using System;
using System.Linq;
using System.Runtime.InteropServices;
using UnityEngine;
using UnityEngine.UIElements;

namespace UnityEditor
{
    internal class Toast : EditorWindow
    {
        private const int DWMWA_WINDOW_CORNER_PREFERENCE = 33;

        private enum DWM_WINDOW_CORNER_PREFERENCE
        {
            DWMWCP_DEFAULT = 0,
            DWMWCP_DONOTROUND = 1,
            DWMWCP_ROUND = 2,
            DWMWCP_ROUNDSMALL = 3
        }

        public enum ToastSeverity
        {
            Info,
            Warning,
            Error
        }

        public enum ToastPosition
        {
            TopLeft,
            TopRight,
            TopCenter,
            BottomLeft,
            BottomRight,
            BottomCenter
        }

        public struct ToastData
        {
            public float TimeCreated { get; set; }
            public ToastArgs ToastArgs { get; set; }
        }

        public struct ToastArgs
        {
            public string Title { get; set; }
            public string Message { get; set; }
            public ToastPosition ToastPosition { get; set; }
            public float LifeTime { get; set; }
            public bool NoTimeOut { get; set; }
            public Func<VisualElement> CustomContent { get; set; }
            public ToastSeverity Severity { get; set; }
        }

        [DllImport("user32.dll")]
        private static extern IntPtr GetActiveWindow();

        [DllImport("dwmapi.dll")]
        private static extern int DwmSetWindowAttribute(IntPtr hwnd, int attr, ref DWM_WINDOW_CORNER_PREFERENCE pref, int attrLen);

        private const float POSITION_SPEED = 10f;
        private const float POSITION_THRESHOLD = 0.1f;
        private const float ROOT_CORNER_RADIUS = 9.2f;
        private const float ROOT_BORDER_WIDTH = 2f;

        public ToastData Data { get; set; }
        public ToastArgs Args;

        public event Action<Toast> OnClose;

        private Rect currentPosition;

        private VisualElement titleBar;
        private Label titleLabel;
        private Label messageLabel;
        private Button closeButton;
        private VisualElement contentContainer;
        private ProgressBar lifetimeBar;

        public void SetupWindow(ToastData toastData)
        {
            Data = toastData;
            Args = toastData.ToastArgs;
            position = this.GetEditorWindowPosition(Args.ToastPosition);
            currentPosition = position;

            titleLabel.text = Args.Title;
            messageLabel.text = Args.Message;
            contentContainer.Add(Args.CustomContent?.Invoke());

            var backgroundColor = Args.Severity switch
            {
                ToastSeverity.Info => new Color(0.27f, 0.38f, 0.49f),
                ToastSeverity.Warning => new Color(0.69f, 0.5f, 0.02f),
                _ => new Color(0.49f, 0f, 0f)
            };

            lifetimeBar.lowValue = 0;
            var datatoastArgs = Data.ToastArgs;
            lifetimeBar.value = lifetimeBar.highValue = datatoastArgs.NoTimeOut ? 1f : datatoastArgs.LifeTime;

            var lifetimeBarContainer = lifetimeBar.Children().First();
            var lifetimeBarBackground = lifetimeBarContainer.Children().First();
            var lifetimeBarFill = lifetimeBarBackground.Children().First();
            if (lifetimeBarFill != null)
            {
                lifetimeBarFill.style.backgroundColor = backgroundColor;
            }

            titleBar.style.backgroundColor = backgroundColor;

            closeButton.RegisterCallback<PointerEnterEvent>(evt =>
            {
                closeButton.style.backgroundColor = backgroundColor;
            });

            closeButton.RegisterCallback<PointerLeaveEvent>(evt =>
            {
                closeButton.style.backgroundColor = new Color(0.31f, 0.31f, 0.31f);
            });

