using System.Collections;
using BaseGames.Core;
using BaseGames.Core.Events;
using BaseGames.Input;
using BaseGames.World;
using UnityEngine;

namespace BaseGames.Dialogue
{
    /// <summary>
    /// 对话管理器（架构 14_NarrativeModule §4）。
    /// 驱动 DialogueUI 打字机效果；管理 Action Map 切换；向 QuestManager 广播对话完成事件。
    /// 在 Awake 中注册到 ServiceLocator。
    /// </summary>
    public class DialogueManager : MonoBehaviour, IDialogueService
    {
        [SerializeField] private DialogueUI          _dialogueBox;
        [SerializeField] private InputReaderSO       _inputReader;
        [SerializeField] private WorldStateRegistry  _worldState;

        [Header("事件频道")]
        [SerializeField] private VoidEventChannelSO   _onDialogueStarted;
        [SerializeField] private VoidEventChannelSO   _onDialogueEnded;
        [SerializeField] private StringEventChannelSO _onNpcDialogueCompleted;  // → EVT_NpcDialogueCompleted (npcId)

        private bool _skipRequested;

        /// <summary>当前是否有对话正在播放。</summary>
        public bool IsDialogueActive { get; private set; }

        // ── 生命周期 ──────────────────────────────────────────────────────

        private void Awake()
        {
            if (ServiceLocator.GetOrDefault<IDialogueService>() != null) { Destroy(gameObject); return; }
            ServiceLocator.Register<IDialogueService>(this);
        }

        private void OnDestroy()
        {
            ServiceLocator.Unregister<IDialogueService>(this);
        }

        private void OnEnable()
        {
            if (_inputReader != null) _inputReader.SubmitEvent += OnSubmit;
        }

        private void OnDisable()
        {
            if (_inputReader != null) _inputReader.SubmitEvent -= OnSubmit;
        }

        // ── 公开 API ──────────────────────────────────────────────────────

        /// <summary>
        /// 启动对话序列。若已有对话在播放则忽略新请求。
        /// 由 InteractableNPC.Interact() 调用。
        /// </summary>
        /// <param name="sequence">要播放的对话序列 SO。</param>
        /// <param name="npcId">NPC 标识符，对话结束时随 EVT_NpcDialogueCompleted 广播。</param>
        public void StartDialogue(DialogueSequenceSO sequence, string npcId = "")
        {
            if (IsDialogueActive || sequence == null) return;
            IsDialogueActive = true;
            _skipRequested = false;

            // 切换到 UI Action Map（禁用玩家移动输入）
            _inputReader.EnableUIInput();

            _onDialogueStarted?.Raise();
            StartCoroutine(PlaySequence(sequence, npcId));
        }

        // ── 输入回调 ──────────────────────────────────────────────────────

        private void OnSubmit() => _skipRequested = true;

        // ── 内部协程 ──────────────────────────────────────────────────────

        private IEnumerator PlaySequence(DialogueSequenceSO sequence, string npcId)
        {
            // 选择条件变体（查询 ConditionalVariant.conditionFlag — 未实现 WorldStateRegistry 查询时直接使用默认序列）
            var resolved = ResolveVariant(sequence);

            foreach (var line in resolved.lines)
            {
                _skipRequested = false;
                _dialogueBox.ShowLine(line);

                // 等待打字完成，期间允许跳过
                yield return new WaitUntil(() => !_dialogueBox.IsTyping || _skipRequested);
                if (_dialogueBox.IsTyping) _dialogueBox.SkipTyping();

                // 等待玩家按 Submit 推进下一行
                _skipRequested = false;
                yield return new WaitUntil(() => _skipRequested);
            }

            EndDialogue(npcId);
        }

        private void EndDialogue(string npcId)
        {
            _dialogueBox.Hide();
            IsDialogueActive = false;

            // 恢复 Gameplay Action Map
            _inputReader.EnableGameplayInput();

            _onDialogueEnded?.Raise();

            if (!string.IsNullOrEmpty(npcId))
                _onNpcDialogueCompleted?.Raise(npcId);
        }

        /// <summary>
        /// 根据 ConditionalVariant 选择正确的序列版本。
        /// 按顺序检查 variants：第一个满足 WorldStateRegistry 标志的变体胜出；
        /// 未注入 WorldStateRegistry 或无满足条件的变体时，返回原序列（默认）。
        /// </summary>
        private DialogueSequenceSO ResolveVariant(DialogueSequenceSO sequence)
        {
            if (sequence.variants == null || sequence.variants.Length == 0)
                return sequence;

            if (_worldState != null)
            {
                foreach (var variant in sequence.variants)
                {
                    if (!string.IsNullOrEmpty(variant.conditionFlag)
                        && variant.sequence != null
                        && _worldState.HasFlag(variant.conditionFlag))
                        return variant.sequence;
                }
            }

            return sequence;
        }
    }
}