namespace Holo.Virtual.Rooms.Pathfinding
{
    using System;
    using System.Collections;

    public sealed class AStar
    {
        private Heap FClosedList = new Heap();
        private AStarNode FGoalNode;
        private Heap FOpenList = new Heap();
        private ArrayList FSolution = new ArrayList();
        private AStarNode FStartNode;
        private ArrayList FSuccessors = new ArrayList();

        public void FindPath(AStarNode AStartNode, AStarNode AGoalNode)
        {
            this.FStartNode = AStartNode;
            this.FGoalNode = AGoalNode;
            this.FOpenList.Add(this.FStartNode);
            while (this.FOpenList.Count > 0)
            {
                AStarNode NodeCurrent = (AStarNode) this.FOpenList.Pop();
                if (NodeCurrent.IsGoal())
                {
                    while (NodeCurrent != null)
                    {
                        this.FSolution.Insert(0, NodeCurrent);
                        NodeCurrent = NodeCurrent.Parent;
                    }
                    break;
                }
                NodeCurrent.GetSuccessors(this.FSuccessors);
                foreach (AStarNode NodeSuccessor in this.FSuccessors)
                {
                    AStarNode NodeOpen = null;
                    if (this.FOpenList.Contains(NodeSuccessor))
                    {
                        NodeOpen = (AStarNode) this.FOpenList[this.FOpenList.IndexOf(NodeSuccessor)];
                    }
                    if ((NodeOpen == null) || (NodeSuccessor.TotalCost <= NodeOpen.TotalCost))
                    {
                        AStarNode NodeClosed = null;
                        if (this.FClosedList.Contains(NodeSuccessor))
                        {
                            NodeClosed = (AStarNode) this.FClosedList[this.FClosedList.IndexOf(NodeSuccessor)];
                        }
                        if ((NodeClosed == null) || (NodeSuccessor.TotalCost <= NodeClosed.TotalCost))
                        {
                            this.FOpenList.Remove(NodeOpen);
                            this.FClosedList.Remove(NodeClosed);
                            this.FOpenList.Push(NodeSuccessor);
                        }
                    }
                }
                this.FClosedList.Add(NodeCurrent);
            }
        }

        private void PrintNodeList(object ANodeList)
        {
            Console.WriteLine("Node list:");
            foreach (AStarNode n in ANodeList as IEnumerable)
            {
                n.PrintNodeInfo();
            }
            Console.WriteLine("=====");
        }

        public ArrayList Solution
        {
            get
            {
                return this.FSolution;
            }
        }
    }
}