// Copyright 2017 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using UnityEngine;
using UnityEngine.UI;
using UnityEditor;

[CustomPropertyDrawer(typeof(GvrPointerScrollInput), true)]
public class GvrPointerScrollInputEditor : PropertyDrawer {
  private bool isExpanded = true;

  public override void OnGUI(Rect position, SerializedProperty property, GUIContent label) {
    EditorGUI.BeginProperty(position, label, property);

    int rows = GetNumRows(property);
    float totalHeight = position.height;
    float rowHeight = totalHeight / rows;
    position.height = rowHeight;

    isExpanded = EditorGUI.Foldout(position, isExpanded, label);

    if (isExpanded) {
      EditorGUI.indentLevel++;

      // Inertia property.
      SerializedProperty inertia =
        property.FindPropertyRelative(GvrPointerScrollInput.PROPERTY_NAME_INERTIA);

      position.y += rowHeight;
      EditorGUI.PropertyField(position, inertia);

      if (inertia.boolValue) {
        EditorGUI.indentLevel++;

        // Deceleration rate property.
        SerializedProperty decelerationRate =
          property.FindPropertyRelative(GvrPointerScrollInput.PROPERTY_NAME_DECELERATION_RATE);

        position.y += rowHeight;
        EditorGUI.PropertyField(position, decelerationRate);

        EditorGUI.indentLevel--;
      }
      EditorGUI.indentLevel--;
    }

    EditorGUI.EndProperty();
  }

  public override float GetPropertyHeight(SerializedProperty property, GUIContent label) {
    return base.GetPropertyHeight(property, label) * GetNumRows(property);
  }

  private int GetNumRows(SerializedProperty property) {
    SerializedProperty inertia =
      property.FindPropertyRelative(GvrPointerScrollInput.PROPERTY_NAME_INERTIA);

    if (!isExpanded) {
      return 1;
    } else if (!inertia.boolValue) {
      return 2;
    } else {
      return 3;
    }
  }
}