using RobotNet10.GlobalPathPlanner.Model;
using RobotNet10.GlobalPathPlanner.Space;

namespace RobotNet10.GlobalPathPlanner.AStar;

public class AStarPlanner(List<GlobalNode> Nodes, List<GlobalEdge> Edges)
{
    private GlobalEdge[]? GetClosesEdges(GlobalNode nodeRef, double limitDistance)
    {
        double minDistance = double.MaxValue;
        List<GlobalEdge> edgesResult = [];
        foreach (var edge in Edges)
        {
            var startNode = Nodes.FirstOrDefault(node => node.Id == edge.StartNodeId);
            var endNode = Nodes.FirstOrDefault(node => node.Id == edge.EndNodeId);
            if (startNode is null || endNode is null) continue;

            var distance = MathExtensions.DistanceToEdge(nodeRef, startNode, endNode, edge);
            if (distance < minDistance)
            {
                minDistance = distance;
                edgesResult = [edge];
                var reverseEdge = Edges.FirstOrDefault(e => e.EndNodeId == startNode.Id && e.StartNodeId == endNode.Id);
                if (reverseEdge != null) edgesResult = [.. edgesResult, reverseEdge];
            }
        }
        if (minDistance <= limitDistance) return [.. edgesResult];
        else return null;
    }

    private GlobalNode? GetOnNode(double x, double y, double limitDistance)
    {
        KDTree KDTree = new(Nodes);
        return KDTree.FindNearest(x, y, limitDistance);
    }

    private List<GlobalNode> GetNegativeNodes(Guid nodeId)
    {
        var node = Nodes.FirstOrDefault(p => p.Id == nodeId);
        if (node is null) return [];

        var ListNegativeNodes = new List<GlobalNode>();
        var ListPaths = Edges.Where(p => p.StartNodeId == nodeId);
        foreach (var path in ListPaths)
        {
            var negativeNode = Nodes.FirstOrDefault(p => p.Id == path.EndNodeId);
            if (negativeNode is not null) ListNegativeNodes.Add(negativeNode);
        }
        return ListNegativeNodes;
    }

    private double GetNegativeCost(AStarNode currenNode, AStarNode negativeNode)
    {
        var negativeEdges = Edges.Where(e => e.StartNodeId == currenNode.Id && e.EndNodeId == negativeNode.Id || e.StartNodeId == negativeNode.Id && e.EndNodeId == currenNode.Id).ToList();
        double minDistance = double.MaxValue;
        foreach (var edge in negativeEdges)
        {
            var startNode = Nodes.FirstOrDefault(n => n.Id == edge.StartNodeId);
            var endNode = Nodes.FirstOrDefault(n => n.Id == edge.EndNodeId);
            if (startNode is null || endNode is null) return 0;
            var distance = MathExtensions.GetEdgeLength(startNode, endNode, edge);
            if (distance < minDistance) minDistance = distance;
        }
        return minDistance != double.MaxValue ? minDistance : 0;
    }

    private List<AStarNode> GetNegativeAStarNodes(AStarNode nodeCurrent, GlobalNode endNode)
    {
        var possiblePointNegative = new List<AStarNode>();
        foreach (var nodeNegative in nodeCurrent.NegativeNodes)
        {
            nodeNegative.Parent = nodeCurrent;
            var ListNodesNegative = GetNegativeNodes(nodeNegative.Id);
            foreach (var item in ListNodesNegative)
            {
                nodeNegative.NegativeNodes.Add(new AStarNode()
                {
                    Id = item.Id,
                    X = item.X,
                    Y = item.Y,
                    Name = item.Name,
                });
            }
            var cost = GetNegativeCost(nodeCurrent, nodeNegative);
            nodeNegative.Cost = (cost > 0 ? cost : Math.Sqrt(Math.Pow(nodeCurrent.X - nodeNegative.X, 2) + Math.Pow(nodeCurrent.Y - nodeNegative.Y, 2))) + nodeCurrent.Cost;
            nodeNegative.Heuristic = Math.Abs(endNode.X - nodeNegative.X) + Math.Abs(endNode.Y - nodeNegative.Y);
            possiblePointNegative.Add(nodeNegative);
        }
        return possiblePointNegative;
    }

