using FluentAssertions;
using Marathon.Infrastructure.Scraping.Parsers;

namespace Marathon.Infrastructure.Tests.Scraping;

public sealed class MoscowDateParserTests
{
    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);

    // Server time anchor: 2026-05-05 00:42:28 Moscow
    private static readonly DateTimeOffset Anchor =
        new(2026, 5, 5, 0, 42, 28, MoscowOffset);

    [Fact]
    public void TryParse_TimeOnlyFormat_UsesAnchorDateWithParsedTime()
    {
        // "03:00" → today's date from anchor + 03:00
        var result = MoscowDateParser.TryParse("03:00", Anchor);

        result.Should().NotBeNull();
        result!.Value.Year.Should().Be(2026);
        result.Value.Month.Should().Be(5);
        result.Value.Day.Should().Be(5);
        result.Value.Hour.Should().Be(3);
        result.Value.Minute.Should().Be(0);
        result.Value.Offset.Should().Be(MoscowOffset);
    }

    [Fact]
    public void TryParse_FullDateFormat_ParsesCorrectly()
    {
        var result = MoscowDateParser.TryParse("06 мая 22:00", Anchor);

        result.Should().NotBeNull();
        result!.Value.Year.Should().Be(2026);
        result.Value.Month.Should().Be(5);
        result.Value.Day.Should().Be(6);
        result.Value.Hour.Should().Be(22);
        result.Value.Minute.Should().Be(0);
        result.Value.Offset.Should().Be(MoscowOffset);
    }

    [Fact]
    public void TryParse_FullDateWithLeadingSpaces_ParsesCorrectly()
    {
        var result = MoscowDateParser.TryParse("  07 мая 02:30  ", Anchor);

        result.Should().NotBeNull();
        result!.Value.Day.Should().Be(7);
        result.Value.Hour.Should().Be(2);
        result.Value.Minute.Should().Be(30);
    }

    [Fact]
    public void TryParse_NullInput_ReturnsNull()
    {
        MoscowDateParser.TryParse(null, Anchor).Should().BeNull();
    }

    [Fact]
    public void TryParse_EmptyInput_ReturnsNull()
    {
        MoscowDateParser.TryParse(string.Empty, Anchor).Should().BeNull();
    }

    [Fact]
    public void TryParse_UnrecognizedFormat_ReturnsNull()
    {
        MoscowDateParser.TryParse("tomorrow at noon", Anchor).Should().BeNull();
    }

    [Fact]
    public void TryParse_YearRollover_AddsOneYear()
    {
        // Anchor is Dec 31, event is Jan 1 next year
        var decAnchor = new DateTimeOffset(2026, 12, 31, 10, 0, 0, MoscowOffset);
        var result    = MoscowDateParser.TryParse("01 января 12:00", decAnchor);

        result.Should().NotBeNull();
        result!.Value.Year.Should().Be(2027);
        result.Value.Month.Should().Be(1);
        result.Value.Day.Should().Be(1);
    }

    [Fact]
    public void TryParse_ResultAlwaysHasMoscowOffset()
    {
        var result = MoscowDateParser.TryParse("15:30", Anchor);
        result!.Value.Offset.Should().Be(TimeSpan.FromHours(3));
    }
}