using System;
using System.Collections.Generic;
using System.Text;

using UnityEngine;

using Colosseum.Skills;
using Colosseum.Stats;

namespace Colosseum.Passives
{
    /// <summary>
    /// 선택된 패시브 노드를 실제 전투 수치에 적용합니다.
    /// </summary>
    [DisallowMultipleComponent]
    public class PassiveRuntimeController : MonoBehaviour
    {
        [Header("References")]
        [Tooltip("CharacterStats 컴포넌트 (없으면 자동 검색)")]
        [SerializeField] private CharacterStats characterStats;

        [Header("Debug")]
        [Tooltip("현재 적용된 패시브 프리셋 이름")]
        [SerializeField] private string currentPresetName = string.Empty;
        [Tooltip("현재 적용된 노드 ID 목록")]
        [SerializeField] private string currentSelectionSummary = string.Empty;
        [Tooltip("현재 사용한 패시브 포인트")]
        [Min(0)] [SerializeField] private int usedPoints = 0;

        private readonly List<PassiveEffectEntry> activeEffects = new List<PassiveEffectEntry>();
        private readonly List<string> selectedNodeIds = new List<string>();
        private PassiveTreeData currentTree;

        public string CurrentPresetName => currentPresetName;
        public int UsedPoints => usedPoints;
        public int RemainingPoints => currentTree != null ? Mathf.Max(0, currentTree.InitialPoints - usedPoints) : 0;
        public IReadOnlyList<string> SelectedNodeIds => selectedNodeIds;

        private void Awake()
        {
            if (characterStats == null)
            {
                characterStats = GetComponent<CharacterStats>();
            }
        }

        /// <summary>
        /// 외부에서 참조를 보정합니다.
        /// </summary>
        public void Initialize(CharacterStats stats)
        {
            if (stats != null)
            {
                characterStats = stats;
            }
            else if (characterStats == null)
            {
                characterStats = GetComponent<CharacterStats>();
            }
        }

        /// <summary>
        /// 선택된 노드 구성을 적용합니다.
        /// </summary>
        public bool TryApplySelection(PassiveTreeData tree, IReadOnlyList<string> nodeIds, string presetName, out string reason)
        {
            Initialize(characterStats);
            ClearAppliedState();

            currentTree = tree;
            currentPresetName = presetName ?? string.Empty;

            if (currentTree == null)
            {
                reason = "패시브 트리 데이터가 없습니다.";
                return false;
            }

            if (!currentTree.TryResolveSelection(nodeIds, out List<PassiveNodeData> resolvedNodes, out reason))
            {
                return false;
            }

            usedPoints = currentTree.CalculateUsedPoints(resolvedNodes);

            for (int i = 0; i < resolvedNodes.Count; i++)
            {
                PassiveNodeData node = resolvedNodes[i];
                if (node == null)
                    continue;

                selectedNodeIds.Add(node.NodeId);

                IReadOnlyList<PassiveEffectEntry> effects = node.Effects;
                if (effects == null)
                    continue;

                for (int j = 0; j < effects.Count; j++)
                {
                    PassiveEffectEntry effect = effects[j];
                    if (effect == null)
                        continue;

                    ApplyEffect(effect);
                }
            }

            currentSelectionSummary = BuildSelectionSummary();
            reason = string.Empty;
            return true;
        }

        /// <summary>
        /// 현재 선택 상태를 해제합니다.
        /// </summary>
        public void ClearSelection()
        {
            ClearAppliedState();
            currentTree = null;
            currentPresetName = string.Empty;
            currentSelectionSummary = string.Empty;
        }

        public float GetDamageMultiplier(SkillData skill = null)
        {
            return GetScalarMultiplier(PassiveEffectType.DamageMultiplier, skill);
        }

        public float GetHealMultiplier(SkillData skill = null)
        {
            return GetScalarMultiplier(PassiveEffectType.HealMultiplier, skill);
        }

        public float GetShieldDoneMultiplier(SkillData skill = null)
        {
            return GetScalarMultiplier(PassiveEffectType.ShieldDoneMultiplier, skill);
        }

        public float GetShieldReceivedMultiplier()
        {
            return GetScalarMultiplier(PassiveEffectType.ShieldReceivedMultiplier, null);
        }

        public float GetThreatGeneratedMultiplier()
        {
            return GetScalarMultiplier(PassiveEffectType.ThreatGeneratedMultiplier, null);
        }

        public float GetIncomingDamageMultiplier()
        {
            return GetScalarMultiplier(PassiveEffectType.IncomingDamageMultiplier, null);
        }

        public float GetManaCostMultiplier(SkillData skill = null)
        {
            return GetScalarMultiplier(PassiveEffectType.ManaCostMultiplier, skill);
        }

