/*=========================================================================

   Library: iMSTK-Unity

   Copyright (c) Kitware, Inc. 

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0.txt

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

=========================================================================*/

using Unity.Profiling;
using UnityEngine;

namespace ImstkUnity
{


    /// <summary>
    /// Used for models with deformable vertices. That is the vertices are changing
    /// per update of the model in global configuration.
    /// </summary>
    public abstract class DeformableModel : DynamicalModel
    {
        static readonly ProfilerMarker s_UpdatePerfMarker = new ProfilerMarker(ProfilerCategory.Physics, "Imstk.DeformableUpdate");
        TimingBuffer _updateTimes = new TimingBuffer(100);

        // These filters can accept either imstk or unity geometry input
        // and output imstk geometry
        public GeometryFilter visualGeomFilter = null;
        public GeometryFilter physicsGeomFilter = null;
        public GeometryFilter collisionGeomFilter = null;

        public bool cleanVisualMesh;

        public TimingBuffer UpdateTimes {
            get { return _updateTimes; }    
        }

        protected override void OnImstkInit()
        {
            if (imstkObject != null) return;
            // Get dependencies
            meshFilter = visualGeomFilter.gameObject.GetComponentFatal<MeshFilter>();

            if (meshFilter.mesh == null)
            {
                meshFilter.mesh = new Mesh();
            }
            // Make sure mesh filter is read/writable
            meshFilter.mesh.MarkDynamic();
            if (!meshFilter.mesh.isReadable)
            {
                Debug.LogError(gameObject.name + "'s MeshFilter Mesh must be readable (check the meshes import settings)");
                return;
            }

            imstkObject = InitObject();

            // TODO move to simulation manager 
            SimulationManager.sceneManager.getActiveScene().addSceneObject(imstkObject);
            InitGeometry();
            InitGeometryMaps();
            ProcessBoundaryConditions(gameObject.GetComponents<BoundaryCondition>());
            Configure();
        }

        protected override void InitGeometry()
        {
            // Copy all the geometries over to imstk, set the transform and
            // apply later. (to avoid applying transform twice *since two
            // geometries could point to the same one*)

            Imstk.Geometry visualGeom = null;
            // Setup the visual geometry
            if (visualGeomFilter != null)
            {
                visualGeom = GetVisualGeometry();
                visualGeomFilter.MoveToGlobalSpace();
                imstkObject.setVisualGeometry(visualGeom);
            }

            // Visual geometry is Unity this also means it's either a surface or a line mesh
            // For either we do want to clean up the mesh.
            // As the indices not going to match after cleanup a map from the (cleaned) physics mesh 
            // to the visual mesh needs to be added as well
            Imstk.Geometry physicsGeom = null;
            Imstk.PointwiseMap physicsToUnityMeshMap = null;
            if (visualGeomFilter == physicsGeomFilter && cleanVisualMesh)
            {
                var visualMesh = Imstk.Utils.CastTo<Imstk.SurfaceMesh>(visualGeom);
                Debug.Assert(visualMesh != null);

                Debug.Log("Cleaning Mesh");
                Debug.Log("Visual Mesh " + visualMesh.getNumVertices() + " vertices");

                var cleaner = new Imstk.CleanMesh();
                cleaner.setInputMesh(visualMesh);
                cleaner.setTolerance(0.001);
                cleaner.update();
                var physicsMesh = cleaner.getOutputMesh();
                physicsGeom = physicsMesh;
                Debug.Log("Physics Mesh " + physicsMesh.getNumVertices() + " vertices");


                physicsToUnityMeshMap = new Imstk.PointwiseMap(physicsGeom, visualGeom);
                // Tolerance needed to avoid issues with double/float conversions
                physicsToUnityMeshMap.setTolerance(1e-4);
                physicsToUnityMeshMap.compute();
                // TODO Should warn the user if the map doesn't actually map any points

