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

namespace StellaOps.ElkSharp;

internal static partial class ElkEdgeRouterIterative
{
    private static bool IsBetterCandidate(
        EdgeRoutingScore candidate,
        RoutingRetryState candidateRetryState,
        EdgeRoutingScore best,
        RoutingRetryState bestRetryState)
    {
        if (HasHardRuleRegression(candidateRetryState, bestRetryState))
        {
            return false;
        }

        var retryComparison = CompareRetryStates(candidateRetryState, bestRetryState);
        if (retryComparison != 0)
        {
            return retryComparison < 0;
        }

        if (candidate.NodeCrossings != best.NodeCrossings)
        {
            return candidate.NodeCrossings < best.NodeCrossings;
        }

        return candidate.Value > best.Value;
    }

    private static bool HasHardRuleRegression(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
            || candidate.LongDiagonalViolations > baseline.LongDiagonalViolations
            || candidate.EntryAngleViolations > baseline.EntryAngleViolations
            || candidate.GatewaySourceExitViolations > baseline.GatewaySourceExitViolations
            || candidate.SharedLaneViolations > baseline.SharedLaneViolations
            || candidate.BoundarySlotViolations > baseline.BoundarySlotViolations
            || candidate.TargetApproachJoinViolations > baseline.TargetApproachJoinViolations
            || candidate.TargetApproachBacktrackingViolations > baseline.TargetApproachBacktrackingViolations
            || candidate.ExcessiveDetourViolations > baseline.ExcessiveDetourViolations;
    }

    private static bool HasBlockingSharedLanePromotionRegression(
        RoutingRetryState candidate,
        RoutingRetryState baseline)
    {
        var allowsTemporaryBoundarySlotTrade =
            candidate.SharedLaneViolations < baseline.SharedLaneViolations
            && baseline.BoundarySlotViolations > 0
            && candidate.BoundarySlotViolations <= baseline.BoundarySlotViolations + 1;

        return candidate.RemainingShortHighways > baseline.RemainingShortHighways
            || candidate.RepeatCollectorCorridorViolations > baseline.RepeatCollectorCorridorViolations
            || candidate.RepeatCollectorNodeClearanceViolations > baseline.RepeatCollectorNodeClearanceViolations
            || candidate.BelowGraphViolations > baseline.BelowGraphViolations
            || candidate.UnderNodeViolations > baseline.UnderNodeViolations
            || candidate.LongDiagonalViolations > baseline.LongDiagonalViolations
            || candidate.EntryAngleViolations > baseline.EntryAngleViolations
            || candidate.GatewaySourceExitViolations > baseline.GatewaySourceExitViolations
            || candidate.SharedLaneViolations > baseline.SharedLaneViolations
            || (!allowsTemporaryBoundarySlotTrade
                && candidate.BoundarySlotViolations > baseline.BoundarySlotViolations)
            || candidate.TargetApproachJoinViolations > baseline.TargetApproachJoinViolations
            || candidate.TargetApproachBacktrackingViolations > baseline.TargetApproachBacktrackingViolations
            || candidate.ExcessiveDetourViolations > baseline.ExcessiveDetourViolations;
    }

    private static bool HasBlockingSetterFamilyPromotionRegression(
        RoutingRetryState candidate,
        RoutingRetryState baseline,
        bool localImproved)
    {
        var allowTemporaryDetourTrade =
            localImproved
            && candidate.RemainingShortHighways <= baseline.RemainingShortHighways
            && candidate.UnderNodeViolations <= baseline.UnderNodeViolations
            && candidate.ExcessiveDetourViolations <= baseline.ExcessiveDetourViolations + 1;
        var allowTemporaryBoundarySlotTrade =
            localImproved
            && candidate.BoundarySlotViolations <= baseline.BoundarySlotViolations + 1;

        return candidate.RemainingShortHighways > baseline.RemainingShortHighways
            || candidate.RepeatCollectorCorridorViolations > baseline.RepeatCollectorCorridorViolations
            || candidate.RepeatCollectorNodeClearanceViolations > baseline.RepeatCollectorNodeClearanceViolations
            || candidate.BelowGraphViolations > baseline.BelowGraphViolations
            || candidate.UnderNodeViolations > baseline.UnderNodeViolations
            || candidate.LongDiagonalViolations > baseline.LongDiagonalViolations
            || candidate.EntryAngleViolations > baseline.EntryAngleViolations
            || candidate.GatewaySourceExitViolations > baseline.GatewaySourceExitViolations
            || candidate.SharedLaneViolations > baseline.SharedLaneViolations
            || (!allowTemporaryBoundarySlotTrade
                && candidate.BoundarySlotViolations > baseline.BoundarySlotViolations)
            || candidate.TargetApproachJoinViolations > baseline.TargetApproachJoinViolations
            || candidate.TargetApproachBacktrackingViolations > baseline.TargetApproachBacktrackingViolations
            || (!allowTemporaryDetourTrade
                && candidate.ExcessiveDetourViolations > baseline.ExcessiveDetourViolations);
    }

