private IEnumerable GetLineup()

in code/KustoCopyConsole/Runner/ExportingRunner.cs [165:210]
42 lines of code
2 McCabe index (conditional complexity)

        private IEnumerable<BlockRowItem> GetLineup(
            IterationKey iterationKey,
            IEnumerable<BlockRowItem> candidates,
            int freeCapacity)
        {
            const int MIN_STAT_COUNT = 5;
            const long MIN_ROW_COUNT_STATS = 100000;
            const long MAX_ROW_COUNT = 16000000;
            const int LEAP_RATIO = 3;
            var MAX_EXPORT_DURATION = TimeSpan.FromMinutes(4);

            var latestBlocks = RowItemGateway.InMemoryCache
                .ActivityMap[iterationKey.ActivityName]
                .IterationMap[iterationKey.IterationId]
                .BlockMap
                .Values
                .Select(c => c.RowItem)
                .Where(b => b.State >= BlockState.Exported)
                //  We want representative export, i.e. meaningful size
                .Where(b => b.ExportedRowCount > MIN_ROW_COUNT_STATS)
                .OrderByDescending(b => b.ExportedRowCount)
                .Take(MIN_STAT_COUNT)
                .ToImmutableArray();

            if (latestBlocks.Length == MIN_STAT_COUNT)
            {   //  Replan blocks
                var totalDuration = latestBlocks.Sum(b => b.ExportDuration!.Value.TotalSeconds);
                var totalRows = latestBlocks.Sum(b => b.ExportedRowCount);
                var maxRowCount = latestBlocks.Max(b => b.ExportedRowCount);
                var averageDurationPerRow = TimeSpan.FromSeconds(totalDuration / totalRows);
                var targetRowCount = Math.Max(
                    1,
                    Math.Min(
                        Math.Min(MAX_ROW_COUNT, LEAP_RATIO * maxRowCount),
                        MAX_EXPORT_DURATION / averageDurationPerRow));

                return GetReplannedLineup(candidates, targetRowCount, freeCapacity);
            }
            else
            {   //  Just return the top blocks
                return candidates
                    .OrderBy(b => b.IngestionTimeStart)
                    .Take(freeCapacity)
                    .ToImmutableArray();
            }
        }