using System.Collections.Generic;

using UnityEngine;

using Colosseum.Abnormalities;

namespace Colosseum.Skills
{
    /// <summary>
    /// 단일 슬롯에서 사용할 스킬과 장착된 젬 조합입니다.
    /// </summary>
    [System.Serializable]
    public class SkillLoadoutEntry
    {
        private const int DefaultGemSlotCount = 2;

        [Tooltip("이 슬롯의 기반 스킬")]
        [SerializeField] private SkillData baseSkill;
        [Tooltip("기반 스킬에 장착된 젬")]
        [SerializeField] private SkillGemData[] socketedGems = new SkillGemData[DefaultGemSlotCount];

        public SkillData BaseSkill => baseSkill;
        public IReadOnlyList<SkillGemData> SocketedGems => socketedGems;

        public static SkillLoadoutEntry CreateTemporary(SkillData skill)
        {
            SkillLoadoutEntry entry = new SkillLoadoutEntry();
            entry.SetBaseSkill(skill);
            entry.EnsureGemSlotCapacity();
            return entry;
        }

        public SkillLoadoutEntry CreateCopy()
        {
            SkillLoadoutEntry copy = new SkillLoadoutEntry();
            copy.baseSkill = baseSkill;
            copy.socketedGems = new SkillGemData[socketedGems != null ? socketedGems.Length : DefaultGemSlotCount];

            if (socketedGems != null)
            {
                for (int i = 0; i < socketedGems.Length; i++)
                {
                    copy.socketedGems[i] = socketedGems[i];
                }
            }

            copy.SanitizeInvalidGems();
            return copy;
        }

        public void EnsureGemSlotCapacity(int slotCount = -1)
        {
            if (slotCount < 0)
            {
                slotCount = baseSkill != null ? baseSkill.MaxGemSlotCount : DefaultGemSlotCount;
            }

            slotCount = Mathf.Max(0, slotCount);
            if (socketedGems != null && socketedGems.Length == slotCount)
            {
                SanitizeInvalidGems();
                return;
            }

            SkillGemData[] resized = new SkillGemData[slotCount];
            if (socketedGems != null)
            {
                int copyCount = Mathf.Min(socketedGems.Length, resized.Length);
                for (int i = 0; i < copyCount; i++)
                {
                    resized[i] = socketedGems[i];
                }
            }

            socketedGems = resized;
            SanitizeInvalidGems();
        }

        public void SetBaseSkill(SkillData skill)
        {
            baseSkill = skill;
            EnsureGemSlotCapacity();
            SanitizeInvalidGems();
        }

        public void SetGem(int slotIndex, SkillGemData gem)
        {
            if (!TrySetGem(slotIndex, gem, out string reason) && gem != null)
            {
                string skillName = baseSkill != null ? baseSkill.SkillName : "(없음)";
                Debug.LogWarning($"[SkillLoadout] 젬 장착 실패 | Skill={skillName} | Slot={slotIndex} | Gem={gem.GemName} | Reason={reason}");
            }
        }

        public SkillGemData GetGem(int slotIndex)
        {
            EnsureGemSlotCapacity();
            if (slotIndex < 0 || slotIndex >= socketedGems.Length)
                return null;

            return socketedGems[slotIndex];
        }

        /// <summary>
        /// 지정한 슬롯에 젬을 장착 시도하고, 실패 이유를 반환합니다.
        /// </summary>
        public bool TrySetGem(int slotIndex, SkillGemData gem, out string reason)
        {
            reason = string.Empty;
            EnsureGemSlotCapacity();

            if (slotIndex < 0 || slotIndex >= socketedGems.Length)
            {
                reason = "유효하지 않은 젬 슬롯입니다.";
                return false;
            }

            if (gem == null)
            {
                socketedGems[slotIndex] = null;
                return true;
            }

            if (!TryValidateGemForSlot(slotIndex, gem, null, out reason))
                return false;

            socketedGems[slotIndex] = gem;
            return true;
        }

        /// <summary>
        /// 현재 로드아웃의 잘못된 젬 조합을 제거합니다.
        /// </summary>
        public void SanitizeInvalidGems(bool logWarnings = false)
        {
            if (socketedGems == null || socketedGems.Length == 0)
                return;

            List<SkillGemData> acceptedGems = new List<SkillGemData>(socketedGems.Length);
            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null)
                    continue;

                if (TryValidateGemForSlot(i, gem, acceptedGems, out string reason))
                {
                    acceptedGems.Add(gem);
                    continue;
                }

                if (logWarnings)
                {
                    string skillName = baseSkill != null ? baseSkill.SkillName : "(없음)";
                    Debug.LogWarning($"[SkillLoadout] 젬 장착 제약으로 제거됨 | Skill={skillName} | Slot={i} | Gem={gem.GemName} | Reason={reason}");
                }

                socketedGems[i] = null;
            }
        }

        public float GetResolvedManaCost()
        {
            if (baseSkill == null)
                return 0f;

            float resolved = baseSkill.ManaCost;
            if (socketedGems == null)
                return resolved;

