using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using LehrerApp.Core.Interfaces;
using LehrerApp.Core.Models;
using LehrerApp.Core.Services;

namespace LehrerApp.Desktop.ViewModels.Groups;

public partial class AddGroupDialogViewModel : ObservableObject
{
    private readonly IGroupRepository _groups;
    private readonly SchoolYearService _schoolYearService;

    [ObservableProperty] private string _name = "";
    [ObservableProperty] private string _subject = "";
    [ObservableProperty] private GroupType _type = GroupType.Course;
    [ObservableProperty] private int _gradeLevel = 10;
    [ObservableProperty] private GradingSystem _gradingSystem = GradingSystem.Grades1To6;
    [ObservableProperty] private int? _hoursPerWeek;
    [ObservableProperty] private string _selectedSchoolYear = "";
    [ObservableProperty] private string _validationMessage = "";

    public List<string> SchoolYears { get; }
    public List<GroupTypeItem> GroupTypes { get; } =
    [
        new(GroupType.Course, "Fachkurs"),
        new(GroupType.Class, "Klassenverband"),
    ];
    public List<GradingSystemItem> GradingSystems { get; } =
    [
        new(GradingSystem.Grades1To6, "Noten 1–6 (Sek I)"),
        new(GradingSystem.Points0To15, "Punkte 0–15 (Oberstufe)"),
    ];

    // Wird vom Dialog aufgerufen wenn OK geklickt wurde
    public LearningGroup? Result { get; private set; }

    public AddGroupDialogViewModel(
        IGroupRepository groups,
        SchoolYearService schoolYearService)
    {
        _groups = groups;
        _schoolYearService = schoolYearService;
        SchoolYears = schoolYearService.RecentSchoolYears(3);
        SelectedSchoolYear = schoolYearService.CurrentSchoolYear();

        // Automatisch Notensystem vorschlagen wenn Klassenstufe sich ändert
        PropertyChanged += (_, e) =>
        {
            if (e.PropertyName == nameof(GradeLevel))
                GradingSystem = GradeLevel >= 11
                    ? GradingSystem.Points0To15
                    : GradingSystem.Grades1To6;
        };
    }

    [RelayCommand]
    private void Save()
    {
        // Validierung
        if (string.IsNullOrWhiteSpace(Name))
        {
            ValidationMessage = "Bitte einen Namen eingeben.";
            return;
        }
        if (GradeLevel is < 1 or > 13)
        {
            ValidationMessage = "Klassenstufe muss zwischen 1 und 13 liegen.";
            return;
        }

        Result = new LearningGroup
        {
            Name = Name.Trim(),
            Subject = string.IsNullOrWhiteSpace(Subject) ? null : Subject.Trim(),
            Type = Type,
            GradeLevel = GradeLevel,
            GradingSystem = GradingSystem,
            SchoolYear = SelectedSchoolYear,
            HoursPerWeek = HoursPerWeek,
        };

        _groups.Save(Result);
        ValidationMessage = "";
    }
}

public record GroupTypeItem(GroupType Value, string Label);
public record GradingSystemItem(GradingSystem Value, string Label);