using System.Collections;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Reactive.Subjects;
using InnovEnergy.Lib.Protocols.DBus.Protocol.DataTypes;

namespace InnovEnergy.Lib.Victron.VeDBus;

public class VeProperties : IEnumerable<VeProperty>
{
    // Thread safe

    private ImmutableDictionary<ObjectPath, VeProperty> _Dict = ImmutableDictionary<ObjectPath, VeProperty>.Empty;
    
    private readonly Subject<VeProperty>                                  _PropertyChanged   = new();
    private readonly Subject<ImmutableDictionary<ObjectPath, VeProperty>> _PropertiesChanged = new();

    public IObservable<VeProperty>                                  PropertyChanged   => _PropertyChanged;
    public IObservable<ImmutableDictionary<ObjectPath, VeProperty>> PropertiesChanged => _PropertiesChanged;

    public Variant GetValueOfAllProperties(String prefix = "")
    {
        return _Dict
               .Where(p => p.Key.Path.StartsWith(prefix))
               .ToDictionary(p => p.Key.Path, p => p.Value.Value.Variant())
               .Variant();
    }

    
    public Dictionary<String, String> GetTextOfAllProperties(String prefix = "")
    {
        return _Dict
               .Where(p => p.Key.Path.StartsWith(prefix))
               .ToDictionary(p => p.Key.Path, p => p.Value.Text);
    }

    
    public Dictionary<String, Dictionary<String, Variant>> GetAllItems(String prefix = "")
    {
        return _Dict
               .Where(p => p.Key.Path.StartsWith(prefix))
               .ToDictionary(p => p.Key.Path, p => p.Value.GetItem());
    }
    
    public VeProperty? Get(ObjectPath path)
    {
        return _Dict.TryGetValue(path, out var v) ? v : null;
    }

    public Boolean Set(ObjectPath path, Object value, String? text = null)
    {
        var txt = text ?? (value is Variant v ? v.Value.ToString() : value.ToString());
                                           
        var p = new VeProperty(path, value, txt!);
        return Set(p);
    }
    
    public Boolean Set(ObjectPath path, Object value, Boolean writable, String? text = null)
    {
        var txt = text ?? (value is Variant v ? v.Value.ToString() : value.ToString());
                                           
        var p = new VeProperty(path, value, Text:txt!, writable);
        return Set(p);
    }
    
    public Boolean Set(VeProperty prop)
    {
        
        // TODO: reenable optimization? 
        
        // var p = Get(prop.ObjectPath);
        //
        // if (p.HasValue && p.Value == prop)
        //     return false;

        Debug.WriteLine($"Property changed: {prop.ObjectPath} {prop.Value} {prop.Text}");
        
        _Dict = _Dict.SetItem(prop.ObjectPath, prop); // thread safe

        _PropertiesChanged.OnNext(_Dict);
        _PropertyChanged.OnNext(prop);
        
        return true;
    }



    #region Collection initializer

    public Boolean Add(ObjectPath path, Object value, String? text = null) => Set(path, value, text:text);
    public Boolean Add(VeProperty prop) => Set(prop);
    public IEnumerator<VeProperty> GetEnumerator() => _Dict.Values.GetEnumerator();
    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();    

    #endregion Collection initializer
}