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
{
    // ── Ferien & Feiertage (4.3.5, aus dem Stundenplan hierher verschoben) ───

    [ObservableProperty] private string _selectedStateName = "";
    [ObservableProperty] private string _newHolidayName = "";
    [ObservableProperty] private string _newHolidayStartText = "";
    [ObservableProperty] private string _newHolidayEndText = "";
    [ObservableProperty] private string _holidayNameError = "";
    [ObservableProperty] private string _holidayDateError = "";
    [ObservableProperty] private string _schoolName = "";
    [ObservableProperty] private string _schoolStreet = "";
    [ObservableProperty] private string _schoolPostalCode = "";
    [ObservableProperty] private string _schoolCity = "";
    [ObservableProperty] private string _schoolNameError = "";
    [ObservableProperty] private string _schoolStreetError = "";
    [ObservableProperty] private string _schoolPostalCodeError = "";
    [ObservableProperty] private string _schoolCityError = "";
    [ObservableProperty] private string _schoolLocationStatus = "";
    [ObservableProperty] private string _resolvedSchoolAddress = "";

    public List<string> StateOptions { get; } = GermanStateDisplay.Options.ToList();
    public ObservableCollection<SchoolHolidayItem> SchoolHolidayEntries { get; } = [];

    // ── Ferien & Feiertage: Bundesland / Schulferien pflegen ─────────────────

    partial void OnSelectedStateNameChanged(string value) =>
        _calendarSettings.SetState(GermanStateDisplay.FromLabel(value));

    [RelayCommand]
    private async Task LoadSchoolLocation()
    {
        if (_schoolWeather is null) return;
        try
        {
            var location = await _schoolWeather.GetLocationAsync();
            if (location is null) return;
            SchoolName = location.SchoolName;
            SchoolStreet = location.Street;
            SchoolPostalCode = location.PostalCode;
            SchoolCity = location.City;
            SelectedStateName = GermanStateDisplay.Label(location.State);
            ResolvedSchoolAddress = location.ResolvedAddress;
        }
        catch (SchoolWeatherException ex) { SchoolLocationStatus = ex.Message; }
    }

    [RelayCommand]
    private async Task SaveSchoolLocation()
    {
        SchoolNameError = ""; SchoolStreetError = ""; SchoolPostalCodeError = "";
        SchoolCityError = ""; SchoolLocationStatus = "";
        var valid = true;
        if (string.IsNullOrWhiteSpace(SchoolName))
        { SchoolNameError = "Name der Schule erforderlich."; valid = false; }
        if (string.IsNullOrWhiteSpace(SchoolStreet))
        { SchoolStreetError = "Straße und Hausnummer erforderlich."; valid = false; }
        if (!System.Text.RegularExpressions.Regex.IsMatch(SchoolPostalCode.Trim(), @"^\d{5}$"))
        { SchoolPostalCodeError = "Bitte eine fünfstellige PLZ angeben."; valid = false; }
        if (string.IsNullOrWhiteSpace(SchoolCity))
        { SchoolCityError = "Ort erforderlich."; valid = false; }
        if (!valid) return;
        if (_schoolWeather is null)
        {
            SchoolLocationStatus = "Der Wetterdienst ist nicht verfügbar.";
            return;
        }

        SchoolLocationStatus = "Adresse wird geprüft …";
        try
        {
            var profile = await _schoolWeather.SaveLocationAsync(new SchoolLocationRequest
            {
                SchoolName = SchoolName.Trim(), Street = SchoolStreet.Trim(),
                PostalCode = SchoolPostalCode.Trim(), City = SchoolCity.Trim(),
                State = GermanStateDisplay.FromLabel(SelectedStateName),
            });
            ResolvedSchoolAddress = profile.ResolvedAddress;
            SchoolLocationStatus = "Schulstandort gespeichert. Wetterdaten werden serverseitig abgerufen.";
        }
        catch (SchoolWeatherException ex) { SchoolLocationStatus = ex.Message; }
    }

    private void LoadSchoolHolidays()
    {
        SchoolHolidayEntries.Clear();
        foreach (var h in _schoolHolidays.GetAll().OrderBy(h => h.StartDate))
            SchoolHolidayEntries.Add(new SchoolHolidayItem(h));
    }

    [RelayCommand]
    private void AddSchoolHoliday()
    {
        HolidayNameError = ""; HolidayDateError = "";
        var valid = true;

        if (string.IsNullOrWhiteSpace(NewHolidayName)) { HolidayNameError = "Name erforderlich."; valid = false; }

        var hasStart = DateOnly.TryParseExact(NewHolidayStartText, "dd.MM.yyyy", CultureInfo.InvariantCulture,
            System.Globalization.DateTimeStyles.None, out var start);
        var hasEnd = DateOnly.TryParseExact(NewHolidayEndText, "dd.MM.yyyy", CultureInfo.InvariantCulture,
            System.Globalization.DateTimeStyles.None, out var end);

        if (!hasStart || !hasEnd) { HolidayDateError = "Bitte Beginn und Ende im Format TT.MM.JJJJ angeben."; valid = false; }
        else if (end < start) { HolidayDateError = "Das Ende darf nicht vor dem Beginn liegen."; valid = false; }

        if (!valid) return;

        _schoolHolidays.Save(new SchoolHoliday { Name = NewHolidayName.Trim(), StartDate = start, EndDate = end });
        NewHolidayName = ""; NewHolidayStartText = ""; NewHolidayEndText = "";
        LoadSchoolHolidays();
    }

    [RelayCommand]
    private void RemoveSchoolHoliday(SchoolHolidayItem? item)
    {
        if (item is null) return;
        _schoolHolidays.Delete(item.Id);
        SchoolHolidayEntries.Remove(item);
    }
}

public class SchoolHolidayItem(SchoolHoliday h)
{
    public Guid   Id           { get; } = h.Id;
    public string Name         { get; } = h.Name;
    public string RangeDisplay { get; } = $"{h.StartDate:dd.MM.yyyy} – {h.EndDate:dd.MM.yyyy}";
}