namespace HSchool.Content.Tests;

/// <summary>
/// Two sittings instead of one crowded canteen: juniors eat after the third lesson, seniors after
/// the fourth. The list also decides which breaks are long, because fifteen minutes of lunch do
/// not fit into ten.
/// </summary>
public class LunchBreakTests
{
    private readonly CatalogLoader _loader = new();

    [Fact]
    public void VanillaCore_FeedsJuniorsAndSeniorsAtDifferentBreaks()
    {
        var frame = LoadVanilla().DayFrame!;

        Assert.Equal(2, frame.LunchBreaks.Count);
        Assert.Equal(3, SchoolDay.LunchBreakAfter(frame, year: 1));
        Assert.Equal(3, SchoolDay.LunchBreakAfter(frame, year: 5));
        Assert.Equal(4, SchoolDay.LunchBreakAfter(frame, year: 6));
        Assert.Equal(4, SchoolDay.LunchBreakAfter(frame, year: 11));
    }

    [Fact]
    public void EveryBreakSomebodyEatsIn_IsALongOne()
    {
        var frame = LoadVanilla().DayFrame!;

        Assert.True(SchoolDay.IsLongBreakAfter(frame, 3));
        Assert.True(SchoolDay.IsLongBreakAfter(frame, 4));
        Assert.False(SchoolDay.IsLongBreakAfter(frame, 2));

        // The fourth break is twenty minutes now, so the fifth lesson starts at half past noon
        // rather than twenty past: the second sitting has to fit into the day.
        Assert.Equal(new TimeOnly(12, 30), SchoolDay.PeriodStart(frame, 5));
    }

    [Fact]
    public void LunchWindow_IsOpenOnlyAtTheSittingOfThatParallel()
    {
        var frame = LoadVanilla().DayFrame!;

        Assert.True(SchoolDay.IsLunchWindow(frame, DaySlot.BreakAfter(3), year: 4));
        Assert.False(SchoolDay.IsLunchWindow(frame, DaySlot.BreakAfter(4), year: 4));
        Assert.False(SchoolDay.IsLunchWindow(frame, DaySlot.BreakAfter(3), year: 9));
        Assert.True(SchoolDay.IsLunchWindow(frame, DaySlot.BreakAfter(4), year: 9));

        // Staff belong to no parallel and can eat at either sitting; a lesson is never a window.
        Assert.True(SchoolDay.IsLunchWindow(frame, DaySlot.BreakAfter(3), year: null));
        Assert.True(SchoolDay.IsLunchWindow(frame, DaySlot.BreakAfter(4), year: null));
        Assert.False(SchoolDay.IsLunchWindow(frame, DaySlot.Lesson(3), year: 4));
    }

    [Fact]
    public void ASittingAfterTheLastLesson_FailsTheCatalog()
    {
        var error = Assert.Throws<ContentLoadException>(() => LoadWithSittings(
            """{ "afterLesson": 7, "gradeMin": 1, "gradeMax": 11 }"""));

        Assert.Contains("lunch break", error.Message, StringComparison.OrdinalIgnoreCase);
    }

    [Fact]
    public void TwoSittingsForTheSameParallel_FailTheCatalog()
    {
        var error = Assert.Throws<ContentLoadException>(() => LoadWithSittings(
            """{ "afterLesson": 3, "gradeMin": 1, "gradeMax": 5 }, { "afterLesson": 4, "gradeMin": 5, "gradeMax": 11 }"""));

        Assert.Contains("two lunch breaks", error.Message, StringComparison.OrdinalIgnoreCase);
    }

    private DefCatalog LoadWithSittings(string sittings) =>
        _loader.Load(
            [CatalogLoader.CorePackId],
            [
                PackDocuments.Def(
                    CatalogLoader.CorePackId,
                    "dayframe",
                    "day",
                    $$"""
                    {
                      "defName": "Day",
                      "firstLesson": "08:30",
                      "lessonCount": 7,
                      "lessonMinutes": 45,
                      "breakMinutes": 10,
                      "longBreakAfter": 3,
                      "longBreakMinutes": 20,
                      "lunchBreaks": [{{sittings}}]
                    }
                    """),
            ]);

    private DefCatalog LoadVanilla()
    {
        var root = Path.Combine(AppContext.BaseDirectory, "vanilla");
        return _loader.Load([CatalogLoader.CorePackId], PackDocuments.FromDirectory(CatalogLoader.CorePackId, root));
    }
}