using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;
#endif
using System.Reflection;

/// <summary>
/// This attribute can only be applied to fields because its
/// associated PropertyDrawer only operates on fields (either
/// public or tagged with the [SerializeField] attribute) in
/// the target MonoBehaviour.
/// </summary>
[System.AttributeUsage(System.AttributeTargets.Field)]
public class InspectorButtonAttribute : PropertyAttribute
{
  public static float kDefaultButtonWidth = 80;

  public readonly string MethodName;

  private float _buttonWidth = kDefaultButtonWidth;
  public float ButtonWidth
  {
    get { return _buttonWidth; }
    set { _buttonWidth = value; }
  }

  public InspectorButtonAttribute(string MethodName)
  {
    this.MethodName = MethodName;
  }
}

#if UNITY_EDITOR
[CustomPropertyDrawer(typeof(InspectorButtonAttribute))]
public class InspectorButtonPropertyDrawer : PropertyDrawer
{
  private MethodInfo _eventMethodInfo = null;

  public override void OnGUI(Rect position, SerializedProperty prop, GUIContent label)
  {
    InspectorButtonAttribute inspectorButtonAttribute = (InspectorButtonAttribute)attribute;
    Rect buttonRect = new Rect(position.x + (position.width - inspectorButtonAttribute.ButtonWidth) * 0.5f, position.y, inspectorButtonAttribute.ButtonWidth, position.height);
    if (GUI.Button(buttonRect, label.text))
    {
      System.Type eventOwnerType = prop.serializedObject.targetObject.GetType();
      string eventName = inspectorButtonAttribute.MethodName;

      if (_eventMethodInfo == null)
        _eventMethodInfo = eventOwnerType.GetMethod(eventName, BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);

      if (_eventMethodInfo != null)
        _eventMethodInfo.Invoke(prop.serializedObject.targetObject, null);
      else
        Debug.LogWarning(string.Format("InspectorButton: Unable to find method {0} in {1}", eventName, eventOwnerType));
    }
  }
}
#endif