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

// Documentation text normalized.
// Documentation text normalized.
public class EnemyCombatant : MonoBehaviour, ICombatant
{
    public EnemyData_SO sourceData;

    private int _currentDifficultyID;
    private GameObject _lastAttacker;

    // 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;

    // Keep an unbuffed attack baseline so temporary Buff.attackMultiplier can be applied/reverted correctly.
    private int _attackBaseUnbuffed = 0;
    private bool _attackBaseInitialized = false;

    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";
    }

    // Documentation text normalized.
    public void InitializeFromSO(EnemyData_SO so, int difficultyID)
    {
        // This enemy GameObject can be reused for multiple enemy entries in sequence.
        // Clear any runtime buffs so they don't leak across enemy transitions.
        activeBuffs.Clear();
        _attackBaseInitialized = false;
        _attackBaseUnbuffed = 0;
        _lastAttacker = null;
        _currentDifficultyID = difficultyID;

        sourceData = so;
        if (so != null)
        {
            var stats = so.GetStatsByDifficultyID(difficultyID);
            maxHP = Mathf.Max(1, stats.enemy_maxHP);
            damageResistance = stats.enemy_damageResistance;
            SetAttack(stats.enemy_baseAttack);
            maxMana = Mathf.Max(0, stats.enemy_maxMana);
        }
        else
        {
            maxHP = 100;
            damageResistance = 0f;
            SetAttack(0);
            maxMana = 0;
        }

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

        GameplaySkillLogger.RecordEnemyLifeState(
            gameObject.name,
            "Spawned",
            currentHP,
            maxHP,
            currentMana,
            maxMana,
            sourceData != null ? sourceData.name : "None");

        iBudeffPrefabController.Instance?.RegisterEnemyBaseline(this);

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

        // Notify SkillBuilder so ally skills with OnEnemyRevive can react
        if (Application.isPlaying && SkillBuilder.Instance != null)
        {
            SkillBuilder.Instance.TriggerOnEnemyRevive(this);
        }

        // Trigger configured enemy skills on revive if defined and trigger condition matches.
        TryTriggerConfiguredSkills(SkillDefinition.SkillTrigger.OnEnemyRevive);
    }

    private void TryTriggerConfiguredSkills(SkillDefinition.SkillTrigger when)
    {
        if (sourceData == null) return;

        HashSet<SkillDefinition> executed = new HashSet<SkillDefinition>();
        SkillDefinition primary = sourceData.GetPrimarySkill();
        ExecuteEnemySkillIfMatched(primary, when, executed);

        int[] groupIds = sourceData.GetEffectiveEquippedSkillGroupIDs();
        if (groupIds == null || groupIds.Length == 0)
            return;

        for (int i = 0; i < groupIds.Length; i++)
        {
            int groupId = groupIds[i];
            if (groupId == 0) continue;

            SkillGroup group = sourceData.GetSkillGroupByID(groupId);
            if (group == null || group.skills == null)
                continue;

            for (int j = 0; j < group.skills.Length; j++)
            {
                ExecuteEnemySkillIfMatched(group.skills[j], when, executed);
            }
        }
    }

    private void ExecuteEnemySkillIfMatched(SkillDefinition def, SkillDefinition.SkillTrigger when, HashSet<SkillDefinition> executed)
    {
        if (def == null || executed == null) return;
        if (executed.Contains(def)) return;
        if (def.triggerCondition != when) return;

        executed.Add(def);

        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;
        bool scaleByTicks =
            !def.IsSingleInstance &&
            (def.effectType == EffectType.DamageOverTimeEnemy ||
             def.effectType == EffectType.DamageOverTimeAlly ||
             def.effectType == EffectType.HealOverTimeEnemy ||
             def.effectType == EffectType.HealOverTimeSelf ||
             def.effectType == EffectType.HealGroupOverTime ||
             def.effectType == EffectType.IncreaseManaOverTime);
        if (scaleByTicks)
        {
            float tickInterval = def.GetEffectiveTickInterval();
            int ticks = Mathf.Max(1, Mathf.CeilToInt(def.defaultDuration / tickInterval));
            totalAmount = perTick * ticks;
        }

        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, bool deferPopup = false)
    {
        if (isDead) return;

        // Check if any allies are active before receiving damage
        if (teamUIController.Instance != null && !teamUIController.Instance.IsAnyAllyActive())
        {
            return;
        }

