using System;
using System.Collections.Generic;
using UnityEngine;

// EnemyCombatant 是单个场上敌人的运行时表现（所有敌人共用同一个 GameObject，按顺序登场）
// 实现 ICombatant：被 EffectSystem/SkillBuilder 调用
public class EnemyCombatant : MonoBehaviour, ICombatant
{
    public EnemyData_SO sourceData;

    // runtime stats
    public int maxHP = 100;
    public int currentHP = 100;
    public int maxMana = 0;
    public int currentMana = 0;
    public float damageResistance = 0f;
    public int attack = 0;

    private List<Buff> activeBuffs = new List<Buff>();

    // Events to notify manager/UI
    public event Action<EnemyCombatant> OnEnemyDied;
    public event Action<EnemyCombatant> OnEnemyRevived;

    private bool isDead = false;

    private void Awake()
    {
        // Ensure consistent name so EffectSystem can find it
        gameObject.name = "thisEnemy";
    }

    // 初始化/复活为指定的 EnemyData_SO
    public void InitializeFromSO(EnemyData_SO so)
    {
        sourceData = so;
        if (so != null)
        {
            maxHP = Mathf.Max(1, so.enemy_maxHP);
            damageResistance = so.enemy_damageResistance;
            attack = so.enemy_baseAttack;
            maxMana = Mathf.Max(0, so.GetEffectiveMaxMana());
        }
        else
        {
            maxHP = 100;
            damageResistance = 0f;
            attack = 0;
            maxMana = 0;
        }

        // revive
        currentHP = maxHP;
        currentMana = 0;
        isDead = false;

        // notify listeners (UI/manager) that enemy revived
        OnEnemyRevived?.Invoke(this);

        // Trigger primary skill on revive if defined and trigger condition matches
        TryTriggerPrimarySkill(SkillDefinition.SkillTrigger.OnEnemyRevive);
    }

    // 尝试触发 primary skill，当触发条件匹配时调用 SkillBuilder
    private void TryTriggerPrimarySkill(SkillDefinition.SkillTrigger when)
    {
        if (sourceData == null) return;
        var def = sourceData.GetPrimarySkill();
        if (def == null) return;
        if (def.triggerCondition != when) return;

        // Evaluate formula into amount using enemy fields as variables
        float perTick = 0f;
        var vars = new Dictionary<string, float>();
        vars["maxHP"] = maxHP;
        vars["maxMana"] = maxMana;
        vars["damageResistance"] = damageResistance;
        vars["attack"] = attack;
        vars["enemy_currentHP"] = currentHP;

        if (!string.IsNullOrWhiteSpace(def.formula))
        {
            if (!SkillDefinition.TryEvaluateFormula(def.formula, vars, out float result))
                perTick = 0f;
            else
                perTick = result;
        }

        float totalAmount = perTick;
        if (!def.IsSingleInstance)
        {
            float tickInterval = def.GetEffectiveTickInterval();
            int ticks = Mathf.Max(1, Mathf.CeilToInt(def.defaultDuration / tickInterval));
            totalAmount = perTick * ticks;
        }

        // Use SkillBuilder to execute effect, using this Enemy GameObject as caster
        if (SkillBuilder.Instance != null)
        {
            SkillBuilder.Instance.ExecuteSkill(def.displayName ?? def.skillId, def.effectType, totalAmount, def.defaultSelector, this.gameObject, null, def.defaultDuration, def.defaultTickInterval);
        }
    }

    public void ReceiveDamage(float amount, GameObject source)
    {
        if (isDead) return;

        float effective = amount * (1f - damageResistance);
        int delta = Mathf.CeilToInt(effective);
        currentHP = Mathf.Clamp(currentHP - delta, 0, maxHP);

        // grant mana based on sourceData setting
        if (sourceData != null && sourceData.manaGainOnDamagePercent > 0f && maxMana > 0)
        {
            float manaGainRaw = effective * sourceData.manaGainOnDamagePercent;
            int manaGain = Mathf.CeilToInt(manaGainRaw);
            ModifyMana(manaGain, true);
        }

        if (currentHP <= 0)
        {
            Die();
        }
    }

    public void ReceiveHeal(float amount, GameObject source)
    {
        if (isDead) return;
        int delta = Mathf.CeilToInt(amount);
        currentHP = Mathf.Clamp(currentHP + delta, 0, maxHP);
    }

    public void ApplyBuff(Buff buff, GameObject source)
    {
        if (buff == null) return;
        activeBuffs.Add(buff);
        // Simple apply: only modify healReceivedMultiplier or attackMultiplier as example
        if (buff.attackMultiplier != 1f) attack = Mathf.RoundToInt(attack * buff.attackMultiplier);
    }

    public void RemoveBuff(string buffId)
    {
        var b = activeBuffs.Find(x => x.buffId == buffId);
        if (b != null)
        {
            activeBuffs.Remove(b);
        }
    }

    public void ModifyHP(int delta)
    {
        if (isDead && delta > 0) return;
        currentHP = Mathf.Clamp(currentHP + delta, 0, maxHP);
        if (currentHP <= 0) Die();
    }

    public void ModifyMana(int delta, bool animate = true)
    {
        if (maxMana <= 0) return;
        int old = currentMana;
        currentMana = Mathf.Clamp(currentMana + delta, 0, maxMana);

        // If mana reached full, trigger primary skill and reset mana
        if (currentMana >= maxMana && maxMana > 0 && Application.isPlaying)
        {
            Debug.Log($"[EnemyCombatant] Mana full for {gameObject.name} (slot) - triggering OnManaFull");
            try
            {
                // Trigger primary skill configured for OnManaFull
                TryTriggerPrimarySkill(SkillDefinition.SkillTrigger.OnManaFull);
            }
            catch (Exception ex)
            {
                Debug.LogError($"[EnemyCombatant] TryTriggerPrimarySkill threw: {ex}");
            }

            // reset mana after casting
            currentMana = 0;
        }
    }

    private void Die()
    {
        if (isDead) return;
        isDead = true;
        // notify listeners before possibly being reused
        OnEnemyDied?.Invoke(this);

        // Trigger primary skill on death if configured
        TryTriggerPrimarySkill(SkillDefinition.SkillTrigger.OnEnemyDead);
    }

    // Utility: expose a read-only status
    public bool IsDead => isDead;
}