new SelectionModel<BillViewItem>(true, []);

  constructor(
    private dialog: MatDialog,
    private toaster: ToasterService,
    private ser: VoucherService,
    private modifierCategoryService: ModifierCategoryService,
  ) {
    this.data = [];
    this.dataObs = new BehaviorSubject<BillViewItem[]>(this.data);
    this.netAmount = new BehaviorSubject(0);
    this.discountAmount = new BehaviorSubject(0);
    this.taxAmount = new BehaviorSubject(0);
    this.amount = new BehaviorSubject(0);
  }

  loadData(bill: Bill): void {
    this.bill = bill;
    const view: BillViewItem[][] = this.bill.kots.map((k: Kot) => [
      new BillViewItem({
        id: k.id,
        isKot: true,
        info: `Kot: ${k.code} / ${k.date} (${k.user.name}) `,
      }),
      ...k.inventories.map(
        (i) =>
          new BillViewItem({
            id: i.id,
            kotId: k.id,
            isKot: false,
            product: i.product,
            productId: i.product.id,
            isHappyHour: i.isHappyHour,
            isPrinted: true,
            info: `${i.product.name} @ ${i.price} - ${math.round(i.discount * 100, 2)}%`,
            price: i.price,
            quantity: i.quantity,
            discount: i.discount,
            taxRate: i.taxRate,
            tax: i.tax,
            modifiers: i.modifiers,
          }),
      ),
    ]);
    this.data = view.reduce((a, c) => a.concat(c), []);
    this.data.push(new BillViewItem({ isKot: true, info: '== New Kot ==' }));
    this.dataObs.next(this.data);
    this.updateAmounts();
  }

  minimum(productId: string, happyHour: boolean): number {
    return this.data.reduce(
      (a, c) => (c.productId === productId && c.isHappyHour === happyHour ? a + c.quantity : a),
      0,
    );
  }

  addProduct(product: Product, quantity: number, discount: number): void {
    const old = this.data.find(
      (x) =>
        !x.isKot && !x.id && x.productId === product.id && x.isHappyHour === product.hasHappyHour,
    );
    if (quantity < 0) {
      const minimum = this.minimum(product.id as string, product.hasHappyHour) + quantity;
      if (minimum + quantity < 0) {
        this.toaster.show('Error', 'Total quantity cannot be negative!');
        return;
      }
    }
    if (old !== undefined) {
      old.quantity += quantity;
    } else {
      const item = new BillViewItem({
        isKot: false,
        product,
        productId: product.id,
        isHappyHour: product.hasHappyHour,
        info: `${product.name} @ ${product.price} - ${0}%`,
        price: product.price,
        quantity,
        discount,
        taxRate: product.tax.rate,
        tax: product.tax,
        modifiers: [],
      });
      this.data.push(item);
      this.modifierCategoryService.listForProduct(product.id as string).subscribe((result) => {
        if (
          result.reduce((a: number, c: ModifierCategory) => {
            return a + c.minimum;
          }, 0)
        ) {
          this.showModifier(item);
        }
      });
    }
    this.dataObs.next(this.data);
    this.updateAmounts();
  }

  showModifier(item: BillViewItem): void {
    // [routerLink]="['/sales', 'modifiers', item.id]"
    const dialogRef = this.dialog.open(ModifiersComponent, {
      position: {
        top: '10vh',
      },
      data: {
        list: this.modifierCategoryService.listForProduct(item.productId as string),
        selected: item.modifiers,
      },
    });

    dialogRef.afterClosed().subscribe((result) => {
      if (result !== undefined) {
        item.modifiers = result;
      }
    });
  }

  addOne(item: BillViewItem): void {
    item.quantity += 1;
    this.dataObs.next(this.data);
    this.updateAmounts();
  }

  quantity(item: BillViewItem, quantity: number): void {
    item.quantity = quantity;
    this.dataObs.next(this.data);
    this.updateAmounts();
  }

  subtractOne(item: BillViewItem, canEdit: boolean): void {
    if (
      item.quantity > 1 ||
      (canEdit && this.minimum(item.productId as string, item.isHappyHour) >= 1)
    ) {
      item.quantity -= 1;
      this.dataObs.next(this.data);
      this.updateAmounts();
    } else if (item.quantity === 0) {
      this.removeItem(item);
    }
  }

  removeItem(item: BillViewItem): void {
    this.data.splice(this.data.indexOf(item), 1);
    this.dataObs.next(this.data);
    this.updateAmounts();
  }

