/**

 * @author Alan Krempler

 * Created on Sep 19, 2003

 */

package isac.interfaces;

import java.rmi.Remote;

import java.rmi.RemoteException;

import isac.util.formulae.*;

import isac.util.tactics.*;

/**

 * Interface to be used to communicate in the direction towards the Math Engine.

 * 

 * @author Alan Krempler WN040924 rename to ICalcTree ?

 */

public interface IToCalc extends Remote {

    /** remove the CalcTree in the math-engine

     */

    public boolean destruct() throws RemoteException;

    /**

     * Get a new iterator referencing the root element of the calculation tree.

     * <p>

     * The functionality for navigating the calculation is implemented in the

     * CalcIterator object.

     * 

     * @return new instance of CalcIterator

     */

    public ICalcIterator iterator() throws RemoteException;

    /**

     * Register a new listener who wants to be notified of changes in the data.

     * The listener has to implement the IToUser interface.

     * 

     * @param listener

     *            New listener to be registered.

     * @return false on success, true otherwise.

     */

    public boolean addDataChangeListener(IToUser listener)

            throws RemoteException;

    /**

     * @return an iterator referencing the current "hot spot" in the

     *         calculation, i.e. the active formula.

     */

    public ICalcIterator getActiveFormula() throws RemoteException;

    /**

     * Makes the passed formula the active formula, i.e. the formula the next

     * tactic is applied to.

     * 

     * @param newActiveFormula

     *            Iterator referencing the new desired position

     */

    public void moveActiveFormula(ICalcIterator newActiveFormula)

            throws RemoteException;

    /**

     * Set the Descriptions for all ModelItems given by the problem which is

     * specified in the CalcHead held in the MathEngine (this may still be

     * hidden from the front-end).

     * 

     * in contrary to isac.interfaces.IToCalc#setNextTactic this method has a

     * returnvalue from the calculation.

     * 

     * @return CalcHead with Descriptions (e.g. equality, solveFor)

     * @exception RemoteException

     */

    public CalcHead modelProblem() throws RemoteException;

    /**

     * Add _ONE_ item to the Model or to the Specification, as long as the

     * CalcHead is not complete.

     * 

     * in contrary to the methods for the solve-phase this method returns a

     * value from the calculation.

     * 

     * @return CalcHead with one item added; if the CalcHead was complete, the

     *         CalcHead remains unchanged

     * @exception RemoteException

     */

    public CalcHead nextSpecify() throws RemoteException;

    /**

     * Check a given CalcHead. The result is the same CalcHead with status flags

     * for each item

     * 

     * in contrary to the methods for the solve-phase this method returns a

     * value from the calculation.

     * 

     * @see CalcHead for possible status flags

     * @param calc_head

     *            CalcHead to be checked

     * @return new CalcHead with a status for each item

     */

    public CalcHead checkCalcHead(CalcHead calc_head) throws RemoteException;

    /**

     * Complete the Model of a CalcHead: Tell the Kernel to fill out all the

     * missing fields in the Model; this may not succeed if the (manual) input

     * is too messed up (in this case first a resetCalcHead must be done).

     * 

     * in contrary to the methods for the solve-phase this method returns a

     * value from the calculation.

     * 

     * @return the CalcHead with the completed Model

     */

    public CalcHead completeModel() throws RemoteException;

    /**

     * Transfer the Theory selected in the TheoryBrowser to the SML-kernel. This

     * method is used for transferring the Theory to the Worksheet (i.e. the

     * CalcHead with the Theory inserted and checked has to be fetched from the

     * SML-kernel by the front-end)

     * 

     * in contrary to the methods for the solve-phase this method returns a

     * value from the calculation.

     * 

     * @param thy_id

     *            the identifier of the theory

     * @return CalcHead with the Theory inserted; the new Theory may cause parse

     *         errors (because parts of a formula are unknown in this Theory)

     *         displayed in the Model (or in the guard)

     * @exception RemoteException

     */

    public CalcHead setTheory(String thy_id) throws RemoteException;

    /**

     * Transfer the Problem selected in the ProblemBrowser to the SML-kernel.

