using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;

namespace Attributes.Editor
{
    [CustomPropertyDrawer(typeof(RequireAttribute))]
    public class RequireAttributeDrawer : PropertyDrawer
    {
        private readonly string HELPBOX_CONTENT = "Property has to be set!";
        
        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            bool isNull = !property.objectReferenceValue;
            
            if (isNull) position.height = EditorGUIUtility.singleLineHeight;
            
            EditorGUI.PropertyField(position, property, label);

            if (isNull)
            {
                position.y += position.height + EditorGUIUtility.standardVerticalSpacing;
                position.height = EditorStyles.helpBox.CalcHeight(new GUIContent(HELPBOX_CONTENT),
                    EditorGUIUtility.currentViewWidth) + 10.0f;
                EditorGUI.HelpBox(position, HELPBOX_CONTENT, MessageType.Error);
            }
        }

        public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
        {
            if (property.objectReferenceValue) return EditorGUIUtility.singleLineHeight;
            return EditorGUIUtility.singleLineHeight + EditorGUIUtility.standardVerticalSpacing + EditorStyles.helpBox.CalcHeight(new GUIContent(HELPBOX_CONTENT), EditorGUIUtility.currentViewWidth) + 10.0f;
        }
    }
}