using LehrerApp.Core.Models;
using LehrerApp.Data.Repositories;
using Xunit;

namespace LehrerApp.Data.Tests;

public sealed class RepositoryTests
{
    private static LiteDbContext NewInMemoryContext() => new(new MemoryStream());

    // ── StudentRepository ─────────────────────────────────────────────────────

    [Fact]
    public void StudentRepository_GetByGroup_FindetNurZugeordneteSchueler()
    {
        using var db = NewInMemoryContext();
        var repo = new StudentRepository(db);
        var groupId = Guid.NewGuid();
        var inGroup = new Student { FirstName = "Anna", LastName = "Beispiel" };
        var notInGroup = new Student { FirstName = "Ben", LastName = "Muster" };
        repo.Save(inGroup);
        repo.Save(notInGroup);
        db.Memberships.Insert(new GroupMembership { StudentId = inGroup.Id, GroupId = groupId });

        var result = repo.GetByGroup(groupId);

        Assert.Single(result);
        Assert.Equal(inGroup.Id, result[0].Id);
    }

    [Fact]
    public void StudentRepository_GetAll_OhneInactiveFiltertDeaktivierteSchuelerAus()
    {
        using var db = NewInMemoryContext();
        var repo = new StudentRepository(db);
        repo.Save(new Student { FirstName = "Anna", LastName = "Aktiv", IsActive = true });
        repo.Save(new Student { FirstName = "Ben", LastName = "Inaktiv", IsActive = false });

        Assert.Single(repo.GetAll(includeInactive: false));
        Assert.Equal(2, repo.GetAll(includeInactive: true).Count);
    }

    // ── GroupRepository ───────────────────────────────────────────────────────

    [Fact]
    public void GroupRepository_Save_LehntUnbekanntesFachAb()
    {
        using var db = NewInMemoryContext();
        var repo = new GroupRepository(db);
        var group = new LearningGroup { Name = "Mathe G", SchoolYear = "2025/26", SubjectId = Guid.NewGuid() };

        Assert.Throws<InvalidOperationException>(() => repo.Save(group));
    }

    [Fact]
    public void GroupRepository_Save_AkzeptiertVorhandenesFach()
    {
        using var db = NewInMemoryContext();
        var subjectRepo = new SubjectRepository(db);
        var groupRepo = new GroupRepository(db);
        var subject = new Subject { Name = "Mathematik" };
        subjectRepo.Save(subject);

        groupRepo.Save(new LearningGroup { Name = "Mathe G", SchoolYear = "2025/26", SubjectId = subject.Id });

        Assert.NotNull(groupRepo.GetAll(includeInactive: true).FirstOrDefault(g => g.Name == "Mathe G"));
    }

    [Fact]
    public void GroupRepository_Delete_LoeschtAlleAbhaengigenDatensaetzeKaskadierend()
    {
        using var db = NewInMemoryContext();
        var groupRepo = new GroupRepository(db);
        var groupId = Guid.NewGuid();
        groupRepo.Save(new LearningGroup { Id = groupId, Name = "Mathe G", SchoolYear = "2025/26" });

        var studentId = Guid.NewGuid();
        var membershipId = Guid.NewGuid();
        db.Memberships.Insert(new GroupMembership { Id = membershipId, StudentId = studentId, GroupId = groupId });

        var examId = Guid.NewGuid();
        var examResultId = Guid.NewGuid();
        db.Exams.Insert(new Exam { Id = examId, GroupId = groupId });
        db.ExamResults.Insert(new ExamResult { Id = examResultId, ExamId = examId, StudentId = studentId });

        var gradeId = Guid.NewGuid();
        db.Grades.Insert(new Grade { Id = gradeId, GroupId = groupId, StudentId = studentId });

        var unitId = Guid.NewGuid();
        var lessonInUnitId = Guid.NewGuid();
        db.Units.Insert(new Unit { Id = unitId, GroupId = groupId });
        db.Lessons.Insert(new Lesson { Id = lessonInUnitId, UnitId = unitId, GroupId = groupId });

        var looseLessonId = Guid.NewGuid();
        db.Lessons.Insert(new Lesson { Id = looseLessonId, UnitId = Guid.NewGuid(), GroupId = groupId });

        var sessionId = Guid.NewGuid();
        var entryId = Guid.NewGuid();
        db.ParticipationSessions.Insert(new ParticipationSession { Id = sessionId, GroupId = groupId });
        db.ParticipationEntries.Insert(new ParticipationEntry { Id = entryId, SessionId = sessionId, StudentId = studentId });

        var aspectId = Guid.NewGuid();
        db.ParticipationAspects.Insert(new ParticipationAspect { Id = aspectId, GroupId = groupId, Key = "quality" });

        groupRepo.Delete(groupId);

