/*******************************************************************************
 * Copyright (c) 2017 Politecnico di Torino and others.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Apache License, Version 2.0
 * which accompanies this distribution, and is available at
 * http://www.apache.org/licenses/LICENSE-2.0
 *******************************************************************************/

package mcnet.components;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.microsoft.z3.BoolExpr;
import com.microsoft.z3.Context;
import com.microsoft.z3.DatatypeExpr;
import com.microsoft.z3.Expr;
import com.microsoft.z3.IntExpr;
import com.microsoft.z3.Solver;
import com.microsoft.z3.Z3Exception;

/**Model for a network, encompasses routing and wiring
 * 
 */
public class Network extends Core{

	Context ctx;
	NetContext nctx;
	List<BoolExpr> constraints; 
	List<NetworkObject> elements;



	public Network(Context ctx,Object[]... args) {
		super(ctx, args);
	}

	@Override
	protected void init(Context ctx, Object[]... args) {
		this.ctx = ctx;
		this.nctx = (NetContext) args[0][0];
        constraints = new ArrayList<BoolExpr>();
        elements = new ArrayList<NetworkObject>();

	}

	/**Composes the network linking the configured network objects
	 *
	 * @param elements
	 */
	public void attach (NetworkObject ... elements){
	      for(NetworkObject el : elements)
		  this.elements.add(el);
	}

	@Override
	protected void addConstraints(Solver solver) {
		try {
			BoolExpr[] constr = new BoolExpr[constraints.size()];
		    solver.add(constraints.toArray(constr));
		} catch (Z3Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * Specify host to address mapping.
	 * Handles the case in which we have more than one address for a node
	 * @param addrmap
	 */
	 public void setAddressMappings(ArrayList<Tuple<NetworkObject,ArrayList<DatatypeExpr>>> addrmap){
		 // Set address mapping for nodes.
		 for (Tuple<NetworkObject,ArrayList<DatatypeExpr>> entry : addrmap) {
	    	    NetworkObject node=entry._1;
	    	    List<DatatypeExpr> addr=entry._2;
	            Expr a_0 = ctx.mkConst(node+"_address_mapping_a_0",nctx.address);
	   		    ArrayList<BoolExpr> or_clause = new ArrayList<BoolExpr>();

	   		   // Constraint 1 			addrToNode(foreach ad in addr) = node
	    	    for (DatatypeExpr ad : addr){
	              constraints.add(ctx.mkEq(nctx.addrToNode.apply(ad), node.getZ3Node()));
	              or_clause.add(ctx.mkEq(a_0,ad));
		        }
	            BoolExpr[] orClause = new BoolExpr[or_clause.size()];

	            // Constraint 2			nodeHasAddr(node, a_0) == Or(foreach ad in addr (a_0 == ad))
	        	// Note we need the iff here to make sure that we set nodeHasAddr to false
		        // for other addresses.
	            constraints.add(ctx.mkForall(new Expr[]{a_0},
	                  ctx.mkEq(ctx.mkOr(or_clause.toArray(orClause)), nctx.nodeHasAddr.apply(node.getZ3Node(), a_0)),1,null,null,null,null));
			}
	 }



	/**
	 * Don't forward packets addressed to node
	 * @param node
	 */
	 public void saneSend(NetworkObject node){
	     Expr n_0 = ctx.mkConst(node+"_saneSend_n_0", nctx.node);
	     Expr p_0 = ctx.mkConst(node+"_saneSend_p_0", nctx.packet);
	     IntExpr t_0 = ctx.mkIntConst(node+"_saneSend_t_0");
	     	// Constant: node
	        //Constraint	 send(node, n_0, p, t_0) -> !nodeHasAddr(node, p.dest)
	        constraints.add(
	                ctx.mkForall(new Expr[]{n_0, p_0, t_0},
	                    ctx.mkImplies((BoolExpr)nctx.send.apply(node.getZ3Node(),n_0, p_0, t_0),
	                    		ctx.mkNot((BoolExpr)nctx.nodeHasAddr.apply( node.getZ3Node(),
	                    				nctx.pf.get("dest").apply(p_0)))),1,null,null,null,null));
	    }

	 /**
	  * Node sends all traffic through gateway
	  * @param node
	  * @param gateway
	  */
	  public void setGateway (NetworkObject node, NetworkObject gateway){
	        // SetGateway(self, node, gateway): All packets from node are sent through gateway
	        Expr n_0 = ctx.mkConst(node+"_gateway_n_0", nctx.node);
	        Expr p_0 = ctx.mkConst(node+"_gateway_p_0", nctx.packet);
	        IntExpr t_0 = ctx.mkIntConst(node+"_gateway_t_0");

