/**
 * 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 { ActivatedRoute } from '@angular/router';
import { MatIconModule } from '@angular/material/icon';
import { catchError, of } from 'rxjs';
import { CashierService } from '../cashier.service';
import { businessToday } from 'app/core/utils/business-today';
import { VoucherStatusComponent, VoucherStatus } from '../voucher-status/voucher-status.component';

/**
 * Which side of the register a screen shows.
 *
 * 'CR' is the Received report (money in), 'DR' the Payment report (money out). Set from the route,
 * so the two screens are the same component pointed at opposite sides.
 */
export type VoucherSide = 'CR' | 'DR' | 'ALL';

/** One voucher as the register shows it: the number, the two sides, and who raised it. */
interface VoucherRow {
  voucherNo: string;
  /** Where the voucher stands after a correction: active, revoked, under correction, or corrected. */
  voucherStatus?: VoucherStatus;
  revokedByVoucherNo?: string | null;
  replacesVoucherNo?: string | null;
  correctionNote?: string | null;
  voucherType: string | null;
  amount: number | null;
  createdAt: string | null;
  /** The business date the posting belongs to, which is not always the day it was written. */
  ledgerDate?: string | null;
  /** True when the voucher was written after the day it posts against had already closed. */
  postedAfterClose?: boolean;
  userId: number | null;
  username: string | null;
  branchName: string | null;
  verificationStatus: string | null;
  debitParty: string | null;
  debitAccount: string | null;
  creditParty: string | null;
  creditAccount: string | null;
  /** Sides beyond the one debit and one credit shown — a DD's charges, a compound journal. */
  extraLines: number;
  /**
   * Whether a denomination breakdown was recorded against this voucher.
   *
   * True proves cash was counted. False does not prove the opposite: several registers pay real
   * money out without recording a breakdown, so this marks a row as unconfirmed, not as non-cash.
   */
  denominationCounted: boolean;
}

interface VoucherReport {
  from: string;
  to: string;
  username: string | null;
  /** Set by the server from the caller's roles; a cashier is never offered the user filter. */
  canSeeAllUsers: boolean;
  /** Whether the server restricted the register to cash movements. */
  cashOnly: boolean;
  vouchers: VoucherRow[];
  count: number;
  totalAmount: number;
}

/**
 * The vouchers raised over a day or a month, one row each.
 *
 * A cashier sees their own work; a clerk, head cashier or manager sees everyone's and can narrow to
 * one user. That is decided by the server, not here — this screen only shows or hides the filter.
 */
@Component({
  selector: 'mifosx-voucher-report',
  templateUrl: './voucher-report.component.html',
  styleUrls: [
    '../cashier-shared.scss',
    './voucher-report.component.scss'
  ],
  standalone: true,
  imports: [
    CommonModule,
    FormsModule,
    MatIconModule,
    VoucherStatusComponent
  ]
})
export class VoucherReportComponent implements OnInit {
  private service = inject(CashierService);
  private route = inject(ActivatedRoute);

  /** Day is the working default; a month is what you ask for at a close. */
  period: 'DAY' | 'MONTH' = 'DAY';
  /** Anchor date — the day itself, or any day inside the month wanted. */
  anchor = this.todayIso();
  usernameFilter = '';
  typeFilter = '';

  /** Which side this screen is: Received (CR) or Payment (DR). Comes from the route's data. */
  side: VoucherSide = 'CR';

  /**
   * Whether this screen is the cash register rather than the whole voucher register.
   *
   * A cashier handles notes and coins, so entries that cannot be cash — an interest posting, a
   * clearing settlement, a cheque book fee — are left out, and everything that could have crossed
   * the counter stays in. The filter errs towards keeping a row: a book entry on the register can
   * be seen and recognised, whereas cash that never appears is invisible until it turns up as an
   * unexplained difference at the end of the day.
   */
  cashOnly = false;

  /**
   * Whether this register is the counter's own — only the people who hold a drawer.
   *
   * These two screens reconcile the counter: what came in over it and what went out. Everyone
   * else's work is their own to account for, and each person reads it on My Vouchers. Mixed in here
   * it buried the cashier rows the registers exist for and left the totals matching no drawer.
   */
  cashiersOnly = false;

