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

namespace StellaOps.ElkSharp;

internal static partial class ElkEdgeRouterIterative
{
    private static IEnumerable<RoutingStrategy> GenerateStrategies(
        ElkRoutedEdge[] edges,
        ElkPositionedNode[] nodes,
        IterativeRoutingConfig config,
        double minLineClearance)
    {
        var nodesById = nodes.ToDictionary(n => n.Id, StringComparer.Ordinal);
        var connectionCount = new Dictionary<string, int>(StringComparer.Ordinal);
        foreach (var edge in edges)
        {
            var srcId = edge.SourceNodeId ?? "";
            var tgtId = edge.TargetNodeId ?? "";
            connectionCount[srcId] = connectionCount.GetValueOrDefault(srcId) + 1;
            connectionCount[tgtId] = connectionCount.GetValueOrDefault(tgtId) + 1;
        }

        var orderings = new[]
        {
            OrderByLongestFirst(edges, nodesById),
            OrderByShortestFirst(edges, nodesById),
            OrderByMostConnectedFirst(edges, connectionCount),
            OrderByReverse(edges),
        };

        // Strategies 1-4: base params, clearance = half avg node dimension
        var baseParams = new AStarRoutingParams(18d, 200d, 500d, 2.0d, minLineClearance, 40d, true);
        foreach (var order in orderings)
        {
            yield return new RoutingStrategy
            {
                EdgeOrder = order,
                BaseLineClearance = minLineClearance,
                MinLineClearance = minLineClearance,
                RoutingParams = baseParams,
            };
        }

        // Strategies 5-8: higher penalties and tighter clearance
        var highParams = new AStarRoutingParams(18d, 400d, 600d, 3.0d, minLineClearance, 40d, true);
        foreach (var order in orderings)
        {
            yield return new RoutingStrategy
            {
                EdgeOrder = order,
                BaseLineClearance = minLineClearance,
                MinLineClearance = minLineClearance,
                RoutingParams = highParams,
            };
        }

        // Strategies 9+: seeded random with clearance
        for (var i = 0; i < 8; i++)
        {
            var seed = HashCode.Combine(edges.Length, nodes.Length, i + 8);
            var rng = new Random(seed);
            var order = Enumerable.Range(0, edges.Length).ToArray();
            Shuffle(order, rng);
            var randomParams = new AStarRoutingParams(
                18d,
                80d + (rng.NextDouble() * 420d),
                300d + (rng.NextDouble() * 500d),
                1.0d + (rng.NextDouble() * 3.0d),
                minLineClearance * (0.5d + rng.NextDouble()),
                40d,
                true);
            yield return new RoutingStrategy
            {
                EdgeOrder = order,
                BaseLineClearance = minLineClearance,
                MinLineClearance = minLineClearance,
                RoutingParams = randomParams,
            };
        }
    }

    private static RoutingRetryState BuildRetryState(EdgeRoutingScore score, int remainingBrokenHighways)
    {
        return new RoutingRetryState(
            RemainingShortHighways: remainingBrokenHighways,
            RepeatCollectorCorridorViolations: score.RepeatCollectorCorridorViolations,
            RepeatCollectorNodeClearanceViolations: score.RepeatCollectorNodeClearanceViolations,
            TargetApproachJoinViolations: score.TargetApproachJoinViolations,
            TargetApproachBacktrackingViolations: score.TargetApproachBacktrackingViolations,
            ExcessiveDetourViolations: score.ExcessiveDetourViolations,
            SharedLaneViolations: score.SharedLaneViolations,
            BoundarySlotViolations: score.BoundarySlotViolations,
            BelowGraphViolations: score.BelowGraphViolations,
            UnderNodeViolations: score.UnderNodeViolations,
            LongDiagonalViolations: score.LongDiagonalViolations,
            ProximityViolations: score.ProximityViolations,
            EntryAngleViolations: score.EntryAngleViolations,
            GatewaySourceExitViolations: score.GatewaySourceExitViolations,
            LabelProximityViolations: score.LabelProximityViolations,
            EdgeCrossings: score.EdgeCrossings);
    }

    private static string DescribeRetryState(RoutingRetryState retryState)
    {
        var parts = new List<string>(5);
        if (retryState.RemainingShortHighways > 0)
        {
            parts.Add($"short-highways={retryState.RemainingShortHighways}");
        }

        if (retryState.RepeatCollectorCorridorViolations > 0)
        {
            parts.Add($"collector-corridors={retryState.RepeatCollectorCorridorViolations}");
        }

        if (retryState.RepeatCollectorNodeClearanceViolations > 0)
        {
            parts.Add($"collector-clearance={retryState.RepeatCollectorNodeClearanceViolations}");
        }

        if (retryState.TargetApproachJoinViolations > 0)
        {
            parts.Add($"target-joins={retryState.TargetApproachJoinViolations}");
        }

        if (retryState.TargetApproachBacktrackingViolations > 0)
        {
            parts.Add($"approach-backtracking={retryState.TargetApproachBacktrackingViolations}");
        }

        if (retryState.ExcessiveDetourViolations > 0)
        {
            parts.Add($"detour={retryState.ExcessiveDetourViolations}");
        }

        if (retryState.GatewaySourceExitViolations > 0)
        {
            parts.Add($"gateway-source={retryState.GatewaySourceExitViolations}");
        }

        if (retryState.SharedLaneViolations > 0)
        {
            parts.Add($"shared-lanes={retryState.SharedLaneViolations}");
        }

        if (retryState.BoundarySlotViolations > 0)
        {
            parts.Add($"boundary-slots={retryState.BoundarySlotViolations}");
        }

        if (retryState.BelowGraphViolations > 0)
        {
            parts.Add($"below-graph={retryState.BelowGraphViolations}");
        }

        if (retryState.UnderNodeViolations > 0)
        {
            parts.Add($"under-node={retryState.UnderNodeViolations}");
        }

        if (retryState.LongDiagonalViolations > 0)
        {
            parts.Add($"long-diagonal={retryState.LongDiagonalViolations}");
        }

        if (retryState.ProximityViolations > 0)
        {
            parts.Add($"proximity={retryState.ProximityViolations}");
        }

        if (retryState.EntryAngleViolations > 0)
        {
            parts.Add($"entry={retryState.EntryAngleViolations}");
        }

        if (retryState.LabelProximityViolations > 0)
        {
            parts.Add($"label={retryState.LabelProximityViolations}");
        }

        if (retryState.EdgeCrossings > 0)
        {
            parts.Add($"edge-crossings={retryState.EdgeCrossings}");
        }

        return parts.Count > 0
            ? string.Join(", ", parts)
            : "none";
    }

}