/*
 * @(#)file      SnmpMibTree.java
 * @(#)author    Sun Microsystems, Inc.
 * @(#)version   4.7
 * @(#)date      01/02/09
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 */


package com.sun.jmx.snmp.daemon;



// java imports
//
import java.util.Vector;
import java.util.Enumeration;

// jmx imports
//
import com.sun.jmx.snmp.SnmpOid;

// SNMP Runtime imports
//
import com.sun.jmx.snmp.agent.SnmpMibAgent;
  
/**
 * The class is used for building a tree representation of the different
 * root oids of the supported MIBs. Each node is associated to a specific MIB.
 */
final class SnmpMibTree {
    
    public SnmpMibTree() {
      defaultAgent= null;
      root= new TreeNode(-1, null, null);
    }
    
    public void setDefaultAgent(SnmpMibAgent def) {
        defaultAgent= def;
        root.agent= def;
    }
  
    public SnmpMibAgent getDefaultAgent() {
        return defaultAgent;
    }
  
    public void register(SnmpMibAgent agent) {
        root.registerNode(agent);
    }

    public void register(SnmpMibAgent agent, long[] oid) {
      root.registerNode(oid, 0, agent);
    }
  
    public SnmpMibAgent getAgentMib(SnmpOid oid) {
        TreeNode node= root.retrieveMatchingBranch(oid.longValue(), 0);
        if (node == null)
            return defaultAgent;
        else
	    if(node.getAgentMib() == null)
		return defaultAgent;
	    else
		return node.getAgentMib();
    }

    public void unregister(SnmpMibAgent agent, SnmpOid[] oids) {
	for(int i = 0; i < oids.length; i++) {
	    long[] oid = oids[i].longValue();
	    TreeNode node = root.retrieveMatchingBranch(oid, 0);
	    if (node == null)
		continue;
	    node.removeAgent(agent);
	}
    }

    
    public void unregister(SnmpMibAgent agent) {
	
	root.removeAgentFully(agent);
    }

    /*    
    public void unregister(SnmpMibAgent agent) {
        long[] oid= agent.getRootOid();
        TreeNode node= root.retrieveMatchingBranch(oid, 0);
        if (node == null)
            return;
        node.removeAgent(agent);
    }
    */
    public void printTree() {
        root.printTree(">");
    }
   
    private SnmpMibAgent defaultAgent;    
    private TreeNode root;
    
    // A SnmpMibTree object is a tree of TreeNode
    //
    final class TreeNode {
          
        void registerNode(SnmpMibAgent agent) {
            long[] oid= agent.getRootOid();
            registerNode(oid, 0, agent);
        }
      
        TreeNode retrieveMatchingBranch(long[] oid, int cursor) {
	    TreeNode node= retrieveChild(oid, cursor);
            if (node == null)
                return this;
            if (children.size() == 0) {
                // In this case, the node does not have any children. So no point to
                // continue the search ...
                return node;
            }
            if( cursor + 1 == oid.length) {
                // In this case, the oid does not have any more element. So the search
                // is over.
                return node;
            }
	    
            TreeNode n = node.retrieveMatchingBranch(oid, cursor + 1);
	    //If the returned node got a null agent, we have to replace it by 
	    //the current one (in case it is not null)
	    //
	    return n.agent == null ? this : n;
        }
      
        SnmpMibAgent getAgentMib() {
            return agent;
        }
      
        public void printTree(String ident) {
	
            StringBuffer buff= new StringBuffer();
            if (agents == null) {
                return;
            }
      
            for(Enumeration e= agents.elements(); e.hasMoreElements(); ) {
                SnmpMibAgent mib= (SnmpMibAgent) e.nextElement();
                if (mib == null)
                    buff.append("empty ");
                else
                    buff.append(mib.getMibName() + " ");
            }
            ident+= " ";
            if (children == null) {
                return;
            }
            for(Enumeration e= children.elements(); e.hasMoreElements(); ) {
                TreeNode node= (TreeNode) e.nextElement();
                node.printTree(ident);
            }
        }
	
        // PRIVATE STUFF
        //--------------
      
        /**
         * Only the treeNode class can create an instance of treeNode.
         * The creation occurs when registering a new oid.
         */
        private TreeNode(long nodeValue, SnmpMibAgent agent, TreeNode sup) {
            this.nodeValue= nodeValue;
            this.parent= sup;
            agents.addElement(agent);
        }
	
	private void removeAgentFully(SnmpMibAgent agent) {
	    Vector v = new Vector();
	    for(Enumeration e= children.elements(); e.hasMoreElements(); ) {
		
                TreeNode node= (TreeNode) e.nextElement();
                node.removeAgentFully(agent);
		if(node.agents.isEmpty())
		    v.add(node);
		
            }
	    for(Enumeration e= v.elements(); e.hasMoreElements(); ) {
		children.removeElement(e.nextElement());
	    }
            removeAgent(agent);
	    
	}

        private void removeAgent(SnmpMibAgent mib) {
            if (!agents.contains(mib))
                return;
            agents.removeElement(mib);
	    
	    if (!agents.isEmpty())
		agent= (SnmpMibAgent)agents.firstElement();
	   
        }

      private void setAgent(SnmpMibAgent agent) {
	this.agent = agent;
      }

        private void registerNode(long[] oid, int cursor, SnmpMibAgent agent) {

            if (cursor >= oid.length)
                //That's it !
                //
                return;	    
            TreeNode child = retrieveChild(oid, cursor);
            if (child == null) {
                // Create a child and register it !
                //
                long theValue= oid[cursor];
		child= new TreeNode(theValue, agent, this);
                children.addElement(child);
            }
	    else
		if (agents.contains(agent) == false) {
		    agents.addElement(agent);
		}
	    
	    // We have to set the agent attribute
	    //
	    if(cursor == (oid.length - 1)) {
	      child.setAgent(agent);
	    }
	    else
	      child.registerNode(oid, cursor+1, agent);
        }
	
        private TreeNode retrieveChild(long[] oid, int current) {
            long theValue= oid[current];
	
            for(Enumeration e= children.elements(); e.hasMoreElements(); ) {
                TreeNode node= (TreeNode) e.nextElement();
                if (node.match(theValue))
                    return node;
            }
            return null;
        }
      
        final private boolean match(long value) {
            return (nodeValue == value) ? true : false;
        }
      
        private Vector children= new Vector();
        private Vector agents= new Vector();
        private long nodeValue;
        protected SnmpMibAgent agent;
        private TreeNode parent;
        
    }; // end of class TreeNode
}