package net.onrc.onos.ofcontroller.topology;

import java.util.ArrayList;
import java.util.List;
import java.util.LinkedList;
import java.util.Map;
import java.util.TreeMap;

import net.onrc.onos.graph.DBOperation;
import net.onrc.onos.graph.IDBOperation;
import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IPortObject;
import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.ISwitchObject;
import net.onrc.onos.ofcontroller.core.ISwitchStorage.SwitchState;

import org.apache.commons.lang.StringUtils;
import org.openflow.util.HexString;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.tinkerpop.blueprints.Direction;
import com.tinkerpop.blueprints.Vertex;

/**
 * A class for storing Node and Link information for fast computation
 * of shortest paths.
 */
class Node {
    /**
     * A class for storing Link information for fast computation of shortest
     * paths.
     */
    class Link {
        public Node me;                        // The node this link originates from
        public Node neighbor;                // The neighbor node on the other side
        public int myPort;                // Local port ID for the link
        public int neighborPort;        // Neighbor port ID for the link

        /**
         * Link constructor.
         *
         * @param me the node this link originates from.
         * @param the neighbor node on the other side of the link.
         * @param myPort local port ID for the link.
         * @param neighborPort neighbor port ID for the link.
         */
        public Link(Node me, Node neighbor, int myPort, int neighborPort) {
        	this.me = me;
        	this.neighbor = neighbor;
        	this.myPort = myPort;
        	this.neighborPort = neighborPort;
        }
    };

    public long nodeId;				// The node ID
    // TODO Change type of PortNumber to Short
    public TreeMap<Integer, Link> links;	// The links from this node:
						//     (src PortNumber -> Link)
    private TreeMap<Integer, Link> reverseLinksMap; // The links to this node:
						//     (dst PortNumber -> Link)
    private TreeMap<Integer, Integer> portsMap;	// The ports on this node:
						//     (PortNumber -> PortNumber)
						// TODO: In the future will be:
						//     (PortNumber -> Port)

    /**
     * Node constructor.
     *
     * @param nodeId the node ID.
     */
    public Node(long nodeId) {
	this.nodeId = nodeId;
	links = new TreeMap<Integer, Link>();
	reverseLinksMap = new TreeMap<Integer, Link>();
	portsMap = new TreeMap<Integer, Integer>();
    }

    /**
     * Get all ports.
     *
     * @return all ports.
     */
    public Map<Integer, Integer> ports() {
	return portsMap;
    }

    /**
     * Get the port for a given Port ID.
     *
     * Note: For now the port itself is just the Port ID. In the future
     * it might contain more information.
     *
     * @return the port if found, otherwise null.
     */
    public Integer getPort(int portId) {
	return portsMap.get(portId);
    }

    /**
     * Add a port for a given Port ID.
     *
     * Note: For now the port itself is just the Port ID. In the future
     * it might contain more information.
     *
     * @param portId the Port ID of the port to add.
     * @return the added Port.
     */
    Integer addPort(int portId) {
	Integer port = new Integer(portId);
	portsMap.put(portId, port);
	return port;
    }

    /**
     * Remove a port for a given Port ID.
     *
     * NOTE: The outgoing and incoming links using this port are removed as
     * well.
     */
    void removePort(int portId) {
	// Remove the outgoing link
	Link link = getLink(portId);
	if (link != null) {
	    link.neighbor.removeReverseLink(link);
	    removeLink(portId);
	}

	// Remove the incoming link
	Link reverseLink = reverseLinksMap.get(portId);
	if (reverseLink != null) {
	    // NOTE: reverseLink.myPort is the neighbor's outgoing port
	    reverseLink.me.removeLink(reverseLink.myPort);
	    removeReverseLink(reverseLink);
	}

	portsMap.remove(portId);
    }

    /**
     * Get a link on a port to a neighbor.
     *
     * @param myPortId the local port ID for the link to the neighbor.
     * @return the link if found, otherwise null.
     */
    public Link getLink(int myPortId) {
	return links.get(myPortId);
    }

    /**
     * Add a link to a neighbor.
     *
     * @param myPortId the local port ID for the link to the neighbor.
     * @param neighbor the neighbor for the link.
     * @param neighborPortId the neighbor port ID for the link.
     * @return the added Link.
     */
    public Link addLink(int myPortId, Node neighbor, int neighborPortId) {
	Link link = new Link(this, neighbor, myPortId, neighborPortId);
	links.put(myPortId, link);
	neighbor.addReverseLink(link);
	return link;
    }