        public string BuildSummary()
        {
            StringBuilder builder = new StringBuilder();
            builder.Append("[Passive] ");
            builder.Append(string.IsNullOrWhiteSpace(currentPresetName) ? "미적용" : currentPresetName);
            builder.Append(" | Used=");
            builder.Append(usedPoints);

            if (currentTree != null)
            {
                builder.Append('/');
                builder.Append(currentTree.InitialPoints);
            }

            if (selectedNodeIds.Count > 0)
            {
                builder.Append(" | Nodes=");
                builder.Append(currentSelectionSummary);
            }

            return builder.ToString();
        }

        private void ApplyEffect(PassiveEffectEntry effect)
        {
            if (effect.EffectType == PassiveEffectType.StatModifier)
            {
                ApplyStatModifier(effect);
                return;
            }

            activeEffects.Add(effect);
        }

        private void ApplyStatModifier(PassiveEffectEntry effect)
        {
            if (characterStats == null || effect == null)
                return;

            CharacterStat stat = characterStats.GetStat(effect.StatType);
            if (stat == null)
                return;

            stat.AddModifier(new StatModifier(effect.Value, effect.ModType, this));
        }

        private float GetScalarMultiplier(PassiveEffectType effectType, SkillData skill)
        {
            float result = 1f;
            for (int i = 0; i < activeEffects.Count; i++)
            {
                PassiveEffectEntry effect = activeEffects[i];
                if (effect == null || effect.EffectType != effectType)
                    continue;

                if (!effect.AppliesToSkill(skill))
                    continue;

                result *= Mathf.Max(0f, effect.Value);
            }

            return result;
        }

        private void ClearAppliedState()
        {
            RemoveAllPassiveStatModifiers();
            activeEffects.Clear();
            selectedNodeIds.Clear();
            usedPoints = 0;
        }

        private void RemoveAllPassiveStatModifiers()
        {
            if (characterStats == null)
                return;

            foreach (StatType statType in Enum.GetValues(typeof(StatType)))
            {
                CharacterStat stat = characterStats.GetStat(statType);
                stat?.RemoveAllModifiersFromSource(this);
            }
        }

        private string BuildSelectionSummary()
        {
            if (selectedNodeIds.Count <= 0)
                return string.Empty;

            return string.Join(", ", selectedNodeIds);
        }
    }

    /// <summary>
    /// 패시브 전투 배율을 안전하게 조회하는 유틸리티입니다.
    /// </summary>
    public static class PassiveRuntimeModifierUtility
    {
        public static float GetDamageMultiplier(GameObject actor)
        {
            PassiveRuntimeController controller = GetController(actor);
            return controller != null ? controller.GetDamageMultiplier(GetCurrentSkill(actor)) : 1f;
        }

        public static float GetHealMultiplier(GameObject actor)
        {
            PassiveRuntimeController controller = GetController(actor);
            return controller != null ? controller.GetHealMultiplier(GetCurrentSkill(actor)) : 1f;
        }

        public static float GetShieldDoneMultiplier(GameObject actor)
        {
            PassiveRuntimeController controller = GetController(actor);
            return controller != null ? controller.GetShieldDoneMultiplier(GetCurrentSkill(actor)) : 1f;
        }

        public static float GetShieldReceivedMultiplier(GameObject actor)
        {
            PassiveRuntimeController controller = GetController(actor);
            return controller != null ? controller.GetShieldReceivedMultiplier() : 1f;
        }

        public static float GetThreatGeneratedMultiplier(GameObject actor)
        {
            PassiveRuntimeController controller = GetController(actor);
            return controller != null ? controller.GetThreatGeneratedMultiplier() : 1f;
        }

        public static float GetIncomingDamageMultiplier(GameObject actor)
        {
            PassiveRuntimeController controller = GetController(actor);
            return controller != null ? controller.GetIncomingDamageMultiplier() : 1f;
        }

        public static float GetManaCostMultiplier(GameObject actor, SkillData skill)
        {
            PassiveRuntimeController controller = GetController(actor);
            return controller != null ? controller.GetManaCostMultiplier(skill) : 1f;
        }

        public static string GetCurrentPresetName(GameObject actor)
        {
            PassiveRuntimeController controller = GetController(actor);
            return controller != null ? controller.CurrentPresetName : string.Empty;
        }

        public static string BuildSummary(GameObject actor)
        {
            PassiveRuntimeController controller = GetController(actor);
            return controller != null ? controller.BuildSummary() : "[Passive] 미적용";
        }

        private static PassiveRuntimeController GetController(GameObject actor)
        {
            if (actor == null)
                return null;

            return actor.GetComponent<PassiveRuntimeController>() ?? actor.GetComponentInParent<PassiveRuntimeController>();
        }

        private static SkillData GetCurrentSkill(GameObject actor)
        {
            if (actor == null)
                return null;

            SkillController skillController = actor.GetComponent<SkillController>() ?? actor.GetComponentInParent<SkillController>();
            return skillController != null ? skillController.CurrentSkill : null;
        }
    }
}