using System;
using System.Collections;
using Core;
using Gameplay.Enemy;
using Gameplay.Player;
using Interface;
using UnityEngine;

namespace Gameplay
{
    /// <summary>
    /// 战斗流程管理器（回合制、循环抽牌）
    /// 使用方法：在场景中挂载一个空物体并配置 player 与 enemy 的 Combatant 引用。
    /// 该管理器通过事件回调让 UI 或其它系统接入“双方牌都打空时”的选择（继续/逃跑）。
    /// </summary>
    public class CombatFlowManager : MonoSingleton<CombatFlowManager>
    {
        [Header("Participants")]
        public PlayerController player;
        public EnemyController enemy;

        [Header("Flow Settings")]
        [Tooltip("玩家是否先手（true=玩家先出一张）")]
        public bool playerStarts = true;
        [Tooltip("每出一张牌后的间隔（秒）")]
        public float turnDelay = 0.8f;

        // Events
        public event Action OnCombatStarted;
        public event Action<ICharacter, Card> OnCardPlayed;
        public event Action<ICharacter> OnCombatEnded; // 参数为胜利方（null 表示平局或逃跑）
        public event Action OnBothEmpty; // 当双方都没有卡可以出时触发，UI 需要通过 ContinueAfterBothEmpty 或 EscapeFromCombat 响应

        // internal state
        private Coroutine runningRoutine;
        private bool waitingForDecision = false;
        private bool decisionContinue = false;
        private bool decisionEscape = false;

        /// <summary>
        /// 启动战斗流程（也可以在 Inspector 中提前绑定 player/enemy，然后只调用 StartCombat()）
        /// </summary>
        public void StartCombat(PlayerController playerController = null, EnemyController enemyController = null)
        {
            if (playerController != null) player = playerController;
            if (enemyController != null) enemy = enemyController;

            if (player == null || enemy == null)
            {
                Debug.LogError("CombatFlowManager: player 或 enemy 未设置。");
                return;
            }

            // 初始化双方状态
            player.StartCombat();
            enemy.StartCombat();
            player.InitializeDeckCycle();
            enemy.InitializeDeckCycle();


            runningRoutine = StartCoroutine(CombatRoutine());
            OnCombatStarted?.Invoke();
        }

        public void StopCombat()
        {
            if (runningRoutine != null) StopCoroutine(runningRoutine);
            runningRoutine = null;
        }

        private IEnumerator CombatRoutine()
        {
            ICharacter current = playerStarts ? player : enemy;

            while (true)
            {
                // 结束检查
                if (player.IsDead || enemy.IsDead)
                {
                    ICharacter winner = player.IsDead ? enemy : player;
                    OnCombatEnded?.Invoke(winner);
                    runningRoutine = null;
                    yield break;
                }

                bool playerHas = player.HasCardsLeft();
                bool enemyHas = enemy.HasCardsLeft();

                if (!playerHas && !enemyHas)
                {
                    // 双方都打空，等待玩家选择（由 UI 调用 ContinueAfterBothEmpty 或 EscapeFromCombat）
                    waitingForDecision = true;
                    decisionContinue = false;
                    decisionEscape = false;
                    OnBothEmpty?.Invoke();

                    // 等待选择
                    while (waitingForDecision)
                        yield return null;

                    if (decisionEscape)
                    {
                        // 玩家选择逃跑 -> 结束战斗，胜者设为 null（或按需要设成敌人/玩家）
                        OnCombatEnded?.Invoke(null);
                        runningRoutine = null;
                        yield break;
                    }

                    if (decisionContinue)
                    {
                        // 重新从卡册读取（重置抽牌队列），保持生命与其它状态不变
                        player.InitializeDeckCycle();
                        enemy.InitializeDeckCycle();
                        // 继续循环（当前先手不变）
                        yield return null;
                        continue;
                    }
                }

                // 当前回合：如果当前方没有牌则跳过（空过）
                if (current.HasCardsLeft())
                {
                    var card = current.GetNextCard();
                    ICharacter target;
                    if (current is PlayerController)
                    {
                        target = enemy;
                    }
                    else
                    {
                        target = player;
                    }
                    

                    // 触发卡牌效果（当前仅支持直接伤害）
                    if (card != null)
                    {
                        card.PlayCard(new CardContext(current, target));
                        OnCardPlayed?.Invoke(current, card);
                    }

                    // 检查死亡（将在下一循环顶部处理）
                    yield return new WaitForSeconds(turnDelay);
                }
                else
                {
                    // 跳过一轮，不延迟太久
                    yield return new WaitForSeconds(0.1f);
                }

                // 切换行动方
                current = (current == player) ? enemy : player;
            }
        }

        /// <summary>
        /// 当双方都打空时，UI 调用此方法选择继续下一轮（重新从卡册读取卡牌）
        /// </summary>
        public void ContinueAfterBothEmpty()
        {
            if (!waitingForDecision) return;
            decisionContinue = true;
            waitingForDecision = false;
        }

        /// <summary>
        /// 当双方都打空时，UI 调用此方法选择逃跑
        /// </summary>
        public void EscapeFromCombat()
        {
            if (!waitingForDecision) return;
            decisionEscape = true;
            waitingForDecision = false;
        }
    }
}