  modifier(item: BillViewItem): void {
    this.showModifier(item);
  }

  discount(discounts: { id: string; name: string; discount: number }[]): void {
    this.data.forEach((x) => {
      if (!x.isKot) {
        x.discount =
          (discounts.find((d) => d.id === x.product.saleCategory.id) as {
            id: string;
            name: string;
            discount: number;
          }).discount / 100;
        x.info = `${x.product.name} @ ${x.price} - ${math.round(x.discount * 100, 2)}%`;
      }
    });
    this.dataObs.next(this.data);
    this.updateAmounts();
  }

  private getKot(): Kot {
    return new Kot({
      inventories: this.data
        .filter((x) => !x.isKot && !x.isPrinted)
        .map(
          (y) =>
            new Inventory({
              product: y.product,
              quantity: y.quantity,
              price: y.price,
              isHappyHour: y.isHappyHour,
              discount: y.discount,
              modifiers: y.modifiers,
              taxRate: y.taxRate,
              tax: y.tax,
            }),
        ),
    });
  }

  printKot(guestBookId: string | null): Observable<boolean> {
    const item = JSON.parse(JSON.stringify(this.bill));
    const newKot = this.getKot();
    if (newKot.inventories.length === 0) {
      this.toaster.show('Error', 'Cannot print a blank KOT\nPlease add some products!');
    }
    item.kots.push(newKot);
    return this.ser.saveOrUpdate(item, VoucherType.Kot, guestBookId, true);
  }

  printBill(guest_book_id: string | null, voucherType: VoucherType): Observable<boolean> {
    const item = JSON.parse(JSON.stringify(this.bill));
    item.kots.forEach((k: Kot) => {
      k.inventories.forEach((i: Inventory) => {
        i.discount = (this.data.find((x) => !x.isKot && x.id === i.id) as BillViewItem).discount;
      });
    });
    item.kots.push(this.getKot());
    return this.ser.saveOrUpdate(item, voucherType, guest_book_id, true);
  }

  type() {
    return this.bill.voucherType;
  }

  receivePayment(
    amounts: { id: number; name: string; amount: number }[],
    name: string,
  ): Observable<boolean> {
    return this.ser.receivePayment(this.bill.id as string, amounts, name, true);
  }

  moveTable(table: Table): Observable<boolean> {
    return this.ser.moveTable(this.bill.id as string, table);
  }

  mergeTable(table: Table): Observable<boolean> {
    return this.ser.mergeTable(this.bill.id as string, table);
  }

  moveKot(kotId: string, table: Table): Observable<boolean> {
    return this.ser.moveKotToNewTable(this.bill.id as string, kotId, table);
  }

  mergeKot(kotId: string, table: Table): Observable<boolean> {
    return this.ser.mergeKotWithOldBill(this.bill.id as string, kotId, table);
  }

  voidBill(reason: string): Observable<boolean> {
    return this.ser.voidBill(this.bill.id as string, reason, true);
  }

  updateAmounts() {
    this.netAmount.next(
      math.round(
        this.data
          .filter((x) => !x.isKot)
          .reduce(
            (ca: number, c: BillViewItem) => ca + (c.isHappyHour ? 0 : c.price) * c.quantity,
            0,
          ),
      ),
    );
    this.discountAmount.next(
      math.round(
        this.data
          .filter((x) => !x.isKot)
          .reduce(
            (ca: number, c: BillViewItem) =>
              ca + (c.isHappyHour ? 0 : c.price) * c.quantity * c.discount,
            0,
          ),
      ),
    );
    this.taxAmount.next(
      math.round(
        this.data
          .filter((x) => !x.isKot)
          .reduce(
            (ca: number, c: BillViewItem) =>
              ca + (c.isHappyHour ? 0 : c.price) * c.quantity * (1 - c.discount) * c.taxRate,
            0,
          ),
      ),
    );
    this.amount.next(
      math.round(
        this.data
          .filter((x) => !x.isKot)
          .reduce(
            (ca: number, c: BillViewItem) =>
              ca + (c.isHappyHour ? 0 : c.price) * c.quantity * (1 - c.discount) * (1 + c.taxRate),
            0,
          ),
      ),
    );
  }

  amountVal(): number {
    return math.round(
      this.bill.kots.reduce(
        (ka: number, k: Kot) =>
          ka +
          k.inventories.reduce(
            (ca: number, c: Inventory) =>
              ca + (c.isHappyHour ? 0 : c.price) * c.quantity * (1 - c.discount) * (1 + c.taxRate),
            0,
          ),
        0,
      ),
    );
  }

  splitBill(table: Table): Observable<boolean> {
    const inventoriesToMove: string[] = this.selection.selected.map(
      (x: BillViewItem) => x.id as string,
    );
    return this.ser.splitBill(this.bill.id as string, inventoriesToMove, table);
  }
}