  /**
   * Whether this register is the system's own postings rather than anybody's work.
   *
   * Interest a nightly run credited, a charge taken from a balance, an escheat, a journal keyed
   * straight to the ledger. These belong to no member of staff, so My Vouchers cannot show them —
   * it is scoped to the reader — and the two counter registers deliberately exclude them. That left
   * no screen answering "what did the system post last night".
   */
  systemOnly = false;

  report: VoucherReport | null = null;
  loading = false;
  error: string | null = null;

  ngOnInit(): void {
    this.side = (this.route.snapshot.data['side'] as VoucherSide) ?? 'CR';
    this.cashOnly = this.route.snapshot.data['cashOnly'] === true;
    this.cashiersOnly = this.route.snapshot.data['cashiersOnly'] === true;
    this.systemOnly = this.route.snapshot.data['systemOnly'] === true;
    this.load();
  }

  get isReceived(): boolean {
    return this.side === 'CR';
  }

  get title(): string {
    if (this.systemOnly) {
      return 'System Vouchers';
    }
    return this.isReceived ? 'Received Report' : 'Payment Report';
  }

  get subtitle(): string {
    if (this.systemOnly) {
      return 'What the system posted on its own — interest, charges, escheats and journals. Nobody raised these, so they appear on no one’s own list.';
    }
    // Said plainly, because a register that silently omits the reader's own entries is worse than
    // one that explains why: their work is on My Vouchers, and the line points them there.
    if (this.cashiersOnly) {
      return this.isReceived
        ? 'Cash taken in at the counter by each cashier. Other staff read their own work on My Vouchers.'
        : 'Cash paid out at the counter by each cashier. Other staff read their own work on My Vouchers.';
    }
    if (this.cashOnly) {
      return this.isReceived
        ? 'Cash taken in over a day or a month, and who took it — book entries left out.'
        : 'Cash paid out over a day or a month, and who paid it — book entries left out.';
    }
    return this.isReceived
      ? 'Every receipt voucher raised over a day or a month — money taken in, and who took it.'
      : 'Every payment voucher raised over a day or a month — money paid out, and who paid it.';
  }

  /** The word for one row on this side, for counts and the empty state. */
  get noun(): string {
    if (this.systemOnly) {
      return 'posting';
    }
    return this.isReceived ? 'receipt' : 'payment';
  }

  load(): void {
    this.loading = true;
    this.error = null;

    const { from, to } = this.range();
    this.service
      .voucherReport(
        from,
        to,
        this.usernameFilter.trim() || undefined,
        this.typeFilter.trim() || undefined,
        this.cashOnly,
        this.cashiersOnly,
        this.systemOnly
      )
      .pipe(
        catchError((err: any) => {
          this.error =
            err?.error?.errors?.[0]?.defaultUserMessage ??
            err?.error?.developerMessage ??
            'The voucher report could not be loaded.';
          return of(null);
        })
      )
      .subscribe((res: VoucherReport | null) => {
        this.loading = false;
        this.report = res;
      });
  }

  /** The period the anchor date names: that day, or the whole calendar month around it. */
  private range(): { from: string; to: string } {
    if (this.period === 'DAY') {
      return { from: this.anchor, to: this.anchor };
    }
    const [
      year,
      month
    ] = this.anchor.split('-').map(Number);
    // Day 0 of the next month is the last day of this one, which is how a 28/30/31-day month is
    // ended correctly without a table of month lengths.
    const lastDay = new Date(year, month, 0).getDate();
    const mm = String(month).padStart(2, '0');
    return { from: `${year}-${mm}-01`, to: `${year}-${mm}-${String(lastDay).padStart(2, '0')}` };
  }

  private todayIso(): string {
    const now = businessToday();
    return `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, '0')}-${String(now.getDate()).padStart(2, '0')}`;
  }

