/**
 * 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/.
 */

/**
 * Deductees, their deposit interest and the challans, for the two TDS reports.
 *
 * Everything here is what the platform returned. The challans used to be generated from the
 * computed deductions - challan numbers, BSR codes and deposit dates made up, one quarter
 * deliberately late - so the remittance report reconciled against figures nobody had entered.
 */

import {
  configuredFys,
  Declaration,
  InterestCredit,
  TdsAccountInput
} from '../letter-mgmt/certificates/form-15gh/tds-15gh.compute';

/** The years the reports can show: every year configured on Organization › TDS Configuration. */
export function tdsFys(): string[] {
  return configuredFys();
}

/** A deposit as the platform reports it: the interest credited and the TDS actually withheld. */
export interface TdsReportAccount extends TdsAccountInput {
  /** TDS the platform actually deducted from this account in the year. */
  deductions: InterestCredit[];
  /** The account's own holder, when the tax is deducted against somebody else (minor, joint). */
  holderClientId?: number;
  holderName?: string;
}

export interface TdsDeductee {
  clientId: number;
  customerId: string;
  name: string;
  pan: string;
  dob: string;
  branchCode: string;
  /** Declarations on record, keyed by financial year. */
  declarations: Record<string, Declaration>;
  accounts: TdsReportAccount[];
}

/** One challan Head Office entered: tax remitted to the Government. */
export interface TdsChallan {
  id: number;
  fy: string;
  /** Month the tax was deducted in, e.g. '2026-06'. */
  month: string;
  amount: number;
  challanNo: string;
  bsrCode: string;
  depositedOn: string;
  paidFrom: string;
  remarks: string | null;
  reversed: boolean;
}

/** Tax the platform withheld in one month. */
export interface TdsDeductedMonth {
  month: string;
  amount: number;
  postings: number;
}

/**
 * The deductees the reports run on, loaded from the platform.
 *
 * It is set once by whoever loads the screen and read by the pure computation, which is why
 * this is a module-level holder rather than a service the compute would have to inject.
 */
let liveDeductees: TdsDeductee[] = [];

export function setTdsDeductees(deductees: TdsDeductee[]): void {
  liveDeductees = deductees || [];
  // The row cache in the compute is keyed on the financial year alone, so it has to be told that
  // the underlying set changed or it would serve rows built from the previous load.
  tdsDeducteesVersion++;
}

/** Bumped on every load, so memoised rows can tell one data set from the next. */
export let tdsDeducteesVersion = 0;

export function tdsDeductees(): TdsDeductee[] {
  return liveDeductees;
}

/**
 * Statutory date by which tax deducted in a given month must be deposited.
 *
 * The seventh of the following month, except for March, which runs to 30 April.
 */
export function depositDueDate(month: string): string {
  const [
    y,
    m
  ] = month.split('-').map(Number);
  if (m === 3) {
    return `${y}-04-30`;
  }
  const nextY = m === 12 ? y + 1 : y;
  const nextM = m === 12 ? 1 : m + 1;
  return `${nextY}-${`${nextM}`.padStart(2, '0')}-07`;
}