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

namespace StellaOps.ElkSharp;

internal static partial class ElkEdgeRouterIterative
{
    private static bool TryPromoteFinalBoundarySlotCandidate(
        CandidateSolution current,
        ElkRoutedEdge[] candidateEdges,
        ElkPositionedNode[] nodes,
        out CandidateSolution promoted)
    {
        promoted = current;
        var candidateScore = ElkEdgeRoutingScoring.ComputeScore(candidateEdges, nodes);
        var candidateRetryState = BuildRetryState(
            candidateScore,
            HighwayProcessingEnabled
                ? ElkEdgeRouterHighway.DetectRemainingBrokenHighways(candidateEdges, nodes).Count
                : 0);
        if (!IsBetterBoundarySlotRepairCandidate(
            candidateScore,
            candidateRetryState,
            current.Score,
            current.RetryState))
        {
            return false;
        }

        promoted = current with
        {
            Score = candidateScore,
            RetryState = candidateRetryState,
            Edges = candidateEdges,
        };
        return true;
    }

    private static bool HasBlockingBoundarySlotPromotionRegression(
        RoutingRetryState candidate,
        RoutingRetryState baseline)
    {
        return candidate.RemainingShortHighways > baseline.RemainingShortHighways
            || candidate.RepeatCollectorCorridorViolations > baseline.RepeatCollectorCorridorViolations
            || candidate.RepeatCollectorNodeClearanceViolations > baseline.RepeatCollectorNodeClearanceViolations
            || candidate.BelowGraphViolations > baseline.BelowGraphViolations
            || candidate.UnderNodeViolations > baseline.UnderNodeViolations;
    }

    private static bool HasEdgeGeometryChanged(
        IReadOnlyList<ElkRoutedEdge> baselineEdges,
        IReadOnlyList<ElkRoutedEdge> candidateEdges,
        string edgeId)
    {
        var baseline = baselineEdges.FirstOrDefault(edge => string.Equals(edge.Id, edgeId, StringComparison.Ordinal));
        var candidate = candidateEdges.FirstOrDefault(edge => string.Equals(edge.Id, edgeId, StringComparison.Ordinal));
        if (baseline is null || candidate is null)
        {
            return false;
        }

        var baselinePath = ExtractEdgePath(baseline);
        var candidatePath = ExtractEdgePath(candidate);
        if (baselinePath.Count != candidatePath.Count)
        {
            return true;
        }

        for (var i = 0; i < baselinePath.Count; i++)
        {
            if (!ElkEdgeRoutingGeometry.PointsEqual(baselinePath[i], candidatePath[i]))
            {
                return true;
            }
        }

        return false;
    }

    private static List<ElkPoint> ExtractEdgePath(ElkRoutedEdge edge)
    {
        var path = new List<ElkPoint>();
        foreach (var section in edge.Sections)
        {
            if (path.Count == 0 || !ElkEdgeRoutingGeometry.PointsEqual(path[^1], section.StartPoint))
            {
                path.Add(section.StartPoint);
            }

            foreach (var bendPoint in section.BendPoints)
            {
                if (path.Count == 0 || !ElkEdgeRoutingGeometry.PointsEqual(path[^1], bendPoint))
                {
                    path.Add(bendPoint);
                }
            }

            if (path.Count == 0 || !ElkEdgeRoutingGeometry.PointsEqual(path[^1], section.EndPoint))
            {
                path.Add(section.EndPoint);
            }
        }

        return path;
    }

    private static bool TryPromoteFinalHardRuleCandidate(
        CandidateSolution current,
        ElkRoutedEdge[] candidateEdges,
        ElkPositionedNode[] nodes,
        out CandidateSolution promoted)
    {
        promoted = current;
        var candidateScore = ElkEdgeRoutingScoring.ComputeScore(candidateEdges, nodes);
        var candidateRetryState = BuildRetryState(
            candidateScore,
            HighwayProcessingEnabled
                ? ElkEdgeRouterHighway.DetectRemainingBrokenHighways(candidateEdges, nodes).Count
                : 0);
        if (!IsBetterBoundarySlotRepairCandidate(
            candidateScore,
            candidateRetryState,
            current.Score,
            current.RetryState))
        {
            return false;
        }

        promoted = current with
        {
            Score = candidateScore,
            RetryState = candidateRetryState,
            Edges = candidateEdges,
        };
        return true;
    }

    private static ElkRoutedEdge[] ApplyAggressiveSharedLaneClosure(
        ElkRoutedEdge[] edges,
        ElkPositionedNode[] nodes,
        ElkLayoutDirection direction,
        double minLineClearance,
        IReadOnlyCollection<string> focusEdgeIds)
    {
        var result = edges;
        result = ElkEdgePostProcessor.SeparateSharedLaneConflicts(result, nodes, minLineClearance, focusEdgeIds);
        result = ElkEdgePostProcessor.SeparateRepeatCollectorLocalLaneConflicts(result, nodes, minLineClearance, focusEdgeIds);
        result = ElkRepeatCollectorCorridors.SeparateSharedLanes(result, nodes, focusEdgeIds);
        result = ElkEdgePostProcessor.SpreadSourceDepartureJoins(result, nodes, minLineClearance, focusEdgeIds);
        result = ElkEdgePostProcessor.SeparateMixedNodeFaceLaneConflicts(result, nodes, minLineClearance, focusEdgeIds);
        result = ElkEdgePostProcessor.SpreadTargetApproachJoins(result, nodes, minLineClearance, focusEdgeIds, forceOutwardAxisSpacing: true);
        result = ElkEdgePostProcessor.SpreadRectTargetApproachFeederBands(result, nodes, minLineClearance, focusEdgeIds);
        result = ElkEdgePostProcessor.RepairBoundaryAnglesAndTargetApproaches(result, nodes, minLineClearance, focusEdgeIds);
        result = ElkEdgePostProcessor.FinalizeGatewayBoundaryGeometry(result, nodes, focusEdgeIds);
        result = ClampBelowGraphEdges(result, nodes, focusEdgeIds);
        result = ElkEdgePostProcessor.AvoidNodeCrossings(result, nodes, direction, focusEdgeIds);
        result = ElkEdgePostProcessor.NormalizeBoundaryAngles(result, nodes);
        result = ElkEdgePostProcessor.NormalizeSourceExitAngles(result, nodes);
        result = ElkEdgePostProcessor.SeparateMixedNodeFaceLaneConflicts(result, nodes, minLineClearance, focusEdgeIds);
        result = ElkEdgePostProcessor.SeparateSharedLaneConflicts(result, nodes, minLineClearance, focusEdgeIds);
        return result;
    }

}