/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation 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.eclipse.dltk.core;

import org.eclipse.dltk.annotations.Nullable;

/**
 * Common protocol for Script elements that support source code assist and code
 * resolve.
 * <p>
 * This interface is not intended to be implemented by clients.
 * </p>
 */
public interface ICodeAssist {

	/**
	 * Performs code completion at the given offset position in this compilation
	 * unit, reporting results to the given completion requestor. The
	 * <code>offset</code> is the 0-based index of the character, after which
	 * code assist is desired. An <code>offset</code> of -1 indicates to code
	 * assist at the beginning of this compilation unit.
	 * <p>
	 * 
	 * @param offset
	 *            the given offset position
	 * @param requestor
	 *            the given completion requestor
	 * @exception ModelException
	 *                if code assist could not be performed. Reasons include:
	 *                <ul>
	 *                <li>This Script element does not exist
	 *                (ELEMENT_DOES_NOT_EXIST)</li> <li> The position specified
	 *                is < -1 or is greater than this compilation unit's source
	 *                length (INDEX_OUT_OF_BOUNDS)
	 *                </ul>
	 * 
	 * @exception IllegalArgumentException
	 *                if <code>requestor</code> is <code>null</code>
	 * @since 2.0
	 * 
	 */
	void codeComplete(int offset, CompletionRequestor requestor, long timeout)
			throws ModelException;

	/**
	 * Performs code completion at the given offset position in this compilation
	 * unit, reporting results to the given completion requestor. The
	 * <code>offset</code> is the 0-based index of the character, after which
	 * code assist is desired. An <code>offset</code> of -1 indicates to code
	 * assist at the beginning of this compilation unit.
	 * <p>
	 * 
	 * @param offset
	 *            the given offset position
	 * @param requestor
	 *            the given completion requestor
	 * @exception ModelException
	 *                if code assist could not be performed. Reasons include:
	 *                <ul>
	 *                <li>This Script element does not exist
	 *                (ELEMENT_DOES_NOT_EXIST)</li> <li> The position specified
	 *                is < -1 or is greater than this compilation unit's source
	 *                length (INDEX_OUT_OF_BOUNDS)
	 *                </ul>
	 * 
	 * @exception IllegalArgumentException
	 *                if <code>requestor</code> is <code>null</code>
	 */
	void codeComplete(int offset, CompletionRequestor requestor)
			throws ModelException;

	/**
	 * Performs code completion at the given offset position in this compilation
	 * unit, reporting results to the given completion requestor. The
	 * <code>offset</code> is the 0-based index of the character, after which
	 * code assist is desired. An <code>offset</code> of -1 indicates to code
	 * assist at the beginning of this compilation unit. It considers types in
	 * the working copies with the given owner first. In other words, the
	 * owner's working copies will take precedence over their original
	 * compilation units in the workspace.
	 * <p>
	 * Note that if a working copy is empty, it will be as if the original
	 * compilation unit had been deleted.
	 * </p>
	 * 
	 * @param offset
	 *            the given offset position
	 * @param requestor
	 *            the given completion requestor
	 * @param owner
	 *            the owner of working copies that take precedence over their
	 *            original compilation units
	 * @exception ModelException
	 *                if code assist could not be performed. Reasons include:
	 *                <ul>
	 *                <li>This model element does not exist
	 *                (ELEMENT_DOES_NOT_EXIST)</li>
	 *                <li>The position specified is < -1 or is greater than this
	 *                compilation unit's source length (INDEX_OUT_OF_BOUNDS)
	 *                </ul>
	 * 
	 * @exception IllegalArgumentException
	 *                if <code>requestor</code> is <code>null</code>
	 * @since 2.0
	 * 
	 */
	void codeComplete(int offset, CompletionRequestor requestor,
			WorkingCopyOwner owner, long timeout) throws ModelException;

	/**
	 * @deprecated
	 */
	@Deprecated
	void codeComplete(int offset, CompletionRequestor requestor,
			WorkingCopyOwner owner) throws ModelException;

	/**
	 * Returns the model elements corresponding to the given selected text in
	 * this compilation unit. The <code>offset</code> is the 0-based index of
	 * the first selected character. The <code>length</code> is the number of
	 * selected characters.
	 * <p>
	 * Note that if the <code>length</code> is 0 and the <code>offset</code> is
	 * inside an identifier or the index just after an identifier then this
	 * identifier is considered as the selection.
	 * </p>
	 * 
	 * @param offset
	 *            the given offset position
	 * @param length
	 *            the number of selected characters
	 * @return the model elements corresponding to the given selected text, not
	 *         <code>null</code>
	 * 
	 * @exception ModelException
	 *                if code resolve could not be performed. Reasons include:
	 *                <ul>
	 *                <li>This model element does not exist
	 *                (ELEMENT_DOES_NOT_EXIST)</li>
	 *                <li>The range specified is not within this element's
	 *                source range (INDEX_OUT_OF_BOUNDS)
	 *                </ul>
	 * 
	 */
	IModelElement[] codeSelect(int offset, int length) throws ModelException;

	/**
	 * Returns the model elements corresponding to the given selected text in
	 * this compilation unit. The <code>offset</code> is the 0-based index of
	 * the first selected character. The <code>length</code> is the number of
	 * selected characters. It considers types in the working copies with the
	 * given owner first. In other words, the owner's working copies will take
	 * precedence over their original compilation units in the workspace.
	 * <p>
	 * Note that if the <code>length</code> is 0 and the <code>offset</code> is
	 * inside an identifier or the index just after an identifier then this
	 * identifier is considered as the selection.
	 * </p>
	 * <p>
	 * Note that if a working copy is empty, it will be as if the original
	 * compilation unit had been deleted.
	 * </p>
	 * 
	 * @param offset
	 *            the given offset position
	 * @param length
	 *            the number of selected characters
	 * @param owner
	 *            the owner of working copies that take precedence over their
	 *            original compilation units
	 * @return the model elements corresponding to the given selected text, not
	 *         <code>null</code>
	 * 
	 * @exception ModelException
	 *                if code resolve could not be performed. Reasons include:
	 *                <ul>
	 *                <li>This model element does not exist
	 *                (ELEMENT_DOES_NOT_EXIST)</li>
	 *                <li>The range specified is not within this element's
	 *                source range (INDEX_OUT_OF_BOUNDS)
	 *                </ul>
	 * 
	 */
	IModelElement[] codeSelect(int offset, int length, WorkingCopyOwner owner)
			throws ModelException;

	/**
	 * Returns the elements corresponding to the given selected text in this
	 * compilation unit.
	 * 
	 * @return the elements corresponding to the given selected text, or
	 *         <code>null</code> if nothing found
	 * @since 5.0
	 */
	@Nullable
	ICodeSelection codeSelectAll(int offset, int length) throws ModelException;

	/**
	 * Returns the elements corresponding to the given selected text in this
	 * compilation unit.
	 * 
	 * @return the elements corresponding to the given selected text, or
	 *         <code>null</code> if nothing found
	 * @since 5.0
	 */
	@Nullable
	ICodeSelection codeSelectAll(int offset, int length, WorkingCopyOwner owner)
			throws ModelException;

}