import 'package:flutter_test/flutter_test.dart';
import 'package:fuel_tax_tracker/models/fuel_entry.dart';
import 'package:fuel_tax_tracker/models/vehicle.dart';
import 'package:fuel_tax_tracker/services/fuel_report.dart';

void main() {
  final truck = Vehicle(
    id: 'v1',
    vin: '1FMPU18L1TLB51349',
    nickname: 'Truck',
    updatedAt: DateTime.utc(2026, 1, 1),
  );
  final car = Vehicle(
    id: 'v2',
    vin: '1GNWK5EG4DR302326',
    updatedAt: DateTime.utc(2026, 1, 1),
  );

  FuelEntry entry({
    required String id,
    required String vehicleId,
    required DateTime date,
    double gallons = 10,
    double totalCost = 35,
    String? receiptImagePath,
    String? receiptDriveFileId,
  }) =>
      FuelEntry(
        id: id,
        vehicleId: vehicleId,
        date: date,
        gallons: gallons,
        pricePerGallon: totalCost / gallons,
        totalCost: totalCost,
        updatedAt: date,
        receiptImagePath: receiptImagePath,
        receiptDriveFileId: receiptDriveFileId,
      );

  test('sums gallons and cost per vehicle, only for entries with a receipt', () {
    final report = buildFuelReport(
      vehicles: [truck, car],
      fuelEntries: [
        entry(
            id: 'e1',
            vehicleId: 'v1',
            date: DateTime(2026, 3, 5),
            gallons: 10,
            totalCost: 35,
            receiptImagePath: '/local/a.jpg'),
        entry(
            id: 'e2',
            vehicleId: 'v1',
            date: DateTime(2026, 3, 20),
            gallons: 12,
            totalCost: 42,
            receiptDriveFileId: 'remote-1'),
        // No receipt at all — should be excluded even though it's in range.
        entry(id: 'e3', vehicleId: 'v1', date: DateTime(2026, 3, 10), gallons: 99, totalCost: 999),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    expect(report.rows, hasLength(1));
    expect(report.rows.single.vehicle.id, 'v1');
    expect(report.rows.single.entryCount, 2);
    expect(report.rows.single.totalGallons, 22);
    expect(report.rows.single.totalCost, 77);
  });

  test('date range is inclusive of both endpoints', () {
    final report = buildFuelReport(
      vehicles: [truck],
      fuelEntries: [
        entry(
            id: 'first-day',
            vehicleId: 'v1',
            date: DateTime(2026, 3, 1),
            receiptImagePath: '/a.jpg'),
        entry(
            id: 'last-day',
            vehicleId: 'v1',
            date: DateTime(2026, 3, 31),
            receiptImagePath: '/b.jpg'),
        entry(
            id: 'day-after',
            vehicleId: 'v1',
            date: DateTime(2026, 4, 1),
            receiptImagePath: '/c.jpg'),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    expect(report.rows.single.entryCount, 2);
  });

  test('a receipt-photo time-of-day does not push it out of range', () {
    final report = buildFuelReport(
      vehicles: [truck],
      fuelEntries: [
        entry(
          id: 'late-in-day',
          vehicleId: 'v1',
          date: DateTime(2026, 3, 31, 23, 59),
          receiptImagePath: '/a.jpg',
        ),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    expect(report.rows.single.entryCount, 1);
  });

  test('omits vehicles with no qualifying entries rather than a zero row', () {
    final report = buildFuelReport(
      vehicles: [truck, car],
      fuelEntries: [
        entry(id: 'e1', vehicleId: 'v1', date: DateTime(2026, 3, 5), receiptImagePath: '/a.jpg'),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    expect(report.rows, hasLength(1));
    expect(report.rows.single.vehicle.id, 'v1');
  });

  test('rows are sorted by vehicle display label', () {
    final zVehicle = Vehicle(
      id: 'v3',
      vin: 'ZZZ00000000000000',
      nickname: 'Zeta',
      updatedAt: DateTime.utc(2026, 1, 1),
    );
    final aVehicle = Vehicle(
      id: 'v4',
      vin: 'AAA00000000000000',
      nickname: 'Alpha',
      updatedAt: DateTime.utc(2026, 1, 1),
    );

    final report = buildFuelReport(
      vehicles: [zVehicle, aVehicle],
      fuelEntries: [
        entry(id: 'e1', vehicleId: 'v3', date: DateTime(2026, 3, 5), receiptImagePath: '/a.jpg'),
        entry(id: 'e2', vehicleId: 'v4', date: DateTime(2026, 3, 5), receiptImagePath: '/b.jpg'),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    expect(report.rows.map((r) => r.vehicle.id), ['v4', 'v3']);
  });