        Assert.Null(db.Groups.FindById(groupId));
        Assert.Null(db.Memberships.FindById(membershipId));
        Assert.Null(db.Exams.FindById(examId));
        Assert.Null(db.ExamResults.FindById(examResultId));
        Assert.Null(db.Grades.FindById(gradeId));
        Assert.Null(db.Units.FindById(unitId));
        Assert.Null(db.Lessons.FindById(lessonInUnitId));
        Assert.Null(db.Lessons.FindById(looseLessonId));
        Assert.Null(db.ParticipationSessions.FindById(sessionId));
        Assert.Null(db.ParticipationEntries.FindById(entryId));
        Assert.Null(db.ParticipationAspects.FindById(aspectId));
    }

    [Fact]
    public void GroupRepository_Delete_LaesstDatenAndererGruppenUnberuehrt()
    {
        using var db = NewInMemoryContext();
        var groupRepo = new GroupRepository(db);
        var deletedGroupId = Guid.NewGuid();
        var otherGroupId = Guid.NewGuid();
        groupRepo.Save(new LearningGroup { Id = deletedGroupId, Name = "Löschen", SchoolYear = "2025/26" });
        groupRepo.Save(new LearningGroup { Id = otherGroupId, Name = "Bleibt", SchoolYear = "2025/26" });

        var otherExamId = Guid.NewGuid();
        db.Exams.Insert(new Exam { Id = otherExamId, GroupId = otherGroupId });

        groupRepo.Delete(deletedGroupId);

        Assert.Null(db.Groups.FindById(deletedGroupId));
        Assert.NotNull(db.Groups.FindById(otherGroupId));
        Assert.NotNull(db.Exams.FindById(otherExamId));
    }

    // ── GroupMembershipRepository ────────────────────────────────────────────

    [Fact]
    public void GroupMembershipRepository_Save_LehntZweiteZuordnungFuerGleichesPaarAb()
    {
        using var db = NewInMemoryContext();
        var repo = new GroupMembershipRepository(db);
        var studentId = Guid.NewGuid();
        var groupId = Guid.NewGuid();
        repo.Save(new GroupMembership { StudentId = studentId, GroupId = groupId });

        var duplicate = new GroupMembership { StudentId = studentId, GroupId = groupId };
        Assert.Throws<InvalidOperationException>(() => repo.Save(duplicate));
    }

    [Fact]
    public void GroupMembershipRepository_Save_ErlaubtAktualisierenDerselbenZuordnung()
    {
        using var db = NewInMemoryContext();
        var repo = new GroupMembershipRepository(db);
        var membership = new GroupMembership { StudentId = Guid.NewGuid(), GroupId = Guid.NewGuid(), Period = MembershipPeriod.FullYear };
        repo.Save(membership);

        membership.Period = MembershipPeriod.H1Only;
        repo.Save(membership); // gleiche Id -> darf keine Ausnahme werfen

        var reloaded = repo.GetByStudentAndGroup(membership.StudentId, membership.GroupId);
        Assert.Equal(MembershipPeriod.H1Only, reloaded?.Period);
    }

    // ── ExamRepository ────────────────────────────────────────────────────────

    [Fact]
    public void ExamRepository_Delete_LoeschtZugehoerigeErgebnisseMit()
    {
        using var db = NewInMemoryContext();
        var repo = new ExamRepository(db);
        var exam = new Exam { GroupId = Guid.NewGuid() };
        repo.Save(exam);
        var resultId = Guid.NewGuid();
        db.ExamResults.Insert(new ExamResult { Id = resultId, ExamId = exam.Id, StudentId = Guid.NewGuid() });

        repo.Delete(exam.Id);

        Assert.Null(repo.GetById(exam.Id));
        Assert.Null(db.ExamResults.FindById(resultId));
    }

