/**
 * 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 { Injectable } from '@angular/core';
import { Observable, delay, of, throwError } from 'rxjs';
import { demoBorrower, demoBorrowers, demoSummary } from './loan-eligibility.mock';

export type BorrowerCategory = 'GOOD' | 'WATCH' | 'BAD';

export interface LoanStageRow {
  stage: string;
  label: string;
  dpdRange: string;
  group: 'PERFORMING' | 'NPA' | 'CLOSED';
  loans: number;
  outstanding: number;
  overdue: number;
}

export interface LoanProductRow {
  productId: number;
  productName: string;
  activeLoans: number;
  performingLoans: number;
  npaLoans: number;
  outstanding: number;
  npaOutstanding: number;
}

/** Loan book health as on the business date (RBI asset classes, products, borrowers). */
export interface LoanEligibilitySummary {
  asOnDate: string;
  activeLoans: number;
  activeOutstanding: number;
  performingLoans: number;
  performingOutstanding: number;
  npaLoans: number;
  npaOutstanding: number;
  grossNpaPct: number;
  closedLoans: number;
  writtenOffLoans: number;
  writtenOffAmount: number;
  /** Share linking to borrowing across members with running loans. */
  shareRequired: number;
  shareHeld: number;
  shareShortMembers: number;
  shareShortfall: number;
  goodBorrowers: number;
  watchBorrowers: number;
  badBorrowers: number;
  stages: LoanStageRow[];
  products: LoanProductRow[];
  notes: string[];
}

export interface BorrowerLoan {
  loanId: number;
  accountNo: string;
  productName: string;
  status: string;
  stage: string;
  dpd: number;
  emisPaid: number;
  emisLate: number;
  disbursed: number;
  outstanding: number;
  overdue: number;
  sharePct: number;
  shareRequired: number;
}

export interface AccountMonth {
  month: string;
  credits: number;
  debits: number;
  avgBalance: number;
  returns: number;
}

/** Savings / current account statement, month by month. */
export interface BorrowerAccount {
  type: 'Savings' | 'Current';
  accountNo: string;
  months: AccountMonth[];
}

export interface ProductEligibility {
  productId: number;
  productName: string;
  eligible: boolean;
  eligibleAmount?: number;
  sharePct: number;
  /** Shares to be taken with this loan (incl. any existing shortfall). */
  shareToBuy?: number;
  netInHand?: number;
  minAmount?: number;
  maxAmount?: number;
  passed: string[];
  failed: string[];
  notes: string[];
}

export interface Borrower {
  clientId: number;
  clientName: string;
  clientAccountNo: string;
  category: BorrowerCategory;
  activeLoans: number;
  closedLoans: number;
  writtenOffLoans: number;
  outstanding: number;
  maxDpd: number;
  worstStage?: string;
  monthlyIncome?: number;
  age?: number;
  depositBalance: number;
  currentEmi: number;
  eligibleProducts: number;
  /** Repayment record over all loans: EMIs fallen due and how many were paid late. */
  emisPaid: number;
  emisLate: number;
  shareHeld: number;
  shareRequired: number;
  /** Six-month averages of the operative account. */
  accountType: 'Savings' | 'Current';
  avgCredits: number;
  avgDebits: number;
  returns: number;
  accounts?: BorrowerAccount[];
  loans?: BorrowerLoan[];
  eligibility?: ProductEligibility[];
}

/** Loan Eligibility (AI / Intelligence – Lending & Risk): demo data, worked out on the eligibility rules. */
@Injectable({ providedIn: 'root' })
export class LoanEligibilityService {
  getSummary(): Observable<LoanEligibilitySummary> {
    return of(demoSummary()).pipe(delay(2800));
  }

  getBorrowers(category: BorrowerCategory | '', search: string): Observable<Borrower[]> {
    return of(demoBorrowers(category, search)).pipe(delay(700));
  }

  getBorrower(clientId: number): Observable<Borrower> {
    const b = demoBorrower(clientId);
    return b ? of(b).pipe(delay(900)) : throwError(() => new Error('Borrower not found'));
  }
}