  /**
   * The rows belonging to this screen's side.
   *
   * The side is read off the first segment of the voucher number — `CR/001/2608/0003` — which the
   * server stamps when it raises the voucher: a deposit credits the member and gets CR, everything
   * that takes money out gets DR. That prefix is the authoritative record of the side, so it is
   * matched directly rather than re-deriving the side from the voucher type here — a new type added
   * on the server then lands on the correct report with no change needed on this screen.
   */
  get rows(): VoucherRow[] {
    const all = this.report?.vouchers ?? [];
    return this.side === 'ALL' ? all : all.filter((row) => this.sideOf(row) === this.side);
  }

  /**
   * Whether a voucher has its two sides recorded against it.
   *
   * The registers raise a voucher when the request is made and only attach its sides once it is
   * approved and posted, so a voucher raised before that step existed carries a number but no
   * lines. Those rows are labelled rather than shown as an empty dash, which reads like the money
   * went nowhere.
   */
  hasSides(row: VoucherRow): boolean {
    return !!(row.debitParty || row.creditParty);
  }

  /** How many rows on this side are missing their debit/credit lines. */
  get missingSidesCount(): number {
    return this.rows.filter((row) => !this.hasSides(row)).length;
  }

  /** A voucher's side, from its number's prefix. Null when the number is missing or unrecognised. */
  private sideOf(row: VoucherRow): VoucherSide | null {
    const no = (row.voucherNo ?? '').toUpperCase();
    if (no.startsWith('CR/')) {
      return 'CR';
    }
    if (no.startsWith('DR/')) {
      return 'DR';
    }
    return null;
  }

  /** How many rows on this side — not the server's count, which spans both. */
  get count(): number {
    return this.rows.length;
  }

  /** Total for this side only. */
  get totalAmount(): number {
    return this.rows.reduce((sum, row) => sum + (row.amount ?? 0), 0);
  }

  /**
   * The part of this side's total whose notes and coins were actually counted.
   *
   * Always at most `totalAmount`: a voucher can be real cash and still be missing its breakdown,
   * because the register that raised it records none. So this is the confirmed part of the cash,
   * not the whole of it, and the gap is reported rather than treated as book entries.
   */
  get countedTotal(): number {
    return this.rows.filter((row) => row.denominationCounted).reduce((sum, row) => sum + (row.amount ?? 0), 0);
  }

  /** Rows carrying no denomination breakdown — unconfirmed against the drawer, not non-cash. */
  get uncountedCount(): number {
    return this.rows.filter((row) => !row.denominationCounted).length;
  }

  /** How much of this side's total has no note-and-coin breakdown behind it. */
  get uncountedTotal(): number {
    return this.totalAmount - this.countedTotal;
  }

  /**
   * Vouchers whose number carries neither prefix, so they appear on neither report.
   *
   * Counted and shown rather than silently dropped: a voucher that vanishes from both sides of the
   * register is exactly the kind of thing a cashier must be told about, not left to discover when
   * the two reports do not add up to the day.
   */
  get unclassifiedCount(): number {
    const all = this.report?.vouchers ?? [];
    return all.filter((row) => this.sideOf(row) === null).length;
  }

  /** Totals per user, for the summary a manager reads before the rows. */
  get byUser(): { username: string; count: number; total: number }[] {
    const rows = this.rows;
    const tally = new Map<string, { username: string; count: number; total: number }>();
    for (const row of rows) {
      const key = row.username ?? '—';
      const entry = tally.get(key) ?? { username: key, count: 0, total: 0 };
      entry.count += 1;
      entry.total += row.amount ?? 0;
      tally.set(key, entry);
    }
    return [...tally.values()].sort((a, b) => b.total - a.total);
  }

  /** Totals per voucher type — deposits against withdrawals against journals. */
  get byType(): { type: string; count: number; total: number }[] {
    const rows = this.rows;
    const tally = new Map<string, { type: string; count: number; total: number }>();
    for (const row of rows) {
      const key = row.voucherType ?? '—';
      const entry = tally.get(key) ?? { type: key, count: 0, total: 0 };
      entry.count += 1;
      entry.total += row.amount ?? 0;
      tally.set(key, entry);
    }
    return [...tally.values()].sort((a, b) => b.total - a.total);
  }

  print(): void {
    window.print();
  }
}