    /**
     * Add a reverse link from a neighbor.
     *
     * @param link the reverse link from a neighbor to add.
     */
    private void addReverseLink(Link link) {
	// NOTE: link.neghborPort is my port
	reverseLinksMap.put(link.neighborPort, link);
    }

    /**
     * Remove a link to a neighbor.
     *
     * @param myPortId the local port ID for the link to the neighbor.
     */
    public void removeLink(int myPortId) {
	links.remove(myPortId);
    }

    /**
     * Remove a reverse link from a neighbor.
     *
     * @param link the reverse link from a neighbor to remove.
     */
    private void removeReverseLink(Link link) {
	// NOTE: link.neghborPort is my port
	reverseLinksMap.remove(link.neighborPort);
    }
};

/**
 * A class for storing topology information.
 */
public class Topology {
    private final static Logger log = LoggerFactory.getLogger(Topology.class);

    private Map<Long, Node> nodesMap;	// The dpid->Node mapping

    /**
     * Default constructor.
     */
    public Topology() {
	nodesMap = new TreeMap<Long, Node>();
    }

    /**
     * Add a topology element to the topology.
     *
     * @param topologyElement the topology element to add.
     * @return true if the topology was modified, otherwise false.
     */
    public boolean addTopologyElement(TopologyElement topologyElement) {
	boolean isModified = false;

	switch (topologyElement.getType()) {
	case ELEMENT_SWITCH: {
	    // Add the switch
	    Node node = getNode(topologyElement.getSwitch());
	    if (node == null) {
		node = addNode(topologyElement.getSwitch());
		isModified = true;
	    }
	    break;
	}
	case ELEMENT_PORT: {
	    // Add the switch
	    Node node = getNode(topologyElement.getSwitch());
	    if (node == null) {
		node = addNode(topologyElement.getSwitch());
		isModified = true;
	    }
	    // Add the port for the switch
	    Integer port = node.getPort(topologyElement.getSwitchPort());
	    if (port == null) {
		node.addPort(topologyElement.getSwitchPort());
		isModified = true;
	    }
	    break;
	}
	case ELEMENT_LINK: {
	    // Add the "from" switch
	    Node fromNode = getNode(topologyElement.getFromSwitch());
	    if (fromNode == null) {
		fromNode = addNode(topologyElement.getFromSwitch());
		isModified = true;
	    }
	    // Add the "to" switch
	    Node toNode = getNode(topologyElement.getToSwitch());
	    if (toNode == null) {
		toNode = addNode(topologyElement.getToSwitch());
		isModified = true;
	    }
	    // Add the "from" port
	    Integer fromPort = fromNode.getPort(topologyElement.getFromPort());
	    if (fromPort == null) {
		fromNode.addPort(topologyElement.getFromPort());
		isModified = true;
	    }
	    // Add the "to" port
	    Integer toPort = fromNode.getPort(topologyElement.getToPort());
	    if (toPort == null) {
		toNode.addPort(topologyElement.getToPort());
		isModified = true;
	    }
	    Node.Link link = fromNode.getLink(topologyElement.getFromPort());
	    if (link == null) {
		fromNode.addLink(topologyElement.getFromPort(),
				 toNode,
				 topologyElement.getToPort());
		isModified = true;
	    }

	    break;
	}
	case ELEMENT_UNKNOWN:
	    // TODO: Adding "assert(false);" here can be dangerous
	    break;
	}

	return isModified;
    }

    /**
     * Remove a topology element from the topology.
     *
     * @param topologyElement the topology element to remove.
     * @return true if the topology was modified, otherwise false.
     */
    public boolean removeTopologyElement(TopologyElement topologyElement) {
	boolean isModified = false;

