using System.Collections.Generic;
using UnityEngine;
using BaseGames.Core;

namespace BaseGames.Combat
{
    /// <summary>
    /// 攻击判定盒。挂载在武器 Prefab 或技能 HitBox Prefab 的子节点上。
    /// 直接挂在 Player Prefab 子节点 [HitBoxGround/Up/Down/Air]。
    /// Collider2D 需设 IsTrigger = true，Layer = PlayerHitBox 或 EnemyHitBox。
    /// </summary>
    [RequireComponent(typeof(Collider2D))]
    public class HitBox : MonoBehaviour
    {
        [SerializeField] private DamageSourceSO _defaultSource;
        [SerializeField] private float          _hitCooldown = 0.1f;

        /// <summary>
        /// HitBox 标识符，供 PlayerAnimationEvents / EnemyAnimationEvents 按名称精确激活特定判定盒。
        /// 留空表示"无 Id"；事件 payload 为空时将操作所有 HitBox。
        /// </summary>
        [SerializeField] private string _id = "";
        public string Id => _id;

        /// <summary>
        /// 对立阵营 HitBox 所在的 Layer 掩码（用于拼刀检测）。
        /// Inspector 中将 PlayerHitBox 与 EnemyHitBox 两个 Layer 均勾选。
        /// </summary>
        [SerializeField] private LayerMask _rivalHitBoxMask;

        private DamageSourceSO _currentSource;
        private Transform      _attackerTransform;
        private Rigidbody2D    _ownerRigidbody;
        private bool           _isActive;
        private IClashService  _clashService;
        private Collider2D     _collider;

        /// <summary>HitBox 当前是否激活（供 ClashResolver 查询）。</summary>
        public bool IsActive => _isActive;

        /// <summary>当前 Source 是否携带 CanClash 标记（供 ClashResolver 查询）。</summary>
        public bool CanClash => _currentSource != null && _currentSource.Flags.HasFlag(DamageFlags.CanClash);

        /// <summary>宿主角色的 Rigidbody2D（用于拼刀弹开力计算）。</summary>
        public Rigidbody2D OwnerRigidbody => _ownerRigidbody;

        // 拼刀检测所需的对立层掩码（Inspector 配置）

        /// <summary>命中确认委托（PlayerCombat / EnemyCombat 订阅）。</summary>
        public event System.Action<DamageInfo> OnHitConfirmed;

        // 宿主投射物缓存（Activate 时填入，DamageInfo.SourceProjectile 写入用）
        private Projectile _ownerProjectile;

        /// <summary>
        /// 激活 HitBox。source/attacker 均可选，未传则使用 Inspector 默认值。
        /// ⚠️ 不存在 Activate(float duration) 重载。
        /// </summary>
        public void Activate(DamageSourceSO source = null, Transform attacker = null)
        {
            _currentSource     = source   ?? _defaultSource;
            _attackerTransform = attacker ?? transform;
            _isActive          = true;
            // 缓存宿主 Rigidbody2D（沿父层级向上查找）
            _ownerRigidbody    = _attackerTransform.GetComponentInParent<Rigidbody2D>();
            // 每次激活清空当前激活期已命中目标集合（防止连击连段导致同一阶段多次命中目标）
            _hitThisActivation.Clear();
            _hitCooldownTimers.Clear();
        }

        public void Deactivate()
        {
            _isActive = false;
            _hitThisActivation.Clear();
            _hitCooldownTimers.Clear();
        }

        /// <summary>仅替换当前 DamageSource（不改变激活状态，供 PlayerCombat 连击段切换）。</summary>
        public void SetDamageSource(DamageSourceSO source)
        {
            if (source != null) _currentSource = source;
        }

        private void Awake()
        {
            // 确保 Collider2D 是 Trigger
            _collider = GetComponent<Collider2D>();
            if (!_collider.isTrigger)
                Debug.LogWarning($"[HitBox] {name}: Collider2D.isTrigger 应为 true。", this);
            // 缓存 IClashService：OnTriggerEnter2D 为物理热路径，避免每次调用 Dictionary 查找
            _clashService = ServiceLocator.GetOrDefault<IClashService>();
            // 缓存宿主投射物（仅 Projectile GameObject 上挂载的 HitBox 非 null）
            _ownerProjectile = GetComponent<Projectile>();
        }

        private void OnDisable()
        {
            _isActive = false;
            _hitThisActivation.Clear();
            _hitCooldownTimers.Clear();
        }

