레벨 생성 완화 및 체크포인트 강화

Program.cs

@@ -84,8 +84,8 @@ internal static class Program
 
     private static readonly GenerationTuning Tuning = new GenerationTuning
     {
-        MaxAttemptsPerLevel = 10_000,
-        MaxMillisecondsPerLevel = 200_000,
+        MaxAttemptsPerLevel = 100_000,
+        MaxMillisecondsPerLevel = 2_000_000,
         RelaxationSteps = 3,
         PushLimitPadding = 2,
         PushLimitScale = 0.35,
@@ -130,14 +130,36 @@ internal static class Program
             (startId, endId) = (endId, startId);
         }
 
-        var totalWatch = Stopwatch.StartNew();
-        var levels = generator.BuildRange(startId, endId);
-        totalWatch.Stop();
         var options = new JsonSerializerOptions
         {
             WriteIndented = true,
             PropertyNamingPolicy = JsonNamingPolicy.CamelCase
         };
+        var checkpointPath = Environment.GetEnvironmentVariable("NEKOBAN_CHECKPOINT");
+        // 비워 있으면 기본 경로를 사용한다. (쉘 리다이렉션과 별개로 누적 체크포인트를 보관)
+        checkpointPath = string.IsNullOrWhiteSpace(checkpointPath) ? "stage_checkpoint.json" : checkpointPath;
+        var checkpointEnabled = !string.IsNullOrWhiteSpace(checkpointPath);
+
+        void SaveCheckpoint(List<GeneratedLevel> snapshot, int lastId)
+        {
+            if (!checkpointEnabled) return;
+            // 10단위(또는 마지막 레벨)마다 누적 JSON을 디스크에 기록한다.
+            if (lastId % 10 != 0 && lastId != endId) return;
+            try
+            {
+                var json = JsonSerializer.Serialize(snapshot, options);
+                File.WriteAllText(checkpointPath, json);
+                status.ShowLine($"체크포인트 저장: 레벨 {lastId}까지 -> {checkpointPath}");
+            }
+            catch (Exception ex)
+            {
+                status.ShowLine($"[warn] 체크포인트 저장 실패({checkpointPath}): {ex.Message}");
+            }
+        }
+
+        var totalWatch = Stopwatch.StartNew();
+        var levels = generator.BuildRange(startId, endId, SaveCheckpoint);
+        totalWatch.Stop();
 
         Console.WriteLine(JsonSerializer.Serialize(levels, options));
         var duration = StatusReporter.FormatDuration(totalWatch.Elapsed);
@@ -265,7 +287,7 @@ internal sealed class LevelGenerator
         _trace = Environment.GetEnvironmentVariable("NEKOBAN_DEBUG") == "1";
     }
 
-    public List<GeneratedLevel> BuildRange(int startId, int endId)
+    public List<GeneratedLevel> BuildRange(int startId, int endId, Action<List<GeneratedLevel>, int>? onCheckpoint = null)
     {
         foreach (var band in _bands)
         {
@@ -282,6 +304,7 @@ internal sealed class LevelGenerator
             var band = ResolveBand(id);
             var level = BuildSingle(id, band);
             output.Add(level);
+            onCheckpoint?.Invoke(output, id);
         }
 
         return output;
@@ -298,13 +321,120 @@ internal sealed class LevelGenerator
     }
 