        _lastAttacker = source;
        int before = currentHP;
        float effective = amount * (1f - damageResistance);
        int delta = Mathf.CeilToInt(effective);
        ModifyHP(-delta, true);

        int actual = before - currentHP;
        if (actual > 0 && source != null && teamUIController.Instance != null)
        {
            var sourceAlly = source.GetComponent<AllyCombatant>();
            if (sourceAlly != null)
            {
                teamUIController.Instance.RecordDamage(sourceAlly.slotIndex, actual);
            }
        }

        GameplaySkillLogger.RecordEnemyHpEvent(
            gameObject.name,
            "Damage",
            amount,
            effective,
            before,
            currentHP,
            damageResistance,
            source != null ? source.name : "None");

        if (actual != 0)
        {
            if (deferPopup)
            {
                QueueDamagePopup(iNumberPrefabController.InstantNumberType.Damage, -actual);
            }
            else
            {
                iNumberPrefabController.SpawnForEnemyStatic(iNumberPrefabController.InstantNumberType.Damage, -actual);
            }
        }

        if (actual > 0)
        {
            GameplayLevelRuleEventBus.NotifyEnemyDamaged(this, actual, source);
        }

        // 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, bool deferPopup = false)
    {
        if (isDead) return;
        int before = currentHP;
        float mult = GetTotalHealReceivedMultiplier();
        int delta = Mathf.CeilToInt(amount * mult);
        ModifyHP(delta, true);
        int actual = currentHP - before;
        GameplaySkillLogger.RecordEnemyHpEvent(
            gameObject.name,
            "Heal",
            amount,
            amount * mult,
            before,
            currentHP,
            damageResistance,
            source != null ? source.name : "None");

        if (actual != 0)
        {
            if (deferPopup)
            {
                QueueDamagePopup(iNumberPrefabController.InstantNumberType.Heal, actual);
            }
            else
            {
                iNumberPrefabController.SpawnForEnemyStatic(iNumberPrefabController.InstantNumberType.Heal, actual);
            }
        }
    }

    public void ApplyBuff(Buff buff, GameObject source)
    {
        if (buff == null) return;
        Debug.LogWarning($"[EnemyCombatant] ApplyBuff: {buff.description} (id={buff.buffId}) to {name}. AtkMult={buff.attackMultiplier}, HealMult={buff.healReceivedMultiplier}, ScoreMult={buff.scoreMultiplier}");
        activeBuffs.Add(buff);
        // Apply reversible multipliers. attackMultiplier is applied via baseline+recalc to ensure it can be reverted.
        if (buff.attackMultiplier != 1f) RecalculateAttackFromBuffs();
        iBudeffPrefabController.Instance?.NotifyEnemyBuffApplied(this, buff);
    }

    public void RemoveBuff(string buffId)
    {
        var b = activeBuffs.Find(x => x.buffId == buffId);
        if (b != null)
        {
            activeBuffs.Remove(b);
            if (b.attackMultiplier != 1f) RecalculateAttackFromBuffs();
            iBudeffPrefabController.Instance?.NotifyEnemyBuffRemoved(this, b);
        }
    }

    public float GetHealReceivedMultiplierForUI()
    {
        float mult = 1f;
        for (int i = 0; i < activeBuffs.Count; i++)
        {
            var b = activeBuffs[i];
            if (b == null) continue;
            mult *= b.healReceivedMultiplier;
        }
        return mult;
    }

    private void EnsureAttackBaseInitialized()
    {
        if (_attackBaseInitialized) return;
        _attackBaseInitialized = true;
        _attackBaseUnbuffed = Mathf.Max(0, attack);
    }

    private float GetTotalAttackMultiplier()
    {
        float mult = 1f;
        for (int i = 0; i < activeBuffs.Count; i++)
        {
            var b = activeBuffs[i];
            if (b == null) continue;
            mult *= b.attackMultiplier;
        }
        return mult;
    }

    private float GetTotalHealReceivedMultiplier()
    {
        float mult = 1f;
        for (int i = 0; i < activeBuffs.Count; i++)
        {
            var b = activeBuffs[i];
            if (b == null) continue;
            mult *= b.healReceivedMultiplier;
        }
        return mult;
    }

    private void RecalculateAttackFromBuffs()
    {
        EnsureAttackBaseInitialized();
        float mult = GetTotalAttackMultiplier();
        attack = Mathf.Max(0, Mathf.RoundToInt(_attackBaseUnbuffed * mult));
    }

    public void ModifyAttack(int delta)
    {
        EnsureAttackBaseInitialized();
        _attackBaseUnbuffed = Mathf.Max(0, _attackBaseUnbuffed + delta);
        RecalculateAttackFromBuffs();
    }

    public void SetAttack(int value)
    {
        EnsureAttackBaseInitialized();
        _attackBaseUnbuffed = Mathf.Max(0, value);
        RecalculateAttackFromBuffs();
    }