        private void OnTriggerExit2D(Collider2D other)
        {
            // 目标离开判定区域时清除其冷却记录，防止持续激活的 HitBox（环境危险等）
            // 因有效目标持续流动而无限积累已离场对象。
            // 注意：_hitThisActivation 刻意保留，确保同一激活期内不重复命中。
            _hitCooldownTimers.Remove(other);
        }

        private void OnTriggerEnter2D(Collider2D other)        {
            if (!_isActive) return;
            if (_currentSource == null)
            {
                Debug.LogWarning($"[HitBox] {name}: 无 DamageSourceSO，跳过命中。", this);
                return;
            }
            // 同一激活期防止对同一 Collider 重复命中（一次攻击每个目标至多命中一次）
            if (!_hitThisActivation.Add(other)) return;
            if (!CheckCooldown(other)) return;
            // 排除自身：攻击方与受击方属于同一根 GameObject 时跳过（防止近战 EnemyHitBox 命中同一敌人的 EnemyHurtBox）
            if (other.transform.root == _attackerTransform.root) return;

            Vector2 knockDir = ((Vector2)other.bounds.center
                               - (Vector2)_attackerTransform.position).normalized;

            // ⚡ 零 GC：struct 工厂，运行时字段内联传入
            var info = DamageInfo.From(
                _currentSource,
                knockDir,
                _attackerTransform.position,
                _attackerTransform.gameObject.layer,
                _ownerProjectile);

            // ① 拼刀检测：当前 HitBox 携带 CanClash 标记，且碰到对立阵营的 HitBox 层
            int otherLayer = other.gameObject.layer;
            bool isRivalHitBoxLayer = (_rivalHitBoxMask.value & (1 << otherLayer)) != 0;
            if (isRivalHitBoxLayer && CanClash)
            {
                var rivalHitBox = other.GetComponent<HitBox>();
                if (rivalHitBox != null && rivalHitBox.IsActive && rivalHitBox.CanClash)
                {
                    _clashService?.ResolveClash(this, rivalHitBox);
                    return; // 拼刀，中止伤害流水线
                }
            }

            // ② 命中 HurtBox
            var hurtBox = other.GetComponent<HurtBox>();
            if (hurtBox != null)
            {
                // 用 HitBox 自身碰撞盒中心在 HurtBox 表面上的最近点作为受击位置。
                // 对大体积/长条形受击体（如地刺），此点远比 HurtBox 节点中心更准确。
                Vector3 hitPoint = other.ClosestPoint(_collider.bounds.center);
                hurtBox.ReceiveDamage(info, hitPoint);
                OnHitConfirmed?.Invoke(info);
                return;
            }

            // ③ 命中 IBreakable（机关/障碍物）
            other.GetComponent<IBreakable>()?.TryInteract(info);
        }

        // ── 当前激活期已命中目标集合（防止复合子 Collider 导致同帧多次命中）────────────
        private readonly HashSet<Collider2D>           _hitThisActivation = new(8);
        // ── 同目标多帧命中冷却（防止 Trigger 处于重叠状态时重入等殊情导致的连击）──
        private readonly Dictionary<Collider2D, float> _hitCooldownTimers = new(8);

        private bool CheckCooldown(Collider2D other)
        {
            float now = Time.time;
            if (_hitCooldownTimers.TryGetValue(other, out float last) && now - last < _hitCooldown)
                return false;
            _hitCooldownTimers[other] = now;
            return true;
        }

#if UNITY_EDITOR
        private void OnDrawGizmos()
        {
            var col = GetComponent<Collider2D>();
            if (col == null) return;
            // HitBox：激活 = 鲜红，非激活 = 极淡红轮廓
            Gizmos.color = _isActive
                ? new Color(1f, 0.15f, 0.15f, 1f)
                : new Color(1f, 0.15f, 0.15f, 0.2f);
            DrawCollider2DWire(col);
        }