    [Fact]
    public void ExamRepository_GetByGroup_SortiertAbsteigendNachDatum()
    {
        using var db = NewInMemoryContext();
        var repo = new ExamRepository(db);
        var groupId = Guid.NewGuid();
        repo.Save(new Exam { GroupId = groupId, Title = "Früh", Date = new DateOnly(2025, 9, 1) });
        repo.Save(new Exam { GroupId = groupId, Title = "Spät", Date = new DateOnly(2025, 11, 1) });

        var result = repo.GetByGroup(groupId);

        Assert.Equal("Spät", result[0].Title);
        Assert.Equal("Früh", result[1].Title);
    }

    // ── SubjectRepository ─────────────────────────────────────────────────────

    [Fact]
    public void SubjectRepository_Save_TrimmtNamenUndKuerzel()
    {
        using var db = NewInMemoryContext();
        var repo = new SubjectRepository(db);
        var subject = new Subject { Name = "  Chemie  ", ShortName = " Ch " };

        repo.Save(subject);

        var reloaded = repo.GetById(subject.Id);
        Assert.Equal("Chemie", reloaded?.Name);
        Assert.Equal("Ch", reloaded?.ShortName);
    }

    [Fact]
    public void SubjectRepository_Save_LehntLeerenNamenAb()
    {
        using var db = NewInMemoryContext();
        var repo = new SubjectRepository(db);

        Assert.Throws<ArgumentException>(() => repo.Save(new Subject { Name = "   " }));
    }

    [Fact]
    public void SubjectRepository_Save_LehntDuplikatUnabhaengigVonGrossKleinschreibungAb()
    {
        using var db = NewInMemoryContext();
        var repo = new SubjectRepository(db);
        repo.Save(new Subject { Name = "Chemie" });

        Assert.Throws<InvalidOperationException>(() => repo.Save(new Subject { Name = "chemie" }));
    }

    [Fact]
    public void SubjectRepository_Delete_WirdBlockiertWennGruppeDasFachVerwendet()
    {
        using var db = NewInMemoryContext();
        var subjectRepo = new SubjectRepository(db);
        var subject = new Subject { Name = "Chemie" };
        subjectRepo.Save(subject);
        db.Groups.Insert(new LearningGroup { Name = "Chemie G", SchoolYear = "2025/26", SubjectId = subject.Id });

        Assert.Throws<InvalidOperationException>(() => subjectRepo.Delete(subject.Id));
    }

    [Fact]
    public void SubjectRepository_Delete_FunktioniertWennUnbenutzt()
    {
        using var db = NewInMemoryContext();
        var repo = new SubjectRepository(db);
        var subject = new Subject { Name = "Chemie" };
        repo.Save(subject);

        repo.Delete(subject.Id);

        Assert.Null(repo.GetById(subject.Id));
    }

    // ── GradingSchemeRepository ───────────────────────────────────────────────

    [Fact]
    public void GradingSchemeRepository_UnterscheidetGruppenspezifischesSchemaVonVoreinstellung()
    {
        using var db = NewInMemoryContext();
        var repo = new GradingSchemeRepository(db);
        var groupId = Guid.NewGuid();
        repo.Save(new GradingScheme { GroupId = groupId, ExamsPercent = 60, ParticipationPercent = 30, OtherPercent = 10 });
        repo.Save(new GradingScheme { GroupType = GroupType.Class, ExamsPercent = 50, ParticipationPercent = 40, OtherPercent = 10 });

        var forGroup = repo.GetByGroup(groupId);
        var defaultForClass = repo.GetDefaultForType(GroupType.Class);
        var defaultForCourse = repo.GetDefaultForType(GroupType.Course);

        Assert.Equal(60, forGroup?.ExamsPercent);
        Assert.Equal(50, defaultForClass?.ExamsPercent);
        Assert.Null(defaultForCourse);
    }

    // ── ReportGradeRepository ─────────────────────────────────────────────────

    [Fact]
    public void ReportGradeRepository_GetByStudentGroupPeriod_UnterscheidetZeitraeume()
    {
        using var db = NewInMemoryContext();
        var repo = new ReportGradeRepository(db);
        var studentId = Guid.NewGuid();
        var groupId = Guid.NewGuid();
        repo.Save(new ReportGrade { StudentId = studentId, GroupId = groupId, Period = "1. Halbjahr", CalculatedValue = "2" });
        repo.Save(new ReportGrade { StudentId = studentId, GroupId = groupId, Period = "2. Halbjahr", CalculatedValue = "3" });

        var h1 = repo.GetByStudentGroupPeriod(studentId, groupId, "1. Halbjahr");
        var h2 = repo.GetByStudentGroupPeriod(studentId, groupId, "2. Halbjahr");
        var unbekannt = repo.GetByStudentGroupPeriod(studentId, groupId, "Gesamtes Schuljahr");

