using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using Rokid.UXR.Interaction;
namespace Rokid.UXR.Editor
{

    public class InterfacePicker : EditorWindow
    {
        private class MonoInspector
        {
            public readonly MonoBehaviour Mono;
            public readonly UnityEditor.Editor Editor;

            public MonoInspector(MonoBehaviour mono)
            {
                Mono = mono;
                Editor = UnityEditor.Editor.CreateEditor(mono);
            }

            public void Destroy()
            {
                DestroyImmediate(Editor);
            }
        }

        private static class GUIStyles
        {
            public static readonly GUIStyle Default;
            public static readonly GUIStyle Window;
            public static readonly GUIStyle Inspector;

            private static readonly RectOffset padding =
                new RectOffset(EDGE_PADDING_PX,
                               EDGE_PADDING_PX,
                               EDGE_PADDING_PX,
                               EDGE_PADDING_PX);

            static GUIStyles()
            {
                Default = new GUIStyle();
                Window = new GUIStyle(Default);
                Window.padding = padding;
                Inspector = new GUIStyle(GUI.skin.window);
                Inspector.padding = padding;
            }
        }

        private const float SELECT_BUTTON_HEIGHT_PX = 32f;
        private const float LABEL_COLUMN_RATIO = 0.4f;
        private const int EDGE_PADDING_PX = 8;

        public static bool AnyOpen => HasOpenInstances<InterfacePicker>();

        private Object _target;
        private string _propertyPath;
        private List<MonoInspector> _monoInspectors;
        private Vector2 _scrollPos = Vector2.zero;

        public static void Show(SerializedProperty prop, List<MonoBehaviour> monos)
        {
            if (monos == null ||
                monos.Count == 0 ||
                prop == null)
            {
                return;
            }

            InterfacePicker picker = GetWindow<InterfacePicker>(true);

            picker._propertyPath = prop.propertyPath;
            picker._target = prop.serializedObject.targetObject;
            picker._monoInspectors?.ForEach((mi) => mi.Destroy());
            picker._monoInspectors = new List<MonoInspector>();
            picker.titleContent = new GUIContent(monos[0].gameObject.name);
            monos.ForEach((m) => picker._monoInspectors.Add(new MonoInspector(m)));

            picker.ShowUtility();
        }

        private void OnGUI()
        {
            if (_target == null)
            {
                Close();
                return;
            }

            Prune();
            DrawAll();
        }

        private void OnDestroy()
        {
            _monoInspectors.ForEach((mi) => mi.Destroy());
        }

        private void Prune()
        {
            _monoInspectors.FindAll((m) => m.Mono == null).ForEach((mi) =>
            {
                _monoInspectors.Remove(mi);
                mi.Destroy();
            });
        }

        private void DrawAll()
        {
            _scrollPos = EditorGUILayout.BeginScrollView(_scrollPos, GUIStyles.Window);
            foreach (var monoInspector in _monoInspectors)
            {
                EditorGUILayout.Separator();
                EditorGUILayout.BeginVertical(GUIStyles.Inspector);
                DrawHeader(monoInspector);
                EditorGUILayout.Separator();
                DrawComponent(monoInspector);
                EditorGUILayout.EndVertical();
            }
            GUILayout.FlexibleSpace();
            EditorGUILayout.EndScrollView();
        }

        private void DrawHeader(MonoInspector monoInspector)
        {
            if (GUILayout.Button($"{monoInspector.Mono.GetType().Name}",
                GUILayout.Height(SELECT_BUTTON_HEIGHT_PX)))
            {
                Apply(monoInspector.Mono);
                Close();
            }
        }

        private void DrawComponent(MonoInspector monoInspector)
        {
            GUI.enabled = false;
            EditorGUIUtility.labelWidth = position.width * LABEL_COLUMN_RATIO;
            monoInspector.Editor.OnInspectorGUI();
            GUI.enabled = true;
        }

        private void Apply(MonoBehaviour mono)
        {
            SerializedProperty property =
                new SerializedObject(_target).FindProperty(_propertyPath);
            property.objectReferenceValue = mono;
            property.serializedObject.ApplyModifiedProperties();
        }
    }
}