	        //Constraint	 send(node, n_0, p_0, t_0) -> n_0 = gateway
	        constraints.add(
	        		 ctx.mkForall(new Expr[]{n_0, p_0, t_0},
	        				 ctx.mkImplies(
	        						 (BoolExpr)nctx.send.apply(node.getZ3Node(), n_0, p_0, t_0),
	                                           ctx.mkEq(n_0,gateway.getZ3Node())),1,null,null,null,null));

//	        constraints.add(ctx.mkForall(new Expr[]{n_0, p_0, t_0},
//	            ctx.mkImplies((BoolExpr)nctx.recv.apply(n_0, node.getZ3Node(),  p_0, t_0),
//	                                            ctx.mkEq(n_0,gateway.getZ3Node())),1,null,null,null,null));
	  }

	  /**
	   * Assigns a specific routing table to a network object. Routing entries in the form: address -> node
	   * @param node
	   * @param routing_table
	   */
       public void routingTable (NetworkObject node,ArrayList<Tuple<DatatypeExpr,NetworkObject>> routing_table){
	       compositionPolicy(node,routing_table);
	   }

       /**
        * Composition policies steer packets between middleboxes.
        * @param node
        * @param policy
        */
       public void compositionPolicy (NetworkObject node,ArrayList<Tuple<DatatypeExpr,NetworkObject>> policy){
	        //Policy is of the form predicate -> node
	    	Expr p_0 = ctx.mkConst(node+"_composition_p_0", nctx.packet);
	    	Expr n_0 = ctx.mkConst(node+"_composition_n_0", nctx.node);
	    	Expr t_0 = ctx.mkIntConst(node+"_composition_t_0");

	    	HashMap<String,ArrayList<BoolExpr>> collected = new HashMap<String,ArrayList<BoolExpr>>();
	        HashMap<String,NetworkObject> node_dict = new HashMap<String,NetworkObject>();
            BoolExpr predicates;
            for(int y=0;y<policy.size();y++){
            	Tuple<DatatypeExpr,NetworkObject> tp = policy.get(y);
            	if(collected.containsKey(""+tp._2))	 collected.get(""+tp._2).add(nctx.destAddrPredicate(p_0,tp._1));
            	else{
            		ArrayList<BoolExpr> alb = new ArrayList<BoolExpr>();
            		alb.add(nctx.destAddrPredicate(p_0,tp._1));
            		collected.put(""+tp._2,alb);
            	}
            	node_dict.put(""+tp._2, tp._2);
            }

    	    //Constraint		foreach rtAddr,rtNode in rt( send(node, n_0, p_0, t_0) &&
    	    //					Or(foreach rtAddr in rt destAddrPredicate(p_0,rtAddr)) -> n_0 == rtNode )
    	 	for (Map.Entry<String,ArrayList<BoolExpr>> entry : collected.entrySet()) {
         		BoolExpr[] pred = new BoolExpr[entry.getValue().size()];
        	    predicates = ctx.mkOr(entry.getValue().toArray(pred));

        	    constraints.add(ctx.mkForall(new Expr[]{n_0, p_0, t_0},
                    ctx.mkImplies(ctx.mkAnd((BoolExpr)nctx.send.apply(node.getZ3Node(), n_0, p_0, t_0), predicates),
                                ctx.mkEq(n_0, node_dict.get(entry.getKey()).getZ3Node())),1,null,null,null,null));
         	}
        }

	    /**
	     * Routing entries are in the form: address -> node. Also allows packet to be sent to another box for further processing
	     * @param node
	     * @param routing_table
	     * @param shunt_node
	     */
	   public void routingTableShunt (NetworkObject node,ArrayList<Tuple<DatatypeExpr,NetworkObject>> routing_table,NetworkObject shunt_node){
	    	   compositionPolicyShunt(node,routing_table,shunt_node);
	   	    }

	    /**
	     * Composition policies steer packets between middleboxes.Policy is in the form: predicate -> node
	     * @param node
	     * @param routing_table
	     * @param shunt_node
	     */
	   public void compositionPolicyShunt (NetworkObject node,ArrayList<Tuple<DatatypeExpr,NetworkObject>> routing_table,NetworkObject shunt_node){
		    Expr p_0 = ctx.mkConst(node+"_composition_p_0", nctx.packet);
	    	Expr n_0 = ctx.mkConst(node+"_composition_n_0", nctx.node);
	    	Expr t_0 = ctx.mkIntConst(node+"_composition_t_0");

