/* File: MessageInterpreter.java
 * Contains: The interpreter for significant messages
 * Author: Jeff Dalton <J.Dalton@ed.ac.uk>
 * Created: June 2000
 * Updated: Wed May 30 18:27:33 2001 by Jeff Dalton
 * Copyright: (c) 2000, 2001, AIAI, University of Edinburgh
 */

package ix.ileed;

import java.util.*;

import ix.util.*;
import ix.util.lisp.*;

/**
 * Interprets messages sent during the operation of the CoAX process.
 */

public class MessageInterpreter {

    public WatcherListener listener;

    protected Date creationDate = new Date();

    protected Hashtable statusTable = new Hashtable();

    /**
     * Create a MessageInterpreter connected to a WatcherListener.
     */
    public MessageInterpreter(WatcherListener listener) {
	this.listener = listener;
    }

    /**
     * Change the WatcherListener that the interpreter tells of status changes.
     */
    public void setListener(WatcherListener listener) {
	this.listener = listener;
    }

    public synchronized void reset() {
	statusTable.clear();
    }

    /**
     * Determines what, if anything, a message means in terms understood
     * by a WatcherListener (typically a process model / stepper), by
     * calling the appropriate WatcherListener method(s).
     */
    public synchronized void interpret(String message) {
	Debug.noteln("Interpreting", message);
	Vector cases = (Vector)interpretations.get(message);
	if (cases == null) {
	    Debug.warn("Cannot understand message " + message);
	}
	else for (Enumeration e = cases.elements(); e.hasMoreElements(); ) {
	    handleMessageCase(message, (Case)e.nextElement());
	}
    }

    // /\/: Some of the status changes in the interpretations table are
    // redundant, but rather than work out which they are, we filter them
    // out as we go.  We have to do something to avoid sending them to
    // the WatcherListener, because we don't want to make it look like
    // something happened twice when it happened only once.

    protected void handleMessageCase(String message, Case c) {

	// Here's where we finally send something to the process model.

	Debug.noteln("Case", c);

	if (statusTable.get(c.action) == c.status) {
	    Debug.noteln("Redundant change", c);
	    return;
	}

	if (c.status == K_COMPLETE) {
	    listener.finishAction(c.action);
	}
	else if (c.status == K_EXECUTING) {
	    listener.startAction(c.action);
	}
	else {
	    Debug.warn("Unknown status " + c.status);
	    return;
	}

	statusTable.put(c.action, c.status);

    }


    /*
     * Interpretation table
     */

    // /\/: Some of the status changes in the interpretations table are
    // redundant.  See handleMessageCase() above.

    // The MultiHashtable maps a message string to a Vector
    // of Case objects.

    public MultiHashtable interpretations = new MultiHashtable();

    public static final Symbol
        K_COMPLETE  = Symbol.intern(":complete"),
	K_EXECUTING = Symbol.intern(":executing");

    static class Case {
	String action;
	Symbol status;

	Case(String action, Symbol status) {
	    this.action = action;
	    this.status = status;
	}

	public String toString() {
	    return "Case[" + action + ", " + status + "]";
	}

    }

    public void addCase(String message, String action, Symbol status) {
	interpretations.put(message, new Case(action, status));
    }

    {
	addCase("S1M1a",
		"transmit mission to JFACC [message S1M1a]",
		K_COMPLETE);
	addCase("S1M1a",
		"confirm receipt of S1M1a [message S1M1b]",
		K_EXECUTING);

	addCase("S1M1b",
		"transmit mission to JFACC [message S1M1a]",
		K_COMPLETE);
	addCase("S1M1b",
		"confirm receipt of S1M1a [message S1M1b]",
		K_COMPLETE);

	addCase("S1M2a",
		"transmit JTFC's mission directive to JFACC [message S1M2a]",
		K_COMPLETE);
	addCase("S1M2a",
		"confirm receipt of S1M2a [message S1M2b]",
		K_EXECUTING);

	addCase("S1M2b",
		"transmit JTFC's mission directive to JFACC [message S1M2a]",
		K_COMPLETE);
	addCase("S1M2b",
		"confirm receipt of S1M2a [message S1M2b]",
		K_COMPLETE);

	addCase("S1M3a",
		"transmit JTFC's intent to JFACC [message S1M3a]", // ?
		K_COMPLETE);
	addCase("S1M3a",
		"confirm receipt of S1M3a [message S1M3b]",
		K_EXECUTING);

	addCase("S1M3b",
		"transmit JTFC's intent to JFACC [message S1M3a]", // ?
		K_COMPLETE);
	addCase("S1M3b",
		"confirm receipt of S1M3a [message S1M3b]",
		K_COMPLETE);

	addCase("I1a",
		"request intelligence report [message I1a]",
		K_COMPLETE);
	addCase("I1a",
		"wait for rfi",
		K_EXECUTING);

	addCase("I1b",
		"request intelligence report [message I1a]",
		K_COMPLETE);
	addCase("I1b",
		"provide intelligence [message I1b]",
		K_COMPLETE);

	addCase("S1M4a",
		"request JFACC draft estimate [message S1M4a]",	// ?
		K_COMPLETE);
	addCase("S1M4a",
		"provide JFACC draft estimate [message S1M4b]", // ?
		K_EXECUTING);

	addCase("S1M4b",
		"request JFACC draft estimate [message S1M4a]",	// ?
		K_COMPLETE);
	addCase("S1M4b",
		"provide JFACC draft estimate [message S1M4b]", // ?
		K_COMPLETE);

	addCase("S2M1a",
	    "request information on availability of assets [message S2M1a]",
	    K_COMPLETE);
	addCase("S2M1a",
	    "provide information on availability of assets [message S2M1b]",
	    K_EXECUTING);

	addCase("S2M1b",
	    "request information on availability of assets [message S2M1a]",
	    K_COMPLETE);
	addCase("S2M1b",
	    "provide information on availability of assets [message S2M1b]",
	    K_COMPLETE);

	addCase("S2M2a",
		"request for apportionment recommendation [message S2M2a]",
		K_COMPLETE);
	addCase("S2M2a",
		"provide apportionment recommendation [message S2M2b]",
		K_EXECUTING);

	addCase("S2M2b",
		"request for apportionment recommendation [message S2M2a]",
		K_COMPLETE);
	addCase("S2M2b",
		"provide apportionment recommendation [message S2M2b]",
		K_COMPLETE);


    }

}