// 1. 从目标点（基地）开始，反向 BFS
public void GenerateFlowField(Vector2Int goal)
{
    Queue<Vector2Int> queue = new Queue<Vector2Int>();
    queue.Enqueue(goal);
    distanceField[goal.x, goal.y] = 0;

    while (queue.Count > 0)
    {
        Vector2Int current = queue.Dequeue();
        foreach (Vector2Int neighbor in GetNeighbors(current))
        {
            \text{if} (IsWalkable(neighbor))
            {
                int newDist = distanceField[current.x, current.y] + 1;
                \text{if} (newDist < distanceField[neighbor.x, neighbor.y])
                {
                    distanceField[neighbor.x, neighbor.y] = newDist;
                    queue.Enqueue(neighbor);
                }
            }
        }
    }

    // 2. 根据距离场生成流向
    GenerateVectorField();
}

// 3. 怪物移动：直接查表
public Vector3 GetFlowDirection(Vector3 position)
{
    Vector2Int gridPos = WorldToGrid(position);
    return flowField[gridPos.x, gridPos.y];
}

public bool CanPlaceTower(Vector2Int position)
{
    // 临时标记这个格子为阻挡
    SetBlocked(position, true);

    // 重新计算 Flow Field
    GenerateFlowField(basePosition);

    // 检查所有刷怪点是否还能到达基地
    foreach (Vector2Int spawner in spawnerPositions)
    {
        \text{if} (distanceField[spawner.x, spawner.y] == int.MaxValue)
        {
            // 无法到达，不允许建塔
            SetBlocked(position, false);
            return false;
        }
    }

    return true;
}

{
  "wave_types": {
    "Standard": {
      "enemy_count_range": [20, 50],
      "spawn_interval": 1.0,
      "spawner_count": 1
    },
    "Burst": {
      "enemy_count_range": [100, 200],
      "spawn_interval": 0.1,
      "spawner_count": 1,
      "description": "瞬间刷出大量弱怪"
    },
    "Pincer": {
      "enemy_count_range": [30, 60],
      "spawn_interval": 0.5,
      "spawner_count": 2,
      "spawners": ["North", "South"],
      "description": "双向夹击"
    },
    "Elite": {
      "enemy_count_range": [5, 10],
      "spawn_interval": 3.0,
      "elite_ratio": 1.0,
      "description": "所有怪都是精英"
    },
    "Boss": {
      "enemy_count_range": [1, 1],
      "spawn_interval": 0,
      "boss_id": "BossName"
    }
  }
}

{
  "intensity_curve": {
    "type": "sine_wave",
    "parameters": {
      "amplitude": 1.5,
      "frequency": 0.2,
      "baseline": 1.0
    }
  }
}

public float GetWaveIntensity(int waveNumber)
{
    float t = waveNumber * frequency;
    float intensity = baseline + amplitude * Mathf.Sin(t);
    return Mathf.Max(0.5f, intensity); // 最低 0.5x 难度
}

public int GetEnemyCount(int baseCount, int waveNumber)
{
    return Mathf.RoundToInt(baseCount * GetWaveIntensity(waveNumber));
}

public class EnemyPool : MonoBehaviour
{
    private Dictionary<string, Queue<Enemy>> pools = new Dictionary<string, Queue<Enemy>>();

    public Enemy Spawn(string enemyId, Vector3 position)
    {
        \text{if} (!pools.ContainsKey(enemyId))
            pools[enemyId] = new Queue<Enemy>();

        Enemy enemy;
        \text{if} (pools[enemyId].Count > 0)
        {
            enemy = pools[enemyId].Dequeue();
            enemy.transform.position = position;
            enemy.gameObject.SetActive(true);
        }
        else
        {
            enemy = Instantiate(GetEnemyPrefab(enemyId), position, Quaternion.identity);
        }

        enemy.OnDeath += () => Recycle(enemyId, enemy);
        return enemy;
    }

    private void Recycle(string enemyId, Enemy enemy)
    {
        enemy.gameObject.SetActive(false);
        pools[enemyId].Enqueue(enemy);
    }
}

public class LevelDebugger : MonoBehaviour
{
    private void OnGUI()
    {
        GUILayout.BeginArea(new Rect(10, 10, 300, 500));

        GUILayout.Label($"Current Wave: {WaveManager.Instance.CurrentWave}");
        GUILayout.Label($"Enemies Alive: {EnemyManager.Instance.AliveCount}");

        \text{if} (GUILayout.Button("Skip to Wave +5"))
            WaveManager.Instance.SkipToWave(WaveManager.Instance.CurrentWave + 5);

        \text{if} (GUILayout.Button("Add 1000 Gold"))
            PlayerData.Gold += 1000;

        GUILayout.EndArea();
    }
}

private void OnDrawGizmos()
{
    \text{if} (!Application.isPlaying || flowField == null) return;

    for (int x = 0; x < gridWidth; x++)
    {
        for (int y = 0; y < gridHeight; y++)
        {
            Vector3 worldPos = GridToWorld(new Vector2Int(x, y));
            Vector3 flow = flowField[x, y];

