import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:metatron_student_erp/features/fees/fees_screen.dart';
import 'package:metatron_student_erp/models/fee.dart';
import 'package:metatron_student_erp/models/student.dart';
import 'package:metatron_student_erp/providers/fee_provider.dart';
import 'package:metatron_student_erp/repositories/fee_repository.dart';

void main() {
  const sampleSummary = FeeSummary(
    totalFees: 30000.0,
    totalPaid: 10000.0,
    outstandingBalance: 20000.0,
    overdueAmount: 0.0,
    paymentStatus: 'partial',
    nextDueDate: '2026-10-23',
    lastPaymentDate: '2026-10-08',
    lastReceiptNumber: 'REC/000001',
    currency: CurrencyInfo(id: 20, name: 'INR', symbol: '₹'),
  );

  final sampleInvoices = [
    const FeeInvoice(
      id: 59,
      invoiceNumber: 'INV/2026/00035',
      title: 'B.Tech CS - Sem 1 Fee Structure (Demo)',
      academicYear: NamedRecord(id: 10, name: 'Test Year'),
      semester: NamedRecord(id: 4, name: 'Semester 1'),
      assignmentDate: '2026-09-23',
      dueDate: '2026-10-23',
      amount: 30000.0,
      amountPaid: 10000.0,
      amountDue: 20000.0,
      paymentStatus: 'partial',
      state: 'confirmed',
      currency: CurrencyInfo(id: 20, name: 'INR', symbol: '₹'),
      lines: [
        FeeInvoiceLine(id: 75, name: 'Tuition Fee', category: 'Academic Fees', amount: 25000.0, mandatory: true),
        FeeInvoiceLine(id: 76, name: 'Laboratory & Library Fee', category: 'Academic Fees', amount: 5000.0, mandatory: true),
      ],
      payments: [
        FeeInvoicePayment(
          id: 29,
          receiptNumber: 'REC/000001',
          paymentDate: '2026-10-08',
          paymentMethod: 'online',
          paymentMethodLabel: 'Online Payment',
          amount: 10000.0,
          referenceNumber: 'DEMO-PAY-001',
        ),
      ],
    ),
  ];

  final samplePayments = [
    const FeePayment(
      id: 29,
      receiptNumber: 'REC/000001',
      paymentDate: '2026-10-08',
      paymentMethod: 'online',
      paymentMethodLabel: 'Online Payment',
      amount: 10000.0,
      referenceNumber: 'DEMO-PAY-001',
      remarks: 'Partial Online Fee Payment',
      status: 'confirmed',
      invoiceId: 59,
      invoiceNumber: 'INV/2026/00035',
      currency: CurrencyInfo(id: 20, name: 'INR', symbol: '₹'),
    ),
  ];

  Widget buildTestableScreen(List<Override> overrides) {
    return ProviderScope(
      overrides: overrides,
      child: const MaterialApp(
        home: FeesScreen(),
      ),
    );
  }

  testWidgets('FeesScreen renders loading state initially', (tester) async {
    await tester.pumpWidget(
      buildTestableScreen([
        feeSummaryProvider.overrideWith(
          (ref) => Future.delayed(const Duration(seconds: 1), () => sampleSummary),
        ),
        feeInvoicesProvider.overrideWith(
          (ref) => Future.delayed(
            const Duration(seconds: 1),
            () => FeeInvoicesPageResult(invoices: sampleInvoices, totalCount: 1, page: 1, limit: 20),
          ),
        ),
      ]),
    );

    expect(find.byType(CircularProgressIndicator), findsWidgets);
    await tester.pumpAndSettle();
  });

  testWidgets('FeesScreen renders fee summary and invoice cards with status badges', (tester) async {
    await tester.pumpWidget(
      buildTestableScreen([
        feeSummaryProvider.overrideWith((ref) async => sampleSummary),
        feeInvoicesProvider.overrideWith(
          (ref) async => FeeInvoicesPageResult(invoices: sampleInvoices, totalCount: 1, page: 1, limit: 20),
        ),
      ]),
    );

    await tester.pumpAndSettle();

    // Verify Title & Tabs
    expect(find.text('Fee Management'), findsOneWidget);
    expect(find.text('Invoices & Summary'), findsOneWidget);
    expect(find.text('Payment History'), findsOneWidget);

    // Verify Summary Card
    expect(find.text('Financial Overview'), findsOneWidget);
    expect(find.text('Partially Paid'), findsOneWidget); // Status badge
    expect(find.text('₹20000.00'), findsWidgets); // Outstanding dues
    expect(find.text('₹30000.00'), findsWidgets); // Assessed
    expect(find.text('₹10000.00'), findsWidgets); // Paid
    expect(find.text('Next Due Date: 2026-10-23'), findsOneWidget);

