import java.util.*;
/****************************************************************
 *
 * Class: Switch
 * Author:  Robert Taracha
 * purpose:  This class models the activity of a layer 2 switch in a network
 * data members:  camTable: SwitchEntry[] - holds the camTable of switch
 *          numEntries: int - number of entries currently in camTable
 *          maxEntries: int - size of camTable
 * methods:  processFrame(Frame): boolean - uses info in Frame parameter to update camTable
 *                             based on source address, then send frame on its way based on destination
 *        find (MACAddress):int - searches for parameter in camTable - returns index in camTable or -1 if not found
 *        displayTable() - displays current elements in table
 *        addInOrder(Frame) - add Frame parameter source address to table
 */
public class Switch {
    private ArrayList<LinkedList> camTable;
    private int numEntries;
    private int maxEntries;
    LinkedList<SwitchEntry> node;

    public Switch() {
        camTable = new ArrayList<LinkedList>(100);  // default value
        numEntries = 0;
        maxEntries = 100;
        /*Initialize the switch*/
        for(int i = 0;i<maxEntries;i++){
            LinkedList<SwitchEntry> node = new LinkedList<SwitchEntry>();
            node.add(new SwitchEntry());
            camTable.add(i,node);

        }

    }

    public Switch(int maxEntries) {
        camTable = new ArrayList<LinkedList>(maxEntries);
        numEntries = 0;
        this.maxEntries = maxEntries;
        /*Initialize the switch*/
        for(int i = 0;i<maxEntries;i++){
            LinkedList<SwitchEntry> node = new LinkedList<SwitchEntry>();
            node.add(new SwitchEntry());
            camTable.add(i, node);

        }
    }

    public void processFrame(Frame inFrame) {
        // first, add source MAC to camTable (in order) if not already there
        if (find(inFrame.getSource()) == -1) {
            if (numEntries >= maxEntries) {
                System.out.println ("Error...camTable is full - cannot add " + inFrame.getSource());
            } else {
                addInOrder(inFrame);
                System.out.println ("Adding " + inFrame.getSource() + " to camTable");
            }
        }

        //process frame
        int index = find(inFrame.getDestination());
        if (index != -1){
            System.out.print ("Sending frame with data " + inFrame.getData() + " from " + inFrame.getSource() + " to " + inFrame.getDestination());
            System.out.println (" out port " + camTable.get(index).getFirst() );
        } else {
            System.out.print ("Flooding frame with data " + inFrame.getData() + " from " + inFrame.getSource() + " to " + inFrame.getDestination());
            System.out.println (" out all ports"  );

        }

    }

    // return of -1 indicates not found, otherwise returns index of where found
    // uses binary search for efficiency
    public int find (MACAddress source) {
        int low = 0;
        int high = numEntries-1;
        int found = -1;
        int mid = 0;

        if (numEntries == 0)
            return found;
        while (low <= high) {
            mid = (high+low)/2;
            if (source.isEqual (camTable.get(mid).getAddress())){
                found = mid;
                break;
            }
            else if (source.isGreaterThan(camTable.get(mid).getAddress()))
                low = mid+1;
            else high = mid-1;
        }
        return found;
    }

    public void displayTable() {
        System.out.println ("\nCam Table is : ");
        for (int i=0; i < camTable.size(); i++)
            if(camTable.get(i).get(i). != "no"){
            System.out.println ("["+i+"]"+camTable.get(i));
            }
    }

    private int hashIndex(Frame inFrame){

            int index = 0;
            String temp = inFrame.getSource().getAddress();
            for(int i = 0;i<temp.length();i++){
                index += (int)temp.charAt(i);
            }
            return index%100;

    }

    public void addInOrder(Frame inFrame) {
        int index = hashIndex(inFrame);

        camTable.set(index, new SwitchEntry(inFrame.getSource(),inFrame.getPort()));
        System.out.println("ADDED THESE VALUES -------->" + camTable.get(index) + " @ " + index);
        }
    }