using System.Collections.Generic;
using UnityEngine;

namespace UnityMoveIt2.Core
{
    /// <summary>
    /// 可视化引擎 - 碰撞可视化部分 / Visualization Engine - Collision Visualization Part
    /// </summary>
    public partial class VisualizationEngine
    {
        #region Collision Fields

        [Header("碰撞可视化设置 / Collision Visualization Settings")]
        [SerializeField]
        private Color collisionColor = Color.red;

        [SerializeField]
        private Color warningColor = Color.yellow;

        [SerializeField]
        [Tooltip("碰撞透明度 / Collision Transparency")]
        private float collisionTransparency = 0.5f;

        [SerializeField]
        [Tooltip("警告距离(米) / Warning Distance (m)")]
        private float warningDistance = 0.1f;

        [SerializeField]
        [Tooltip("显示碰撞边界 / Show Collision Bounds")]
        private bool showCollisionBounds = true;

        private Dictionary<string, GameObject> collisionHighlights;
        private List<CollisionPair> activeCollisions;
        private Material collisionMaterial;
        private Material warningMaterial;

        #endregion

        #region Collision Initialization

        private void InitializeCollisionVisualization()
        {
            collisionHighlights = new Dictionary<string, GameObject>();
            activeCollisions = new List<CollisionPair>();

            // 创建碰撞材质 / Create collision materials
            collisionMaterial = CreateTransparentMaterial(collisionColor, collisionTransparency);
            warningMaterial = CreateTransparentMaterial(warningColor, collisionTransparency);

            Debug.Log("[VisualizationEngine] 碰撞可视化已初始化 / Collision visualization initialized");
        }

        private Material CreateTransparentMaterial(Color color, float transparency)
        {
            Material mat = new Material(Shader.Find("Standard"));
            mat.SetFloat("_Mode", 3); // Transparent mode
            mat.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
            mat.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
            mat.SetInt("_ZWrite", 0);
            mat.DisableKeyword("_ALPHATEST_ON");
            mat.EnableKeyword("_ALPHABLEND_ON");
            mat.DisableKeyword("_ALPHAPREMULTIPLY_ON");
            mat.renderQueue = 3000;
            mat.color = new Color(color.r, color.g, color.b, transparency);
            return mat;
        }

        #endregion

        #region Collision Update

        private void UpdateCollisionVisualization()
        {
            // 更新碰撞高亮 / Update collision highlights
            UpdateActiveCollisionHighlights();

            // 清理过期的碰撞高亮 / Clean up expired collision highlights
            CleanupInactiveCollisions();
        }

        private void UpdateActiveCollisionHighlights()
        {
            foreach (var collision in activeCollisions)
            {
                if (!collisionHighlights.ContainsKey(collision.objectName))
                {
                    CreateCollisionHighlight(collision);
                }

                UpdateCollisionHighlight(collision);
            }
        }

        private void CreateCollisionHighlight(CollisionPair collision)
        {
            GameObject target = GameObject.Find(collision.objectName);
            if (target == null)
                return;

            GameObject highlight = new GameObject($"CollisionHighlight_{collision.objectName}");
            highlight.transform.SetParent(collisionContainer.transform);

            // 复制目标的网格 / Copy target's mesh
            MeshFilter meshFilter = target.GetComponent<MeshFilter>();
            if (meshFilter != null)
            {
                MeshFilter highlightMesh = highlight.AddComponent<MeshFilter>();
                highlightMesh.mesh = meshFilter.mesh;

                MeshRenderer renderer = highlight.AddComponent<MeshRenderer>();
                renderer.material = collision.isWarning ? warningMaterial : collisionMaterial;
            }

            // 同步位置和旋转 / Sync position and rotation
            highlight.transform.position = target.transform.position;
            highlight.transform.rotation = target.transform.rotation;
            highlight.transform.localScale = target.transform.localScale;

            collisionHighlights[collision.objectName] = highlight;
        }

        private void UpdateCollisionHighlight(CollisionPair collision)
        {
            if (!collisionHighlights.ContainsKey(collision.objectName))
                return;

            GameObject highlight = collisionHighlights[collision.objectName];
            GameObject target = GameObject.Find(collision.objectName);

            if (target != null && highlight != null)
            {
                // 更新位置和旋转 / Update position and rotation
                highlight.transform.position = target.transform.position;
                highlight.transform.rotation = target.transform.rotation;
                highlight.transform.localScale = target.transform.localScale;

