using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using LehrerApp.Core.Interfaces;
using LehrerApp.Core.Models;
using System.Collections.ObjectModel;

namespace LehrerApp.Desktop.ViewModels.Students;

// ── Schülerliste ──────────────────────────────────────────────────────────────

public partial class StudentListViewModel : ObservableObject
{
    private readonly IStudentRepository _students;

    [ObservableProperty] private string _searchText = "";
    [ObservableProperty] private bool _showInactive;
    [ObservableProperty] private StudentListItem? _selectedStudent;

    public ObservableCollection<StudentListItem> Students { get; } = [];

    public StudentListViewModel(IStudentRepository students)
    {
        _students = students;
        LoadStudents();
    }

    partial void OnSearchTextChanged(string value) => LoadStudents();
    partial void OnShowInactiveChanged(bool value) => LoadStudents();

    private void LoadStudents()
    {
        Students.Clear();
        var all = _students.GetAll(includeInactive: ShowInactive);

        var filtered = string.IsNullOrWhiteSpace(SearchText)
            ? all
            : all.Where(s =>
                s.LastName.Contains(SearchText, StringComparison.OrdinalIgnoreCase) ||
                s.FirstName.Contains(SearchText, StringComparison.OrdinalIgnoreCase));

        foreach (var s in filtered)
            Students.Add(new StudentListItem(s));
    }

    [RelayCommand]
    private void AddStudent()
    {
        // TODO: Neuer-Schüler-Dialog
    }

    [RelayCommand]
    private void Refresh() => LoadStudents();
}

public class StudentListItem
{
    public Guid Id { get; }
    public string FullName { get; }
    public string DateOfBirth { get; }
    public bool IsActive { get; }

    public StudentListItem(Student s)
    {
        Id = s.Id;
        FullName = s.FullName;
        DateOfBirth = s.DateOfBirth?.ToString("dd.MM.yyyy") ?? "";
        IsActive = s.IsActive;
    }
}

// ── Schülerdetail ─────────────────────────────────────────────────────────────

public partial class StudentDetailViewModel : ObservableObject
{
    private readonly IStudentRepository _students;
    private readonly IEnrollmentRepository _enrollments;
    private readonly IGroupRepository _groups;
    private readonly IGradeRepository _grades;
    private readonly IDocumentationRepository _docs;

    [ObservableProperty] private Student? _student;
    [ObservableProperty] private string _studentTitle = "";
    [ObservableProperty] private StudentTab _activeTab = StudentTab.Overview;
    [ObservableProperty] private bool _isEditing;

    // Bearbeitbare Felder
    [ObservableProperty] private string _editFirstName = "";
    [ObservableProperty] private string _editLastName = "";
    [ObservableProperty] private string _editNotes = "";

    public ObservableCollection<EnrollmentEntry> Enrollments { get; } = [];
    public ObservableCollection<GradeEntry> Grades { get; } = [];
    public ObservableCollection<DocEntry> Documentation { get; } = [];

    public StudentDetailViewModel(
        IStudentRepository students,
        IEnrollmentRepository enrollments,
        IGroupRepository groups,
        IGradeRepository grades,
        IDocumentationRepository docs)
    {
        _students = students;
        _enrollments = enrollments;
        _groups = groups;
        _grades = grades;
        _docs = docs;
    }

    public void LoadStudent(Guid studentId)
    {
        Student = _students.GetById(studentId);
        if (Student is null) return;

        StudentTitle = Student.FullName;
        EditFirstName = Student.FirstName;
        EditLastName = Student.LastName;
        EditNotes = Student.Notes ?? "";

        LoadEnrollments();
        LoadDocs();
    }

    [RelayCommand]
    private void SwitchTab(StudentTab tab) => ActiveTab = tab;

    [RelayCommand]
    private void StartEdit() => IsEditing = true;

    [RelayCommand]
    private void CancelEdit()
    {
        if (Student is null) return;
        EditFirstName = Student.FirstName;
        EditLastName = Student.LastName;
        EditNotes = Student.Notes ?? "";
        IsEditing = false;
    }

    [RelayCommand]
    private void SaveEdit()
    {
        if (Student is null) return;
        Student.FirstName = EditFirstName;
        Student.LastName = EditLastName;
        Student.Notes = string.IsNullOrWhiteSpace(EditNotes) ? null : EditNotes;
        _students.Save(Student);
        StudentTitle = Student.FullName;
        IsEditing = false;
    }

    private void LoadEnrollments()
    {
        if (Student is null) return;
        Enrollments.Clear();

        var enrollments = _enrollments.GetByStudent(Student.Id);
        var groupIds = enrollments.Select(e => e.GroupId).Distinct();
        var groupMap = groupIds
            .Select(id => _groups.GetById(id))
            .Where(g => g is not null)
            .ToDictionary(g => g!.Id);

        foreach (var e in enrollments.OrderByDescending(e => e.SchoolYear))
        {
            if (!groupMap.TryGetValue(e.GroupId, out var group)) continue;
            Enrollments.Add(new EnrollmentEntry
            {
                SchoolYear = e.SchoolYear,
                GroupName = group.Name,
                Subject = group.Subject ?? "",
            });
        }
    }

    private void LoadDocs()
    {
        if (Student is null) return;
        Documentation.Clear();

        foreach (var doc in _docs.GetByStudent(Student.Id))
        {
            Documentation.Add(new DocEntry
            {
                Date = doc.Date.ToString("dd.MM.yyyy"),
                Title = doc.Title,
                TypeLabel = doc.Type switch
                {
                    DocumentationType.Conversation => "Gespräch",
                    DocumentationType.Incident     => "Vorkommnis",
                    DocumentationType.SupportPlan  => "Förderplan",
                    DocumentationType.Absence      => "Fehlzeit",
                    _ => "",
                },
                IsConfidential = doc.IsConfidential,
            });
        }
    }
}

public enum StudentTab { Overview, Grades, Documentation }

public class EnrollmentEntry
{
    public string SchoolYear { get; set; } = "";
    public string GroupName { get; set; } = "";
    public string Subject { get; set; } = "";
}

public class GradeEntry
{
    public string Date { get; set; } = "";
    public string Value { get; set; } = "";
    public string Category { get; set; } = "";
    public string GroupName { get; set; } = "";
}

public class DocEntry
{
    public string Date { get; set; } = "";
    public string Title { get; set; } = "";
    public string TypeLabel { get; set; } = "";
    public bool IsConfidential { get; set; }
}