using System;
using UnityEngine;

namespace KitsuneCafe.Sys.Attributes
{
  /// <summary>
  /// Draws the field/property ONLY if the compared property compared by the comparison type with the value of comparedValue returns true.
  /// Based on: https://forum.unity.com/threads/draw-a-field-only-if-a-condition-is-met.448855/
  /// </summary>
  [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = true)]
  public class DrawIfAttribute : PropertyAttribute
  {
    #region Fields
    public string ComparedPropertyName { get; private set; }
    public object ComparedValue { get; private set; }
    public DisablingType DisablingType { get; private set; }
    public bool IsEnumWithFlags { get; private set; }

    #endregion
    /// <summary>
    /// Only draws the field if the condition is true.<br></br>
    /// Supports Boolean and Enum.
    /// </summary>
    /// <param name="comparedPropertyName">The name of the property that is being compared (case sensitive).</param>
    /// <param name="comparedValue">The value the property is being compared to.</param>
    /// <param name="disablingType">Determine if it will hide the field or make it read only if the condition is NOT met. 
    /// <param name="type">The type of the ComparedValue object to determine if it's an enum with the [Flags] attribute or not.
    /// Defaulted to DisablingType.DontDraw.</param>
    public DrawIfAttribute(string comparedPropertyName, object comparedValue, DisablingType disablingType = DisablingType.DontDraw, Type type = null)
    {
      ComparedPropertyName = comparedPropertyName;
      ComparedValue = comparedValue;
      DisablingType = disablingType;
      IsEnumWithFlags = HasFlagsAttribute(type);
    }

    /// <summary>
    /// Determine if an Enum type has the [Flags] attribute
    /// </summary>
    /// <param name="type"></param>
    /// <returns></returns>
    private bool HasFlagsAttribute(Type type)
    {
      if (type == null || type.IsEnum == false) { return false; }

      return type.IsDefined(typeof(FlagsAttribute), inherit: false);
    }
  }

  /// <summary>
  /// Types of comperisons.
  /// </summary>
  public enum DisablingType
  {
    ReadOnly = 2,
    DontDraw = 3
  }
}