/*

  * TreeHelper.java

  *

  * Created on February 4, 2007, 11:54 PM

  */

 package net.sf.tacos.components.tree;

 import java.util.Stack;

 import org.apache.tapestry.AbstractComponent;

 import org.apache.tapestry.IMarkupWriter;

 import org.apache.tapestry.IRequestCycle;

 import org.apache.tapestry.engine.NullWriter;

 /**

  *

  * @author andyhot

  */

 public abstract class TreeHelper extends AbstractComponent {

     private Stack stack;

     public abstract TreeIterator getTreeIterator();

     private Stack getCycleStack(IRequestCycle cycle) {

         Stack currStack = (Stack) cycle.getAttribute(TreeHelper.class.getName());

         if (currStack == null) {

             currStack = new Stack();

         }

         return currStack;

     }

     private void setCycleStack(IRequestCycle cycle, Stack currStack) {

         cycle.setAttribute(TreeHelper.class.getName(), currStack);

     }

     protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle) {          

         stack = getCycleStack(cycle);

         if (getTreeIterator() == null) {

             finalRenderComponent();

         } else {  

             int diff = getTreeIterator().getDepth() - getTreeIterator().getPreviousDepth();

             boolean empty = stack.empty();

             if (writer == NullWriter.getSharedInstance()  && cycle.getResponseBuilder().isDynamic()

                     && (empty || stack.peek()==writer)) {

                 renderBody(writer, cycle);

                 return;

             }

             if (empty) {

                 stack.push(writer.getNestedWriter()); 

                 diff = 0;

             }

             IMarkupWriter writerGive = (IMarkupWriter) stack.peek();

             normalRenderComponent(writerGive, cycle, diff, empty);

         }

         setCycleStack(cycle, stack);

     }

     protected void finalRenderComponent() {

         while (!stack.empty()) {

             IMarkupWriter inner = (IMarkupWriter) stack.pop();            

             inner.close();

         }

         stack = null;        

         return;

     }

     protected void normalRenderComponent(IMarkupWriter writer, IRequestCycle cycle, 

             int diff, boolean empty) {                    

         //System.out.println("Doing: " + getClientId() + " Diff:" + diff + "Wr:" + writer);

         if (diff==0) {

             if (!empty)

                 writer.end();

             writer.begin("div");            

             renderIdAttribute(writer, cycle);

             writer.closeTag();

             renderBody(writer, cycle);

         } else if (diff>0) {            

             writer = writer.getNestedWriter();

             stack.push(writer);

             writer.begin("div");            

             renderIdAttribute(writer, cycle);

             writer.closeTag();            

             renderBody(writer, cycle);            

         } else {

             writer = (IMarkupWriter) stack.pop();

             for (int c = diff; c < 0 && !stack.empty(); c++) {

                 writer.close();

                 writer = (IMarkupWriter) stack.pop();

             }

             if (stack.empty() && cycle.getResponseBuilder().isDynamic()) {

                 renderBody(NullWriter.getSharedInstance(), cycle);

                 writer.close();

                 stack.push(NullWriter.getSharedInstance());

                 return;

             }

             writer.end();

             stack.push(writer);

             writer.begin("div");            

             renderIdAttribute(writer, cycle);

             writer.closeTag();

             renderBody(writer, cycle);

         }

     }

 }