using UnityEngine;
using UnityEngine.Events;

/// <summary>
/// 实验流程状态机——整个项目的核心控制器。
/// 负责步骤推进、模式切换、UI 更新、加权考核判分调度。
/// 挂在一个持久化的 GameObject 上。
/// </summary>
public class StepManager : MonoBehaviour
{
    [Header("配置（优先级：Inspector直接赋值 > ExperimentFlowCoordinator兜底 > Resources加载）")]
    public ExperimentConfig Config;

    [Header("事件（拖入场景对象或通过代码绑定）")]
    public UnityEvent<int> OnStepChanged;
    public UnityEvent<string> OnTipChanged;
    public UnityEvent<string> OnDialogueChanged;
    public UnityEvent<StepData> OnExamPopup;
    public UnityEvent<string> OnDetailedContent;
    public UnityEvent OnExperimentComplete;
    public UnityEvent<string, bool> OnVideoToggle;
    public UnityEvent<bool> OnModeUIUpdate;

    // 私有状态
    private StepData[] _activeSteps;
    private int _currentStepIndex = -1;
    private ExperimentMode _mode;
    private FixationMethod _fixation;
    private bool _initialized = false;

    public int CurrentStepIndex => _currentStepIndex;
    public int TotalSteps => _activeSteps != null ? _activeSteps.Length : 0;
    public ExperimentMode Mode => _mode;
    public FixationMethod Fixation => _fixation;
    public bool IsInitialized => _initialized;

    /// <summary>用 GameManager 的当前设置初始化</summary>
    public void InitializeFromGameManager()
    {
        var gm = GameManager.Instance;
        if (gm == null) { Debug.LogError("StepManager: GameManager.Instance is null!"); return; }
        Initialize(gm.CurrentExperimentType, gm.CurrentMode, gm.CurrentFixationMethod);
    }

    /// <summary>显式指定参数初始化</summary>
    public void Initialize(ExperimentType type, ExperimentMode mode, FixationMethod fixation)
    {
        // 如果 Inspector 里没有直接拖 Config，尝试从 ExperimentFlowCoordinator 获取兜底配置
        if (Config == null)
        {
            var coordinator = FindObjectOfType<ExperimentFlowCoordinator>();
            if (coordinator != null && coordinator.DefaultConfig != null)
            {
                Config = coordinator.DefaultConfig;
            }
        }

        // 最后尝试从 Resources 加载
        if (Config == null)
        {
            Config = Resources.Load<ExperimentConfig>($"Configs/{type}Config");
        }

        if (Config == null)
        {
            Debug.LogError($"StepManager: 找不到 ExperimentConfig for {type}。" +
                "请在 Inspector 中直接拖入 Config，或在 ExperimentFlowCoordinator 上设置 Default Config，" +
                "或在 Resources/Configs/ 下创建 ScriptableObject。");
            return;
        }

        _mode = mode;
        _fixation = fixation;

        _activeSteps = Config.GetStepsFor(mode, fixation);
        if (_activeSteps == null || _activeSteps.Length == 0)
        {
            Debug.LogError($"StepManager: 实验 {type} 模式 {mode} 固定方式 {fixation} 无步骤数据！");
            return;
        }

        _currentStepIndex = -1;
        _initialized = true;

        if (mode == ExperimentMode.Exam)
            GameManager.Instance.InitExamRecord(_activeSteps.Length);

        OnModeUIUpdate?.Invoke(mode == ExperimentMode.Exam);
        GoToStep(0);
    }

    public void GoToStep(int index)
    {
        if (_activeSteps == null) return;
        index = Mathf.Clamp(index, 0, _activeSteps.Length - 1);
        if (index == _currentStepIndex) return;

        _currentStepIndex = index;
        var step = _activeSteps[index];

        if (_mode == ExperimentMode.Learn)
        {
            OnTipChanged?.Invoke(step.TipText);
            OnDialogueChanged?.Invoke(step.DialogueText);
            OnDetailedContent?.Invoke(step.DetailedContent);
            if (step.ShowPipVideo)
                OnVideoToggle?.Invoke(step.VideoFileName, true);
            else
                OnVideoToggle?.Invoke(null, false);
        }
        else
        {
            OnTipChanged?.Invoke("");
            OnDialogueChanged?.Invoke("");
            OnDetailedContent?.Invoke("");
            OnVideoToggle?.Invoke(null, false);

            if (!string.IsNullOrEmpty(step.ExamQuestionText))
                OnExamPopup?.Invoke(step);
        }

        OnStepChanged?.Invoke(_currentStepIndex);
    }

    public void NextStep()
    {
        if (_activeSteps == null) return;
        if (_currentStepIndex >= _activeSteps.Length - 1)
        {
            CompleteExperiment();
            return;
        }
        GoToStep(_currentStepIndex + 1);
    }

    public void PreviousStep()
    {
        if (_activeSteps == null || _currentStepIndex <= 0) return;
        GoToStep(_currentStepIndex - 1);
    }

    public StepData GetCurrentStep()
    {
        if (_activeSteps == null || _currentStepIndex < 0 || _currentStepIndex >= _activeSteps.Length)
            return null;
        return _activeSteps[_currentStepIndex];
    }

    public void OnStepInteractionComplete(float proportion = 1f, string feedback = "")
    {
        var step = GetCurrentStep();
        if (step == null) return;

        if (_mode == ExperimentMode.Exam)
        {
            string fb = string.IsNullOrEmpty(feedback) ? step.ErrorFeedback : feedback;
            GameManager.Instance.RecordExamResult(_currentStepIndex, step.ScoreWeight, proportion, fb);
        }

        if (_mode == ExperimentMode.Learn)
            NextStep();
    }

    private void CompleteExperiment()
    {
        Debug.Log("StepManager: 实验流程结束");
        OnExperimentComplete?.Invoke();
    }

    public void SwitchMode(ExperimentMode newMode)
    {
        GameManager.Instance.CurrentMode = newMode;
        Initialize(GameManager.Instance.CurrentExperimentType, newMode, GameManager.Instance.CurrentFixationMethod);
    }

    public void SwitchFixation(FixationMethod newFixation)
    {
        GameManager.Instance.CurrentFixationMethod = newFixation;
        Initialize(GameManager.Instance.CurrentExperimentType, GameManager.Instance.CurrentMode, newFixation);
    }
}