/*
 * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */

package org.opendaylight.controller.forwardingrulesmanager;

import java.io.Serializable;
import java.util.Date;

import org.opendaylight.controller.sal.core.ContainerFlow;
import org.opendaylight.controller.sal.core.Node;
import org.opendaylight.controller.sal.flowprogrammer.Flow;
import org.opendaylight.controller.sal.match.Match;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Represents a flow applications request Forwarding Rules Manager to install on
 * a network node. A FlowEntry is constituted of a flow (match + actions), the
 * target network node, and the flow name. It also includes a group name. For
 * instance the flows constituting a policy all share the same group name.
 */
public class FlowEntry implements Cloneable, Serializable {
    protected static final Logger logger = LoggerFactory.getLogger(FlowEntry.class);
    private static final long serialVersionUID = 1L;
    private static final Logger log = LoggerFactory.getLogger(FlowEntry.class);
    private String groupName; // group name
    private String flowName; // flow name (may be null)
    private Node node; // network node where to install the flow
    private Flow flow; // match + action

    public FlowEntry(String groupName, String flowName, Flow flow, Node node) {
        this.groupName = groupName;
        this.flow = flow;
        this.node = node;
        this.flowName = (flowName != null) ? flowName : constructFlowName();
    }

    public String getGroupName() {
        return groupName;
    }

    public void setGroupName(String name) {
        this.groupName = name;
    }

    /**
     * Return the actual Flow contained in this entry
     *
     * @return the flow
     */
    public Flow getFlow() {
        return flow;
    }

    public Node getNode() {
        return node;
    }

    public void setNode(Node n) {
        this.node = n;
    }

    public String getFlowName() {
        return flowName;
    }

    public void setFlowName(String n) {
        this.flowName = n;
    }

    @Override
    public FlowEntry clone() {
        FlowEntry cloned = null;
        try {
            cloned = (FlowEntry) super.clone();
            cloned.flow = this.flow.clone();
        } catch (CloneNotSupportedException e) {
            log.warn("exception in clone", e);
        }
        return cloned;
    }

    /*
     * Only accounts fields which uniquely identify a flow for collision
     * purposes: node, match and priority
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((node == null) ? 0 : node.hashCode());
        result = prime * result + ((flow == null) ? 0 : (int) flow.getPriority());
        result = prime * result + ((flow == null || flow.getMatch() == null) ? 0 : flow.getMatch().hashCode());

        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        FlowEntry other = (FlowEntry) obj;

        if (node == null) {
            if (other.node != null) {
                return false;
            }
        } else if (!node.equals(other.node)) {
            return false;
        }

        if (flow == null) {
            return (other.flow == null) ? true : false;
        } else if (other.flow == null) {
            return false;
        }
        if (flow.getPriority() != other.flow.getPriority()) {
            return false;
        }
        if (flow.getMatch() == null) {
            if (other.flow.getMatch() != null) {
                return false;
            }
        } else if (!flow.getMatch().equals(other.flow.getMatch())) {
            return false;
        }

        return true;
    }

    @Override
    public String toString() {
        return "FlowEntry[flowName = " + flowName + ", groupName = " + groupName + ", node = " + node + ", flow = "
                + flow + "]";
    }

    private String constructFlowName() {
        return this.groupName + "_" + new Date().toString();
    }

    public boolean equalsByNodeAndName(Node node, String flowName) {
        return this.node.equals(node) && this.flowName.equals(flowName);
    }

    /**
     * Merges the current Flow with the passed Container Flow
     *
     * Note: Container Flow merging is not an injective function. Be m1 and m2
     * two different matches, and be f() the flow merge function, such that y1 =
     * f(m1) and y2 = f(m2) are the two merged matches, we may have: y1 = y2
     *
     *
     * @param containerFlow
     * @return this merged FlowEntry
     */
    public FlowEntry mergeWith(ContainerFlow containerFlow) {
        Match myMatch = flow.getMatch();

        Match filter = containerFlow.getMatch();

        // Merge
        Match merge = myMatch.mergeWithFilter(filter);

        // Replace this Flow's match with merged version
        flow.setMatch(merge);

        return this;
    }

    /**
     * Returns whether this entry is the result of an internal generated static
     * flow
     *
     * @return true if internal generated static flow, false otherwise
     */
    public boolean isInternal() {
        return flowName.startsWith(FlowConfig.INTERNALSTATICFLOWBEGIN)
                && flowName.endsWith(FlowConfig.INTERNALSTATICFLOWEND);
    }
}