using SQLInsight.Contracts;
using SQLInsight.Hub.Support;

namespace SQLInsight.IntegrationTests;

/// <summary>Pure logic behind support cases: no database, so these run with the unit tests.</summary>
public class HubSupportLogicTests
{
    [Fact]
    public void First_case_number_is_SUP_000001() => Assert.Equal("SUP-000001", CaseNumbers.Next([]));

    [Fact]
    public void Next_number_follows_the_highest_SUP_number() =>
        Assert.Equal("SUP-000013", CaseNumbers.Next(["SUP-000002", "sup-000012", "SUP-000009"]));

    [Fact]
    public void Hand_typed_references_do_not_affect_the_sequence() =>
        Assert.Equal("SUP-000004", CaseNumbers.Next(["SUP-000003", "INC-99999", "SUP-12A", "Sag fra telefon"]));

    [Fact]
    public void Old_short_numbers_continue_in_six_digits() => Assert.Equal("SUP-001235", CaseNumbers.Next(["SUP-1234"]));

    private static readonly DateTime T0 = new(2026, 9, 1, 0, 0, 0, DateTimeKind.Utc);

    private static SupportReportCase Case(int id, int customer, double createdDays, double? closedAfterHours, string source = SupportCaseSources.Staff) =>
        new(id, customer, $"Kunde {customer}", $"SUP-{id:D6}", "Titel", source, T0.AddDays(createdDays), closedAfterHours is { } h ? T0.AddDays(createdDays).AddHours(h) : null);

    [Fact]
    public void Report_counts_created_closed_and_open_and_computes_average_and_median()
    {
        var cases = new[]
        {
            Case(1, 1, 1, 2, SupportCaseSources.Customer),
            Case(2, 1, 2, 4),
            Case(3, 1, 3, 30),
            Case(4, 1, 4, null, SupportCaseSources.Customer),
            Case(5, 2, -40, 1),   // created and closed before the period: not counted
            Case(6, 2, -40, null), // created before, still open: open now
        };

        var report = SupportReport.Build(cases, T0, T0.AddDays(30), T0.AddDays(10));
        var first = report.Customers.Single(c => c.CustomerId == 1);
        var second = report.Customers.Single(c => c.CustomerId == 2);

        Assert.Equal((4, 3, 1), (first.Created, first.Closed, first.OpenNow));
        Assert.Equal(TimeSpan.FromHours(12), first.AverageResolution);
        Assert.Equal(TimeSpan.FromHours(4), first.MedianResolution);
        Assert.Equal(TimeSpan.FromDays(6), first.OldestOpenAge);
        Assert.Equal(0.5, first.CustomerCreatedShare);
        Assert.Equal((0, 0, 1), (second.Created, second.Closed, second.OpenNow));
        Assert.Equal(TimeSpan.FromDays(50), second.OldestOpenAge);
        Assert.Equal((4, 3, 2), (report.Total.Created, report.Total.Closed, report.Total.OpenNow));
        Assert.Equal([4, 3, 2, 1], report.Cases.Select(c => c.Id));
    }

    [Fact]
    public void Median_of_an_even_count_is_the_mean_of_the_middle_two() =>
        Assert.Equal(TimeSpan.FromHours(3), SupportReport.Median([TimeSpan.FromHours(1), TimeSpan.FromHours(2), TimeSpan.FromHours(4), TimeSpan.FromHours(9)]));

    [Theory]
    [InlineData(30, "30 min")]
    [InlineData(90, "1,5 t")]
    [InlineData(4320, "3 dage")]
    public void Durations_are_readable(double minutes, string expected) => Assert.Equal(expected, SupportReport.Duration(TimeSpan.FromMinutes(minutes)));

    [Fact]
    public void Default_period_is_the_last_90_days_including_today()
    {
        var (from, to) = SupportReportPeriod.Resolve(null, null, new DateTime(2026, 10, 1, 14, 0, 0, DateTimeKind.Utc));

        Assert.Equal(new DateTime(2026, 10, 2, 0, 0, 0, DateTimeKind.Utc), to);
        Assert.Equal(to.AddDays(-90), from);
    }

    [Fact]
    public void Csv_has_bom_semicolons_and_defuses_formulas()
    {
        var report = SupportReport.Build([Case(1, 1, 1, 6) with { Title = "=HYPERLINK(\"x\"); ond" }], T0, T0.AddDays(30), T0.AddDays(10));

        var bytes = SupportReport.Csv(report);
        var text = System.Text.Encoding.UTF8.GetString(bytes, 3, bytes.Length - 3);

        Assert.Equal([0xEF, 0xBB, 0xBF], bytes[..3]);
        Assert.StartsWith("Sag;Kunde;Titel;Kilde;", text, StringComparison.Ordinal);
        Assert.Contains("\"'=HYPERLINK(\"\"x\"\"); ond\"", text, StringComparison.Ordinal);
        Assert.Contains(";6,0\r\n", text, StringComparison.Ordinal);
    }

    [Fact]
    public void Request_validation_rejects_missing_contact_and_long_titles()
    {
        var valid = new SupportCaseRequest(Guid.NewGuid(), "Langsom server", null, "Anna", "anna@kunde.dk", null, null);

        Assert.Null(valid.Validate());
        Assert.NotNull((valid with { ContactEmail = "anna" }).Validate());
        Assert.NotNull((valid with { Title = new string('x', 201) }).Validate());
        Assert.NotNull((valid with { ClientRequestId = Guid.Empty }).Validate());
    }
}