            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null)
                    continue;

                resolved *= gem.ManaCostMultiplier;
            }

            return resolved;
        }

        public float GetResolvedCooldown()
        {
            if (baseSkill == null)
                return 0f;

            float resolved = baseSkill.Cooldown;
            if (socketedGems == null)
                return resolved;

            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null)
                    continue;

                resolved *= gem.CooldownMultiplier;
            }

            return resolved;
        }

        public float GetResolvedAnimationSpeed()
        {
            if (baseSkill == null)
                return 0f;

            float resolved = baseSkill.AnimationSpeed;
            if (socketedGems == null)
                return resolved;

            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null)
                    continue;

                resolved *= gem.CastSpeedMultiplier;
            }

            return Mathf.Max(0.05f, resolved);
        }

        public float GetResolvedDamageMultiplier()
        {
            return GetResolvedScalarMultiplier(gem => gem.DamageMultiplier);
        }

        public float GetResolvedHealMultiplier()
        {
            return GetResolvedScalarMultiplier(gem => gem.HealMultiplier);
        }

        public float GetResolvedShieldMultiplier()
        {
            return GetResolvedScalarMultiplier(gem => gem.ShieldMultiplier);
        }

        public float GetResolvedThreatMultiplier()
        {
            return GetResolvedScalarMultiplier(gem => gem.ThreatMultiplier);
        }

        public int GetResolvedRepeatCount()
        {
            if (baseSkill == null)
                return 0;

            int resolved = 1;
            if (socketedGems == null)
                return resolved;

            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null)
                    continue;

                resolved += gem.AdditionalRepeatCount;
            }

            return Mathf.Max(1, resolved);
        }

        public void CollectCastStartEffects(List<SkillEffect> destination)
        {
            if (destination == null)
                return;

            if (baseSkill != null && baseSkill.CastStartEffects != null)
            {
                for (int i = 0; i < baseSkill.CastStartEffects.Count; i++)
                {
                    SkillEffect effect = baseSkill.CastStartEffects[i];
                    if (effect != null)
                        destination.Add(effect);
                }
            }

            if (socketedGems == null)
                return;

            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null || gem.CastStartEffects == null)
                    continue;

                for (int j = 0; j < gem.CastStartEffects.Count; j++)
                {
                    SkillEffect effect = gem.CastStartEffects[j];
                    if (effect != null)
                        destination.Add(effect);
                }
            }
        }

        public void CollectCastStartAbnormalities(List<AbnormalityData> destination)
        {
            if (destination == null || socketedGems == null)
                return;

            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null || gem.SelfAbnormalities == null)
                    continue;

                for (int j = 0; j < gem.SelfAbnormalities.Count; j++)
                {
                    AbnormalityData abnormality = gem.SelfAbnormalities[j];
                    if (abnormality != null)
                        destination.Add(abnormality);
                }
            }
        }

        public void CollectTriggeredEffects(Dictionary<int, List<SkillEffect>> destination)
        {
            if (destination == null)
                return;

            if (baseSkill != null && baseSkill.Effects != null)
            {
                for (int i = 0; i < baseSkill.Effects.Count; i++)
                {
                    SkillEffect effect = baseSkill.Effects[i];
                    if (effect == null)
                        continue;

                    AddTriggeredEffect(destination, i, effect);
                }
            }

            if (socketedGems == null)
                return;

            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null || gem.TriggeredEffects == null)
                    continue;

                for (int j = 0; j < gem.TriggeredEffects.Count; j++)
                {
                    SkillGemTriggeredEffectEntry entry = gem.TriggeredEffects[j];
                    if (entry == null || entry.Effects == null)
                        continue;

                    for (int k = 0; k < entry.Effects.Count; k++)
                    {
                        SkillEffect effect = entry.Effects[k];
                        if (effect == null)
                            continue;

                        AddTriggeredEffect(destination, entry.TriggerIndex, effect);
                    }
                }
            }
        }

        public void CollectTriggeredAbnormalities(Dictionary<int, List<AbnormalityData>> destination)
        {
            if (destination == null || socketedGems == null)
                return;

            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null || gem.OnHitAbnormalities == null)
                    continue;

                for (int j = 0; j < gem.OnHitAbnormalities.Count; j++)
                {
                    SkillGemTriggeredAbnormalityEntry entry = gem.OnHitAbnormalities[j];
                    if (entry == null || entry.Abnormalities == null)
                        continue;

                    for (int k = 0; k < entry.Abnormalities.Count; k++)
                    {
                        AbnormalityData abnormality = entry.Abnormalities[k];
                        if (abnormality == null)
                            continue;

