/*
Copyright (c) 2020 Omar Duarte
Unauthorized copying of this file, via any medium is strictly prohibited.
Writen by Omar Duarte, 2020.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
using System.Linq;
using UnityEngine;

namespace PluginMaster
{
    public static class MeshUtils
    {
        public static bool IsPrimitive(Mesh mesh)
        {
            var assetPath = UnityEditor.AssetDatabase.GetAssetPath(mesh);
            return assetPath.Length < 6 ? false : assetPath.Substring(0, 6) != "Assets";
        }

        public static Collider AddCollider(Mesh mesh, GameObject target)
        {
            Collider collider = null;
            void AddMeshCollider()
            {
                var meshCollider = target.AddComponent<MeshCollider>();
                meshCollider.sharedMesh = mesh;
                collider = meshCollider;
            }
            if (IsPrimitive(mesh))
            {
                if (mesh.name == "Sphere") collider = target.AddComponent<SphereCollider>();
                else if (mesh.name == "Capsule") collider = target.AddComponent<CapsuleCollider>();
                else if (mesh.name == "Cube") collider = target.AddComponent<BoxCollider>();
                else if (mesh.name == "Plane") AddMeshCollider();
            }
            else AddMeshCollider();
            return collider;
        }

        public static GameObject[] FindFilters(LayerMask mask, GameObject[] exclude = null, bool excludeColliders = true)
        {
            var objects = new System.Collections.Generic.HashSet<GameObject>();
#if UNITY_2022_2_OR_NEWER
            var meshFilters = GameObject.FindObjectsByType<MeshFilter>(FindObjectsSortMode.None);
            var skinnedMeshes = GameObject.FindObjectsByType<SkinnedMeshRenderer>(FindObjectsSortMode.None);
#else
            var meshFilters = GameObject.FindObjectsOfType<MeshFilter>();
            var skinnedMeshes = GameObject.FindObjectsOfType<SkinnedMeshRenderer>();
#endif
            objects.UnionWith(meshFilters.Select(comp => comp.gameObject));
            objects.UnionWith(skinnedMeshes.Select(comp => comp.gameObject));

            var filterList = new System.Collections.Generic.List<GameObject>(objects);
            if (exclude != null)
            {
                filterList = new System.Collections.Generic.List<GameObject>(objects.Except(exclude));
                objects = new System.Collections.Generic.HashSet<GameObject>(filterList);
            }
            if (excludeColliders)
            {
#if UNITY_2022_2_OR_NEWER
                var colliders = GameObject.FindObjectsByType<Collider>(FindObjectsSortMode.None);
#else
                var colliders = GameObject.FindObjectsOfType<Collider>();
#endif
                var collidersSet
                    = new System.Collections.Generic.HashSet<GameObject>(colliders.Select(comp => comp.gameObject));
                filterList = new System.Collections.Generic.List<GameObject>(objects.Except(collidersSet));
            }
            filterList = filterList.Where(obj => (mask.value & (1 << obj.layer)) != 0).ToList();
            return filterList.ToArray();
        }


        private static System.Reflection.MethodInfo intersectRayMesh = null;
        public static bool Raycast(Ray ray, out RaycastHit hitInfo,
            out GameObject collider, GameObject[] filters, float maxDistance,
            bool sameOriginAsRay = true, Vector3 origin = new Vector3())
        {
            collider = null;
            hitInfo = new RaycastHit();
            if (intersectRayMesh == null)
            {
                var editorTypes = typeof(UnityEditor.Editor).Assembly.GetTypes();
                var type_HandleUtility = editorTypes.FirstOrDefault(t => t.Name == "HandleUtility");
                intersectRayMesh = type_HandleUtility.GetMethod("IntersectRayMesh",
                    System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic);
            }
            var minDistance = float.MaxValue;
            var result = false;
            foreach (var filter in filters)
            {
                if (filter == null) continue;
                var meshFilter = filter.GetComponent<MeshFilter>();
                Mesh mesh;
                if (meshFilter == null)
                {
                    var skinnedMeshRenderer = filter.GetComponent<SkinnedMeshRenderer>();
                    if (skinnedMeshRenderer == null) continue;
                    mesh = skinnedMeshRenderer.sharedMesh;
                }
                else if (meshFilter.sharedMesh == null) continue;
                else mesh = meshFilter.sharedMesh;

                var parameters = new object[] { ray, mesh, filter.transform.localToWorldMatrix, null };
                if ((bool)intersectRayMesh.Invoke(null, parameters))
                {
                    if (sameOriginAsRay)
                    {
                        if (hitInfo.distance > maxDistance) continue;
                    }
                    else
                    {
                        var hitInfoDistance = (hitInfo.point - origin).magnitude;
                        if (hitInfoDistance > maxDistance) continue;
                    }
                    result = true;
                    var hit = (RaycastHit)parameters[3];
                    var hitDistance = hit.distance;
                    if (!sameOriginAsRay) hitDistance = (hit.point - origin).magnitude;                    
                    if (hitDistance < minDistance)
                    {
                        collider = filter;
                        minDistance = hitDistance;
                        hitInfo = hit;
                    }
                }
            }
            if (result)
            {
                hitInfo.normal = hitInfo.normal.normalized;
            }
            return result;
        }

        public static bool Raycast(Vector3 origin, Vector3 direction,
            out RaycastHit hitInfo, out GameObject collider, GameObject[] filters, float maxDistance)
        {
            var ray = new Ray(origin, direction);
            return Raycast(ray, out hitInfo, out collider, filters, maxDistance);
        }

        public static bool RaycastAll(Ray ray, out RaycastHit[] hitInfo,
            out GameObject[] colliders, GameObject[] filters, float maxDistance)
        {
            System.Collections.Generic.List<RaycastHit> hitInfoList = new System.Collections.Generic.List<RaycastHit>();
            System.Collections.Generic.List<GameObject> colliderList = new System.Collections.Generic.List<GameObject>();
            if (intersectRayMesh == null)
            {
                var editorTypes = typeof(UnityEditor.Editor).Assembly.GetTypes();
                var type_HandleUtility = editorTypes.FirstOrDefault(t => t.Name == "HandleUtility");
                intersectRayMesh = type_HandleUtility.GetMethod("IntersectRayMesh",
                    System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic);
            }
            foreach (var filter in filters)
            {
                if (filter == null) continue;
                var meshFilter = filter.GetComponent<MeshFilter>();
                Mesh mesh;
                if (meshFilter == null)
                {
                    var skinnedMeshRenderer = filter.GetComponent<SkinnedMeshRenderer>();
                    if (skinnedMeshRenderer == null) continue;
                    mesh = skinnedMeshRenderer.sharedMesh;
                }
                else if (meshFilter.sharedMesh == null) continue;
                else mesh = meshFilter.sharedMesh;

                var parameters = new object[] { ray, mesh, filter.transform.localToWorldMatrix, null };
                if ((bool)intersectRayMesh.Invoke(null, parameters))
                {
                    var hit = (RaycastHit)parameters[3];
                    if (hit.distance > maxDistance) continue;
                    hitInfoList.Add(hit);
                    colliderList.Add(filter);
                }
            }
            hitInfo = hitInfoList.ToArray();
            colliders = colliderList.ToArray();
            return hitInfoList.Count > 0;
        }
    }
}