	switch (topologyElement.getType()) {
	case ELEMENT_SWITCH: {
	    // Remove the switch
	    Node node = getNode(topologyElement.getSwitch());
	    if (node != null) {
		removeNode(node);
		isModified = true;
	    }
	    break;
	}
	case ELEMENT_PORT: {
	    // Find the switch
	    Node node = getNode(topologyElement.getSwitch());
	    if (node == null)
		break;
	    // Remove the port for the switch
	    Integer port = node.getPort(topologyElement.getSwitchPort());
	    if (port != null) {
		node.removePort(topologyElement.getSwitchPort());
		isModified = true;
	    }
	    break;
	}
	case ELEMENT_LINK: {
	    // Find the "from" switch
	    Node fromNode = getNode(topologyElement.getFromSwitch());
	    if (fromNode == null)
		break;
	    // Remove the link originating from the "from" port
	    Node.Link link = fromNode.getLink(topologyElement.getFromPort());
	    if (link != null) {
		fromNode.removeLink(topologyElement.getFromPort());
		isModified = true;
	    }
	    break;
	}
	case ELEMENT_UNKNOWN:
	    // TODO: Adding "assert(false);" here can be dangerous
	    break;
	}

	return isModified;
    }

    /**
     * Get a node for a given Node ID.
     *
     * @param nodeId the Node ID to use.
     * @return the corresponding Node if found, otherwise null.
     */
    Node getNode(long nodeId) {
	return nodesMap.get(nodeId);
    }

    /**
     * Add a node for a given Node ID.
     *
     * @param nodeId the Node ID to use.
     * @return the added Node.
     */
    Node addNode(long nodeId) {
	Node node = new Node(nodeId);
	nodesMap.put(nodeId, node);
	return node;
    }

    /**
     * Remove an existing node.
     *
     * @param node the Node to remove.
     */
    void removeNode(Node node) {
	//
	// Remove all ports one-by-one. This operation will also remove the
	// incoming links originating from the neighbors.
	//
	// NOTE: We have to extract all Port IDs in advance, otherwise we
	// cannot loop over the Ports collection and remove entries at the
	// same time.
	// TODO: If there is a large number of ports, the implementation
	// below can be sub-optimal. It should be refactored as follows:
	//   1. Modify removePort() to perform all the cleanup, except
	//     removing the Port entry from the portsMap
	//   2. Call portsMap.clear() at the end of this method
	//   3. In all other methods: if removePort() is called somewhere else,
	//      add an explicit removal of the Port entry from the portsMap.
	//
	List<Integer> allPortIdKeys = new LinkedList<Integer>();
	allPortIdKeys.addAll(node.ports().keySet());
	for (Integer portId : allPortIdKeys)
	    node.removePort(portId);

	nodesMap.remove(node.nodeId);
    }

    /**
     * Read topology state from the database.
     *
     * @param dbHandler the Graph Database handler to use.
     */
    public void readFromDatabase(DBOperation dbHandler) {
		//
		// Fetch the relevant info from the Switch and Port vertices
		// from the Titan Graph.
		//
    	nodesMap.clear();

        // Load all switches into Map
        Iterable<ISwitchObject> switches = dbHandler.getAllSwitches();
        for (ISwitchObject switchObj : switches) {
        	// Ignore inactive ports
            if (!switchObj.getState().equals(SwitchState.ACTIVE.toString())) {
            	continue;
            }
            Vertex nodeVertex = switchObj.asVertex();
            //
            // The Switch info
            //
            String nodeDpid = nodeVertex.getProperty("dpid").toString();
            long nodeId = HexString.toLong(nodeDpid);
            addNode(nodeId);
        }

        //
        // Get All Ports
        //
        Iterable<IPortObject> ports = dbHandler.getAllPorts(); //TODO: Add to DB operations
        for (IPortObject myPortObj : ports) {
            Vertex myPortVertex = myPortObj.asVertex();

            // Ignore inactive ports
            if (! myPortVertex.getProperty("state").toString().equals("ACTIVE")) {
            	continue;
            }

            short myPort = 0;
            String idStr = myPortObj.getPortId();
            String[] splitter = idStr.split(IDBOperation.PORT_ID_DELIM);
            if (splitter.length != 2) {
            	log.error("Invalid port_id : {}", idStr);
            	continue;
            }
            String myDpid = splitter[0];
            myPort = Short.parseShort(splitter[1]);
            long myId = HexString.toLong(myDpid);
            Node me = nodesMap.get(myId);

            if (me == null) {
                // cannot proceed ports and switches are out of sync
                //TODO: Restart the whole read
                continue;
            }

            if (me.getPort(myPort) == null) {
            	me.addPort(myPort);
            } else if (me.getLink(myPort) != null) {
                // Link already added..probably by neighbor
                continue;
            }

