/**
 * 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 { FormsModule } from '@angular/forms';
import { FaIconComponent } from '@fortawesome/angular-fontawesome';
import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';
import * as ExcelJS from 'exceljs';

import { BranchScopeService } from '../core/branch-scope.service';
import { GL_BRANCHES, glBranchName } from '../gl-reports/gl-reports-data';
import { FY_TAX_CONFIG, Quarter, QUARTER_LABEL } from '../letter-mgmt/certificates/form-15gh/tds-15gh.compute';
import { TDS_FYS } from './tds-reports-data';
import {
  NEAR_THRESHOLD_BAND,
  TdsInterestRow,
  TdsInterestSummary,
  TdsReportFilter,
  tdsInterestRows,
  tdsInterestSummary
} from './tds-reports.compute';

@Component({
  selector: 'mifosx-tds-interest-report',
  templateUrl: './tds-interest-report.component.html',
  styleUrls: ['./tds-reports.shared.scss'],
  imports: [
    ...STANDALONE_SHARED_IMPORTS,
    FaIconComponent,
    FormsModule
  ]
})
export class TdsInterestReportComponent implements OnInit {
  private scope = inject(BranchScopeService);

  readonly branches = GL_BRANCHES.filter((b) => b.code !== 'HO');
  readonly financialYears = TDS_FYS;
  readonly quarterLabel = QUARTER_LABEL;
  readonly nearBand = NEAR_THRESHOLD_BAND;
  readonly quarters: Quarter[] = [
    1,
    2,
    3,
    4
  ];

  filter: TdsReportFilter = {
    fy: TDS_FYS[0],
    branchCode: '',
    quarter: 0,
    band: '',
    search: '',
    crossedOnly: false,
    nearThresholdOnly: false
  };

  /** Which customer's quarter-wise detail is open. */
  expandedId: string | null = null;
  exporting = false;

  ngOnInit(): void {
    // A branch login sees only its own book and cannot widen the scope.
    const own = this.scope.ownBranchCode;
    if (own) {
      this.filter.branchCode = own;
    }
  }

  /**
   * Provision and return references for the selected year. The charge moved from
   * section 194A to section 393(1) on 01 April 2026 and the quarterly return
   * became Form 140, so the labels are read from the config rather than written
   * into the template.
   */
  get statute(): { section: string; statement: string; frequency: string } {
    const cfg = FY_TAX_CONFIG[this.filter.fy];
    return {
      section: cfg?.interestTdsSection ?? '—',
      statement: cfg?.tdsStatementForm ?? '—',
      frequency: cfg?.declarationStatementFrequency === 'MONTHLY' ? 'monthly' : 'quarterly'
    };
  }

  get canSelectBranch(): boolean {
    return this.scope.canSelectBranch;
  }

  get scopeLabel(): string {
    return this.filter.branchCode ? glBranchName(this.filter.branchCode) : 'All branches';
  }

  get rows(): TdsInterestRow[] {
    return tdsInterestRows(this.filter);
  }

  get summary(): TdsInterestSummary {
    return tdsInterestSummary(this.filter);
  }

  get hasFilters(): boolean {
    return !!(
      this.filter.search ||
      this.filter.quarter ||
      this.filter.band ||
      this.filter.crossedOnly ||
      this.filter.nearThresholdOnly
    );
  }

  clearFilters(): void {
    this.filter = {
      ...this.filter,
      quarter: 0,
      band: '',
      search: '',
      crossedOnly: false,
      nearThresholdOnly: false
    };
  }

  /** Jump straight to the customers worth chasing a declaration from. */
  showNearThreshold(): void {
    this.filter = { ...this.filter, crossedOnly: false, nearThresholdOnly: true };
  }

  toggleExpanded(row: TdsInterestRow): void {
    this.expandedId = this.expandedId === row.deductee.customerId ? null : row.deductee.customerId;
  }

  isExpanded(row: TdsInterestRow): boolean {
    return this.expandedId === row.deductee.customerId;
  }

  branchName(code: string): string {
    return glBranchName(code);
  }

  trackRow(_: number, row: TdsInterestRow): string {
    return row.deductee.customerId;
  }

  async exportWorkbook(): Promise<void> {
    this.exporting = true;
    try {
      const wb = new ExcelJS.Workbook();
      const ws = wb.addWorksheet(`TDS Interest FY ${this.filter.fy}`);

      ws.addRow([`Deposit Interest & TDS — FY ${this.filter.fy}`]);
      ws.addRow([`Scope: ${this.scopeLabel}`]);
      ws.addRow([]);
      ws.addRow([
        'Customer',
        'CIF',
        'PAN',
        'Branch',
        'Form',
        'Band',
        'Age',
        'Q1',
        'Q2',
        'Q3',
        'Q4',
        'Interest (FD/RD)',
        'Savings interest (exempt)',
        'Threshold',
        'Crossed in',
        'Rate %',
        'TDS payable',
        'Declaration',
        'UIN',
        'TDS saved',
        'Paid without deduction'
      ]);

      for (const r of this.rows) {
        ws.addRow([
          r.deductee.name,
          r.deductee.customerId,
          r.deductee.pan || 'NOT ON RECORD',
          this.branchName(r.branchCode),
          r.form === '121' ? 'Form 121' : `Form ${r.form}`,
          r.band === 'SENIOR' ? 'Senior citizen' : 'General',
          r.age,
          r.quarters[1],
          r.quarters[2],
          r.quarters[3],
          r.quarters[4],
          r.tdsApplicableInterest,
          r.exemptInterest,
          r.threshold,
          r.crossedInQuarter ? `Q${r.crossedInQuarter}` : '—',
          r.rateApplied * 100,
          r.schedule.totalTds,
          r.hasDeclaration ? 'Yes' : 'No',
          r.declarationUin ?? '',
          r.tdsSaved,
          r.paidWithoutDeduction
        ]);
      }

      const s = this.summary;
      ws.addRow([]);
      ws.addRow([
        'TOTAL',
        `${s.deductees} deductees`,
        '',
        '',
        '',
        '',
        '',
        s.byQuarter[0].interest,
        s.byQuarter[1].interest,
        s.byQuarter[2].interest,
        s.byQuarter[3].interest,
        s.applicableInterest,
        s.exemptInterest,
        '',
        '',
        '',
        s.totalTds,
        `${s.declarations} filed`,
        '',
        s.tdsSaved,
        s.paidWithoutDeduction
      ]);

      ws.getRow(1).font = { bold: true, size: 13 };
      ws.getRow(4).font = { bold: true };
      ws.columns.forEach((c) => (c.width = 18));

      const buffer = await wb.xlsx.writeBuffer();
      const blob = new Blob([buffer], {
        type: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
      });
      const url = URL.createObjectURL(blob);
      const a = document.createElement('a');
      a.href = url;
      a.download = `TDS-Interest-FY${this.filter.fy}.xlsx`;
      a.click();
      URL.revokeObjectURL(url);
    } finally {
      this.exporting = false;
    }
  }
}