        Assert.Equal("2", h1?.CalculatedValue);
        Assert.Equal("3", h2?.CalculatedValue);
        Assert.Null(unbekannt);
    }

    // ── ParticipationSessionRepository ───────────────────────────────────────

    [Fact]
    public void ParticipationSessionRepository_Delete_LoeschtZugehoerigeEintraegeMit()
    {
        using var db = NewInMemoryContext();
        var repo = new ParticipationSessionRepository(db);
        var session = new ParticipationSession { GroupId = Guid.NewGuid() };
        repo.Save(session);
        var entryId = Guid.NewGuid();
        db.ParticipationEntries.Insert(new ParticipationEntry { Id = entryId, SessionId = session.Id, StudentId = Guid.NewGuid() });

        repo.Delete(session.Id);

        Assert.Null(repo.GetById(session.Id));
        Assert.Null(db.ParticipationEntries.FindById(entryId));
    }

    [Fact]
    public void ParticipationEntry_EindeutigerIndex_LehntZweitenEintragFuerGleicheSitzungUndSchuelerAb()
    {
        using var db = NewInMemoryContext();
        var repo = new ParticipationRepository(db);
        var sessionId = Guid.NewGuid();
        var studentId = Guid.NewGuid();
        repo.Save(new ParticipationEntry { SessionId = sessionId, StudentId = studentId });

        Assert.Throws<LiteDB.LiteException>(() =>
            db.ParticipationEntries.Insert(new ParticipationEntry { SessionId = sessionId, StudentId = studentId }));
    }

    // ── DocumentationRepository ───────────────────────────────────────────────

    [Fact]
    public void DocumentationRepository_Delete_MarkiertNurAlsGeloescht()
    {
        using var db = NewInMemoryContext();
        var repo = new DocumentationRepository(db);
        var doc = new Documentation { StudentId = Guid.NewGuid(), Title = "Gespräch" };
        repo.Save(doc);

        repo.Delete(doc.Id);

        Assert.Empty(repo.GetByStudent(doc.StudentId));
        var raw = db.Documentation.FindById(doc.Id);
        Assert.NotNull(raw);
        Assert.True(raw.IsDeleted);
        Assert.NotNull(raw.DeletedAt);
    }

    [Fact]
    public void DocumentationRepository_HardDelete_EntferntDenEintragEndgueltig()
    {
        using var db = NewInMemoryContext();
        var repo = new DocumentationRepository(db);
        var doc = new Documentation { StudentId = Guid.NewGuid(), Title = "Vorkommnis" };
        repo.Save(doc);

        repo.HardDelete(doc.Id);

        Assert.Null(db.Documentation.FindById(doc.Id));
    }

    [Fact]
    public void DocumentationRepository_GetAll_FiltertGeloeschteEintraegeUndUmfasstAlleSchueler()
    {
        using var db = NewInMemoryContext();
        var repo = new DocumentationRepository(db);
        var visible = new Documentation { StudentId = Guid.NewGuid(), Title = "Sichtbar" };
        var deleted = new Documentation { StudentId = Guid.NewGuid(), Title = "Gelöscht" };
        repo.Save(visible);
        repo.Save(deleted);
        repo.Delete(deleted.Id);

        var all = repo.GetAll();

        Assert.Single(all);
        Assert.Equal(visible.Id, all[0].Id);
    }

    [Fact]
    public void DocumentationRepository_HardDelete_EntferntAuchDieAnhaenge()
    {
        using var db = NewInMemoryContext();
        var repo = new DocumentationRepository(db);
        var storage = new LiteAttachmentStorage(db);
        string attachmentId;
        using (var ms = new MemoryStream([1, 2, 3]))
            attachmentId = storage.Upload("brief.pdf", ms);

        var doc = new Documentation { StudentId = Guid.NewGuid(), Title = "Elternbrief" };
        doc.Attachments.Add(new DocumentAttachment { StorageId = attachmentId, FileName = "brief.pdf", SizeBytes = 3 });
        repo.Save(doc);

        repo.HardDelete(doc.Id);

        Assert.Null(db.Documentation.FindById(doc.Id));
        Assert.Null(storage.OpenRead(attachmentId));
    }
}