/**
 * Copyright since 2025 Mifos Initiative
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

import { Component, OnInit, inject } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormsModule } from '@angular/forms';
import { MatIconModule } from '@angular/material/icon';
import { MatSnackBar, MatSnackBarModule } from '@angular/material/snack-bar';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatSelectModule } from '@angular/material/select';
import { MatInputModule } from '@angular/material/input';
import { of } from 'rxjs';
import { catchError } from 'rxjs/operators';
import { CashierService } from '../cashier.service';
import { businessToday } from 'app/core/utils/business-today';

interface Denom {
  id: number;
  value: number;
  kind: 'note' | 'coin';
  label: string;
}
interface Cashier {
  id: number;
  label: string;
}
/** One side of the transfer, from GET /cashintercashier/cashier-summary. */
interface CashierSummary {
  cashierId: number;
  cashierName: string;
  tellerName: string;
  officeName: string;
  cashAllocated: boolean;
  allocatedAmount: number;
  totalAmount: number;
  /** Count held per denomination id. */
  held: Record<number, number>;
}

/** Move cash denomination-wise between two cashiers under the same teller. */
@Component({
  selector: 'mifosx-inter-cashier-transfer',
  templateUrl: './inter-cashier-transfer.component.html',
  styleUrls: [
    '../cashier-shared.scss',
    './inter-cashier-transfer.component.scss'
  ],
  standalone: true,
  imports: [
    CommonModule,
    FormsModule,
    MatIconModule,
    MatSnackBarModule,
    MatFormFieldModule,
    MatSelectModule,
    MatInputModule
  ]
})
export class InterCashierTransferComponent implements OnInit {
  private service = inject(CashierService);
  private snackBar = inject(MatSnackBar);

  notes: Denom[] = [];
  coins: Denom[] = [];
  counts: Record<number, number> = {};
  transferDate = '';
  note = '';
  saving = false;

  /**
   * The sending cashier is always the one logged in: cash is handed over from their own drawer, so there is
   * no one else to pick on that side. Only the receiving cashier is chosen.
   */
  ownCashierMissing = false;
  tellerName = '';
  allCashiers: Cashier[] = [];
  selectedTellerId: number | null = null;
  fromCashierId: number | null = null;
  toCashierId: number | null = null;
  fromParty = '';
  toParty = '';
  loadingCashiers = false;

  /** Details and denomination-wise cash of each side, so both are seen before the transfer is recorded. */
  fromSummary: CashierSummary | null = null;
  toSummary: CashierSummary | null = null;
  loadingFrom = false;
  loadingTo = false;

  get denoms(): Denom[] {
    return [
      ...this.notes,
      ...this.coins
    ];
  }
  /** Everyone under the same teller except the sender. */
  get availableTo(): Cashier[] {
    return this.allCashiers.filter((c) => c.id !== this.fromCashierId);
  }

  ngOnInit(): void {
    const d = businessToday();
    this.transferDate = `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}-${String(d.getDate()).padStart(2, '0')}`;
    this.service.getActiveDenominations().subscribe({
      next: (list) => {
        const rows: Denom[] = (list || []).map((x: any) => ({
          id: x.id,
          value: x.denomination,
          kind: x.kind,
          label: '₹' + x.denomination
        }));
        this.notes = rows.filter((r) => r.kind === 'note').sort((a, b) => b.value - a.value);
        this.coins = rows.filter((r) => r.kind === 'coin').sort((a, b) => b.value - a.value);
      },
      error: () => {
        this.notes = [];
        this.coins = [];
      }
    });
    // The sender is the cashier behind this login; their counter then gives the receivers to pick from.
    this.service.getCurrentCashierInfo().subscribe((info) => {
      if (!info) {
        this.ownCashierMissing = true;
        return;
      }
      this.fromCashierId = info.cashierId;
      this.fromParty = info.cashierName;
      this.loadSummary('from');
    });
  }

  /** The other cashiers at this counter, one of whom receives the cash. */
  private loadReceivers(tellerId: number): void {
    this.loadingCashiers = true;
    this.service
      .getCashiersForTeller(tellerId)
      .pipe(catchError(() => of({ cashiers: [] })))
      .subscribe((r: any) => {
        this.allCashiers = (r?.cashiers || []).map((c: any) => ({ id: c.id, label: c.staffName }));
        this.loadingCashiers = false;
      });
  }

  onToSelect(cashierId: number): void {
    this.toCashierId = cashierId;
    const c = this.allCashiers.find((x) => x.id === cashierId);
    this.toParty = c ? c.label : '';
    this.loadSummary('to');
  }

  onDateChange(value: string): void {
    this.transferDate = value;
    this.loadSummary('from');
    this.loadSummary('to');
  }

