using UnityEngine;
using BaseGames.Core.Events;

namespace BaseGames.Combat
{
    /// <summary>
    /// 单次伤害信息。流水线：RawDamage → Amount（护盾修改）→ FinalDamage（防御减免后）。
    /// ⚠️ 非 readonly struct — Builder 就地写入字段。
    /// </summary>
    [System.Serializable]
    public struct DamageInfo
    {
        public int           RawDamage;         // HitBox 设定的原始值（Builder.SetRaw 写入一次）
        public int           Amount;            // 流水线中被护盾/防御修改
        public int           FinalDamage;       // HurtBox 写入，最终 HP 扣除量
        public Vector2       KnockbackDirection;
        public float         KnockbackForce;
        public float         HitStunDuration;
        public DamageType    Type;
        public DamageCategory Category;
        public DamageFlags   Flags;
        public DamageTags    Tags;
        public Vector2       SourcePosition;
        public int           SourceLayer;
        public HitFxType     FxType;
        public BreakLevel    Break;
        public string        SourceId;
        public string        SkillId;

        // ── Builder ──────────────────────────────────────────────────────────
        public class Builder
        {
            private DamageInfo _d;

            public Builder() { }

            // SetRaw 同步初始化 Amount（Amount 始终以 RawDamage 为起点）
            public Builder SetRaw(int v)               { _d.RawDamage = v; _d.Amount = v;         return this; }
            public Builder SetType(DamageType v)       { _d.Type = v;                             return this; }
            public Builder SetCategory(DamageCategory v){ _d.Category = v;                        return this; }
            public Builder SetFlags(DamageFlags v)     { _d.Flags = v;                            return this; }
            public Builder SetTags(DamageTags v)       { _d.Tags = v;                             return this; }
            public Builder SetSkillId(string v)        { _d.SkillId = v;                          return this; }
            public Builder SetSourceId(string v)       { _d.SourceId = v;                         return this; }
            public Builder SetKnockback(Vector2 dir, float force)
            { _d.KnockbackDirection = dir; _d.KnockbackForce = force;                             return this; }
            public Builder SetStun(float dur)          { _d.HitStunDuration = dur;                return this; }
            public Builder SetFx(HitFxType v)          { _d.FxType = v;                           return this; }
            public Builder SetBreak(BreakLevel v)      { _d.Break = v;                            return this; }
            public Builder SetSourcePos(Vector2 v)     { _d.SourcePosition = v;                   return this; }
            public Builder SetLayer(int v)             { _d.SourceLayer = v;                      return this; }
            public DamageInfo Build()                  => _d;
        }

        /// <summary>
        /// ⚡ 零堆分配工厂（热路径首选）。直接从 DamageSourceSO 填入基础字段。
        /// KnockbackDirection / SourcePosition / SourceLayer 等运行时字段由调用方就地赋值。
        /// </summary>
        public static DamageInfo From(DamageSourceSO so)
        {
            int baseAmt = Mathf.RoundToInt(so.BaseDamage * so.DamageMultiplier);
            return new DamageInfo
            {
                RawDamage       = baseAmt,
                Amount          = baseAmt,
                Type            = so.Type,
                Category        = so.Category,
                Flags           = so.Flags,
                Tags            = so.Tags,
                HitStunDuration = so.HitStunDuration,
                FxType          = so.FxType,
                Break           = so.BreakLevel,
                SourceId        = so.sourceId,
                SkillId         = so.skillId,
            };
        }
    }

    /// <summary>伤害事件频道（EVT_DamageDealt）。</summary>
    [UnityEngine.CreateAssetMenu(menuName = "Events/DamageDealt")]
    public class DamageInfoEventChannelSO : BaseEventChannelSO<DamageInfo> { }
}