	    	HashMap<String,ArrayList<BoolExpr>> collected = new HashMap<String,ArrayList<BoolExpr>>();
	        HashMap<String,NetworkObject> node_dict = new HashMap<String,NetworkObject>();
	        BoolExpr predicates;
            for(int y=0;y<routing_table.size();y++){
            	Tuple<DatatypeExpr,NetworkObject> tp = routing_table.get(y);
            	if(collected.containsKey(""+tp._2))	 collected.get(""+tp._2).add(nctx.destAddrPredicate(p_0,tp._1));
            	else{
            		ArrayList<BoolExpr> alb = new ArrayList<BoolExpr>();
            		alb.add(nctx.destAddrPredicate(p_0,tp._1));
            		collected.put(""+tp._2,alb);
            	}
            	node_dict.put(""+tp._2, tp._2);
            }

            //Constraint		foreach rtAddr,rtNode in rt( send(node, n_0, p_0, t_0) &&
            //					Or(foreach rtAddr in rt destAddrPredicate(p_0,rtAddr)) -> n_0 == rtNode )
         	for (Map.Entry<String,ArrayList<BoolExpr>> entry : collected.entrySet()) {
        	    BoolExpr[] pred = new BoolExpr[entry.getValue().size()];
        	    predicates = ctx.mkOr(entry.getValue().toArray(pred));

        	    constraints.add(ctx.mkForall(new Expr[]{n_0, p_0, t_0},
                    ctx.mkImplies(ctx.mkAnd((BoolExpr)nctx.send.apply(node.getZ3Node(), n_0, p_0, t_0), predicates),
                               ctx.mkOr(ctx.mkEq(n_0, node_dict.get(entry.getKey()).getZ3Node()),ctx.mkEq(n_0, shunt_node.getZ3Node()))),1,null,null,null,null));
         	}

	    }

//	    public void SimpleIsolation (NetworkObject node, ArrayList<DatatypeExpr> addresses){
//	       Expr p = ctx.mkConst(node+"_s_p", nctx.packet);
//	       Expr n = ctx.mkConst(node+"_s_n", nctx.node);
//	       IntExpr t = ctx.mkInt(node+"_s_t");
//
//	       BoolExpr[] a_pred= new BoolExpr[addresses.size()];
//	        for(int y=0;y<addresses.size();y++){
//	        	DatatypeExpr de = addresses.get(y);
//	        	a_pred[y] = ctx.mkOr(ctx.mkEq(nctx.pf.get("src").apply(p), de),ctx.mkEq(nctx.pf.get("dest").apply(p), de));
//	        }
//
//	        constraints.add(
//	                ctx.mkForall(new Expr[]{p, n, t},
//	                  ctx.mkImplies((BoolExpr)nctx.recv.apply(n, node.getZ3Node(), p, t),
//	                            ctx.mkOr(a_pred)),1,null,null,null,null));
//	        constraints.add(
//	                ctx.mkForall(new Expr[]{p, n, t},
//	                  ctx.mkImplies((BoolExpr)nctx.send.apply(node.getZ3Node(), n, p, t),
//	                            ctx.mkOr(a_pred)),1,null,null,null,null));
//	    }


	   /**
	    * Set isolation constraints on a node.
	    * Doesn't need to be set but useful when interfering policies are in play.
	    * @param node
	    * @param adjacencies
	    *
	    */
	   public void SetIsolationConstraint ( NetworkObject node,  ArrayList<NetworkObject> adjacencies){

		   	Expr n_0 = ctx.mkConst(node+"_isolation_n_0", nctx.node);
	        Expr p_0 = ctx.mkConst(node+"_isolation_p_0", nctx.packet);
	        IntExpr t_0 = ctx.mkInt(node+"_isolation_t_0");

	        BoolExpr[] adj = new BoolExpr[adjacencies.size()];
	        for(int y=0;y<adjacencies.size();y++){
	        	NetworkObject no = adjacencies.get(y);
	        	adj[y] =  ctx.mkEq(n_0,no.getZ3Node());
	        }
	        BoolExpr clause = ctx.mkOr(adj);

	        constraints.add(ctx.mkForall(new Expr[]{n_0, p_0, t_0},
	            ctx.mkImplies((BoolExpr)nctx.send.apply(node.getZ3Node(), n_0, p_0, t_0),
	                                    clause),1,null,null,null,null));
	        constraints.add(ctx.mkForall(new Expr[]{n_0, p_0, t_0},
	            ctx.mkImplies((BoolExpr)nctx.recv.apply(n_0, node.getZ3Node(), p_0, t_0),
	                                    clause),1,null,null,null,null));
	       }

	  /**
	   * Return all currently attached endhosts
	   * @return NetworkObject
	   */
	   public List<String> EndHosts(){
		   List<String> att_nos = new ArrayList<String>();
		   for(NetworkObject el :elements){
			   if(el.isEndHost){
				   System.out.println("el: "+el);
			   		att_nos.add(el.getZ3Node().toString());
		   		}
		   	}
	        return att_nos;
	   }
}