     * This method is used for transferring the Problem to the Worksheet (i.e.

     * the CalcHead with the Problem inserted and checked has to be fetched from

     * the SML-kernel by the front-end)

     * 

     * in contrary to the methods for the solve-phase this method returns a

     * value from the calculation.

     * 

     * @return CalcHead with the Problem inserted; the new Problem may cause

     *         error-status for some ModelItems already input (because they do

     *         not match the Problem selected)

     * @exception RemoteException

     */

    public CalcHead setProblem(ProblemID id) throws RemoteException;

    /**

     * Transfer the Method selected in the MethodBrowser to the SML-kernel. This

     * method is used for transferring the Method to the Worksheet (i.e. the

     * CalcHead with the Method inserted and checked has to be fetched from the

     * SML-kernel by the front-end)

     * 

     * in contrary to the methods for the solve-phase this method returns a

     * value from the calculation.

     * 

     * @return CalcHead with the Method inserted; the new Method may cause

     *         error-status for some ModelItems in the guard (because they do

     *         not match the Method selected)

     * @exception RemoteException

     */

    public CalcHead setMethod(MethodID id) throws RemoteException;

    /**

     * Complete a given CalcHead: Tell the Kernel to fill out all the missing

     * fields in the Model _and_ in the Specification; this may not succeed if

     * the (manual) input is too messed up (in this case first a resetCalcHead

     * must be done).

     * 

     * in contrary to the methods for the solve-phase this method returns a

     * value from the calculation.

     * 

     * @return the completed CalHead

     */

    public CalcHead completeCalcHead() throws RemoteException;

    /**

     * Reset the CalcHead to the state as it was after startCalculation. This

     * may help to escape from a CalcHead with messed input, which may not allow

     * for a successful completeCalcHead.

     * 

     * in contrary to the methods for the solve-phase this method returns a

     * value from the calculation.

     * 

     * @return an empty CalcHead

     * @exception RemoteException

     */

    public CalcHead resetCalcHead() throws RemoteException;

    /**

     * Complete a given calc_head_: Tell the Kernel to fill out a missing field

     * in the calc_head_, which is specified by an parameter

     * 

     * in contrary to the methods for the solve-phase this method returns a

     * value from the calculation.

     * 

     * @param calc_head_

     *            the calc_head_ to be completed

     * @param completeItem

     *            the item which should be added TODO: return int like

     *            replaceFormula etc. WN040916 don't confuse with

     *            autCalculate(...CompleteCalcHead) WN0504 this case is notyet

     *            designed: how indicate the field ???

     * @return the completed CalHead

     */

    public CalcHead completeCalcHead(CalcHead calcHead, int completeItem)

            throws RemoteException;

    /**

     * Tries to replaces the active formula in the calculation tree by the

     * passed formula. This could fail if no valid derivation from the preceding

     * formula to the (new) active formula can be found.

     * <p>

     * Parts of the calculation after the replaced formula are likely to become

     * invalid, listeners will be informed of this with the update message,

     * which contains the last unchanged formula.

     * 

     * @param newFormula

     * @return The method will return 0 on success or a nonzero value indicating

     *         the status otherwise.

     */

    public int replaceFormula(CalcFormula newFormula) throws RemoteException;

    /**

     * Tries to append the passed formula after the active formula. This could

     * fail if no valid derivation from the preceding formula to the (new)

     * active formula can be found. The method will fail as well if the active

     * formula is not the last formula in the (sub)calculation. Parts of the

     * calculation might become invalid.

     * 

     * @param newFormula

     * @return The method will return 0 on success or a nonzero value indicating

     *         the status otherwise.

     */

    public int appendFormula(CalcFormula newFormula) throws RemoteException;

    /**

     * requests the intermediate steps leading to the Formula at the Iterator

     * (i.e. these steps might be calculated by the math-engine)

     * 

     * @param Iterator

     * 

     * @return transactionID also returned in the CalcChanged

     */

    public int intermediateSteps(ICalcIterator ic) throws RemoteException;

    /**

     * Set the tactic to be used in the next step of calculation.

