using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using LehrerApp.Core.Interfaces;
using LehrerApp.Core.Models;
using LehrerApp.Core.Services;
using LehrerApp.Data;
using LehrerApp.Desktop.Services;
using LehrerApp.Desktop.ViewModels.Planning;
using LehrerApp.Sync;
using LehrerApp.Sync.Crypto;
using System.Collections.ObjectModel;
using System.Globalization;
using System.Security.Cryptography;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace LehrerApp.Desktop.ViewModels.Settings;

public partial class SettingsViewModel
{
    // ── Sicherheit: Datenbank-Verschlüsselung (13.3.4) ───────────────────────

    [ObservableProperty] private bool   _isDbEncrypted;
    [ObservableProperty] private string _currentDbPassword    = "";
    [ObservableProperty] private string _newDbPassword        = "";
    [ObservableProperty] private string _newDbPasswordConfirm = "";
    [ObservableProperty] private string _dbPasswordError      = "";

    public string DbEncryptionStatusLabel => IsDbEncrypted ? "verschlüsselt" : "nicht verschlüsselt";

    partial void OnIsDbEncryptedChanged(bool value) => OnPropertyChanged(nameof(DbEncryptionStatusLabel));

    // ── Datenbank-Verschlüsselung: Setzen / Ändern / Entfernen ───────────────

    [RelayCommand]
    private void SaveDbPassword()
    {
        DbPasswordError = "";
        var valid = true;
        var wantsPassword = !string.IsNullOrWhiteSpace(NewDbPassword) || !string.IsNullOrWhiteSpace(NewDbPasswordConfirm);

        if (IsDbEncrypted && !_dbEncryption.VerifyPassword(AppBootstrapper.DbPath, CurrentDbPassword))
        {
            DbPasswordError = "Aktuelles Passwort ist falsch.";
            valid = false;
        }

        if (!wantsPassword)
        {
            DbPasswordError = "Bitte ein neues Passwort eingeben.";
            valid = false;
        }
        else if (NewDbPassword != NewDbPasswordConfirm)
        {
            DbPasswordError = "Neue Passwörter stimmen nicht überein.";
            valid = false;
        }
        else if (NewDbPassword.Length < 4)
        {
            DbPasswordError = "Mindestens 4 Zeichen.";
            valid = false;
        }

        if (!valid) return;

        _dbContext.Dispose();
        _dbEncryption.SetPassword(AppBootstrapper.DbPath, IsDbEncrypted ? CurrentDbPassword : null, NewDbPassword.Trim());
        AppBootstrapper.RestartApplication();
    }

    [RelayCommand]
    private void RemoveDbPassword()
    {
        DbPasswordError = "";
        if (!_dbEncryption.VerifyPassword(AppBootstrapper.DbPath, CurrentDbPassword))
        {
            DbPasswordError = "Aktuelles Passwort ist falsch.";
            return;
        }

        _dbContext.Dispose();
        _dbEncryption.SetPassword(AppBootstrapper.DbPath, CurrentDbPassword, null);
        AppBootstrapper.RestartApplication();
    }
}