难度曲线与动态难度调整 (DDA)

Flow = Challenge ∈ [Skill × 0.8, Skill × 1.3]

                    高手玩家上限
                   /
        心流通道  /
               /
    困难阈值 /__________ 平均玩家
           /
         /
  简单  /______________ 新手玩家下限
      ↓
    时间/关卡进度

Difficulty_t+1 = Difficulty_t + α × (Target_WinRate - Actual_WinRate)

其中:
- α: 学习率 (通常 0.05 ~ 0.15)
- Target_WinRate: 目标胜率 (通常 50% ~ 70%)
- Actual_WinRate: 玩家实际胜率 (滑动窗口统计)

Difficulty_Score = Σ (w_i × factor_i)

常见因子:
- factor_1: 胜率 (WinRate)
- factor_2: 平均存活时间 (AvgSurvivalTime)
- factor_3: 资源利用率 (ResourceEfficiency)
- factor_4: 失误频率 (MistakeFrequency)
- factor_5: 连续失败次数 (StreakFailures)

权重: Σw_i = 1.0

┌─────────────────────────────────────┐
│ 1. 静态难度基线 (Static Baseline)   │ ← 关卡固有难度
├─────────────────────────────────────┤
│ 2. 进度难度伸缩 (Progression Scale) │ ← 角色等级增长
├─────────────────────────────────────┤
│ 3. 动态难度调节 (DDA Layer)         │ ← 玩家表现反馈
├─────────────────────────────────────┤
│ 4. 玩家主动选择 (Player Choice)     │ ← 诅咒/地图词条
└─────────────────────────────────────┘

[System.Serializable]
public class DifficultyConfig
{
    [Header("静态基线")]
    public float baseEnemyHealth = 100f;
    public float baseEnemyDamage = 10f;
    public int baseWaveCount = 5;
    
    [Header("进度伸缩")]
    public AnimationCurve healthScalingCurve;  // X: 关卡, Y: 倍率
    public AnimationCurve damageScalingCurve;
    
    [Header("DDA 参数")]
    [Range(0f, 1f)] public float targetWinRate = 0.65f;
    [Range(0.01f, 0.3f)] public float learningRate = 0.1f;
    public int statisticsWindowSize = 5;  // 滑动窗口大小
    
    [Header("安全阈值")]
    [Range(0.5f, 1.5f)] public float minDifficultyMultiplier = 0.7f;
    [Range(1.0f, 3.0f)] public float maxDifficultyMultiplier = 2.0f;
}

public class PlayerPerformanceTracker
{
    // 滑动窗口统计
    private Queue<BattleResult> recentBattles = new Queue<BattleResult>();
    
    // 多因子评分
    public float CalculatePerformanceScore()
    {
        if (recentBattles.Count == 0) return 0.5f;
        
        float winRate = GetWinRate();
        float avgSurvivalRatio = GetAvgSurvivalTimeRatio();
        float resourceEfficiency = GetResourceEfficiency();
        
        // 加权平均
        return 0.5f * winRate + 
               0.3f * avgSurvivalRatio +
               0.2f * resourceEfficiency;
    }
    
    private float GetWinRate()
    {
        int wins = recentBattles.Count(b => b.isVictory);
        return (float)wins / recentBattles.Count;
    }
    
    private float GetAvgSurvivalTimeRatio()
    {
        float avg = recentBattles.Average(b => b.survivalTime / b.expectedTime);
        return Mathf.Clamp01(avg);
    }
    
    private float GetResourceEfficiency()
    {
        // 资源利用率：剩余生命值、金币使用率等
        float avg = recentBattles.Average(b => b.resourceScore);
        return Mathf.Clamp01(avg);
    }
}

public class DynamicDifficultyManager
{
    private DifficultyConfig config;
    private PlayerPerformanceTracker tracker;
    private float currentMultiplier = 1.0f;
    
    public void AdjustDifficulty(BattleResult result)
    {
        // 1. 记录战斗数据
        tracker.AddBattleResult(result);
        
        // 2. 计算表现分数
        float performanceScore = tracker.CalculatePerformanceScore();
        
        // 3. 橡皮筋调整
        float delta = config.learningRate * (config.targetWinRate - performanceScore);
        currentMultiplier += delta;
        
        // 4. 安全限制 (防止过度波动)
        currentMultiplier = Mathf.Clamp(
            currentMultiplier,
            config.minDifficultyMultiplier,
            config.maxDifficultyMultiplier
        );
        
        // 5. 连续失败保护
        if (tracker.GetConsecutiveFailures() >= 3)
        {
            currentMultiplier = Mathf.Max(currentMultiplier - 0.2f, 0.5f);
            Debug.Log("触发失败保护机制");
        }
    }
    
    public EnemyStats GetAdjustedEnemyStats(EnemyStats baseStats, int level)
    {
        // 静态基线
        var stats = baseStats.Clone();
        
        // 进度伸缩
        float progressionScale = config.healthScalingCurve.Evaluate(level);
        
        // DDA 叠加
        stats.health *= progressionScale * currentMultiplier;
        stats.damage *= progressionScale * currentMultiplier;
        
        return stats;
    }
}

// UI 显示当前难度等级
public void UpdateDifficultyUI()
{
    string difficultyLabel = currentMultiplier switch
    {
        < 0.8f => "简单",
        < 1.2f => "正常",
        < 1.5f => "困难",
        _ => "极难"
    };
    
    difficultyText.text = $"当前难度: {difficultyLabel}";
    
    // ⚠️ 可选：隐藏具体数值，避免"被系统操控"的负面感受
}

Tension_Score = f(Combat_Intensity, Time_Since_Last_Event, Player_Health)

if Tension_Score < Threshold_Low:
    Trigger_Event(Intensity.High)  // 刷特感、Tank
elif Tension_Score > Threshold_High:
    Trigger_RestPeriod()            // 安全屋、补给

玩家感知: "我选择了困难，所以我变强了"
实际情况: "系统检测到我菜，偷偷帮我降低了难度"

[辅助模式] (不影响成就)
- 无敌模式
- 无限冲刺
- 游戏速度调节 (50% ~ 100%)