     * 

     * @param tactic

     *            the Tactic to be used in the the next step

     * @return The return value indicates success, failure or probable success

     *         at a later time.

     */

    public int setNextTactic(Tactic tactic) throws RemoteException;

    /**

     * Retrieve the tactic proposed by the SML-Kernel for the next step in the

     * calculation.

     * 

     * @return proposed tactic. Can be null, if the kernel does not know what to

     *         do next, or if the end of the calculation is reached

     */

    public Tactic fetchProposedTactic() throws RemoteException;

    /**

     * Fetch all tactics applicable to the current situation known to the

     * system.

     * 

     * @see #fetchApplicableTactics(int)

     */

    public static final int TACTICS_ALL = 1;

    /**

     * Fetch all tactics applicable to the current situation, but restrict the

     * result to tactics from the current theory.

     * 

     * @see #fetchApplicableTactics(int)

     */

    public static final int TACTICS_CURRENT_THEORY = 2;

    /**

     * Fetch all tactics applicable to the current situation, but restrict the

     * result to tactics from the method being applied.

     * 

     * @see #fetchApplicableTactics(int)

     */

    public static final int TACTICS_CURRENT_METHOD = 3;

    //	/**

    //	 * Get a list of tactics applicable to the active formula.

    //	 *

    //	 * @param scope

    //	 * The filter parameter selects the scope of search for

    //	 * applicable tactics.

    //	 * @return Array with applicable tactics

    //	 * @see #TACTICS_ALL

    //	 * @see #TACTICS_CURRENT_THEORY

    //	 * @see #TACTICS_CURRENT_METHOD

    //	 */

    //	public Tactic[] fetchApplicableTactics(int scope) throws RemoteException;

    /**

     * Do the number of steps requested, without any restrictions. autoCalculate

     * ... CompleteCalc Do NOT change the value of this constant, as this number

     * has a specifig meaning in other parts of the system!

     * 

     * @see #autoCalculate(int, int)

     */

    public static final int SCOPE_CALCULATION = 7;

    /**

     * Do the number of steps requested, without any restrictions. autoCalculate

     * ... CompleteModel Do NOT change the value of this constant, as this

     * number has a specifig meaning in other parts of the system!

     * 

     * @see #autoCalculate(int, int)

     */

    public static final int SCOPE_MODEL = 6;

    /**

     * Do the number of steps requested, but do not leave the current

     * subcalculation into a subproblem: CompleteToSubpbl Do NOT change the

     * value of this constant, as this number has a specifig meaning in other

     * parts of the system!

     * 

     * @see #autoCalculate(int, int)

     */

    public static final int SCOPE_SUBCALCULATION = 5;

    /**

     * Do the number of steps requested, but do not leave the current

     * subproblem: autoCalculate ... CompleteSubpbl Do NOT change the value of

     * this constant, as this number has a specifig meaning in other parts of

     * the system!

     * 

     * @see #autoCalculate(int, int)

     */

    public static final int SCOPE_SUBPROBLEM = 4;

    /**

     * Calculate the next n steps starting from the active formula or until the

     * specified scope is left, whichever comes first.

     * 

     * @param scope

     *            The scope parameter can have following values:

     * @param nSteps

     *            Specifies the count of steps to be autocalculated. Passing 0

     *            for nSteps will calculate until reaching a final result.

     * @return The method returns an unique id to identify the request when

     *         notifying about updates in the tree.

     * @see #SCOPE_CALCULATION

     * @see #SCOPE_SUBCALCULATION

     * @see #SCOPE_SUBPROBLEM

     */

    /*

     * WN040624: the above design is desirable, but currently not impl. in the

     * math-engine, rather: either steps == 0, then regard SCOPE_* or steps !=

     * 0, then SCOPE_* irrelevant !

     */

    public int autoCalculate(int scope, int nSteps) throws RemoteException;

}