            EnableRoundedCorners();
        }

        private void EnableRoundedCorners()
        {
            IntPtr hwnd = GetActiveWindow();
            if (hwnd != IntPtr.Zero)
            {
                DWM_WINDOW_CORNER_PREFERENCE pref = DWM_WINDOW_CORNER_PREFERENCE.DWMWCP_ROUND;
                DwmSetWindowAttribute(hwnd, DWMWA_WINDOW_CORNER_PREFERENCE, ref pref, sizeof(int));
            }
            else
            {
                Debug.LogWarning("Failed to get window handle.");
            }
        }

        private void CreateGUI()
        {
            rootVisualElement.style.borderTopWidth = ROOT_BORDER_WIDTH;
            rootVisualElement.style.borderBottomWidth = ROOT_BORDER_WIDTH;
            rootVisualElement.style.borderLeftWidth = ROOT_BORDER_WIDTH;
            rootVisualElement.style.borderRightWidth = ROOT_BORDER_WIDTH;
            rootVisualElement.style.borderTopColor = Color.black;
            rootVisualElement.style.borderBottomColor = Color.black;
            rootVisualElement.style.borderLeftColor = Color.black;
            rootVisualElement.style.borderRightColor = Color.black;
            rootVisualElement.style.borderTopLeftRadius = ROOT_CORNER_RADIUS;
            rootVisualElement.style.borderTopRightRadius = ROOT_CORNER_RADIUS;
            rootVisualElement.style.borderBottomLeftRadius = ROOT_CORNER_RADIUS;
            rootVisualElement.style.borderBottomRightRadius = ROOT_CORNER_RADIUS;

            titleBar = new VisualElement
            {
                style =
                {
                    height = 20f,
                    minHeight = 20f,
                    width = new StyleLength(Length.Percent(100)),
                    maxWidth = new StyleLength(Length.Percent(100)),
                    flexDirection = FlexDirection.Row,
                    borderBottomWidth = 1f,
                    borderBottomColor = Color.black
                }
            };
            rootVisualElement.Add(titleBar);
            {
                titleLabel = new Label()
                {
                    style =
                    {
                        flexGrow = 1f,
                        unityFontStyleAndWeight = FontStyle.Bold,
                        fontSize = 13f,
                        unityTextAlign = TextAnchor.MiddleLeft
                    }
                };
                titleBar.Add(titleLabel);

                closeButton = new Button(Close)
                {
                    text = "X",
                    style =
                    {
                        flexGrow = 0f,
                        width = 20f,
                        minWidth = 20f,
                        borderBottomWidth = 0f,
                        borderLeftWidth = 1f,
                        borderRightWidth = 0f,
                        borderTopWidth = 0f,
                        borderTopLeftRadius = 0f,
                        borderTopRightRadius = 0f,
                        borderBottomRightRadius = 0f,
                        borderBottomLeftRadius = 0f,
                        marginRight = 0f,
                        marginLeft = 0f,
                        marginTop = 0f,
                        marginBottom = 0f
                    }
                };
                titleBar.Add(closeButton);
            }

            lifetimeBar = new ProgressBar
            {
                style =
                {
                    marginBottom = 0f,
                    marginLeft = 0f,
                    marginRight = 0f,
                    marginTop = 0f,
                    height = 6f,
                    minHeight = 6f,
                    maxHeight = 6f
                }
            };
            rootVisualElement.Add(lifetimeBar);

            var messageContainer = new VisualElement();
            rootVisualElement.Add(messageContainer);
            {
                messageLabel = new Label
                {
                    style =
                    {
                        marginTop = 2f,
                        marginBottom = 2f,
                        marginLeft = 2f,
                        marginRight = 2f,
                    }
                };
                messageContainer.Add(messageLabel);
            }

            contentContainer = new VisualElement();
            rootVisualElement.Add(contentContainer);
        }

        public float GetHeight() => position.height;

        public void UpdatePosition(Rect positionRect, float currentHeightOffset, double deltaTime)
        {
            var targetPosition = new Rect(positionRect.x, positionRect.y + currentHeightOffset, positionRect.width, positionRect.height);

            if (Mathf.Abs(currentPosition.y - targetPosition.y) < POSITION_THRESHOLD)
            {
                currentPosition.y = targetPosition.y;
                position = currentPosition;
            }
            else
            {
                var newY = Mathf.Lerp(
                    currentPosition.y,
                    targetPosition.y,
                    (float)(POSITION_SPEED * deltaTime)
                );
                currentPosition.y = newY;
                currentPosition.x = targetPosition.x;

                position = currentPosition;
            }
        }

        public bool IsLifetimeOver()
        {
            if (Args.NoTimeOut) return false;

            var currentLifeTime = Time.time - Data.TimeCreated;
            lifetimeBar.value = Args.LifeTime - currentLifeTime;
            return currentLifeTime > Args.LifeTime;
        }

        private void OnDestroy()
        {
            OnClose?.Invoke(this);
        }
    }
}