using System;
using System.Collections.Generic;
using UnityEngine;
using Animancer;
using BaseGames.Player;

namespace BaseGames.Skills
{
    /// <summary>
    /// 技能数值修改维度（架构 09_ProgressionModule §10）。
    /// </summary>
    public enum SkillStat { Damage, Cost, Cooldown, Range, Duration }

    /// <summary>
    /// 插槽覆盖描述符：某护符将指定形态的某个技能槽替换为另一技能。
    /// </summary>
    [Serializable]
    public struct SkillSlotOverride
    {
        public FormSO        targetForm;        // null = 所有形态
        public string        targetSlot;        // 使用 SkillSlotNames 中的常量（SoulSkill / SpiritSkill1 / SpiritSkill2）
        public FormSkillSO   replacementSkill;  // 替换目标技能
        public int           priority;          // 高优先级覆盖低优先级
    }

    /// <summary>
    /// 所有数值修改器叠加后的运行时参数快照（架构 09_ProgressionModule §10）。
    /// 由 SkillModifierRegistry.GetEffectiveParams() 生成，传入 SkillManager 使用。
    /// </summary>
    public struct EffectiveSkillParams
    {
        public FormSkillSO    baseSkill;           // 原始 SO 引用（不变）
        public int            effectiveCost;       // 修改后消耗
        public float          effectiveCooldown;   // 修改后冷却（秒）
        public float          damageMult;          // 伤害倍率（1.0 = 无增益）
        public float          rangeMult;           // 范围倍率
        public FeedbackPresetSO effectiveFeedback; // 最终特效预设（null = 回退原始）
        public ClipTransition effectiveAnimation;  // 最终施法动画（null = 回退原始）

        /// <summary>以技能 SO 默认值初始化，无任何修改器加成。</summary>
        public static EffectiveSkillParams FromBase(FormSkillSO skill) => new()
        {
            baseSkill          = skill,
            effectiveCost      = skill.baseCost,
            effectiveCooldown  = skill.cooldown,
            damageMult         = 1f,
            rangeMult          = 1f,
            effectiveFeedback  = null,
            effectiveAnimation = default,
        };
    }

    // 内部记录结构，存储单条数值修改
    internal struct SkillStatEntry
    {
        public SkillStat stat;
        public float     delta;
        public bool      isPercent;
    }

    /// <summary>
    /// 技能修改器注册表（架构 09_ProgressionModule §10）。
    /// 挂在 Player 上，收集所有护符对技能数值的修改。
    /// SkillManager 在施放技能时调用 GetEffectiveParams() 获取最终参数。
    /// </summary>
    public class SkillModifierRegistry : MonoBehaviour
    {
        // skillId → 一组数值修改
        private readonly Dictionary<string, List<SkillStatEntry>> _modifiers = new();

        // 插槽覆盖列表（按 priority 降序排列）
        private readonly List<SkillSlotOverride> _slotOverrides = new();

        // ── 数值修改 ────────────────────────────────────────────────────────
        public void Register(string skillId, SkillStat stat, float delta, bool isPercent)
        {
            if (!_modifiers.TryGetValue(skillId, out var list))
            {
                list = new List<SkillStatEntry>();
                _modifiers[skillId] = list;
            }
            list.Add(new SkillStatEntry { stat = stat, delta = delta, isPercent = isPercent });
        }

        public void Unregister(string skillId, SkillStat stat, float delta, bool isPercent)
        {
            if (!_modifiers.TryGetValue(skillId, out var list)) return;
            list.RemoveAll(e => e.stat == stat &&
                                Mathf.Approximately(e.delta, delta) &&
                                e.isPercent == isPercent);
        }

        /// <summary>
        /// 对给定技能叠加所有已注册修改器，返回一次性快照供 SkillManager 使用。
        /// </summary>
        public EffectiveSkillParams GetEffectiveParams(FormSkillSO skill)
        {
            var p = EffectiveSkillParams.FromBase(skill);
            if (!_modifiers.TryGetValue(skill.skillId, out var entries)) return p;

            float flatCost      = 0, pctCost      = 1f;
            float flatCooldown  = 0, pctCooldown  = 1f;
            float flatDamage    = 0, pctDamage    = 1f;
            float flatRange     = 0, pctRange     = 1f;

            foreach (var e in entries)
            {
                switch (e.stat)
                {
                    case SkillStat.Cost:
                        if (e.isPercent) pctCost      += e.delta;
                        else             flatCost     += e.delta;
                        break;
                    case SkillStat.Cooldown:
                        if (e.isPercent) pctCooldown  += e.delta;
                        else             flatCooldown += e.delta;
                        break;
                    case SkillStat.Damage:
                        if (e.isPercent) pctDamage    += e.delta;
                        else             flatDamage   += e.delta;
                        break;
                    case SkillStat.Range:
                        if (e.isPercent) pctRange     += e.delta;
                        else             flatRange    += e.delta;
                        break;
                }
            }

            p.effectiveCost     = Mathf.Max(0, Mathf.RoundToInt(skill.baseCost  * pctCost     + flatCost));
            p.effectiveCooldown = Mathf.Max(0, skill.cooldown * pctCooldown + flatCooldown);
            p.damageMult        = 1f + (pctDamage - 1f) + flatDamage;
            p.rangeMult         = 1f + (pctRange  - 1f) + flatRange;
            return p;
        }


        // ── 插槽覆盖 ────────────────────────────────────────────────────────
        public void AddSlotOverride(SkillSlotOverride data)
        {
            _slotOverrides.Add(data);
            _slotOverrides.Sort((a, b) => b.priority.CompareTo(a.priority));
        }

        public void RemoveSlotOverride(SkillSlotOverride data)
        {
            _slotOverrides.RemoveAll(o =>
                o.targetForm == data.targetForm &&
                o.targetSlot == data.targetSlot &&
                o.replacementSkill == data.replacementSkill);
        }

        /// <summary>
        /// 获取当前形态某槽位的实际技能（考虑插槽覆盖）。
        /// 没有覆盖时返回 null（调用方保留原始技能）。
        /// </summary>
        public FormSkillSO GetOverriddenSkill(FormSO form, string slotName)
        {
            foreach (var o in _slotOverrides)
            {
                bool formMatch = o.targetForm == null || o.targetForm == form;
                if (formMatch && o.targetSlot == slotName)
                    return o.replacementSkill;
            }
            return null;
        }
    }
}