            // 绘制箭头
            Gizmos.color = Color.yellow;
            Gizmos.DrawLine(worldPos, worldPos + flow * 0.5f);
        }
    }
}

private void FixedUpdate()
{
    Vector3 desiredVelocity = GetFlowDirection(transform.position) * speed;
    rb.velocity = Vector3.Lerp(rb.velocity, desiredVelocity, 0.5f);

    // 检测穿墙
    \text{if} (Physics.Raycast(transform.position, rb.velocity.normalized, out hit, rb.velocity.magnitude * Time.fixedDeltaTime))
    {
        \text{if} (hit.collider.CompareTag("Wall"))
        {
            rb.velocity = Vector3.zero;
            RegeneratePathToGoal();
        }
    }
}

private Queue<float> recentPerformance = new Queue<float>();

public float GetAveragePerformance()
{
    return recentPerformance.Average();
}

public void AdjustDifficulty()
{
    float avg = GetAveragePerformance();
    \text{if} (avg > 0.8f)
        difficultyMultiplier += 0.1f;
    else \text{if} (avg < 0.3f)
        difficultyMultiplier -= 0.1f;

    difficultyMultiplier = Mathf.Clamp(difficultyMultiplier, 0.5f, 2.0f);
}

{
  "level_id": "Lvl_Graveyard_01",
  "waves": [
    {
      "time_start": 0,
      "duration": 60,
      "spawners": ["North", "South"],
      "enemies": [
        { "id": "Zombie", "count": 50, "interval": 1.0 },
        { "id": "Skeleton_Archer", "count": 10, "interval": 5.0 }
      ]
    },
    {
      "time_start": 70,
      "type": "Rest",
      "duration": 30
    }
  ]
}

{
  "level_id": "Lvl_Graveyard_Hard",
  "level_name": "墓地围攻：困难模式",
  "recommended_player_level": 10,

  "map_config": {
    "grid_size": { "x": 50, "y": 50 },
    "spawners": [
      { "id": "North", "position": { "x": 25, "y": 0 } },
      { "id": "South", "position": { "x": 25, "y": 49 } },
      { "id": "East", "position": { "x": 49, "y": 25 } }
    ],
    "base_position": { "x": 25, "y": 25 },
    "special_zones": [
      {
        "type": "HighGround",
        "area": [
          { "x": 10, "y": 10 },
          { "x": 15, "y": 15 }
        ],
        "bonus": "+20% Range"
      },
      {
        "type": "PowerNode",
        "position": { "x": 30, "y": 30 },
        "bonus": "+30% AttackSpeed",
        "cost_multiplier": 2.0
      }
    ]
  },

  "waves": [
    {
      "wave_number": 1,
      "type": "Standard",
      "time_start": 0,
      "duration": 60,
      "spawners": ["North"],
      "enemies": [
        { "id": "Zombie", "count": 30, "interval": 1.5 },
        { "id": "Skeleton", "count": 10, "interval": 3.0 }
      ]
    },
    {
      "wave_number": 2,
      "type": "Burst",
      "time_start": 70,
      "duration": 20,
      "spawners": ["North", "South"],
      "enemies": [{ "id": "Bat_Swarm", "count": 100, "interval": 0.2 }],
      "warning_message": "蝙蝠群来袭！"
    },
    {
      "wave_number": 3,
      "type": "Rest",
      "time_start": 100,
      "duration": 30,
      "special_event": "WanderingTrader"
    },
    {
      "wave_number": 4,
      "type": "Elite",
      "time_start": 140,
      "duration": 90,
      "spawners": ["North", "South", "East"],
      "enemies": [
        { "id": "Armored_Ghoul", "count": 15, "interval": 5.0 },
        { "id": "Necromancer", "count": 3, "interval": 20.0 }
      ],
      "map_event": { "type": "BloodMoon", "duration": 90 }
    },
    {
      "wave_number": 5,
      "type": "Boss",
      "time_start": 240,
      "spawners": ["North"],
      "enemies": [{ "id": "Boss_Lich_King", "count": 1, "interval": 0 }],
      "music_override": "Music_Boss_Theme",
      "camera_mode": "Cinematic"
    }
  ],

  "difficulty_settings": {
    "base_health_multiplier": 1.5,
    "base_damage_multiplier": 1.3,
    "gold_drop_multiplier": 1.2,
    "dynamic_adjustment": {
      "enabled": true,
      "max_multiplier": 2.0,
      "min_multiplier": 0.7
    }
  },

  "rewards": {
    "first_clear": [
      { "type": "Gold", "amount": 5000 },
      { "type": "Item", "id": "Relic_Death_Knight_Helm" }
    ],
    "perfect_clear": [
      { "type": "Achievement", "id": "No_Damage_Graveyard" },
      { "type": "Title", "id": "Undead_Slayer" }
    ]
  }
}