     private GeneratedLevel BuildSingle(int id, LevelBandConfig band)
+    {
+        // 완화 단계를 순차적으로 적용한다. (총 5단계 + 비상 1단계)
+        var stages = new List<RelaxStage>
+        {
+            new RelaxStage("기본", b => CloneBand(b)),
+            new RelaxStage("완화1-임계치", bandConfig =>
+            {
+                var c = CloneBand(bandConfig);
+                c.MinAllowedPushes = Math.Max(1, c.MinAllowedPushes - 3);
+                c.MinAllowedTurns = Math.Max(0, c.MinAllowedTurns - 1);
+                c.MinAllowedBranching = Math.Max(0, c.MinAllowedBranching - 1);
+                return c;
+            }),
+            new RelaxStage("완화2-마스크확장", bandConfig =>
+            {
+                var c = CloneBand(bandConfig);
+                c.MaskPadMin = -2;
+                c.MaskPadMax = -2;
+                c.ShapeMasks = MaskLibrary.Medium.Concat(MaskLibrary.Large).ToList();
+                c.ShapeMasksExpanded = null; // 변형/패딩을 다시 계산하도록 초기화
+                return c;
+            }),
+            new RelaxStage("완화3-역탐색확대", bandConfig =>
+            {
+                var c = CloneBand(bandConfig);
+                c.ReverseDepthScale = Math.Max(1.0, c.ReverseDepthScale * 1.25);
+                c.ReverseBreadthScale = Math.Max(1.0, c.ReverseBreadthScale * 1.25);
+                return c;
+            }),
+            new RelaxStage("완화4-박스감소", bandConfig =>
+            {
+                var c = CloneBand(bandConfig);
+                c.BoxCountLow = Math.Max(1, c.BoxCountLow - 1);
+                c.BoxCountHigh = Math.Max(c.BoxCountLow, c.BoxCountHigh - 1);
+                return c;
+            }),
+            new RelaxStage("완화5-간격완화", bandConfig =>
+            {
+                var c = CloneBand(bandConfig);
+                c.MinGoalDistance = Math.Max(1, c.MinGoalDistance - 1);
+                c.MinBoxDistance = Math.Max(1, c.MinBoxDistance - 1);
+                c.MinWallDistance = Math.Max(0, c.MinWallDistance - 1);
+                return c;
+            }),
+            new RelaxStage("완화6-최종", bandConfig =>
+            {
+                var c = CloneBand(bandConfig);
+                c.BoxCountLow = 1;
+                c.BoxCountHigh = Math.Max(1, c.BoxCountHigh - 2);
+                c.MinAllowedPushes = 1;
+                c.MinAllowedTurns = 0;
+                c.MinAllowedBranching = 0;
+                c.MinGoalDistance = Math.Max(1, c.MinGoalDistance - 2);
+                c.MinBoxDistance = Math.Max(1, c.MinBoxDistance - 2);
+                c.MinWallDistance = 0;
+                c.ReverseDepthScale = Math.Max(1.0, c.ReverseDepthScale * 2.8);
+                c.ReverseBreadthScale = Math.Max(1.0, c.ReverseBreadthScale * 2.8);
+                c.MaskPadMin = -2;
+                c.MaskPadMax = -2;
+                c.ShapeMasks = MaskLibrary.Medium.Concat(MaskLibrary.Microban).ToList();
+                c.ShapeMasksExpanded = null;
+                return c;
+            }, OverrideRelaxSteps: 6)
+        };
+
+        // 밴드 강등 시도: 현재 밴드 -> 직전 10레벨 밴드 -> 직전 20레벨 밴드
+        var bandCandidates = new List<LevelBandConfig> { band };
+        var minStartId = _bands.Min(b => b.StartId);
+        foreach (var delta in new[] { 10, 20 })
+        {
+            var fallbackId = Math.Max(minStartId, id - delta);
+            if (fallbackId < id)
+            {
+                var fb = CloneBand(ResolveBand(fallbackId));
+                fb.StartId = band.StartId;
+                fb.EndId = band.EndId;
+                bandCandidates.Add(fb);
+            }
+        }
+
+        // 시드 변조 재시도 + 완화 단계 루프
+        const int seedRetries = 5;
+        foreach (var bandCandidate in bandCandidates)
+        {
+            for (var retry = 0; retry < seedRetries; retry++)
+            {
+                var jitterSeed = _rng.Next() ^ (id * 7919) ^ (retry * 104729);
+                var localRng = new Random(jitterSeed);
+
+                foreach (var stage in stages)
+                {
+                    var bandForStage = stage.Adjust(bandCandidate);
+                    var relaxOverride = stage.OverrideRelaxSteps;
+                    if (TryBuildStage(id, bandForStage, stage.Label, localRng, relaxOverride, out var level))
+                    {
+                        return level;
+                    }
+                }
+            }
+        }
+
+        throw new InvalidOperationException($"레벨 {id} 생성 실패 (모든 완화 단계 시도됨)");
+    }
+
+    private bool TryBuildStage(int id, LevelBandConfig band, string stageLabel, Random rng, int? overrideRelaxSteps, out GeneratedLevel level)
     {
         var failReasons = _trace ? new Dictionary<string, int>() : null;
         var baseMasks = band.ShapeMasks.Count > 0 ? band.ShapeMasks : MaskLibrary.Microban;
         band.ShapeMasksExpanded ??= MaskLibrary.ExpandWithTransforms(baseMasks, band.MaskPadMin, band.MaskPadMax);
         var pockets = ResolvePockets(band);
 