    private static int CompareRetryStates(RoutingRetryState left, RoutingRetryState right)
    {
        if (left.RemainingShortHighways != right.RemainingShortHighways)
        {
            return left.RemainingShortHighways.CompareTo(right.RemainingShortHighways);
        }

        if (left.RepeatCollectorCorridorViolations != right.RepeatCollectorCorridorViolations)
        {
            return left.RepeatCollectorCorridorViolations.CompareTo(right.RepeatCollectorCorridorViolations);
        }

        if (left.RepeatCollectorNodeClearanceViolations != right.RepeatCollectorNodeClearanceViolations)
        {
            return left.RepeatCollectorNodeClearanceViolations.CompareTo(right.RepeatCollectorNodeClearanceViolations);
        }

        if (left.BelowGraphViolations != right.BelowGraphViolations)
        {
            return left.BelowGraphViolations.CompareTo(right.BelowGraphViolations);
        }

        if (left.UnderNodeViolations != right.UnderNodeViolations)
        {
            return left.UnderNodeViolations.CompareTo(right.UnderNodeViolations);
        }

        if (left.LongDiagonalViolations != right.LongDiagonalViolations)
        {
            return left.LongDiagonalViolations.CompareTo(right.LongDiagonalViolations);
        }

        if (left.EntryAngleViolations != right.EntryAngleViolations)
        {
            return left.EntryAngleViolations.CompareTo(right.EntryAngleViolations);
        }

        if (left.GatewaySourceExitViolations != right.GatewaySourceExitViolations)
        {
            return left.GatewaySourceExitViolations.CompareTo(right.GatewaySourceExitViolations);
        }

        if (left.SharedLaneViolations != right.SharedLaneViolations)
        {
            return left.SharedLaneViolations.CompareTo(right.SharedLaneViolations);
        }

        if (left.BoundarySlotViolations != right.BoundarySlotViolations)
        {
            return left.BoundarySlotViolations.CompareTo(right.BoundarySlotViolations);
        }

        if (left.TargetApproachJoinViolations != right.TargetApproachJoinViolations)
        {
            return left.TargetApproachJoinViolations.CompareTo(right.TargetApproachJoinViolations);
        }

        if (left.TargetApproachBacktrackingViolations != right.TargetApproachBacktrackingViolations)
        {
            return left.TargetApproachBacktrackingViolations.CompareTo(right.TargetApproachBacktrackingViolations);
        }

        if (left.ExcessiveDetourViolations != right.ExcessiveDetourViolations)
        {
            return left.ExcessiveDetourViolations.CompareTo(right.ExcessiveDetourViolations);
        }

        if (left.ProximityViolations != right.ProximityViolations)
        {
            return left.ProximityViolations.CompareTo(right.ProximityViolations);
        }

        if (left.LabelProximityViolations != right.LabelProximityViolations)
        {
            return left.LabelProximityViolations.CompareTo(right.LabelProximityViolations);
        }

        return left.EdgeCrossings.CompareTo(right.EdgeCrossings);
    }

    private static CandidateSolution SelectBestValidSolution(
        IReadOnlyList<CandidateSolution> solutions)
    {
        var best = solutions[0];
        for (var i = 1; i < solutions.Count; i++)
        {
            var candidate = solutions[i];
            if (IsBetterBoundarySlotRepairCandidate(
                    candidate.Score,
                    candidate.RetryState,
                    best.Score,
                    best.RetryState)
                || candidate.Score.Value > best.Score.Value
                || (Math.Abs(candidate.Score.Value - best.Score.Value) < 0.001d
                    && CompareRetryStates(candidate.RetryState, best.RetryState) < 0)
                || (Math.Abs(candidate.Score.Value - best.Score.Value) < 0.001d
                    && CompareRetryStates(candidate.RetryState, best.RetryState) == 0
                    && candidate.Score.EdgeCrossings < best.Score.EdgeCrossings))
            {
                best = candidate;
            }
        }

        return best;
    }

    private static CandidateSolution SelectBestFallbackSolution(
        IReadOnlyList<CandidateSolution> solutions)
    {
        var best = solutions[0];
        for (var i = 1; i < solutions.Count; i++)
        {
            var candidate = solutions[i];
            if (IsBetterBoundarySlotRepairCandidate(
                    candidate.Score,
                    candidate.RetryState,
                    best.Score,
                    best.RetryState)
                || candidate.Score.NodeCrossings < best.Score.NodeCrossings
                || (candidate.Score.NodeCrossings == best.Score.NodeCrossings
                    && CompareRetryStates(candidate.RetryState, best.RetryState) < 0)
                || (candidate.Score.NodeCrossings == best.Score.NodeCrossings
                    && CompareRetryStates(candidate.RetryState, best.RetryState) == 0
                    && candidate.Score.EdgeCrossings < best.Score.EdgeCrossings)
                || (candidate.Score.NodeCrossings == best.Score.NodeCrossings
                    && CompareRetryStates(candidate.RetryState, best.RetryState) == 0
                    && candidate.Score.EdgeCrossings == best.Score.EdgeCrossings
                    && candidate.Score.Value > best.Score.Value))
            {
                best = candidate;
            }
        }

        return best;
    }

}