  test('report totals sum across all vehicle rows', () {
    final report = buildFuelReport(
      vehicles: [truck, car],
      fuelEntries: [
        entry(
            id: 'e1',
            vehicleId: 'v1',
            date: DateTime(2026, 3, 5),
            gallons: 10,
            totalCost: 35,
            receiptImagePath: '/a.jpg'),
        entry(
            id: 'e2',
            vehicleId: 'v2',
            date: DateTime(2026, 3, 6),
            gallons: 8,
            totalCost: 28,
            receiptImagePath: '/b.jpg'),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    expect(report.totalGallons, 18);
    expect(report.totalCost, 63);
  });

  test('a row\'s entries are sorted oldest-first, regardless of insertion order', () {
    final report = buildFuelReport(
      vehicles: [truck],
      fuelEntries: [
        entry(id: 'newest', vehicleId: 'v1', date: DateTime(2026, 3, 20), receiptImagePath: '/c.jpg'),
        entry(id: 'oldest', vehicleId: 'v1', date: DateTime(2026, 3, 5), receiptImagePath: '/a.jpg'),
        entry(id: 'middle', vehicleId: 'v1', date: DateTime(2026, 3, 12), receiptImagePath: '/b.jpg'),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    expect(report.rows.single.entries.map((e) => e.id), ['oldest', 'middle', 'newest']);
  });

  test('fillCount and avgPricePerGallon are derived from the totals across all rows', () {
    final report = buildFuelReport(
      vehicles: [truck, car],
      fuelEntries: [
        entry(id: 'e1', vehicleId: 'v1', date: DateTime(2026, 3, 5), gallons: 10, totalCost: 40, receiptImagePath: '/a.jpg'),
        entry(id: 'e2', vehicleId: 'v2', date: DateTime(2026, 3, 6), gallons: 10, totalCost: 30, receiptImagePath: '/b.jpg'),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    expect(report.fillCount, 2);
    expect(report.avgPricePerGallon, 3.5); // $70 / 20 gal
  });

  test('avgPricePerGallon is 0, not NaN/infinity, for an empty report', () {
    final report = buildFuelReport(
      vehicles: [truck],
      fuelEntries: const [],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    expect(report.avgPricePerGallon, 0);
  });

  test('allEntries pairs each entry with its vehicle and sorts oldest-first across vehicles', () {
    final report = buildFuelReport(
      vehicles: [truck, car],
      fuelEntries: [
        entry(id: 'truck-later', vehicleId: 'v1', date: DateTime(2026, 3, 20), receiptImagePath: '/a.jpg'),
        entry(id: 'car-earlier', vehicleId: 'v2', date: DateTime(2026, 3, 5), receiptImagePath: '/b.jpg'),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 3, 31),
    );

    final all = report.allEntries;
    expect(all.map((re) => re.entry.id), ['car-earlier', 'truck-later']);
    expect(all[0].vehicle.id, 'v2');
    expect(all[1].vehicle.id, 'v1');
  });

  test('monthlyTotals buckets entries by calendar month across vehicles, oldest month first', () {
    final report = buildFuelReport(
      vehicles: [truck, car],
      fuelEntries: [
        entry(id: 'mar-1', vehicleId: 'v1', date: DateTime(2026, 3, 5), gallons: 10, totalCost: 35, receiptImagePath: '/a.jpg'),
        entry(id: 'mar-2', vehicleId: 'v2', date: DateTime(2026, 3, 20), gallons: 10, totalCost: 35, receiptImagePath: '/b.jpg'),
        entry(id: 'apr-1', vehicleId: 'v1', date: DateTime(2026, 4, 2), gallons: 10, totalCost: 40, receiptImagePath: '/c.jpg'),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 4, 30),
    );

    final months = report.monthlyTotals;
    expect(months, hasLength(2));
    expect(months[0].month, DateTime(2026, 3));
    expect(months[0].fillCount, 2);
    expect(months[0].totalGallons, 20);
    expect(months[0].totalCost, 70);
    expect(months[0].avgPricePerGallon, 3.5);
    expect(months[1].month, DateTime(2026, 4));
    expect(months[1].fillCount, 1);
  });

  test('entriesByMonth is the grouping monthlyTotals is built from', () {
    final report = buildFuelReport(
      vehicles: [truck],
      fuelEntries: [
        entry(id: 'mar-1', vehicleId: 'v1', date: DateTime(2026, 3, 5), receiptImagePath: '/a.jpg'),
        entry(id: 'apr-1', vehicleId: 'v1', date: DateTime(2026, 4, 2), receiptImagePath: '/b.jpg'),
      ],
      startDate: DateTime(2026, 3, 1),
      endDate: DateTime(2026, 4, 30),
    );

    final byMonth = report.entriesByMonth;
    expect(byMonth[DateTime(2026, 3)]!.map((re) => re.entry.id), ['mar-1']);
    expect(byMonth[DateTime(2026, 4)]!.map((re) => re.entry.id), ['apr-1']);
  });
}