Refactor ElkSharp hybrid routing and document speed path

src/__Libraries/StellaOps.ElkSharp/ElkEdgeRouterIterative.WinnerRefinement.Detours.cs

@@ -0,0 +1,75 @@
+using System.Collections.Concurrent;
+using System.Diagnostics;
+using System.Globalization;
+
+namespace StellaOps.ElkSharp;
+
+internal static partial class ElkEdgeRouterIterative
+{
+    private static CandidateSolution ApplyWinnerDetourPolish(
+        CandidateSolution solution,
+        ElkPositionedNode[] nodes,
+        double minLineClearance)
+    {
+        var focusSeverity = new Dictionary<string, int>(StringComparer.Ordinal);
+        ElkEdgeRoutingScoring.CountExcessiveDetourViolations(solution.Edges, nodes, focusSeverity, 10);
+        ElkEdgeRoutingScoring.CountGatewaySourceExitViolations(solution.Edges, nodes, focusSeverity, 10);
+
+        if (focusSeverity.Count > 0)
+        {
+            var batchedRootEdgeIds = focusSeverity
+                .OrderByDescending(pair => pair.Value)
+                .ThenBy(pair => pair.Key, StringComparer.Ordinal)
+                .Take(Math.Min(focusSeverity.Count, MaxWinnerPolishBatchedRootEdges + 2))
+                .Select(pair => pair.Key)
+                .ToArray();
+            var batchedFocusEdgeIds = ExpandWinningSolutionFocus(solution.Edges, batchedRootEdgeIds).ToArray();
+            if (batchedFocusEdgeIds.Length > 0)
+            {
+                var batchedCandidateEdges = ComposeTransactionalFinalDetourCandidate(
+                    solution.Edges,
+                    nodes,
+                    minLineClearance,
+                    batchedFocusEdgeIds);
+                batchedCandidateEdges = ChoosePreferredHardRuleLayout(solution.Edges, batchedCandidateEdges, nodes);
+                if (TryPromoteFinalDetourCandidate(
+                        solution.Edges,
+                        batchedCandidateEdges,
+                        nodes,
+                        solution.Score,
+                        solution.RetryState,
+                        out var batchedPromotedEdges))
+                {
+                    var batchedPromotedScore = ElkEdgeRoutingScoring.ComputeScore(batchedPromotedEdges, nodes);
+                    var batchedPromotedRetryState = BuildRetryState(
+                        batchedPromotedScore,
+                        HighwayProcessingEnabled
+                            ? ElkEdgeRouterHighway.DetectRemainingBrokenHighways(batchedPromotedEdges, nodes).Count
+                            : 0);
+
+                    solution = new CandidateSolution(
+                        batchedPromotedScore,
+                        batchedPromotedRetryState,
+                        batchedPromotedEdges,
+                        solution.StrategyIndex);
+                }
+            }
+        }
+
+        var candidateEdges = ApplyFinalDetourPolish(solution.Edges, nodes, minLineClearance, restrictedEdgeIds: null);
+        if (ReferenceEquals(candidateEdges, solution.Edges))
+        {
+            return solution;
+        }
+
+        var candidateScore = ElkEdgeRoutingScoring.ComputeScore(candidateEdges, nodes);
+        var candidateRetryState = BuildRetryState(
+            candidateScore,
+            HighwayProcessingEnabled
+                ? ElkEdgeRouterHighway.DetectRemainingBrokenHighways(candidateEdges, nodes).Count
+                : 0);
+
+        return new CandidateSolution(candidateScore, candidateRetryState, candidateEdges, solution.StrategyIndex);
+    }
+
+}