#if UNITY_2021_2_OR_NEWER
using System;
using System.Collections.Generic;
using UnityEditor.Overlays;
using UnityEngine.UIElements;
using UnityEditor;
using UnityEngine;
using UnityEditor.Toolbars;

namespace SingularityGroup.HotReload.Editor {
    [Overlay(typeof(SceneView), "Hot Reload", true)]
    [Icon("Assets/HotReload/Editor/Resources/Icon_DarkMode.png")]
    internal class HotReloadOverlay : ToolbarOverlay {
        HotReloadOverlay() : base(HotReloadToolbarIndicationButton.id, HotReloadToolbarEventsButton.id, HotReloadToolbarRecompileButton.id) {
            EditorApplication.update += Update;
        }
        
        EditorIndicationState.IndicationStatus lastIndicationStatus;
        
        [EditorToolbarElement(id, typeof(SceneView))]
        class HotReloadToolbarIndicationButton : EditorToolbarButton, IAccessContainerWindow {
            internal const string id = "HotReloadOverlay/LogoButton";
            public EditorWindow containerWindow { get; set; }

            EditorIndicationState.IndicationStatus lastIndicationStatus;
            
            internal HotReloadToolbarIndicationButton() {
                icon = GetIndicationIcon();
                tooltip = EditorIndicationState.IndicationStatusText;
                clicked += OnClick;
                EditorApplication.update += Update;
            }

            void OnClick() {
                EditorWindow.GetWindow<HotReloadWindow>().Show();
                EditorWindow.GetWindow<HotReloadWindow>().SelectTab(typeof(HotReloadRunTab));
            }
       
            void Update() {
                if (lastIndicationStatus != EditorIndicationState.CurrentIndicationStatus) {
                    icon = GetIndicationIcon();
                    tooltip = EditorIndicationState.IndicationStatusText;
                    lastIndicationStatus = EditorIndicationState.CurrentIndicationStatus;
                }
            }

            ~HotReloadToolbarIndicationButton() {
                clicked -= OnClick;
                EditorApplication.update -= Update;
            }
        }
        
        [EditorToolbarElement(id, typeof(SceneView))]
        class HotReloadToolbarEventsButton : EditorToolbarButton, IAccessContainerWindow {
            internal const string id = "HotReloadOverlay/EventsButton";
            public EditorWindow containerWindow { get; set; }
            
            bool lastShowingRedDot;
            
            internal HotReloadToolbarEventsButton() {
                icon = HotReloadState.ShowingRedDot ? GUIHelper.GetInvertibleIcon(InvertibleIcon.EventsNew) : GUIHelper.GetInvertibleIcon(InvertibleIcon.Events);
                tooltip = "Events";
                clicked += OnClick;
                EditorApplication.update += Update;
            }

            void OnClick() {
                HotReloadEventPopup.Open(PopupSource.Overlay, Event.current.mousePosition);
            }
       
            void Update() {
                if (lastShowingRedDot != HotReloadState.ShowingRedDot) {
                    icon = HotReloadState.ShowingRedDot ? GUIHelper.GetInvertibleIcon(InvertibleIcon.EventsNew) : GUIHelper.GetInvertibleIcon(InvertibleIcon.Events);
                    lastShowingRedDot = HotReloadState.ShowingRedDot;
                }
            }

            ~HotReloadToolbarEventsButton() {
                clicked -= OnClick;
                EditorApplication.update -= Update;
            }
        }
        
        
        [EditorToolbarElement(id, typeof(SceneView))]
        class HotReloadToolbarRecompileButton : EditorToolbarButton, IAccessContainerWindow {
            internal const string id = "HotReloadOverlay/RecompileButton";
            
            public EditorWindow containerWindow { get; set; }
            
            private Texture2D refreshIcon => GUIHelper.GetInvertibleIcon(InvertibleIcon.Recompile);
            internal HotReloadToolbarRecompileButton() {
                icon = refreshIcon;
                tooltip = "Recompile";
                clicked += HotReloadRunTab.RecompileWithChecks;
            }
        }

        private static Texture2D latestIcon;
        private static Dictionary<string, Texture2D> iconTextures = new Dictionary<string, Texture2D>();
        private static Spinner spinner = new Spinner(100);
        private static Texture2D GetIndicationIcon() {
            if (EditorIndicationState.IndicationIconPath == null || EditorIndicationState.SpinnerActive) {
                latestIcon = spinner.GetIcon();
            } else {
                latestIcon = GUIHelper.GetLocalIcon(EditorIndicationState.IndicationIconPath);
            }
            return latestIcon;
        }

        private static Image indicationIcon;
        private static Label indicationText;

        bool initialized;
        /// <summary>
        /// Create Hot Reload overlay panel.
        /// </summary>
        public override VisualElement CreatePanelContent() {
            var root = new VisualElement() { name = "Hot Reload Indication" };
            root.style.flexDirection = FlexDirection.Row;
            
            indicationIcon = new Image() { image = GUIHelper.GetLocalIcon(EditorIndicationState.greyIconPath) };
            indicationIcon.style.height = 30;
            indicationIcon.style.width = 30;
            indicationIcon.style.marginLeft = 2;
            indicationIcon.style.marginTop = 1;
            indicationIcon.style.marginRight = 5;
            
            indicationText = new Label(){text = EditorIndicationState.IndicationStatusText};
            indicationText.style.paddingTop = 9;
            indicationText.style.marginLeft = new StyleLength(StyleKeyword.Auto);
            indicationText.style.marginRight = new StyleLength(StyleKeyword.Auto);
            
            root.Add(indicationIcon);
            root.Add(indicationText);
            root.style.width = 190;
            root.style.height = 32;
            initialized = true;
            return root;
        }

        static bool _repaint;
        static bool _instantRepaint;
        static DateTime _lastRepaint;
        private void Update() {
            if (!initialized) {
                return;
            }
            if (lastIndicationStatus != EditorIndicationState.CurrentIndicationStatus) {
                indicationIcon.image = GetIndicationIcon();
                indicationText.text = EditorIndicationState.IndicationStatusText;
                lastIndicationStatus = EditorIndicationState.CurrentIndicationStatus;
            }
            try {
                if (HotReloadEventPopup.I.open 
                    && EditorWindow.mouseOverWindow
                    && EditorWindow.mouseOverWindow?.GetType() == typeof(UnityEditor.PopupWindow)
                ) {
                    _repaint = true;
                }
            } catch (NullReferenceException) {
                // Unity randomly throws nullrefs when EditorWindow.mouseOverWindow gets accessed
            }
            if (_repaint && DateTime.UtcNow - _lastRepaint > TimeSpan.FromMilliseconds(33)) {
                _repaint = false;
                _instantRepaint = true;
            }
            if (_instantRepaint) {
                HotReloadEventPopup.I.Repaint();
            }
        }

        ~HotReloadOverlay() {
            EditorApplication.update -= Update;
        }
    }
}
#endif