                        AddTriggeredAbnormality(destination, entry.TriggerIndex, abnormality);
                    }
                }
            }
        }

        private static void AddTriggeredEffect(Dictionary<int, List<SkillEffect>> destination, int triggerIndex, SkillEffect effect)
        {
            if (!destination.TryGetValue(triggerIndex, out List<SkillEffect> effectList))
            {
                effectList = new List<SkillEffect>();
                destination.Add(triggerIndex, effectList);
            }

            effectList.Add(effect);
        }

        private static void AddTriggeredAbnormality(Dictionary<int, List<AbnormalityData>> destination, int triggerIndex, AbnormalityData abnormality)
        {
            if (!destination.TryGetValue(triggerIndex, out List<AbnormalityData> abnormalityList))
            {
                abnormalityList = new List<AbnormalityData>();
                destination.Add(triggerIndex, abnormalityList);
            }

            abnormalityList.Add(abnormality);
        }

        private bool TryValidateGemForSlot(int slotIndex, SkillGemData gem, IReadOnlyList<SkillGemData> acceptedGems, out string reason)
        {
            reason = string.Empty;
            if (gem == null)
                return true;

            if (baseSkill == null)
            {
                reason = "기반 스킬이 없는 슬롯에는 젬을 장착할 수 없습니다.";
                return false;
            }

            if (!gem.CanAttachToSkill(baseSkill))
            {
                string skillClassification = SkillClassificationUtility.GetSkillClassificationLabel(baseSkill);
                string allowedClassification =
                    $"{SkillClassificationUtility.GetAllowedRoleSummary(gem.AllowedSkillRoles)}/" +
                    $"{SkillClassificationUtility.GetAllowedActivationSummary(gem.AllowedSkillActivationTypes)}";
                reason = $"장착 가능한 스킬 조합이 아닙니다. Skill={skillClassification}, Allowed={allowedClassification}";
                return false;
            }

            if (acceptedGems != null)
            {
                for (int i = 0; i < acceptedGems.Count; i++)
                {
                    if (!TryValidateGemPair(gem, acceptedGems[i], out reason))
                        return false;
                }

                return true;
            }

            for (int i = 0; i < socketedGems.Length; i++)
            {
                if (i == slotIndex)
                    continue;

                SkillGemData otherGem = socketedGems[i];
                if (otherGem == null)
                    continue;

                if (!TryValidateGemPair(gem, otherGem, out reason))
                    return false;
            }

            return true;
        }

        private static bool TryValidateGemPair(SkillGemData gem, SkillGemData otherGem, out string reason)
        {
            reason = string.Empty;
            if (gem == null || otherGem == null)
                return true;

            if (gem == otherGem)
            {
                reason = "동일한 젬은 하나의 스킬에 여러 개 장착할 수 없습니다.";
                return false;
            }

            if (gem.IsGemIncompatible(otherGem) || otherGem.IsGemIncompatible(gem))
            {
                reason = $"{gem.GemName}과 {otherGem.GemName}은 함께 장착할 수 없습니다.";
                return false;
            }

            if (gem.IsCategoryIncompatible(otherGem.Category) || otherGem.IsCategoryIncompatible(gem.Category))
            {
                reason =
                    $"{SkillClassificationUtility.GetGemCategoryLabel(gem.Category)} / " +
                    $"{SkillClassificationUtility.GetGemCategoryLabel(otherGem.Category)} 효과 분류 조합은 허용되지 않습니다.";
                return false;
            }

            return true;
        }

        private float GetResolvedScalarMultiplier(System.Func<SkillGemData, float> selector)
        {
            if (baseSkill == null)
                return 1f;

            float resolved = 1f;
            if (socketedGems == null)
                return resolved;

            for (int i = 0; i < socketedGems.Length; i++)
            {
                SkillGemData gem = socketedGems[i];
                if (gem == null)
                    continue;

                resolved *= Mathf.Max(0f, selector(gem));
            }

            return resolved;
        }
    }

    /// <summary>
    /// 현재 시전 중인 스킬 로드아웃의 젬 보정값을 안전하게 조회하는 유틸리티입니다.
    /// </summary>
    public static class SkillRuntimeModifierUtility
    {
        public static float GetDamageMultiplier(GameObject caster)
        {
            return GetCurrentLoadout(caster)?.GetResolvedDamageMultiplier() ?? 1f;
        }

        public static float GetHealMultiplier(GameObject caster)
        {
            return GetCurrentLoadout(caster)?.GetResolvedHealMultiplier() ?? 1f;
        }

        public static float GetShieldMultiplier(GameObject caster)
        {
            return GetCurrentLoadout(caster)?.GetResolvedShieldMultiplier() ?? 1f;
        }

        public static float GetThreatMultiplier(GameObject caster)
        {
            return GetCurrentLoadout(caster)?.GetResolvedThreatMultiplier() ?? 1f;
        }

        private static SkillLoadoutEntry GetCurrentLoadout(GameObject caster)
        {
            if (caster == null)
                return null;

            SkillController skillController = caster.GetComponent<SkillController>();
            if (skillController == null)
                return null;

            return skillController.CurrentLoadoutEntry;
        }
    }
}