    private List<(iNumberPrefabController.InstantNumberType type, int val)> _queuedPopups = new List<(iNumberPrefabController.InstantNumberType, int)>();

    public void QueueDamagePopup(iNumberPrefabController.InstantNumberType type, int val)
    {
        _queuedPopups.Add((type, val));
    }

    public void TriggerQueuedPopups()
    {
        foreach (var p in _queuedPopups)
        {
            iNumberPrefabController.SpawnForEnemyStatic(p.type, p.val);
        }
        _queuedPopups.Clear();
    }

    public void ModifyHP(int delta)
    {
        ModifyHP(delta, false);
    }

    public void ModifyHP(int delta, bool skipPopup)
    {
        if (isDead && delta > 0) return;
        int before = currentHP;
        currentHP = Mathf.Clamp(currentHP + delta, 0, maxHP);
        int actual = currentHP - before;
        if (actual != 0 && !skipPopup)
        {
            var type = actual > 0 ? iNumberPrefabController.InstantNumberType.Heal : iNumberPrefabController.InstantNumberType.Damage;
            iNumberPrefabController.SpawnForEnemyStatic(type, actual);
        }
        if (currentHP <= 0)
        {
            if (GameplayLevelRuleEventBus.ShouldPreventEnemyDeath(this))
            {
                currentHP = 1;
                return;
            }

            Die();
        }
    }

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

        if (actual != 0)
        {
            if (iNumberPrefabController.Instance != null)
            {
                var type = actual > 0 ? iNumberPrefabController.InstantNumberType.ManaPlus : iNumberPrefabController.InstantNumberType.ManaMinus;
                iNumberPrefabController.SpawnForEnemyStatic(type, actual);
            }
        }

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

            // reset mana after casting
            ModifyMana(-currentMana, false);
        }
    }

    private void Die()
    {
        if (isDead) return;

        GameplaySkillLogger.RecordEnemyLifeState(
            gameObject.name,
            "Dead",
            currentHP,
            maxHP,
            currentMana,
            maxMana,
            _lastAttacker != null ? _lastAttacker.name : "None");

        // award score to last attacker
        if (sourceData != null)
        {
            var stats = sourceData.GetStatsByDifficultyID(_currentDifficultyID);
            int award = stats.scoreOnBeingDefeated;
            if (award > 0)
            {
                var ally = _lastAttacker != null ? _lastAttacker.GetComponent<AllyCombatant>() : null;
                if (ally != null)
                {
                    ally.AddScoreDirect(award);
                }
                else
                {
                    // If no specific attacker, try to find current primary track or just add to global
                    ScoreManager.Instance?.AddIdolScoreForTrack(0, award);
                }
            }
        }

        AwardBountyScoreToLivingAllies();

        // Finally mark dead
        isDead = true;

        // 播放 KO 特效
        if (GfxController.Instance != null)
        {
            GfxController.Instance.PlayKOFX(this.gameObject);
        }

        // Notify SkillBuilder so allies can react to each enemy death BEFORE listeners that may reuse this Enemy instance
        if (Application.isPlaying)
        {
            // prefer singleton instance but fallback to scene lookup if singleton is null (robustness for scene initialization order)
            if (SkillBuilder.Instance != null)
            {
                SkillBuilder.Instance.TriggerOnEnemyDead(this);
            }
            else
            {
                var sb = SceneObjectLookupCache.FindAny<SkillBuilder>();
                if (sb != null)
                {
                    Debug.LogWarning("[EnemyCombatant] SkillBuilder.Instance was null on Die(); using FindObjectOfType fallback");
                    sb.TriggerOnEnemyDead(this);
                }
                else
                {
                    Debug.LogWarning("[EnemyCombatant] Die(): no SkillBuilder found to notify TriggerOnEnemyDead");
                }
            }
        }

        // Trigger configured enemy skills on death if configured.
        TryTriggerConfiguredSkills(SkillDefinition.SkillTrigger.OnEnemyDead);

        // notify listeners (UI/manager) that enemy died AFTER triggering skills so they operate on the current instance
        OnEnemyDied?.Invoke(this);

