using System;
using System.Collections.Generic;
using System.Linq;
using Continentis.MainGame.Card;
using SLSUtilities.General;
using UnityEngine;
using Random = UnityEngine.Random;

namespace Continentis.MainGame.Character
{
    public partial class IntentionSubmodule
    {
        // ──────────────────────────────────────────────────────────────
        // 原子操作层
        // ──────────────────────────────────────────────────────────────

        /// <summary>移除指定位置的意图卡并销毁其视图。</summary>
        /// <returns>被移除的 IntendedCard，索引越界时返回 null。</returns>
        public IntendedCard RemoveIntendedCardAt(int index)
        {
            if (!IsValidIndex(index)) return null;

            IntendedCard removed = intendedCards[index];
            removed.cardInstance.DestroyIntentionCardView();
            intendedCards.RemoveAt(index);
            
            onIntendedCardRemoved.Invoke(removed, index);
            return removed;
        }

        /// <summary>替换指定位置的意图卡，销毁旧视图并生成新视图。</summary>
        /// <returns>被替换掉的旧 IntendedCard，索引越界时返回 null。</returns>
        public IntendedCard ReplaceIntendedCardAt(int index, IntendedCard newCard)
        {
            if (!IsValidIndex(index)) return null;
            if (newCard == null)
            {
                Debug.LogWarning("[IntentionSubmodule] ReplaceIntendedCardAt: newCard is null, performing remove instead.");
                return RemoveIntendedCardAt(index);
            }

            IntendedCard oldCard = intendedCards[index];
            oldCard.cardInstance.DestroyIntentionCardView();

            intendedCards[index] = newCard;
            newCard.cardInstance.GenerateIntentionCardView();
            
            // 设置文本解析目标
            if (newCard.targets.Count > 0)
            {
                newCard.cardInstance.Targeting(newCard.targets[0]);
                newCard.cardInstance.contentSubmodule.dirtyMark = true;
            }
            
            onIntendedCardReplaced.Invoke(oldCard, newCard, index);
            return oldCard;
        }

        /// <summary>在指定位置插入一张新意图卡并生成视图。</summary>
        public void InsertIntendedCard(int index, IntendedCard newCard)
        {
            if (newCard == null)
            {
                Debug.LogWarning("[IntentionSubmodule] InsertIntendedCard: newCard is null, insertion skipped.");
                return;
            }

            int clampedIndex = Mathf.Clamp(index, 0, intendedCards.Count);
            intendedCards.Insert(clampedIndex, newCard);
            newCard.cardInstance.GenerateIntentionCardView();
            
            // 设置文本解析目标
            if (newCard.targets.Count > 0)
            {
                newCard.cardInstance.Targeting(newCard.targets[0]);
                newCard.cardInstance.contentSubmodule.dirtyMark = true;
            }
            
            onIntendedCardInserted.Invoke(newCard, clampedIndex);
        }

        /// <summary>在末尾追加一张新意图卡并生成视图。</summary>
        public void AddIntendedCard(IntendedCard newCard)
        {
            InsertIntendedCard(intendedCards.Count, newCard);
        }

        // ──────────────────────────────────────────────────────────────
        // 查询 / 工具层
        // ──────────────────────────────────────────────────────────────

        /// <summary>返回 intendedCards 中的随机索引，列表为空时返回 -1。</summary>
        public int GetRandomIntendedCardIndex()
        {
            return intendedCards.Count == 0 ? -1 : Random.Range(0, intendedCards.Count);
        }

        /// <summary>
        /// 使用过滤器从 intendedCards 中筛选出符合条件的意图卡索引列表。
        /// </summary>
        /// <param name="filter">返回 true 表示该意图卡通过筛选。</param>
        public List<int> GetFilteredIntendedCardIndices(Func<IntendedCard, bool> filter)
        {
            List<int> result = new List<int>();
            for (int i = 0; i < intendedCards.Count; i++)
            {
                if (filter(intendedCards[i]))
                    result.Add(i);
            }
            return result;
        }

        /// <summary>
        /// 使用过滤器从 intendedCards 中随机选取一个符合条件的意图卡索引。
        /// </summary>
        /// <returns>随机索引，无符合条件的意图卡时返回 -1。</returns>
        public int GetRandomFilteredIntendedCardIndex(Func<IntendedCard, bool> filter)
        {
            List<int> filtered = GetFilteredIntendedCardIndices(filter);
            return filtered.Count == 0 ? -1 : filtered[Random.Range(0, filtered.Count)];
        }