        // ────────────────────────────────────────────────────
        // Gizmo 辅助（内联，不依赖外部工具类）
        // ────────────────────────────────────────────────────
        /// <summary>
        /// 根据 Collider2D 类型绘制正确的 wire 轮廓。
        /// 使用 <see cref="Gizmos.matrix"/> 统一应用 Transform 的移动/旋转/缩放。
        /// </summary>
        public static void DrawCollider2DWire(Collider2D col)
        {
            var prev = Gizmos.matrix;
            Gizmos.matrix = col.transform.localToWorldMatrix;

            switch (col)
            {
                case BoxCollider2D box:
                    DrawWireRect2D(box.offset, box.size);
                    break;

                case CapsuleCollider2D caps:
                    DrawWireCapsule2D(caps.offset, caps.size, caps.direction);
                    break;

                case PolygonCollider2D poly:
                    for (int p = 0; p < poly.pathCount; p++)
                    {
                        var pts = poly.GetPath(p);
                        for (int i = 0; i < pts.Length; i++)
                            Gizmos.DrawLine(pts[i], pts[(i + 1) % pts.Length]);
                    }
                    break;

                case CircleCollider2D circle:
                    DrawWireCircle2D(circle.offset, circle.radius);
                    break;

                default:
                    // 其他类型回退到 bounds 近似（恢复矩阵后在世界空间绘制）
                    Gizmos.matrix = prev;
                    DrawWireRect2D(col.bounds.center, col.bounds.size);
                    return;
            }

            Gizmos.matrix = prev;
        }

        /// <summary>在当前 Gizmos 坐标系中绘制轴对齐矩形（2D 线框，兼容透视相机）。</summary>
        public static void DrawWireRect2D(Vector2 center, Vector2 size)
        {
            float hx = size.x * 0.5f, hy = size.y * 0.5f;
            Vector3 tl = new Vector3(center.x - hx, center.y + hy, 0f);
            Vector3 tr = new Vector3(center.x + hx, center.y + hy, 0f);
            Vector3 br = new Vector3(center.x + hx, center.y - hy, 0f);
            Vector3 bl = new Vector3(center.x - hx, center.y - hy, 0f);
            Gizmos.DrawLine(tl, tr);
            Gizmos.DrawLine(tr, br);
            Gizmos.DrawLine(br, bl);
            Gizmos.DrawLine(bl, tl);
        }

        /// <summary>用线段近似绘制 2D 圆周（不使用 DrawWireSphere，兼容透视相机）。</summary>
        public static void DrawWireCircle2D(Vector3 center, float radius, int segs = 32)
        {
            float   step     = 360f / segs;
            Vector3 prevPt   = center + new Vector3(radius, 0f, 0f);
            for (int i = 1; i <= segs; i++)
            {
                float   a      = i * step * Mathf.Deg2Rad;
                Vector3 nextPt = center + new Vector3(Mathf.Cos(a) * radius, Mathf.Sin(a) * radius, 0f);
                Gizmos.DrawLine(prevPt, nextPt);
                prevPt = nextPt;
            }
        }

        /// <summary>绘制 2D 胶囊轮廓（在 col.transform 局部坐标系中）。</summary>
        private static void DrawWireCapsule2D(Vector2 offset, Vector2 size, CapsuleDirection2D dir)
        {
            bool   vert     = dir == CapsuleDirection2D.Vertical;
            float  radius   = vert ? size.x * 0.5f : size.y * 0.5f;
            float  half     = Mathf.Max(0f, (vert ? size.y : size.x) * 0.5f - radius);
            Vector2 axis    = vert ? Vector2.up    : Vector2.right;
            Vector2 perp    = vert ? Vector2.right : Vector2.up;
            Vector2 capA    = offset + axis * half;
            Vector2 capB    = offset - axis * half;

            Gizmos.DrawLine(capA + perp * radius, capB + perp * radius);
            Gizmos.DrawLine(capA - perp * radius, capB - perp * radius);
            DrawArc2D(capA, radius, vert ?   0f : -90f, 180f);
            DrawArc2D(capB, radius, vert ? 180f :  90f, 180f);
        }

        /// <summary>用多段直线近似绘制 2D 圆弧。</summary>
        private static void DrawArc2D(Vector2 c, float r, float startDeg, float spanDeg, int segs = 20)
        {
            float step = spanDeg / segs;
            var   prev = c + new Vector2(Mathf.Cos(startDeg * Mathf.Deg2Rad) * r,
                                         Mathf.Sin(startDeg * Mathf.Deg2Rad) * r);
            for (int i = 1; i <= segs; i++)
            {
                float a    = (startDeg + step * i) * Mathf.Deg2Rad;
                var   next = c + new Vector2(Mathf.Cos(a) * r, Mathf.Sin(a) * r);
                Gizmos.DrawLine(prev, next);
                prev = next;
            }
        }
#endif
    }
}