                // 更新材质 / Update material
                MeshRenderer renderer = highlight.GetComponent<MeshRenderer>();
                if (renderer != null)
                {
                    renderer.material = collision.isWarning ? warningMaterial : collisionMaterial;
                }
            }
        }

        private void CleanupInactiveCollisions()
        {
            List<string> toRemove = new List<string>();

            foreach (var kvp in collisionHighlights)
            {
                bool isActive = false;
                foreach (var collision in activeCollisions)
                {
                    if (collision.objectName == kvp.Key)
                    {
                        isActive = true;
                        break;
                    }
                }

                if (!isActive)
                {
                    toRemove.Add(kvp.Key);
                }
            }

            foreach (var key in toRemove)
            {
                if (collisionHighlights[key] != null)
                {
                    Destroy(collisionHighlights[key]);
                }
                collisionHighlights.Remove(key);
            }
        }

        #endregion

        #region Public Collision Methods

        /// <summary>
        /// 高亮显示碰撞对象 / Highlight Collision Objects
        /// </summary>
        public void HighlightCollisions(List<string> objectNames)
        {
            activeCollisions.Clear();

            foreach (var name in objectNames)
            {
                activeCollisions.Add(new CollisionPair
                {
                    objectName = name,
                    isWarning = false,
                    distance = 0f
                });
            }

            UpdateCollisionVisualization();
        }

        /// <summary>
        /// 显示碰撞警告 / Show Collision Warnings
        /// </summary>
        public void ShowCollisionWarnings(List<ProximityInfo> proximities)
        {
            foreach (var proximity in proximities)
            {
                if (proximity.distance < warningDistance)
                {
                    bool found = false;
                    foreach (var collision in activeCollisions)
                    {
                        if (collision.objectName == proximity.objectName)
                        {
                            found = true;
                            break;
                        }
                    }

                    if (!found)
                    {
                        activeCollisions.Add(new CollisionPair
                        {
                            objectName = proximity.objectName,
                            isWarning = true,
                            distance = proximity.distance
                        });
                    }
                }
            }

            UpdateCollisionVisualization();
        }

        /// <summary>
        /// 清除碰撞可视化 / Clear Collision Visualization
        /// </summary>
        public void ClearCollisionVisualization()
        {
            activeCollisions.Clear();

            foreach (var kvp in collisionHighlights)
            {
                if (kvp.Value != null)
                {
                    Destroy(kvp.Value);
                }
            }

            collisionHighlights.Clear();

            Debug.Log("[VisualizationEngine] 已清除碰撞可视化 / Cleared collision visualization");
        }

        /// <summary>
        /// 设置碰撞对象列表 / Set Collision Objects List
        /// </summary>
        public void SetCollisionObjects(List<CollisionPair> collisions)
        {
            activeCollisions = new List<CollisionPair>(collisions);
            UpdateCollisionVisualization();
        }

        #endregion

        #region Collision Gizmos

        private void DrawCollisionGizmos()
        {
            if (!showCollisionBounds)
                return;

            Gizmos.color = collisionColor;

            foreach (var collision in activeCollisions)
            {
                GameObject obj = GameObject.Find(collision.objectName);
                if (obj != null)
                {
                    Bounds bounds = GetObjectBounds(obj);
                    if (bounds.size != Vector3.zero)
                    {
                        Gizmos.DrawWireCube(bounds.center, bounds.size);
                    }
                }
            }
        }

        private Bounds GetObjectBounds(GameObject obj)
        {
            Renderer renderer = obj.GetComponent<Renderer>();
            if (renderer != null)
            {
                return renderer.bounds;
            }

            Collider collider = obj.GetComponent<Collider>();
            if (collider != null)
            {
                return collider.bounds;
            }

            return new Bounds(obj.transform.position, Vector3.zero);
        }

        #endregion
    }

    #region Collision Data Structures

    /// <summary>
    /// 碰撞对信息 / Collision Pair Information
    /// </summary>
    [System.Serializable]
    public class CollisionPair
    {
        public string objectName;
        public bool isWarning;
        public float distance;
    }

    /// <summary>
    /// 接近度信息 / Proximity Information
    /// </summary>
    [System.Serializable]
    public class ProximityInfo
    {
        public string objectName;
        public float distance;
        public Vector3 closestPoint;
    }

    #endregion
}