using UnityEditor.EditorTools;
using UnityEngine;
using UnityEngine.TerrainTools;
using UnityEditor.ShortcutManagement;
using UnityEditor.Overlays;
using UnityEngine.UIElements;


namespace UnityEditor.TerrainTools
{
    
    
    internal class ContrastToolOvl : TerrainToolsPaintTool<ContrastToolOvl>
    {
#if UNITY_2019_1_OR_NEWER
        [Shortcut("Terrain/Select Contrast Tool", typeof(TerrainToolShortcutContext))]
        static void SelectShortcut(ShortcutArguments args)
        {
            TerrainToolShortcutContext context = (TerrainToolShortcutContext)args.context;
            context.SelectPaintToolWithOverlays<ContrastToolOvl>();
            TerrainToolsAnalytics.OnShortcutKeyRelease("Select Contrast Tool");
        }
#endif
        public override string OnIcon => "Packages/com.unity.terrain-tools/Editor/Icons/TerrainOverlays/Contrast_On.png";
        public override string OffIcon => "Packages/com.unity.terrain-tools/Editor/Icons/TerrainOverlays/Contrast.png";
        
        IBrushUIGroup commonUI {
            get
            {
                if (m_commonUI == null)
                {
                    LoadSettings();
                    m_commonUI = new DefaultBrushUIGroup(
                        "ContrastTool",
                        UpdateAnalyticParameters,
                        DefaultBrushUIGroup.Feature.All,
                        new DefaultBrushUIGroup.FeatureDefaults { Strength = 0.83f }
                        );
                    m_commonUI.OnEnterToolMode();
                }

                return m_commonUI;
            }
        }


        [SerializeField]
        float m_FeatureSize = 25.0f;

        Material m_Material = null;
        Material GetPaintMaterial()
        {
            if (m_Material == null)
                m_Material = new Material(Shader.Find("Hidden/TerrainTools/ContrastTool"));
            return m_Material;
        }

        public override int IconIndex
        {
            get { return (int) ToolIndex.SculptIndex.Contrast; }
        }

        public override TerrainCategory Category
        {
            get { return TerrainCategory.Sculpt; }
        }

        public override string GetName()
        {
          return "Effects/Contrast"; 
        }

        public override string GetDescription()
        {
            return "Applies a contrast filter that sharpens the Terrain features."; 
        }
        
        public override bool HasToolSettings => true;
        public override bool HasBrushFilters => true;
        public override bool HasBrushMask => true;
        public override bool HasBrushAttributes => true;

        public override void OnEnterToolMode()
        {
            base.OnEnterToolMode();
            commonUI.OnEnterToolMode();
        }

        public override void OnExitToolMode()
        {
            base.OnExitToolMode();
            commonUI.OnExitToolMode();
        }

        public override void OnSceneGUI(Terrain terrain, IOnSceneGUI editContext)
        {
            commonUI.OnSceneGUI2D(terrain, editContext);

            // only do the rest if user mouse hits valid terrain or they are using the
            // brush parameter hotkeys to resize, etc
            if (!editContext.hitValidTerrain && !commonUI.isInUse)
            {
                return;
            }

            Texture brushTexture = editContext.brushTexture;

            // Only render preview if this is a repaint. losing performance if we do
            if (Event.current.type == EventType.Repaint)
            {
                using (IBrushRenderPreviewUnderCursor brushRender =
                    new BrushRenderPreviewUIGroupUnderCursor(commonUI, "ContrastTool", brushTexture))
                {
                    if (brushRender.CalculateBrushTransform(out BrushTransform brushXform))
                    {
                        PaintContext paintContext =
                            brushRender.AcquireHeightmap(false, brushXform.GetBrushXYBounds(), 1);
                        Material previewMaterial = Utility.GetDefaultPreviewMaterial(commonUI.hasEnabledFilters);
                        var texelCtx = Utility.CollectTexelValidity(paintContext.originTerrain,
                            brushXform.GetBrushXYBounds());
                        Utility.SetupMaterialForPaintingWithTexelValidityContext(paintContext, texelCtx, brushXform,
                            previewMaterial);
                        var filterRT = RTUtils.GetTempHandle(paintContext.sourceRenderTexture.width,
                            paintContext.sourceRenderTexture.height, 0, FilterUtility.defaultFormat);
                        Utility.GenerateAndSetFilterRT(commonUI, paintContext.sourceRenderTexture, filterRT,
                            previewMaterial);
                        TerrainPaintUtilityEditor.DrawBrushPreview(paintContext,
                            TerrainBrushPreviewMode.SourceRenderTexture,
                            editContext.brushTexture, brushXform, previewMaterial, 0);