            //
            // The neighbor Port info
            //
            for (Vertex neighborPortVertex : myPortVertex.getVertices(Direction.OUT, "link")) {
//            	log.debug("state : {}", neighborPortVertex.getProperty("state"));
//            	log.debug("port id : {}", neighborPortVertex.getProperty("port_id"));
                // Ignore inactive ports
                if (! neighborPortVertex.getProperty("state").toString().equals("ACTIVE")) {
                	continue;
                }
                int neighborPort = 0;
                idStr = neighborPortVertex.getProperty("port_id").toString();
                splitter = idStr.split(IDBOperation.PORT_ID_DELIM);
                if (splitter.length != 2) {
                	log.error("Invalid port_id : {}", idStr);
                	continue;
                }
                String neighborDpid = splitter[0];
                neighborPort = Short.parseShort(splitter[1]);
                long neighborId = HexString.toLong(neighborDpid);
                Node neighbor = nodesMap.get(neighborId);
//                log.debug("dpid {},{}  port {}", neighborDpid, neighborId, neighborPort);
                if (neighbor == null) {
                	continue;
                }
                me.addLink(myPort, neighbor, neighborPort);
            }
        }
        dbHandler.commit();
    }


    // Only for debug use
    List<Long> logGetSw = new ArrayList<Long>(100);
    List<Long> logGetPt = new ArrayList<Long>(100);
    List<Long> logAddSw = new ArrayList<Long>(100);
    List<Long> logAddPt = new ArrayList<Long>(100);
    List<Long> logAddLk = new ArrayList<Long>(100);
    List<Long> logCommit = new ArrayList<Long>(100);
    List<Integer> logGetVertices = new ArrayList<Integer>(100);
    List<Integer> logGetProperty = new ArrayList<Integer>(100);
       public void readFromDatabaseBreakdown(DBOperation dbHandler) {
    	int getVerticesCount = 0;
    	int getPropertyCount = 0;
    	int getVCount_sw = 0;
    	int getVCount_pt = 0;
    	int getVCount_lk = 0;
    	int getPCount_sw = 0;
    	int getPCount_pt = 0;
    	int getPCount_lk = 0;

		//
		// Fetch the relevant info from the Switch and Port vertices
		// from the Titan Graph.
		//

    	nodesMap.clear();
    	long t1 = System.nanoTime();

        // Load all switches into Map
        Iterable<ISwitchObject> switches = dbHandler.getAllSwitches();

        long t2 = System.nanoTime();

        long t_addSw = 0;
        for (ISwitchObject switchObj : switches) {
            long t3 = System.nanoTime();
            long t4;

        	// Ignore inactive ports
            ++getPropertyCount;
            ++getPCount_sw;
            if (!switchObj.getState().equals(SwitchState.ACTIVE.toString())) {
                t4 = System.nanoTime();
                t_addSw += t4 - t3;
            	continue;
            }
            Vertex nodeVertex = switchObj.asVertex();
            //
            // The Switch info
            //
            ++getPropertyCount;
            ++getPCount_sw;
            String nodeDpid = nodeVertex.getProperty("dpid").toString();
            long nodeId = HexString.toLong(nodeDpid);
            addNode(nodeId);
            t4 = System.nanoTime();
            t_addSw += t4 - t3;
        }

        long t5 = System.nanoTime();
        //
        // Get All Ports
        //
        Iterable<IPortObject> ports = dbHandler.getAllPorts(); //TODO: Add to DB operations

        long t6 = System.nanoTime();
        long t_addPort = 0;
        long t_addLink = 0;

        for (IPortObject myPortObj : ports) {
            long t7 = System.nanoTime();
            long t8;
            Vertex myPortVertex = myPortObj.asVertex();

            // Ignore inactive ports
            ++getPropertyCount;
            ++getPCount_pt;
            if (! myPortVertex.getProperty("state").toString().equals("ACTIVE")) {
                t8 = System.nanoTime();
                t_addPort += t8 - t7;
            	continue;
            }

            short myPort = 0;
            ++getPropertyCount;
            ++getPCount_pt;
            String idStr = myPortObj.getPortId();
            String[] splitter = idStr.split(IDBOperation.PORT_ID_DELIM);
            if (splitter.length != 2) {
            	log.error("Invalid port_id : {}", idStr);
                t8 = System.nanoTime();
                t_addPort += t8 - t7;
            	continue;
            }
            String myDpid = splitter[0];
            myPort = Short.parseShort(splitter[1]);
            long myId = HexString.toLong(myDpid);
            Node me = nodesMap.get(myId);

            if (me == null) {
                // cannot proceed ports and switches are out of sync
                //TODO: Restart the whole read
                t8 = System.nanoTime();
                t_addPort += t8 - t7;
                continue;
            }

            if (me.getPort(myPort) == null) {
            	me.addPort(myPort);
            } else if (me.getLink(myPort) != null) {
                // Link already added..probably by neighbor
                t8 = System.nanoTime();
                t_addPort += t8 - t7;
                continue;
            }
            t8 = System.nanoTime();
            t_addPort += t8 - t7;