-        for (var relax = 0; relax < _tuning.RelaxationSteps; relax++)
+        var relaxSteps = overrideRelaxSteps ?? _tuning.RelaxationSteps;
+
+        for (var relax = 0; relax < relaxSteps; relax++)
         {
             var attemptsLimit = _tuning.MaxAttemptsPerLevel + relax * 2000;
             var timeLimit = _tuning.MaxMillisecondsPerLevel + relax * 20_000;
@@ -321,24 +451,26 @@ internal sealed class LevelGenerator
 
             var stopwatch = Stopwatch.StartNew();
             var attempts = 0;
-            _status.Show($"레벨 {id} 생성중...");
 
             while (attempts < attemptsLimit &&
                    stopwatch.ElapsedMilliseconds < timeLimit)
             {
                 attempts++;
+                // 진행 상태가 살아 있음을 보여주기 위해, 1초 단위 점(.) 애니메이션을 출력한다.
+                // 예) "레벨 214 [기본] 생성중.", "..", "..." 식으로 순환.
+                _status.Show($"레벨 {id} [{stageLabel}] 생성중", withDots: true);
                 var mask = MaskLibrary.CreateVariant(
-                    MaskLibrary.PickRandom(_rng, band.ShapeMasksExpanded),
-                    _rng,
+                    MaskLibrary.PickRandom(rng, band.ShapeMasksExpanded),
+                    rng,
                     _tuning.ApplyMaskTransforms,
                     _tuning.MaskWallJitter);
 
-                var canvas = LayoutFactory.FromMask(mask, _rng, _tuning, pockets);
+                var canvas = LayoutFactory.FromMask(mask, rng, _tuning, pockets);
 
-                var boxCount = _rng.Next(band.BoxCountLow, band.BoxCountHigh + 1);
+                var boxCount = rng.Next(band.BoxCountLow, band.BoxCountHigh + 1);
                 if (boxCount <= 0) boxCount = 1;
 
-                if (!PiecePlacer.TryPlace(canvas, _rng, boxCount, out var goals, out var boxes, out var player))
+                if (!PiecePlacer.TryPlace(canvas, rng, boxCount, out var goals, out var boxes, out var player))
                 {
                     NoteFail(failReasons, "place");
                     continue;
@@ -352,7 +484,7 @@ internal sealed class LevelGenerator
 
                 var board = Board.FromCanvas(canvas);
                 var reverse = new ReverseSearch(board, reverseDepth, reverseBreadth);
-                var startState = reverse.FindStartState(goals, minPush, _rng);
+                var startState = reverse.FindStartState(goals, minPush, rng);
                 if (startState == null)
                 {
                     NoteFail(failReasons, "reverse_not_found");
@@ -393,7 +525,7 @@ internal sealed class LevelGenerator
                 canvas.Overlay(startState.Boxes, '$');
                 canvas.Set(startState.Player, '@');
 
-                // Final wall normalization; reject if tokens end up on the edge.
+                // 최종 외벽 정규화; 토큰이 가장자리에 닿으면 실패 처리.
                 if (!LayoutFactory.NormalizeOuterWallsStrict(canvas, failOnTokens: true))
                 {
                     NoteFail(failReasons, "boundary");
@@ -420,30 +552,61 @@ internal sealed class LevelGenerator
                     _seenPatterns.Add(patternKey);
                 }
 
-                _status.Show($"레벨 {id} 생성완료 ({StatusReporter.FormatDuration(stopwatch.Elapsed)})");
-                return new GeneratedLevel
+                _status.Show($"레벨 {id} [{stageLabel}] 생성완료 ({StatusReporter.FormatDuration(stopwatch.Elapsed)})");
+                level = new GeneratedLevel
                 {
                     Id = id,
                     Grid = lines,
                     LowestPush = solve.Pushes,
                     PushLimit = pushLimit
                 };
+                return true;
             }
         }
 