                        // draw result preview
                        {
                            ApplyBrushInternal(brushRender, paintContext, commonUI.brushStrength, brushTexture,
                                brushXform);

                            // restore old render target
                            RenderTexture.active = paintContext.oldRenderTexture;

                            previewMaterial.SetTexture("_HeightmapOrig", paintContext.sourceRenderTexture);
                            TerrainPaintUtilityEditor.DrawBrushPreview(paintContext,
                                TerrainBrushPreviewMode.DestinationRenderTexture,
                                editContext.brushTexture, brushXform, previewMaterial, 1);
                        }

                        texelCtx.Cleanup();
                        RTUtils.Release(filterRT);
                        brushRender.Release(paintContext);
                    }
                }
            }
            
            // update brush UI group
            commonUI.OnSceneGUI(terrain, editContext);
        }

        bool m_ShowControls = true;

        public override void OnToolSettingsGUI(Terrain terrain, IOnInspectorGUI editContext)
        {
            m_ShowControls = TerrainToolGUIHelper.DrawHeaderFoldoutForBrush(Styles.controls, m_ShowControls, () => { m_FeatureSize = 25.0f; });
            if (m_ShowControls)
            {
                EditorGUILayout.BeginVertical("GroupBox");
                m_FeatureSize = EditorGUILayout.Slider(Styles.featureSize, m_FeatureSize, 1.0f, 100.0f);
                EditorGUILayout.EndVertical();
            }
        }

        public override void OnInspectorGUI(Terrain terrain, IOnInspectorGUI editContext)
        {
            EditorGUI.BeginChangeCheck();

            commonUI.OnInspectorGUI(terrain, editContext);
            OnToolSettingsGUI(terrain, editContext);


            if (EditorGUI.EndChangeCheck())
            {
                SaveSetting();
                TerrainToolsAnalytics.OnParameterChange();
            }
        }

        public void ApplyBrushInternal(IPaintContextRender renderer, PaintContext paintContext, float brushStrength, Texture brushTexture, BrushTransform brushXform)
        {
            Material mat = GetPaintMaterial();
            Vector4 brushParams = new Vector4(commonUI.brushStrength, 0.0f, m_FeatureSize, 0);

            mat.SetTexture("_BrushTex", brushTexture);
            mat.SetVector("_BrushParams", brushParams);

            renderer.SetupTerrainToolMaterialProperties(paintContext, brushXform, mat);
            renderer.RenderBrush(paintContext, mat, 0);
        }

        public override bool OnPaint(Terrain terrain, IOnPaint editContext)
        {
            Texture brushTexture = editContext.brushTexture;

            commonUI.OnPaint(terrain, editContext);

            if (!commonUI.allowPaint)
            { return true; }

            using (IBrushRenderUnderCursor brushRender = new BrushRenderUIGroupUnderCursor(commonUI, "ContrastTool", brushTexture))
            {
                if (brushRender.CalculateBrushTransform(out BrushTransform brushXform))
                {
                    PaintContext paintContext = brushRender.AcquireHeightmap(true, brushXform.GetBrushXYBounds(), 1);

                    Material mat = GetPaintMaterial();
                    var brushMask = RTUtils.GetTempHandle(paintContext.sourceRenderTexture.width, paintContext.sourceRenderTexture.height, 0, FilterUtility.defaultFormat);
                    Utility.GenerateAndSetFilterRT(commonUI, paintContext.sourceRenderTexture, brushMask, mat);
                    paintContext.sourceRenderTexture.filterMode = FilterMode.Bilinear;
                    ApplyBrushInternal(brushRender, paintContext, commonUI.brushStrength, editContext.brushTexture, brushXform);
                    RTUtils.Release(brushMask);
                }
            }
            return false;
        }

        private static class Styles
        {
            public static readonly GUIContent controls = EditorGUIUtility.TrTextContent("Contrast Tool Controls");
            public static readonly GUIContent featureSize = EditorGUIUtility.TrTextContent("Feature Size", "Larger value will affect larger features, smaller values will affect smaller features");
        }

        private void SaveSetting()
        {
            EditorPrefs.SetFloat("Unity.TerrainTools.Contrast.FeatureSize", m_FeatureSize);
        }

        private void LoadSettings()
        {
            m_FeatureSize = EditorPrefs.GetFloat("Unity.TerrainTools.Contrast.FeatureSize", 25.0f);
        }

        //Analytics Setup
        private TerrainToolsAnalytics.IBrushParameter[] UpdateAnalyticParameters() => new TerrainToolsAnalytics.IBrushParameter[]{
            new TerrainToolsAnalytics.BrushParameter<float>{Name = Styles.featureSize.text, Value = m_FeatureSize},
        };
    }
}