    // Verify Invoice List
    expect(find.text('Fee Invoices'), findsOneWidget);
    expect(find.text('INV/2026/00035'), findsOneWidget);
    expect(find.text('B.Tech CS - Sem 1 Fee Structure (Demo)'), findsOneWidget);
    expect(find.text('Due: 2026-10-23'), findsOneWidget);
    expect(find.text('View Details'), findsOneWidget);
  });

  testWidgets('FeesScreen renders empty state when no invoices exist', (tester) async {
    await tester.pumpWidget(
      buildTestableScreen([
        feeSummaryProvider.overrideWith(
          (ref) async => const FeeSummary(
            totalFees: 0.0,
            totalPaid: 0.0,
            outstandingBalance: 0.0,
            overdueAmount: 0.0,
            paymentStatus: 'no_dues',
          ),
        ),
        feeInvoicesProvider.overrideWith(
          (ref) async => const FeeInvoicesPageResult(invoices: [], totalCount: 0, page: 1, limit: 20),
        ),
      ]),
    );

    await tester.pumpAndSettle();

    expect(find.text('No fee invoices found for your account.'), findsOneWidget);
  });

  testWidgets('FeesScreen opens invoice detail bottom sheet on tap', (tester) async {
    await tester.pumpWidget(
      buildTestableScreen([
        feeSummaryProvider.overrideWith((ref) async => sampleSummary),
        feeInvoicesProvider.overrideWith(
          (ref) async => FeeInvoicesPageResult(invoices: sampleInvoices, totalCount: 1, page: 1, limit: 20),
        ),
        feeInvoiceDetailProvider(59).overrideWith((ref) async => sampleInvoices[0]),
      ]),
    );

    await tester.pumpAndSettle();

    // Tap on invoice card
    await tester.tap(find.text('INV/2026/00035'));
    await tester.pumpAndSettle();

    // Verify Detail Sheet Content
    expect(find.text('Fee Breakdown'), findsOneWidget);
    expect(find.text('Tuition Fee'), findsOneWidget);
    expect(find.text('Laboratory & Library Fee'), findsOneWidget);
    expect(find.text('₹25000.00'), findsOneWidget);
    expect(find.text('₹5000.00'), findsOneWidget);

    // Scroll down to reveal totals and payments
    await tester.drag(find.text('Fee Breakdown'), const Offset(0, -300));
    await tester.pumpAndSettle();

    expect(find.text('Balance Due'), findsOneWidget);
    expect(find.text('Payments Received'), findsOneWidget);
    expect(find.text('REC/000001'), findsOneWidget);
  });

  testWidgets('FeesScreen renders payment history in tab 2', (tester) async {
    await tester.pumpWidget(
      buildTestableScreen([
        feeSummaryProvider.overrideWith((ref) async => sampleSummary),
        feeInvoicesProvider.overrideWith(
          (ref) async => FeeInvoicesPageResult(invoices: sampleInvoices, totalCount: 1, page: 1, limit: 20),
        ),
        feePaymentsProvider.overrideWith(
          (ref) async => FeePaymentsPageResult(payments: samplePayments, totalCount: 1, page: 1, limit: 20),
        ),
      ]),
    );

    await tester.pumpAndSettle();

    // Switch to Payment History Tab
    await tester.tap(find.text('Payment History'));
    await tester.pumpAndSettle();

    // Verify Payment Record
    expect(find.text('REC/000001'), findsOneWidget);
    expect(find.text('Method: Online Payment'), findsOneWidget);
    expect(find.text('Invoice: INV/2026/00035'), findsOneWidget);
    expect(find.text('Ref: DEMO-PAY-001'), findsOneWidget);
    expect(find.text('₹10000.00'), findsOneWidget);
  });

  testWidgets('FeesScreen renders error state and retry on failure', (tester) async {
    await tester.pumpWidget(
      buildTestableScreen([
        feeSummaryProvider.overrideWith(
          (ref) async => throw Exception('Network Connection Refused'),
        ),
        feeInvoicesProvider.overrideWith(
          (ref) async => throw Exception('Network Connection Refused'),
        ),
      ]),
    );

    await tester.pumpAndSettle();

    expect(find.textContaining('Failed to load fee summary'), findsOneWidget);
    expect(find.textContaining('Failed to load invoices'), findsOneWidget);
    expect(find.text('Retry'), findsWidgets);
  });
}