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

namespace StellaOps.ElkSharp;

internal static partial class ElkEdgeRouterIterative
{
    internal static ElkRoutedEdge[] BuildFinalRestabilizedCandidate(
        ElkRoutedEdge[] edges,
        ElkPositionedNode[] nodes,
        ElkLayoutDirection direction,
        double minLineClearance,
        IReadOnlyCollection<string>? restrictedEdgeIds = null)
    {
        var focusEdgeIds = restrictedEdgeIds?.Count > 0
            ? restrictedEdgeIds
            : edges
                .Select(edge => edge.Id)
                .OrderBy(edgeId => edgeId, StringComparer.Ordinal)
                .ToArray();
        var focusEdgeSet = focusEdgeIds.ToHashSet(StringComparer.Ordinal);

        var candidate = ChoosePreferredHardRuleLayout(
            edges,
            CloseRemainingTerminalViolations(edges, nodes, direction, minLineClearance, restrictedEdgeIds),
            nodes);
        if (focusEdgeIds.Count > 0)
        {
            candidate = ChoosePreferredHardRuleLayout(
                candidate,
                ApplyAggressiveSharedLaneClosure(
                    candidate,
                    nodes,
                    direction,
                    minLineClearance,
                    focusEdgeIds),
                nodes);
        }

        candidate = BuildFinalBoundarySlotCandidate(
            candidate,
            nodes,
            direction,
            minLineClearance,
            restrictedEdgeIds,
            allowLateRestabilizedClosure: false);
        if (focusEdgeIds.Count > 0)
        {
            candidate = ChoosePreferredHardRuleLayout(
                candidate,
                ApplyAggressiveSharedLaneClosure(
                    candidate,
                    nodes,
                    direction,
                    minLineClearance,
                    focusEdgeIds),
                nodes);
        }

        candidate = ChoosePreferredBoundarySlotRepairLayout(
            candidate,
            ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                candidate,
                nodes,
                minLineClearance,
                restrictedEdgeIds,
                enforceAllNodeEndpoints: true),
            nodes);
        candidate = ChoosePreferredBoundarySlotRepairLayout(
            candidate,
            CloseRemainingTerminalViolations(candidate, nodes, direction, minLineClearance, restrictedEdgeIds),
            nodes);
        if (focusEdgeIds.Count > 0)
        {
            var lateHardRuleCandidate = ApplyAggressiveSharedLaneClosure(
                candidate,
                nodes,
                direction,
                minLineClearance,
                focusEdgeIds);
            lateHardRuleCandidate = CloseRemainingTerminalViolations(
                lateHardRuleCandidate,
                nodes,
                direction,
                minLineClearance,
                focusEdgeIds);
            candidate = ChoosePreferredHardRuleLayout(candidate, lateHardRuleCandidate, nodes);

            var remainingBadAngles = new Dictionary<string, int>(StringComparer.Ordinal);
            ElkEdgeRoutingScoring.CountBadBoundaryAngles(candidate, nodes, remainingBadAngles, 10);
            var remainingTerminalFocus = ExpandWinningSolutionFocus(
                    candidate,
                    remainingBadAngles.Keys.Where(focusEdgeSet.Contains))
                .Where(focusEdgeSet.Contains)
                .OrderBy(edgeId => edgeId, StringComparer.Ordinal)
                .ToArray();
            if (remainingTerminalFocus.Length > 0)
            {
                var terminalFocus = (IReadOnlyCollection<string>)remainingTerminalFocus;
                var lateTerminalCandidate = ElkEdgePostProcessor.RepairBoundaryAnglesAndTargetApproaches(
                    candidate,
                    nodes,
                    minLineClearance,
                    terminalFocus);
                lateTerminalCandidate = BuildFinalBoundarySlotCandidate(
                    lateTerminalCandidate,
                    nodes,
                    direction,
                    minLineClearance,
                    terminalFocus,
                    allowLateRestabilizedClosure: false);
                lateTerminalCandidate = CloseRemainingTerminalViolations(
                    lateTerminalCandidate,
                    nodes,
                    direction,
                    minLineClearance,
                    terminalFocus);
                candidate = ChoosePreferredBoundarySlotRepairLayout(candidate, lateTerminalCandidate, nodes);
            }
        }

        candidate = ChoosePreferredBoundarySlotRepairLayout(
            candidate,
            ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                candidate,
                nodes,
                minLineClearance,
                restrictedEdgeIds,
                enforceAllNodeEndpoints: true),
            nodes);
        candidate = ChoosePreferredBoundarySlotRepairLayout(
            candidate,
            ApplyPostSlotDetourClosure(candidate, nodes, minLineClearance, restrictedEdgeIds),
            nodes);
        candidate = ChoosePreferredBoundarySlotRepairLayout(
            candidate,
            ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                candidate,
                nodes,
                minLineClearance,
                restrictedEdgeIds,
                enforceAllNodeEndpoints: true),
            nodes);
        candidate = ApplyLateBoundarySlotRestabilization(
            candidate,
            nodes,
            minLineClearance,
            focusEdgeIds);
        candidate = ChoosePreferredBoundarySlotRepairLayout(
            candidate,
            ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                candidate,
                nodes,
                minLineClearance,
                restrictedEdgeIds,
                enforceAllNodeEndpoints: true),
            nodes);

        if (focusEdgeIds.Count > 0)
        {
            var finalSharedLaneCandidate = ElkEdgePostProcessor.SeparateSharedLaneConflicts(
                candidate,
                nodes,
                minLineClearance,
                focusEdgeIds);
            candidate = ChoosePreferredSharedLanePolishLayout(candidate, finalSharedLaneCandidate, nodes);

            var finalSourceJoinCandidate = ElkEdgePostProcessor.SpreadSourceDepartureJoins(
                finalSharedLaneCandidate,
                nodes,
                minLineClearance,
                focusEdgeIds);
            candidate = ChoosePreferredSharedLanePolishLayout(candidate, finalSourceJoinCandidate, nodes);

            var finalTargetJoinCandidate = ElkEdgePostProcessor.SpreadTargetApproachJoins(
                finalSourceJoinCandidate,
                nodes,
                minLineClearance,
                focusEdgeIds,
                forceOutwardAxisSpacing: true);
            candidate = ChoosePreferredSharedLanePolishLayout(candidate, finalTargetJoinCandidate, nodes);

            var finalAggressiveCandidate = ApplyAggressiveSharedLaneClosure(
                candidate,
                nodes,
                direction,
                minLineClearance,
                focusEdgeIds);
            candidate = ChoosePreferredSharedLanePolishLayout(candidate, finalAggressiveCandidate, nodes);

            var forcedFinalSharedLaneCandidate = ElkEdgePostProcessor.SeparateSharedLaneConflicts(
                candidate,
                nodes,
                minLineClearance,
                focusEdgeIds);
            var baselineSharedLaneViolations = ElkEdgeRoutingScoring.CountSharedLaneViolations(candidate, nodes);
            var forcedSharedLaneViolations = ElkEdgeRoutingScoring.CountSharedLaneViolations(forcedFinalSharedLaneCandidate, nodes);
            if (forcedSharedLaneViolations < baselineSharedLaneViolations)
            {
                var baselineScore = ElkEdgeRoutingScoring.ComputeScore(candidate, nodes);
                var forcedScore = ElkEdgeRoutingScoring.ComputeScore(forcedFinalSharedLaneCandidate, nodes);
                if (forcedScore.NodeCrossings <= baselineScore.NodeCrossings)
                {
                    candidate = forcedFinalSharedLaneCandidate;
                }
            }
        }

        return candidate;
    }

}