            //
            // The neighbor Port info
            //
            ++getVerticesCount;
            ++getVCount_pt;
            for (Vertex neighborPortVertex : myPortVertex.getVertices(Direction.OUT, "link")) {
//            	log.debug("state : {}", neighborPortVertex.getProperty("state"));
//            	log.debug("port id : {}", neighborPortVertex.getProperty("port_id"));

                long t9 = System.nanoTime();
                long t10;

                // Ignore inactive ports
                ++getPropertyCount;
                ++getPCount_lk;
                if (! neighborPortVertex.getProperty("state").toString().equals("ACTIVE")) {
                    t10 = System.nanoTime();
                    t_addLink += t10 - t9;
                	continue;
                }
                int neighborPort = 0;
                ++getPropertyCount;
                ++getPCount_lk;
                idStr = neighborPortVertex.getProperty("port_id").toString();
                splitter = idStr.split(IDBOperation.PORT_ID_DELIM);
                if (splitter.length != 2) {
                	log.error("Invalid port_id : {}", idStr);
                    t10 = System.nanoTime();
                    t_addLink += t10 - t9;
                	continue;
                }
                String neighborDpid = splitter[0];
                neighborPort = Short.parseShort(splitter[1]);
                long neighborId = HexString.toLong(neighborDpid);
                Node neighbor = nodesMap.get(neighborId);
//                log.debug("dpid {},{}  port {}", neighborDpid, neighborId, neighborPort);
                if (neighbor == null) {
                    t10 = System.nanoTime();
                    t_addLink += t10 - t9;
                	continue;
                }
                me.addLink(myPort, neighbor, neighborPort);

                t10 = System.nanoTime();
                t_addLink += t10 - t9;
            }
        }
        long t11 = System.nanoTime();
        dbHandler.commit();
        long t12 = System.nanoTime();

        logGetSw.add((t2-t1)/1000);
        logGetPt.add((t6-t5)/1000);
        logAddSw.add(t_addSw/1000);
        logAddPt.add(t_addPort/1000);
        logAddLk.add(t_addLink/1000);
        logCommit.add((t12-t11)/1000);
        logGetVertices.add(getVerticesCount);
        logGetProperty.add(getPropertyCount);
        log.debug("getVertices[N({}),P({}),L({})] getProperty[N({}),P({}),L({})]",
        		new Object[]{getVCount_sw,getVCount_pt,getVCount_lk,
        		getPCount_sw,getPCount_pt,getPCount_lk});
    }

    public void printMeasuredLog() {
    	log.debug("getsw: {}", StringUtils.join(logGetSw, ","));
    	log.debug("getpt: {}", StringUtils.join(logGetPt, ","));
    	log.debug("addsw: {}", StringUtils.join(logAddSw, ","));
    	log.debug("addpt: {}", StringUtils.join(logAddPt, ","));
    	log.debug("addlk: {}", StringUtils.join(logAddLk, ","));
    	log.debug("commit: {}", StringUtils.join(logCommit, ","));
    	log.debug("getvertices: {}", StringUtils.join(logGetVertices, ","));
    	log.debug("getproperty: {}", StringUtils.join(logGetProperty, ","));
    }

    // Only for debug use
    @Override
    public String toString() {
    	long numNodes = nodesMap.size();
    	long numLinks = 0;
    	for (Map.Entry<Long, Node> entry : nodesMap.entrySet()) {
    		Node n = entry.getValue();
    		for (Map.Entry<Integer, Node.Link> linkEntry : n.links.entrySet()) {
    			if (n.nodeId > linkEntry.getValue().neighbor.nodeId) {
    				++numLinks;
    			}
    		}
    	}
    	return "Topology has " + numNodes + " Nodes and " + numLinks + " Links.";
    }
}