using System.Collections.Concurrent;
using System.Diagnostics;
using System.Globalization;

namespace StellaOps.ElkSharp;

internal static partial class ElkEdgeRouterIterative
{
    private static CandidateSolution ApplyFinalSharedLanePolish(
        CandidateSolution solution,
        ElkPositionedNode[] nodes,
        ElkLayoutDirection direction,
        double minLineClearance,
        bool preferLeanTerminalCleanup = false)
    {
        var current = solution;
        if (current.RetryState.SharedLaneViolations <= 0)
        {
            return current;
        }

        var maxRounds = preferLeanTerminalCleanup ? 1 : 3;
        for (var round = 0; round < maxRounds; round++)
        {
            var sharedLaneSeverity = new Dictionary<string, int>(StringComparer.Ordinal);
            ElkEdgeRoutingScoring.CountSharedLaneViolations(current.Edges, nodes, sharedLaneSeverity, 10);
            if (sharedLaneSeverity.Count == 0)
            {
                break;
            }

            var improved = false;
            foreach (var edgeId in sharedLaneSeverity
                         .OrderByDescending(pair => pair.Value)
                         .ThenBy(pair => pair.Key, StringComparer.Ordinal)
                         .Select(pair => pair.Key))
            {
                var focusEdgeIds = ExpandSharedLanePolishFocus(current.Edges, nodes, edgeId).ToArray();
                if (focusEdgeIds.Length == 0)
                {
                    continue;
                }

                var directCandidate = ElkEdgePostProcessor.SeparateSharedLaneConflicts(
                    current.Edges,
                    nodes,
                    minLineClearance,
                    focusEdgeIds);
                var directClosureCandidate = preferLeanTerminalCleanup
                    ? ApplyHybridTerminalRuleCleanupRound(
                        directCandidate,
                        nodes,
                        direction,
                        minLineClearance,
                        focusEdgeIds)
                    : CloseRemainingTerminalViolations(
                        directCandidate,
                        nodes,
                        direction,
                        minLineClearance,
                        focusEdgeIds);
                var closureCandidate = preferLeanTerminalCleanup
                    ? ApplyHybridTerminalRuleCleanupRound(
                        current.Edges,
                        nodes,
                        direction,
                        minLineClearance,
                        focusEdgeIds)
                    : CloseRemainingTerminalViolations(
                        current.Edges,
                        nodes,
                        direction,
                        minLineClearance,
                        focusEdgeIds);
                var aggressiveCandidate = ApplyAggressiveSharedLaneClosure(
                    current.Edges,
                    nodes,
                    direction,
                    minLineClearance,
                    focusEdgeIds);
                var directRetryState = BuildRetryState(
                    ElkEdgeRoutingScoring.ComputeScore(directCandidate, nodes),
                    HighwayProcessingEnabled
                        ? ElkEdgeRouterHighway.DetectRemainingBrokenHighways(directCandidate, nodes).Count
                        : 0);
                var directClosureRetryState = BuildRetryState(
                    ElkEdgeRoutingScoring.ComputeScore(directClosureCandidate, nodes),
                    HighwayProcessingEnabled
                        ? ElkEdgeRouterHighway.DetectRemainingBrokenHighways(directClosureCandidate, nodes).Count
                        : 0);
                var closureRetryState = BuildRetryState(
                    ElkEdgeRoutingScoring.ComputeScore(closureCandidate, nodes),
                    HighwayProcessingEnabled
                        ? ElkEdgeRouterHighway.DetectRemainingBrokenHighways(closureCandidate, nodes).Count
                        : 0);
                var aggressiveRetryState = BuildRetryState(
                    ElkEdgeRoutingScoring.ComputeScore(aggressiveCandidate, nodes),
                    HighwayProcessingEnabled
                        ? ElkEdgeRouterHighway.DetectRemainingBrokenHighways(aggressiveCandidate, nodes).Count
                        : 0);
                ElkLayoutDiagnostics.LogProgress(
                    $"Winner shared-lane focus edge={edgeId} focus=[{string.Join(", ", focusEdgeIds)}] " +
                    $"direct={DescribeRetryState(directRetryState)} " +
                    $"direct-closure={DescribeRetryState(directClosureRetryState)} " +
                    $"closure={DescribeRetryState(closureRetryState)} " +
                    $"aggressive={DescribeRetryState(aggressiveRetryState)}");
                var candidateEdges = ChoosePreferredSharedLanePolishLayout(directCandidate, directClosureCandidate, nodes);
                candidateEdges = ChoosePreferredSharedLanePolishLayout(candidateEdges, closureCandidate, nodes);
                candidateEdges = ChoosePreferredSharedLanePolishLayout(candidateEdges, aggressiveCandidate, nodes);
                candidateEdges = ChoosePreferredSharedLanePolishLayout(current.Edges, candidateEdges, nodes);

                var candidateScore = ElkEdgeRoutingScoring.ComputeScore(candidateEdges, nodes);
                var candidateRetryState = BuildRetryState(
                    candidateScore,
                    HighwayProcessingEnabled
                        ? ElkEdgeRouterHighway.DetectRemainingBrokenHighways(candidateEdges, nodes).Count
                        : 0);

                var improvedSharedLanes = candidateRetryState.SharedLaneViolations < current.RetryState.SharedLaneViolations;
                if (HasBlockingSharedLanePromotionRegression(candidateRetryState, current.RetryState)
                    || (!improvedSharedLanes
                        && !IsBetterCandidate(candidateScore, candidateRetryState, current.Score, current.RetryState)))
                {
                    continue;
                }

                current = current with
                {
                    Score = candidateScore,
                    RetryState = candidateRetryState,
                    Edges = candidateEdges,
                };
                improved = true;
                break;
            }

            if (!improved)
            {
                break;
            }
        }

        return current;
    }

}