    private List<AStarNode> Find(AStarNode startNode, GlobalNode endNode, CancellationToken? cancellationToken = null)
    {
        try
        {
            var activeNodes = new PriorityQueue<AStarNode>((a, b) => a.TotalCost.CompareTo(b.TotalCost));
            var visitedNodes = new HashSet<AStarNode>();
            List<AStarNode> Path = [];
            activeNodes.Enqueue(startNode);

            while (activeNodes.Count != 0 && (!cancellationToken.HasValue || !cancellationToken.Value.IsCancellationRequested))
            {
                var checkNode = activeNodes.Dequeue();
                if (checkNode.Id == endNode.Id)
                {
                    var node = checkNode;
                    while (node != null)
                    {
                        if (cancellationToken.HasValue && cancellationToken.Value.IsCancellationRequested) return [];
                        Path.Add(node);
                        node = node.Parent;
                    }
                    return Path;
                }

                visitedNodes.Add(checkNode);

                var ListNodeNegative = GetNegativeAStarNodes(checkNode, endNode);
                foreach (var node in ListNodeNegative)
                {
                    if (visitedNodes.TryGetValue(node, out AStarNode? value) && value is not null)
                    {
                        if (value.TotalCost > node.TotalCost)
                        {
                            visitedNodes.Remove(value);
                            activeNodes.Enqueue(node);
                        }
                        continue;
                    }

                    var activeNode = activeNodes.Items.FirstOrDefault(n => n.Id == node.Id);
                    if (activeNode is not null && activeNode.TotalCost > node.TotalCost)
                    {
                        activeNodes.Items.Remove(activeNode);
                        activeNodes.Enqueue(node);
                    }
                    else if (activeNode is null)
                    {
                        activeNodes.Enqueue(node);
                    }
                }
            }

            return [];
        }
        catch (OperationCanceledException)
        {
            return [];
        }
    }

    public (GlobalNode[] pathNodes, GlobalEdge? closeEdges) Planning(double x, double y, GlobalNode goal, double maxDistanceToEdge, double maxDistanceToNode, CancellationToken? cancellationToken = null)
    {
        var Path = new List<GlobalNode>();

        AStarNode RobotNode = new()
        {
            Id = Guid.NewGuid(),
            X = x,
            Y = y,
            Name = "RobotCurrentNode",
        };
        GlobalEdge[] closesEdges = [];
        var closesNode = GetOnNode(x, y, maxDistanceToNode);
        if (closesNode is not null)
        {
            if (closesNode.Id == goal.Id) return ([goal], null);
            RobotNode.Name = closesNode.Name;
            RobotNode.Id = closesNode.Id;
            RobotNode.X = closesNode.X;
            RobotNode.Y = closesNode.Y;

            foreach (var negativeNode in GetNegativeNodes(RobotNode.Id))
            {
                var cost = GetNegativeCost(RobotNode, new() { Id = negativeNode.Id, X = negativeNode.X, Y = negativeNode.Y });
                RobotNode.NegativeNodes.Add(new()
                {
                    Id = negativeNode.Id,
                    X = negativeNode.X,
                    Y = negativeNode.Y,
                    Name = negativeNode.Name,
                    Cost = cost > 0 ? cost : Math.Sqrt(Math.Pow(RobotNode.X - negativeNode.X, 2) + Math.Pow(RobotNode.Y - negativeNode.Y, 2)),
                    Heuristic = Math.Abs(goal.X - negativeNode.X) + Math.Abs(goal.Y - negativeNode.Y),
                });
            }
        }
        else
        {
            closesEdges = GetClosesEdges(new() { X = x, Y = y }, maxDistanceToEdge) ?? [];
            if (closesEdges is null || closesEdges.Length == 0) throw new Exception("The robot is too far from the route");

