// /**
//  * File: HopMap.cs
//  * Author: haraldwolff
//  *
//  * This file and it's content is copyrighted by the Author and / or copyright holder.
//  * Any use wihtout proper permission is illegal and may lead to legal actions.
//  *
//  *
//  **/
using System;
using System.Collections.Generic;
using System.Collections;
using Castle.Core.Logging;
using ln.types.odb;
using System.Linq;
using ln.types.btree;
using Castle.Components.DictionaryAdapter.Xml;
using Newtonsoft.Json;
using ln.types.net;
using System.Net.Sockets;
namespace ln.skyscanner.entities
{
    public class HopMap : Persistent
    {
        public Node TopNode { get; private set; }
        public GlobalNetwork GlobalNetwork => SkyScanner.Instance.Entities.GlobalNetwork;

        public int MaxDepth { get; set; } = 16;

        private BTree<Node, HopNode> hopNodes = new BTree<Node, HopNode>(CompareNodes);

        private HashSet<Network4> networks = new HashSet<Network4>();

        public HopMap()
        {
        }

        public HopMap(Node node)
        {
            Reset(node);
        }

        public void Reset(Node node)
        {
            hopNodes.Clear();
            TopNode = node;
            HopNode hopNode = new HopNode(this, node);
        }

        public int GetHopCount(Node node)
        {
            if (!hopNodes.ContainsKey(node))
                return -1;
            return hopNodes[node].HopCount;
        }

        public HopNode[] HopNodes
        {
            get
            {
                return hopNodes.Values.ToArray();
            }
        }



        public class HopNode : IComparable
        {
            [JsonIgnore]
            public HopMap HopMap { get; }
            [JsonIgnore]
            public HopNode Parent { get; private set; }

            public Node Node;

            [JsonIgnore]
            public HopNode[] Peers => peers.ToArray();
            private HashSet<HopNode> peers = new HashSet<HopNode>();

            private int hopCount = 0;

            public HopNode(HopMap hopMap, Node node)
            {
                HopMap = hopMap;
                Node = node;

                HopMap.hopNodes.Add(node, this);

                FindPeers();
            }
            public HopNode(HopNode parent, Node node)
            {
                HopMap = parent.HopMap;
                Node = node;

                Attach(parent);

                FindPeers();
            }

            private void FindPeers()
            {
                foreach (Network4 network in Node.Networks)
                {
                    EnsureNetwork(network);
                }
                EnsureNetwork(HopMap.GlobalNetwork.FindSubnetForIP(Node.PrimaryIP).Network);
            }
            private void EnsureNetwork(Network4 network)
            {
                if (!HopMap.networks.Contains(network))
                {
                    HopMap.networks.Add(network);
                    FindPeers(network);
                }
            }
            private void FindPeers(Network4 network)
            { 
                foreach (Node peerNode in HopMap.GlobalNetwork.FindHostsInSubnet(network))
                {
                    if (!HopMap.hopNodes.ContainsKey(peerNode))
                    {
                        new HopNode(this, peerNode);
                    }
                    else
                    {
                        HopNode existingHopNode = HopMap.hopNodes[peerNode];
                        if (existingHopNode.HopCount > (HopCount + 1))
                        {
                            existingHopNode.Detach();
                            existingHopNode.Attach(this);
                        }
                    }
                }
            }


            public int HopCount
            {
                get => hopCount;
                set
                {
                    hopCount = value;
                    foreach (HopNode peer in peers)
                    {
                        peer.HopCount = hopCount + 1;
                    }
                }
            }

            public void Attach(HopNode parent)
            {
                Detach();

                Parent = parent;
                if (!Object.ReferenceEquals(null, Parent))
                {
                    HopMap.hopNodes.Add(this.Node, this);
                    Parent.peers.Add(this);

                    HopCount = parent.hopCount + 1;
                }
                else
                {
                    HopCount = 0;
                }

            }
            public void Detach()
            {
                if (!Object.ReferenceEquals(null, Parent))
                {
                    Parent.peers.Remove(this);
                    Parent = null;
                    HopMap.hopNodes.Remove(this.Node);
                }
            }

            public int CompareTo(object obj)
            {
                if (obj is HopNode)
                {
                    HopNode you = obj as HopNode;
                    return Node.ID.CompareTo(you.Node.ID);
                }
                return this.GetHashCode() - obj.GetHashCode();
            }

            public IPv4[] Path => _path().ToArray();
            private List<IPv4> _path()
            {
                if (Parent == null)
                    return new List<IPv4>(new IPv4[] { Node.PrimaryIP });
                List<IPv4> l = Parent._path();
                l.Add(Node.PrimaryIP);
                return l;
            }

        }

        private static int CompareNodes(Node a, Node b)
        {
            return a.ID.CompareTo(b.ID);
        }

    }
}