using LiteDB;
using LehrerApp.Core.Models;

namespace LehrerApp.Data;

/// <summary>
/// Zentrale LiteDB-Verbindung. Singleton – eine Datei = ein Nutzer.
/// </summary>
public class LiteDbContext : IDisposable
{
    private readonly LiteDatabase _db;

    public LiteDbContext(string databasePath)
    {
        _db = new LiteDatabase(new ConnectionString(databasePath)
        {
            Connection = ConnectionType.Shared,
        });
        EnsureIndexes();
    }

    public ILiteCollection<Student>       Students      => _db.GetCollection<Student>("students");
    public ILiteCollection<LearningGroup> Groups        => _db.GetCollection<LearningGroup>("groups");
    public ILiteCollection<Enrollment>    Enrollments   => _db.GetCollection<Enrollment>("enrollments");
    public ILiteCollection<Exam>          Exams         => _db.GetCollection<Exam>("exams");
    public ILiteCollection<ExamResult>    ExamResults   => _db.GetCollection<ExamResult>("exam_results");
    public ILiteCollection<Grade>         Grades        => _db.GetCollection<Grade>("grades");
    public ILiteCollection<Unit>          Units         => _db.GetCollection<Unit>("units");
    public ILiteCollection<Lesson>        Lessons       => _db.GetCollection<Lesson>("lessons");
    public ILiteCollection<Documentation> Documentation => _db.GetCollection<Documentation>("documentation");
    public ILiteCollection<WorkTask>      Tasks         => _db.GetCollection<WorkTask>("tasks");
    public ILiteCollection<TimeEntry>     TimeEntries   => _db.GetCollection<TimeEntry>("time_entries");

    public void Checkpoint() => _db.Checkpoint();

    private void EnsureIndexes()
    {
        Students.EnsureIndex(x => x.LastName);
        Students.EnsureIndex(x => x.IsActive);
        Groups.EnsureIndex(x => x.SchoolYear);
        Enrollments.EnsureIndex(x => x.StudentId);
        Enrollments.EnsureIndex(x => x.GroupId);
        Enrollments.EnsureIndex(x => x.SchoolYear);
        Exams.EnsureIndex(x => x.GroupId);
        Exams.EnsureIndex(x => x.Status);
        ExamResults.EnsureIndex(x => x.ExamId);
        ExamResults.EnsureIndex(x => x.StudentId);
        Grades.EnsureIndex(x => x.StudentId);
        Grades.EnsureIndex(x => x.GroupId);
        Units.EnsureIndex(x => x.GroupId);
        Lessons.EnsureIndex(x => x.UnitId);
        Lessons.EnsureIndex(x => x.GroupId);
        Lessons.EnsureIndex(x => x.Date);
        Documentation.EnsureIndex(x => x.StudentId);
        Tasks.EnsureIndex(x => x.Status);
        TimeEntries.EnsureIndex(x => x.Date);
    }

    public void Dispose() => _db.Dispose();
}