        // Check whether all enemies are now defeated.
        // If teamUIController exists, it owns enemy-sequence completion and will fire this event exactly once.
        // Fallback to legacy scene scan only when teamUIController is not present.
        if (Application.isPlaying)
        {
            try
            {
                var ui = SceneObjectLookupCache.FindAny<teamUIController>();
                if (ui != null)
                {
                    return;
                }

                var all = UnityEngine.Object.FindObjectsByType<EnemyCombatant>(FindObjectsInactive.Include, FindObjectsSortMode.None);
                bool anyAlive = false;
                foreach (var e in all)
                {
                    if (e == null) continue;
                    // treat an enemy as alive if its currentHP > 0 and not flagged dead
                    if (e.currentHP > 0 && !e.IsDead)
                    {
                        anyAlive = true; break;
                    }
                }
                if (!anyAlive)
                {
                    // notify SkillBuilder about all enemies defeated
                    if (SkillBuilder.Instance != null)
                    {
                        SkillBuilder.Instance.TriggerOnAllEnemiesDefeated();
                        Debug.Log("[EnemyCombatant] All enemies defeated -> TriggerOnAllEnemiesDefeated fired via singleton");
                    }
                    else
                    {
                        var sb = SceneObjectLookupCache.FindAny<SkillBuilder>();
                        if (sb != null)
                        {
                            sb.TriggerOnAllEnemiesDefeated();
                            Debug.LogWarning("[EnemyCombatant] SkillBuilder.Instance was null when firing AllEnemiesDefeated; used FindObjectOfType fallback");
                        }
                        else
                        {
                            Debug.LogWarning("[EnemyCombatant] All enemies defeated but no SkillBuilder found to notify");
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                Debug.LogError($"[EnemyCombatant] Error while checking all-enemies-defeated: {ex}");
            }
        }
    }

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

    // New: allow EffectSystem/SkillBuilder to adjust enemy max HP safely
    private void AwardBountyScoreToLivingAllies()
    {
        if (sourceData == null)
            return;

        float difficultyLevel = ResolveCurrentDifficultyLevel();
        var stats = sourceData.GetStatsByDifficultyID(_currentDifficultyID);
        int calculatedMaxHp = Mathf.Max(0, stats.enemy_maxHP);
        float totalBounty = calculatedMaxHp * 0.05f * difficultyLevel + sourceData.enemyBountyBonus;
        if (totalBounty <= 0f)
            return;

        AllyCombatant[] allies = UnityEngine.Object.FindObjectsByType<AllyCombatant>(FindObjectsInactive.Include, FindObjectsSortMode.None);
        List<AllyCombatant> livingAllies = new List<AllyCombatant>();
        for (int i = 0; i < allies.Length; i++)
        {
            AllyCombatant ally = allies[i];
            if (ally == null)
                continue;
            if (ally.IsDead || ally.maxHP <= 0 || !ally.gameObject.activeInHierarchy)
                continue;
            livingAllies.Add(ally);
        }

        if (livingAllies.Count == 0)
            return;

        int awardPerAlly = Mathf.CeilToInt(totalBounty / livingAllies.Count);
        if (awardPerAlly <= 0)
            return;

        for (int i = 0; i < livingAllies.Count; i++)
        {
            livingAllies[i].AddScoreDirect(awardPerAlly);
        }
    }

    private float ResolveCurrentDifficultyLevel()
    {
        BeatmapManager beatmapManager = BeatmapManager.Instance;
        if (beatmapManager == null || beatmapManager.assignedSongData == null || beatmapManager.assignedSongData.chartFiles == null)
            return 1f;

        List<ChartFileEntry> chartFiles = beatmapManager.assignedSongData.chartFiles;
        for (int i = 0; i < chartFiles.Count; i++)
        {
            ChartFileEntry entry = chartFiles[i];
            if (entry == null || entry.difficulty != _currentDifficultyID)
                continue;

            return Mathf.Max(0f, entry.difficultyLEVEL);
        }

        return 1f;
    }

    public void SetMaxHP(int newMax, bool keepCurrentRatio = true)
    {
        if (newMax < 1) newMax = 1;
        float ratio = maxHP > 0 ? (float)currentHP / maxHP : 1f;
        maxHP = newMax;
        if (keepCurrentRatio)
            currentHP = Mathf.Clamp(Mathf.RoundToInt(ratio * maxHP), 0, maxHP);
        else
            currentHP = Mathf.Clamp(currentHP, 0, maxHP);
    }

    // New: allow adjusting enemy max mana (mirror of AllyCombatant)
    public void SetMaxMana(int newMax, bool keepCurrentRatio = true)
    {
        if (newMax < 1) newMax = 1;
        float ratio = maxMana > 0 ? (float)currentMana / maxMana : 1f;
        maxMana = newMax;
        if (keepCurrentRatio)
            currentMana = Mathf.Clamp(Mathf.RoundToInt(ratio * maxMana), 0, maxMana);
        else
            currentMana = Mathf.Clamp(currentMana, 0, maxMana);
    }
}