            var edgeToGoal = closesEdges.FirstOrDefault(e => e.EndNodeId == goal.Id);
            if (edgeToGoal != null)
            {
                var endNode = Nodes.FirstOrDefault(n => n.Id == edgeToGoal.EndNodeId);
                if (endNode != null) return ([new() {
                                                        Id = RobotNode.Id,
                                                        X = RobotNode.X,
                                                        Y = RobotNode.Y,
                                                        Name = RobotNode.Name,
                                                        MapId = endNode.MapId,
                                                    }, endNode], edgeToGoal);
            }
            foreach (var edge in closesEdges)
            {
                var node = Nodes.FirstOrDefault(n => n.Id == edge.EndNodeId);
                if (node == null) continue;
                RobotNode.NegativeNodes.Add(new()
                {
                    Id = node.Id,
                    X = node.X,
                    Y = node.Y,
                    Name = node.Name,
                    Cost = Math.Sqrt(Math.Pow(RobotNode.X - node.X, 2) + Math.Pow(RobotNode.Y - node.Y, 2)),
                    Heuristic = Math.Abs(goal.X - node.X) + Math.Abs(goal.Y - node.Y),
                });
            }
        }

        if (RobotNode.NegativeNodes.Count < 1) throw new Exception($"The path to {goal.Name} - {goal.Id} does not exist from [{x}, {y}]");

        var path = Find(RobotNode, goal, cancellationToken);
        if (cancellationToken is not null && cancellationToken.Value.IsCancellationRequested) throw new OperationCanceledException();
        if (path is null || path.Count < 1) throw new Exception($"The path to {goal.Name} - {goal.Id} does not exist from [{x}, {y}]");
        path.Reverse();
        foreach (var node in path)
        {
            if (node.Name == "RobotCurrentNode")
            {
                Path.Add(new()
                {
                    Id = RobotNode.Id,
                    Name = RobotNode.Name,
                    X = RobotNode.X,
                    Y = RobotNode.Y,
                });
                continue;
            }
            var nodedb = Nodes.FirstOrDefault(p => p.Id == node.Id) ?? throw new Exception($"Map data error: Node {node.Id} does not exist in the map");
            Path.Add(nodedb);
        }
        var startEdge = path.Count > 1 ? Edges.FirstOrDefault(e => e.StartNodeId == path[0].Id && e.EndNodeId == path[1].Id) : null;
        if (startEdge is null && closesEdges is not null && closesEdges.Length > 0)
        {
            startEdge = path.Count > 1 ? closesEdges.FirstOrDefault(e => e.EndNodeId == path[1].Id) : null;
        }
        Console.WriteLine($"AStar Planner Found: {string.Join(",", Path.Select(n => $"({n.X} - {n.Y})"))}");
        return ([.. Path], startEdge);
    }

    public (GlobalNode[] pathNodes, GlobalEdge? closeEdges) Planning(GlobalNode startNode, GlobalNode goal, CancellationToken? cancellationToken = null)
    {
        var Path = new List<GlobalNode>();
        var currentNode = new AStarNode
        {
            Id = startNode.Id,
            X = startNode.X,
            Y = startNode.Y,
            NegativeNodes = [..GetNegativeNodes(startNode.Id).Select(n => new AStarNode
            {
                Id = n.Id,
                Name = n.Name,
                X = n.X,
                Y = n.Y,
                Cost = Math.Sqrt(Math.Pow(startNode.X - n.X, 2) + Math.Pow(startNode.Y - n.Y, 2)),
                Heuristic = Math.Abs(goal.X - n.X) + Math.Abs(goal.Y - n.Y),
            })],
        };
        var path = Find(currentNode, goal, cancellationToken);
        if (cancellationToken is not null && cancellationToken.Value.IsCancellationRequested) throw new OperationCanceledException();
        if (path is null || path.Count < 1) throw new Exception($"The path to {goal.Name} - {goal.Id} does not exist from [{startNode.Name} - {startNode.Id}]");
        path.Reverse();
        foreach (var node in path)
        {
            var nodedb = Nodes.FirstOrDefault(p => p.Id == node.Id) ?? throw new Exception($"Map data error: Node {node.Id} does not exist in the map");
            Path.Add(nodedb);
        }
        var startEdge = path.Count > 1 ? Edges.FirstOrDefault(e => e.StartNodeId == path[0].Id && e.EndNodeId == path[1].Id) : null;
        return ([.. Path], startEdge);
    }
}