inabox/InABox.Avalonia/DataModels/QueuedUpdater/QueueUpdater.cs

using InABox.Clients;
using InABox.Core;

namespace InABox.Avalonia;

public class QueueUpdaterState
{
    public Guid ID { get; set; }
    public string OriginalState { get; set; }
    public Dictionary<string,object> Changes { get; set; } = new();
        
    public bool DisableUpdates { get; set; }
}

public class QueueUpdater<TEntity> : IDisposable, IQueueUpdater<TEntity> 
    where TEntity : Entity, IPersistent, IRemotable, new()
{
        
    private static String StateFile(Guid id) => $"{id}.{typeof(TEntity).Name.Split('.').Last()}";
 
    private Dictionary<TEntity, QueueUpdaterState> _cache = new();

    private string _path;
    private IModelHost _host;

    public QueueUpdater(IModelHost host, string path)
    {
        _host = host;
        _path = path;
        LoadCache();
        _host.AddUpdateQueue(this);
    }
        
    public void Add(TEntity entity)
    {
        var _state = new QueueUpdaterState();
        _state.ID = Guid.NewGuid();
        _state.OriginalState = Serialization.Serialize(entity);
        Save(_state);
        _cache[entity] = _state;
            
        entity.PropertyChanged += (sender, args) =>
        {
            var state = _cache[entity];
            state.Changes[args.PropertyName] = CoreUtils.GetPropertyValue(entity,args.PropertyName);
            Save(state);
        };
    }

    public void Update(TEntity entity, Action<TEntity> action)
    {
        var state = _cache[entity];
        state.DisableUpdates = true;
        action(entity);
        Save(state);
        state.DisableUpdates = false;
    }

    private void Save(QueueUpdaterState state)
    {
        var _text = Serialization.Serialize(state);
        File.WriteAllText(StateFile(state.ID), _text);
    }

    public TEntity[] Items => _cache.Keys.ToArray();
        
    private void LoadCache()
    {
        _cache.Clear();
        var files = Directory.GetFiles(_path, $"*.{typeof(TEntity).Name.Split('.').Last()}");
        foreach (var file in files)
        {
            if (!Guid.TryParse(Path.GetFileNameWithoutExtension(file), out Guid id))
                continue;
                
            var _text = File.ReadAllText(file);
            if (string.IsNullOrWhiteSpace(_text))
                continue;
                
            var _state = Serialization.Deserialize<QueueUpdaterState>(_text);
            if (_state == null)
                continue;
                
            var _entity = Serialization.Deserialize<TEntity>(_state.OriginalState);
            if (_entity == null)
                continue;
                
            foreach (var change in _state.Changes) 
                CoreUtils.SetPropertyValue(_entity,change.Key,change.Value);        
                
            _cache[_entity] = _state;
        }
    }

    public void ProcessQueue()
    {
        var item = Items.FirstOrDefault();
        if (item != null)
        {
            if (item.IsChanged() && _host.Status == ConnectionStatus.Connected)
            {
                new Client<TEntity>().Save(item, "Updated from Mobile Device");
                var state = Serialization.Serialize(item);
                File.WriteAllText(StateFile(_cache[item].ID),state);
            }
        }
    }
        
    public void Dispose()
    {
        _host.RemoveUpdateQueue(this);
    }
}