  /** Fetch one side's details, vault allocation and denomination-wise cash for the transfer date. */
  private loadSummary(side: 'from' | 'to'): void {
    const cashierId = side === 'from' ? this.fromCashierId : this.toCashierId;
    if (side === 'from') {
      this.fromSummary = null;
    } else {
      this.toSummary = null;
    }
    if (!cashierId || !this.transferDate) return;
    this.setLoading(side, true);
    this.service
      .getInterCashierCashierSummary(cashierId, this.transferDate)
      .pipe(catchError(() => of(null)))
      .subscribe((r: any) => {
        this.setLoading(side, false);
        // A late answer for a cashier no longer selected on that side is dropped.
        const current = side === 'from' ? this.fromCashierId : this.toCashierId;
        if (!r || current !== cashierId) return;
        // The sender's summary also tells which counter they are at, hence who they can hand cash to.
        if (side === 'from' && r.tellerId && this.selectedTellerId !== Number(r.tellerId)) {
          this.selectedTellerId = Number(r.tellerId);
          this.tellerName = r.tellerName || '';
          this.loadReceivers(this.selectedTellerId);
        }
        const held: Record<number, number> = {};
        for (const d of r.denominations || []) {
          held[d.denominationId] = (held[d.denominationId] || 0) + Number(d.count || 0);
        }
        const summary: CashierSummary = {
          cashierId: r.cashierId,
          cashierName: r.cashierName,
          tellerName: r.tellerName,
          officeName: r.officeName,
          cashAllocated: !!r.cashAllocated,
          allocatedAmount: Number(r.allocatedAmount || 0),
          totalAmount: Number(r.totalAmount || 0),
          held
        };
        if (side === 'from') {
          this.fromSummary = summary;
        } else {
          this.toSummary = summary;
        }
      });
  }

  private setLoading(side: 'from' | 'to', loading: boolean): void {
    if (side === 'from') {
      this.loadingFrom = loading;
    } else {
      this.loadingTo = loading;
    }
  }

  /** Count of the denomination the cashier holds, or null while their figures are not loaded. */
  heldBy(summary: CashierSummary | null, d: Denom): number | null {
    return summary ? summary.held[d.id] || 0 : null;
  }

  /** The sending cashier is asked to hand on more of this denomination than they hold. */
  exceedsHeld(d: Denom): boolean {
    return !!this.fromSummary && this.countFor(d) > (this.fromSummary.held[d.id] || 0);
  }

  get anyExceedsHeld(): boolean {
    return this.denoms.some((d) => this.exceedsHeld(d));
  }

  /** Both sides must have been allocated cash from the vault for the day before they can transfer. */
  get bothAllocated(): boolean {
    return !!this.fromSummary?.cashAllocated && !!this.toSummary?.cashAllocated;
  }

  countFor(d: Denom): number {
    return this.counts[d.id] || 0;
  }
  subtotal(d: Denom): number {
    return this.countFor(d) * d.value;
  }
  onChange(d: Denom, raw: any): void {
    this.counts[d.id] = Math.max(0, Math.floor(Number(raw) || 0));
  }
  bump(d: Denom, delta: number): void {
    this.counts[d.id] = Math.max(0, (this.counts[d.id] || 0) + delta);
  }

  get total(): number {
    return this.denoms.reduce((s, d) => s + this.subtotal(d), 0);
  }
  get valid(): boolean {
    return (
      this.total > 0 &&
      !!this.selectedTellerId &&
      !!this.fromCashierId &&
      !!this.toCashierId &&
      this.bothAllocated &&
      !this.anyExceedsHeld
    );
  }

  clear(): void {
    this.counts = {};
  }

  submit(): void {
    if (!this.valid || this.saving) return;
    this.saving = true;
    const payload = {
      transferDate: this.transferDate,
      tellerId: this.selectedTellerId,
      fromCashierId: this.fromCashierId,
      toCashierId: this.toCashierId,
      fromParty: this.fromParty.trim(),
      toParty: this.toParty.trim(),
      note: this.note || null,
      denominations: this.denoms
        .filter((d) => this.countFor(d) > 0)
        .map((d) => ({ denominationId: d.id, denominationValue: d.value, count: this.countFor(d) }))
    };
    this.service.createInterCashierTransfer(payload).subscribe({
      next: () => {
        this.snackBar.open('Inter-cashier transfer recorded', 'Close', { duration: 3000 });
        this.clear();
        this.note = '';
        // The sender stays the logged-in cashier; the receiver is picked afresh, and the sender's holdings
        // are read again now that part of them has gone.
        this.toCashierId = null;
        this.toParty = '';
        this.toSummary = null;
        this.loadSummary('from');
        this.saving = false;
      },
      error: () => {
        this.saving = false;
      }
    });
  }
}