using LehrerApp.Core.Models;
using LiteDB;

namespace LehrerApp.Api;

/// <summary>Unverschlüsselte Serverdaten, die der Server zur Abfrage standortbezogener öffentlicher
/// Wetterdaten benötigt. Bewusst getrennt vom clientseitig verschlüsselten EventStore.</summary>
public sealed class SchoolWeatherStore : IDisposable
{
    private readonly LiteDatabase _db;

    public SchoolWeatherStore(string dataPath)
    {
        Directory.CreateDirectory(dataPath);
        _db = new LiteDatabase(Path.Combine(dataPath, "school-weather.db"));
    }

    private ILiteCollection<LocationEntry> Locations
    {
        get
        {
            var col = _db.GetCollection<LocationEntry>("locations");
            col.EnsureIndex(x => x.UserId, unique: true);
            return col;
        }
    }

    private ILiteCollection<WeatherEntry> Weather
    {
        get
        {
            var col = _db.GetCollection<WeatherEntry>("weather");
            col.EnsureIndex(x => x.UserId, unique: true);
            return col;
        }
    }

    public SchoolLocationProfile? GetLocation(string userId) =>
        Locations.FindOne(x => x.UserId == userId)?.Profile;

    public void SaveLocation(string userId, SchoolLocationProfile profile)
    {
        var existing = Locations.FindOne(x => x.UserId == userId);
        Locations.Upsert(new LocationEntry
        {
            Id = existing?.Id ?? ObjectId.NewObjectId(),
            UserId = userId,
            Profile = profile,
        });
        // Ein geänderter Standort darf niemals den Wetterstand des alten Orts liefern.
        Weather.DeleteMany(x => x.UserId == userId);
    }

    public WeatherSnapshot? GetWeather(string userId) =>
        Weather.FindOne(x => x.UserId == userId)?.Snapshot;

    public void SaveWeather(string userId, WeatherSnapshot snapshot)
    {
        var existing = Weather.FindOne(x => x.UserId == userId);
        Weather.Upsert(new WeatherEntry
        {
            Id = existing?.Id ?? ObjectId.NewObjectId(),
            UserId = userId,
            Snapshot = snapshot,
        });
    }

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

    private sealed class LocationEntry
    {
        public ObjectId Id { get; set; } = ObjectId.NewObjectId();
        public string UserId { get; set; } = "";
        public SchoolLocationProfile Profile { get; set; } = new();
    }

    private sealed class WeatherEntry
    {
        public ObjectId Id { get; set; } = ObjectId.NewObjectId();
        public string UserId { get; set; } = "";
        public WeatherSnapshot Snapshot { get; set; } = new();
    }
}