-        _status.Show($"레벨 {id} 생성 실패");
+        _status.Show($"레벨 {id} [{stageLabel}] 생성 실패");
         if (_trace && failReasons != null)
         {
-            Console.Error.WriteLine($"[trace] level {id} failed. Reasons:");
+            Console.Error.WriteLine($"[trace] level {id} stage {stageLabel} failed. Reasons:");
             foreach (var kv in failReasons.OrderByDescending(kv => kv.Value))
             {
                 Console.Error.WriteLine($" - {kv.Key}: {kv.Value}");
             }
         }
 
-        throw new InvalidOperationException($"레벨 {id} 생성 실패 (attempts {_tuning.MaxAttemptsPerLevel})");
+        level = default!;
+        return false;
     }
 
+    private static LevelBandConfig CloneBand(LevelBandConfig src)
+    {
+        // 완화 단계마다 원본 밴드를 손상시키지 않도록 복사본을 만든다.
+        return new LevelBandConfig
+        {
+            StartId = src.StartId,
+            EndId = src.EndId,
+            BoxCountLow = src.BoxCountLow,
+            BoxCountHigh = src.BoxCountHigh,
+            MinAllowedPushes = src.MinAllowedPushes,
+            MinAllowedTurns = src.MinAllowedTurns,
+            MinAllowedBranching = src.MinAllowedBranching,
+            MinGoalDistance = src.MinGoalDistance,
+            MinBoxDistance = src.MinBoxDistance,
+            MinWallDistance = src.MinWallDistance,
+            ReverseDepthScale = src.ReverseDepthScale,
+            ReverseBreadthScale = src.ReverseBreadthScale,
+            PocketCarveMin = src.PocketCarveMin,
+            PocketCarveMax = src.PocketCarveMax,
+            PocketMaxRadius = src.PocketMaxRadius,
+            MaskPadMin = src.MaskPadMin,
+            MaskPadMax = src.MaskPadMax,
+            ShapeMasks = src.ShapeMasks.ToList(),
+            ShapeMasksExpanded = src.ShapeMasksExpanded?.ToList()
+        };
+    }
+
+    private sealed record RelaxStage(string Label, Func<LevelBandConfig, LevelBandConfig> Adjust, int? OverrideRelaxSteps = null);
+
     private LevelBandConfig ResolveBand(int id)
     {
         foreach (var band in _bands)
@@ -498,24 +661,24 @@ internal sealed class GeneratedLevel
 
 internal sealed class LevelBandConfig
 {
-    public int StartId { get; init; }
-    public int EndId { get; init; }
-    public int BoxCountLow { get; init; }
-    public int BoxCountHigh { get; init; }
-    public int MinAllowedPushes { get; init; }
-    public int MinAllowedTurns { get; init; } = 0;
-    public int MinAllowedBranching { get; init; } = 0;
-    public int MinGoalDistance { get; init; } = 1;
-    public int MinBoxDistance { get; init; } = 1;
-    public int MinWallDistance { get; init; } = 0;
-    public double ReverseDepthScale { get; init; } = 1.0;
-    public double ReverseBreadthScale { get; init; } = 1.0;
-    public int PocketCarveMin { get; init; } = -1;
-    public int PocketCarveMax { get; init; } = -1;
-    public int PocketMaxRadius { get; init; } = -1;
-    public int MaskPadMin { get; init; } = -1;
-    public int MaskPadMax { get; init; } = 1;
-    public List<string[]> ShapeMasks { get; init; } = new();
+    public int StartId { get; set; }
+    public int EndId { get; set; }
+    public int BoxCountLow { get; set; }
+    public int BoxCountHigh { get; set; }
+    public int MinAllowedPushes { get; set; }
+    public int MinAllowedTurns { get; set; } = 0;
+    public int MinAllowedBranching { get; set; } = 0;
+    public int MinGoalDistance { get; set; } = 1;
+    public int MinBoxDistance { get; set; } = 1;
+    public int MinWallDistance { get; set; } = 0;
+    public double ReverseDepthScale { get; set; } = 1.0;
+    public double ReverseBreadthScale { get; set; } = 1.0;
+    public int PocketCarveMin { get; set; } = -1;
+    public int PocketCarveMax { get; set; } = -1;
+    public int PocketMaxRadius { get; set; } = -1;
+    public int MaskPadMin { get; set; } = -1;
+    public int MaskPadMax { get; set; } = 1;
+    public List<string[]> ShapeMasks { get; set; } = new();
     public List<string[]>? ShapeMasksExpanded { get; set; }
 }