feat: 导入和导出谱面时均支持clock_count(MET)，即谱面一开头咔咔咔的那几声的数量

Author: Starrah

MaiChartManager/Controllers/Music/MusicTransferController.cs

@@ -585,6 +585,13 @@ public async Task ExportAsMaidata(int id, string assetDir, bool ignoreVideo = fa
         {
             // ignore preview time errors
         }
+
+        var ma2Contents = new Dictionary<int, string[]>();
+        
+        // 关于clock_count功能，我决定不走MaiLib了，而是我们自己解析。因为ma2.Compose返回的是裸谱面inote中的内容，没有办法合理的把clock信息插进去。因此，我们自己解析吧。
+        // 选用最难的一张有效谱面的MET值作为全曲的&clock_count
+        int clockCount = 0;
+
         for (var i = 0; i < music.Charts.Length; i++)
         {
             var chart = music.Charts[i];
@@ -599,6 +606,19 @@ public async Task ExportAsMaidata(int id, string assetDir, bool ignoreVideo = fa
             }
 
             var ma2Content = await System.IO.File.ReadAllLinesAsync(chartPath);
+            ma2Contents[i] = ma2Content;
+
+            // 从谱面内容中寻找MET行
+            var metLine = ma2Content.FirstOrDefault(it => it.StartsWith("MET\t"));
+            if (metLine is not null && int.TryParse(metLine.Split('\t')[4], out var v)) clockCount = v;
+        }
+
+        if (clockCount > 0) simaiFile.AppendLine($"&clock_count={clockCount}");
+
+        // 根据前面读取的结果，向simaiFile中最终写入谱面信息相关字段
+        foreach (var (i, ma2Content) in ma2Contents)
+        {
+            var chart = music.Charts[i];
             var ma2 = parser.ChartOfToken(ma2Content);
             var simai = ma2.Compose(ChartEnum.ChartVersion.SimaiFes);
             simaiFile.AppendLine($"&lv_{i + 2}={chart.Level}.{chart.LevelDecimal}");

MaiChartManager/Services/MaidataImportService.cs

@@ -256,6 +256,31 @@ public static Dictionary<ShiftMethod, float> CalcChartPadding(List<MaiChart> cha
     }
 
     private record AllChartsEntry(string chartText, MaiChart simaiSharpChart);
+    
+    [GeneratedRegex(@"^(CLK_DEF\t)(\d+\s*)$", RegexOptions.Multiline)]
+    private static partial Regex ClockDefRegex();
+    
+    [GeneratedRegex(@"^(MET\t\d+\t\d+\t\d+\t)(\d+\s*)$", RegexOptions.Multiline)]
+    private static partial Regex FirstMetLineRegex();
+
+    private static string replaceGroup2ByRegex(string input, Match match, int value)
+    {
+        if (!match.Success) return input;
+        return string.Concat(
+            input.AsSpan(0, match.Index),
+            match.Groups[1].ValueSpan,
+            value.ToString(CultureInfo.InvariantCulture),
+            input.AsSpan(match.Index + match.Length));
+    }
+    
+    private static string ApplyClockCountToFirstMetLine(string ma2Content, int clockCount)
+    {
+        var clockdefMatch = ClockDefRegex().Match(ma2Content);
+        ma2Content = replaceGroup2ByRegex(ma2Content, clockdefMatch, 96 * clockCount);
+        var metMatch = FirstMetLineRegex().Match(ma2Content);
+        ma2Content = replaceGroup2ByRegex(ma2Content, metMatch, clockCount);
+        return ma2Content;
+    }
 
     public ImportChartResult ImportMaidata(
         MusicXml music,
@@ -410,6 +435,12 @@ public ImportChartResult ImportMaidata(
                 errors.Add(new ImportChartMessage(Locale.ChartNotesMissing, MessageLevel.Warning));
                 logger.LogWarning("BUG! shiftedConverted: {shiftedLen}, originalConverted: {originalLen}", shiftedConverted.Split('\n').Length, originalConverted.Split('\n').Length);
             }
+            
+            // 如果maidata中声明了clock_count，应用之，修改CLOCK_DEF和MET
+            if (int.TryParse(maiData.GetValueOrDefault("clock_count"), out var clockCount))
+            {
+                shiftedConverted = ApplyClockCountToFirstMetLine(shiftedConverted, clockCount);
+            }
 
             // Just use T_NUM_ALL value in ma2 file
             targetChart.MaxNotes = ParseTNumAllFromMa2(shiftedConverted);