using System;
using System.Diagnostics;

namespace SpaceInvaders
{
    public abstract class Composite : GameObject
    {
        //-------------------------------------------------------------------
        //  FIELDS
        //-------------------------------------------------------------------

        protected DLinkMan pDLinkMan;
        protected int numNodes = 0;


        //-------------------------------------------------------------------
        //  CONSTRUCTION
        //-------------------------------------------------------------------

        public Composite() 
            : base(Component.Type.Composite, GameObject.ObjectName.NullObject, Sprite.SpriteName.NullObject)
        {
            //LTN: own by composite
            this.pDLinkMan = new DLinkMan();
        }     

        public Composite(GameObject.ObjectName name, Sprite.SpriteName spriteName)
            : base(Component.Type.Composite, name, spriteName)
        {
            this.pDLinkMan = new DLinkMan();
        }


        //-------------------------------------------------------------------
        //  PUBLIC METHODS
        //-------------------------------------------------------------------

        public Component GetHead()
        {
            Debug.Assert(this.pDLinkMan != null);
            Component pHead = (GameObject)this.pDLinkMan.pHead;

            return pHead;
        }

        public int GetNumNodes()
        {
            return this.numNodes;
        }

        public GameObject GetNodeIndex(int index)
        {
            Debug.Assert(index >= 0);
            Debug.Assert(index < numNodes);

            Iterator pIterator = this.pDLinkMan.GetIterator();
            Debug.Assert(pIterator != null);

            GameObject pObj = (GameObject)pIterator.First();
            int count = 0;

            while(!pIterator.IsDone())
            {
                if(count == index)
                {
                    break;
                }

                pObj = (GameObject)pIterator.Next();
                count++;
            }

            return pObj;
        }

        public override void AddComponent(Component pComponent)
        {
            Debug.Assert(pComponent != null);
            Debug.Assert(this.pDLinkMan != null);

            this.pDLinkMan.AddToFront(pComponent);
            pComponent.pParent = this;

            this.numNodes++;
        }

        public override void RemoveComponent(Component pComponent)
        {
            Debug.Assert(pComponent != null);
            Debug.Assert(this.pDLinkMan != null);

            this.pDLinkMan.Remove(pComponent);
            this.numNodes--;
        }

        public override void Ressurect()
        {
            Debug.Assert(this.pDLinkMan.pHead == null);
            base.Ressurect();
        }

        public override void Move(float x, float y)
        {
            //get iterator
            Iterator pIterator = this.pDLinkMan.GetIterator();
            Debug.Assert(pIterator != null);

            GameObject pObject = (GameObject)pIterator.First();
            //iterate thro nodes
            while(!pIterator.IsDone())
            {
                //check node before update
                Debug.Assert(pObject != null);
                pObject.Move(x, y);

                pObject = (GameObject)pIterator.Next();
            }
        }

        public override void PrintComponent()
        {
            Debug.WriteLine("\nComposite:");

            // walk through the list and render
            Iterator pIt = this.pDLinkMan.GetIterator();
            Debug.Assert(pIt != null);

            GameObject pNode = (GameObject)pIt.First();

            // Walk through the nodes
            while (!pIt.IsDone())
            {
                // Update the node
                Debug.Assert(pNode != null);
                pNode.PrintComponent();

                pNode = (GameObject)pIt.Next();
            }
        }


    }
}