using System;
using System.Collections.Generic;

namespace Cryville.Common.Unity.Input {
	public class SimpleInputConsumer {
		readonly InputManager _manager;
		readonly object _lock = new object();
		readonly Dictionary<InputIdentifier, InputVector> _vectors = new Dictionary<InputIdentifier, InputVector>();
		readonly List<InputEvent> _events = new List<InputEvent>();
		public SimpleInputConsumer(InputManager manager) { _manager = manager; }
		public void Activate() {
			lock (_lock) {
				_events.Clear();
			}
			_manager.EnumerateHandlers(h => h.OnInput += OnInput);
		}
		public void Deactivate() {
			_manager.EnumerateHandlers(h => h.OnInput -= OnInput);
		}
		protected void OnInput(InputIdentifier id, InputVector vec) {
			lock (_lock) {
				InputVector vec0;
				if (_vectors.TryGetValue(id, out vec0)) {
					_events.Add(new InputEvent {
						Id = id,
						From = vec0,
						To = vec,
					});
					if (vec.IsNull) _vectors.Remove(id);
					else _vectors[id] = vec;
				}
				else {
					_events.Add(new InputEvent {
						Id = id,
						From = new InputVector(vec.Time),
						To = vec,
					});
					_vectors.Add(id, vec);
				}
			}
		}
		public void EnumerateEvents(Action<InputEvent> cb) {
			lock (_lock) {
				foreach (var ev in _events) cb(ev);
				_events.Clear();
			}
		}
	}
}