                (imstkObject as Imstk.DynamicObject).setPhysicsGeometry(physicsGeom);
                (imstkObject as Imstk.DynamicObject).getDynamicalModel().setModelGeometry(physicsGeom);
                (imstkObject as Imstk.DynamicObject).setPhysicsToVisualMap(physicsToUnityMeshMap);
            }
            else if (physicsGeomFilter != null)
            {
                physicsGeom = GetPhysicsGeometry();
                physicsGeomFilter.MoveToGlobalSpace();
                (imstkObject as Imstk.DynamicObject).setPhysicsGeometry(physicsGeom);
                (imstkObject as Imstk.DynamicObject).getDynamicalModel().setModelGeometry(physicsGeom);
            }
            else
            {
                Debug.LogError("No physics geometry provided to DynamicalModel on object " + gameObject.name);
            }


            if (collisionGeomFilter != null)
            {
                if (visualGeomFilter == collisionGeomFilter && visualGeomFilter == physicsGeomFilter)
                {
                    imstkObject.setCollidingGeometry(physicsGeom);
                }
                else
                {
                    Imstk.Geometry colGeom = GetCollidingGeometry();
                    collisionGeomFilter.MoveToGlobalSpace();
                    imstkObject.setCollidingGeometry(colGeom);
                }
            }
            else
            {
                Debug.LogError("No collision geometry provided to DynamicalModel on object " + gameObject.name);
            }
        }

        protected void InitGeometryMaps()
        {
            // Setup any geometry maps on the object
            // \todo: Generalize geometry maps in imstk, currently
            // well test geometry types to figure out maps
            GeometryMap[] geomMaps = gameObject.GetComponents<GeometryMap>();

            // \todo: Currently imstk only supports physicstovisual and physicstocollision
            // this needs to be generalized. For now we will only support two maps. There are
            // some other minute but tricky details to be worked out here.
            for (int i = 0; i < geomMaps.Length; i++)
            {
                GeometryMap map = geomMaps[i];
                // Test if map contains physics or visual
                if (map.parentGeom == physicsGeomFilter &&
                    map.childGeom == collisionGeomFilter)
                {
                    Imstk.DynamicObject dynObj = imstkObject as Imstk.DynamicObject;
                    Imstk.GeometryMap geomMap = map.GetMap();
                    if (geomMap != null)
                    {
                        dynObj.setPhysicsToCollidingMap(geomMap);
                        Debug.Log("Set up Physics to Collision Map");
                        geomMap.compute();
                    }
                }
                else if (map.parentGeom == physicsGeomFilter &&
                    map.childGeom == visualGeomFilter)
                {
                    Imstk.DynamicObject dynObj = imstkObject as Imstk.DynamicObject;
                    Imstk.GeometryMap geomMap = map.GetMap();
                    if (geomMap != null)
                    {
                        dynObj.setPhysicsToVisualMap(geomMap);
                        Debug.Log("Set up Physics to Visual Map");
                        geomMap.compute();
                    }
                }
                else if (map.parentGeom == collisionGeomFilter &&
                    map.childGeom == visualGeomFilter)
                {
                    Imstk.GeometryMap geomMap = map.GetMap();
                    if (geomMap != null)
                    {
                        imstkObject.setCollidingToVisualMap(geomMap);
                        Debug.Log("Set up Physics to Visual Map");
                        geomMap.compute();
                    }
                }
            }
        }

        /// <summary>
        /// Visual update of the geometry (only needs to call before render)
        /// </summary>
        public void Update()
        {
            if (SimulationManager.sceneManager == null)
            {
                Debug.LogWarning("Failed to update dynamical model on " + gameObject.name + " no sceneManager from the SimulationManager");
                return;
            }

            s_UpdatePerfMarker.Begin();
            _updateTimes.Begin();

            Imstk.PointSet visualGeom = Imstk.Utils.CastTo<Imstk.PointSet>(imstkObject.getVisualGeometry());
            meshFilter.mesh.vertices = MathUtil.ToVector3Array(visualGeom.getVertexPositions());

            if (meshFilter.mesh.GetTopology(0) == MeshTopology.Triangles ||
                meshFilter.mesh.GetTopology(0) == MeshTopology.Quads)
            {
                meshFilter.mesh.RecalculateNormals();
            }
            meshFilter.mesh.RecalculateBounds();

            _updateTimes.End();
            s_UpdatePerfMarker.End();
        }

        public override Imstk.Geometry GetVisualGeometry()
        {
            return visualGeomFilter.GetOutputGeometry();
        }
        public override Imstk.Geometry GetPhysicsGeometry()
        {
            return physicsGeomFilter.GetOutputGeometry();
        }
        public override Imstk.Geometry GetCollidingGeometry()
        {
            return collisionGeomFilter.GetOutputGeometry();
        }
    }
}