// Unity C# reference source
// Copyright (c) Unity Technologies. For terms of use, see
// https://unity3d.com/legal/licenses/Unity_Reference_Only_License

using UnityEngine;
using UnityEditor;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;

namespace UnityEditor
{
    class TooltipView : GUIView
    {
        private const float MAX_WIDTH = 300.0f;

        private GUIContent m_tooltip = new GUIContent();
        private Vector2 m_optimalSize;
        private GUIStyle m_Style;
        private Rect m_hoverRect;

        static TooltipView s_guiView;

        protected override void OnEnable()
        {
            base.OnEnable();
            s_guiView = this;
        }

        protected override void OnDisable()
        {
            base.OnDisable();
            s_guiView = null;
        }

        protected override void OldOnGUI()
        {
            if (window != null)
            {
                GUI.Box(new Rect(0, 0, m_optimalSize.x, m_optimalSize.y) , m_tooltip, m_Style);
            }
        }

        void Setup(string tooltip, Rect rect)
        {
            m_hoverRect = rect;
            m_tooltip.text = tooltip;

            // Calculate size and position tooltip view
            m_Style = EditorStyles.tooltip;

            m_Style.wordWrap = false;
            m_optimalSize = m_Style.CalcSize(m_tooltip);

            if (m_optimalSize.x > MAX_WIDTH)
            {
                m_Style.wordWrap = true;
                m_optimalSize.x = MAX_WIDTH;
                m_optimalSize.y = m_Style.CalcHeight(m_tooltip, MAX_WIDTH);
            }

            window.position = new Rect(
                Mathf.Floor(m_hoverRect.x + (m_hoverRect.width / 2) - (m_optimalSize.x / 2)),
                Mathf.Floor(m_hoverRect.y + (m_hoverRect.height) + 10.0f),
                m_optimalSize.x, m_optimalSize.y);

            position = new Rect(0, 0, m_optimalSize.x, m_optimalSize.y);

            window.ShowTooltip();
            window.SetAlpha(1.0f);
            s_guiView.mouseRayInvisible = true;

            RepaintImmediately(); // Force repaint to fix that the tooltip text did sometimes not update (we did not get a new OnGUI if the rect had the same size)
        }

        public static void Show(string tooltip, Rect rect)
        {
            if (s_guiView == null)
            {
                s_guiView = ScriptableObject.CreateInstance<TooltipView>();
            }

            if (s_guiView.window == null)
            {
                var newWindow = ScriptableObject.CreateInstance<ContainerWindow>();
                newWindow.m_DontSaveToLayout = true;
                newWindow.rootView = s_guiView;
                newWindow.SetMinMaxSizes(new Vector2(10.0f, 10.0f), new Vector2(2000.0f, 2000.0f));
                s_guiView.SetWindow(newWindow);
            }

            if (s_guiView.m_tooltip.text == tooltip && rect == s_guiView.m_hoverRect)
                return;

            s_guiView.Setup(tooltip, rect);
        }

        public static void Close()
        {
            if (s_guiView != null)
                s_guiView.window.Close();
        }

        public static void SetAlpha(float percent)
        {
            if (s_guiView != null)
                s_guiView.window.SetAlpha(percent);
        }
    }
}