        /// <summary>
        /// 尝试从 PoolPile 中获取一张可替换的随机卡牌（排除当前已在 intendedCards 中的卡牌）。
        /// </summary>
        /// <param name="result">生成的 IntendedCard，失败时为 null。</param>
        /// <param name="checkAffordability">是否检查体力/法力消耗。</param>
        /// <returns>是否成功找到可替换的卡牌。</returns>
        public bool TryGetRandomReplacementCard(out IntendedCard result, bool checkAffordability = false)
        {
            result = null;
            
            HashSet<CardInstance> currentCards = new HashSet<CardInstance>(
                intendedCards.Select(ic => ic.cardInstance));

            List<CardInstance> candidates = owner.deckSubmodule.PoolPile
                .Where(card => !currentCards.Contains(card) && !card.weightSubmodule.forceIgnore)
                .ToList();

            if (checkAffordability)
            {
                int stamina = owner.GetAttribute(CharacterAttributes.Stamina);
                int mana = owner.GetAttribute(CharacterAttributes.Mana);
                candidates = candidates.Where(card =>
                    card.GetAttribute(CardAttributes.StaminaCost) <= stamina &&
                    card.GetAttribute(CardAttributes.ManaCost) <= mana).ToList();
            }

            if (candidates.Count == 0) return false;

            CardInstance chosen = candidates[Random.Range(0, candidates.Count)];
            if (!owner.CheckAvailabilityAndSetTargets(chosen, out List<CharacterBase> targets))
                return false;

            result = new IntendedCard(chosen, targets);
            return true;
        }

        // ──────────────────────────────────────────────────────────────
        // 组合操作层
        // ──────────────────────────────────────────────────────────────

        /// <summary>随机移除一张意图卡。</summary>
        /// <returns>被移除的 IntendedCard，列表为空时返回 null。</returns>
        public IntendedCard RemoveRandomIntendedCard()
        {
            int index = GetRandomIntendedCardIndex();
            return index < 0 ? null : RemoveIntendedCardAt(index);
        }

        /// <summary>
        /// 随机移除一张符合过滤条件的意图卡。
        /// </summary>
        /// <param name="filter">返回 true 表示该意图卡可被移除。</param>
        /// <returns>被移除的 IntendedCard，无符合条件的意图卡时返回 null。</returns>
        public IntendedCard RemoveRandomIntendedCard(Func<IntendedCard, bool> filter)
        {
            int index = GetRandomFilteredIntendedCardIndex(filter);
            return index < 0 ? null : RemoveIntendedCardAt(index);
        }

        /// <summary>
        /// 随机将一张意图卡替换为 PoolPile 中的另一张卡牌。
        /// 若无可替换卡牌则降级为移除。
        /// </summary>
        /// <param name="checkAffordability">是否检查体力/法力消耗。</param>
        /// <returns>操作是否成功执行（移除或替换均算成功）。</returns>
        public bool ChangeRandomIntendedCard(bool checkAffordability = false)
        {
            int index = GetRandomIntendedCardIndex();
            if (index < 0) return false;

            if (TryGetRandomReplacementCard(out IntendedCard replacement, checkAffordability))
            {
                ReplaceIntendedCardAt(index, replacement);
            }
            else
            {
                RemoveIntendedCardAt(index);
            }
            return true;
        }

        /// <summary>
        /// 随机将一张符合过滤条件的意图卡替换为 PoolPile 中的另一张卡牌。
        /// 若无可替换卡牌则降级为移除。
        /// </summary>
        /// <param name="filter">返回 true 表示该意图卡可被替换。</param>
        /// <param name="checkAffordability">是否检查体力/法力消耗。</param>
        /// <returns>操作是否成功执行。</returns>
        public bool ChangeRandomIntendedCard(Func<IntendedCard, bool> filter, bool checkAffordability = false)
        {
            int index = GetRandomFilteredIntendedCardIndex(filter);
            if (index < 0) return false;

            if (TryGetRandomReplacementCard(out IntendedCard replacement, checkAffordability))
            {
                ReplaceIntendedCardAt(index, replacement);
            }
            else
            {
                RemoveIntendedCardAt(index);
            }
            return true;
        }

        // ──────────────────────────────────────────────────────────────
        // 内部工具
        // ──────────────────────────────────────────────────────────────

        private bool IsValidIndex(int index)
        {
            if (index >= 0 && index < intendedCards.Count) return true;
            Debug.LogWarning($"[IntentionSubmodule] Index {index} out of range (count: {intendedCards.Count}).");
            return false;
        }
    }
}