/*******************************************************************************
 * Copyright (c) 2004, 2006 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
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/

module org.eclipse.jface.bindings.keys.KeyStroke;

import org.eclipse.jface.bindings.keys.IKeyLookup;
import org.eclipse.jface.bindings.keys.KeyLookupFactory;

import org.eclipse.jface.bindings.Trigger;
import org.eclipse.jface.bindings.keys.formatting.KeyFormatterFactory;
import org.eclipse.jface.util.Util;

import java.lang.all;
import java.util.Set;
import java.text.ParseException;
static import tango.text.Util;
/**
 * <p>
 * A <code>KeyStroke</code> is defined as an optional set of modifier keys
 * followed optionally by a natural key. A <code>KeyStroke</code> is said to
 * be complete if it contains a natural key. A natural key is any Unicode
 * character (e.g., "backspace", etc.), any character belonging to a natural
 * language (e.g., "A", "1", "[", etc.), or any special control character
 * specific to computers (e.g., "F10", "PageUp", etc.).
 * </p>
 * <p>
 * All <code>KeyStroke</code> objects have a formal string representation
 * available via the <code>toString()</code> method. There are a number of
 * methods to get instances of <code>KeyStroke</code> objects, including one
 * which can parse this formal string representation.
 * </p>
 * <p>
 * All <code>KeyStroke</code> objects, via the <code>format()</code> method,
 * provide a version of their formal string representation translated by
 * platform and locale, suitable for display to a user.
 * </p>
 * <p>
 * <code>KeyStroke</code> objects are immutable. Clients are not permitted to
 * extend this class.
 * </p>
 *
 * @since 3.1
 */
public final class KeyStroke : Trigger, Comparable {

    /**
     * The delimiter between multiple keys in a single key strokes -- expressed
     * in the formal key stroke grammar. This is not to be displayed to the
     * user. It is only intended as an internal representation.
     */
    public static const String KEY_DELIMITER = "\u002B"; //$NON-NLS-1$

    /**
     * The set of delimiters for <code>Key</code> objects allowed during
     * parsing of the formal string representation.
     */
    public static const String KEY_DELIMITERS = KEY_DELIMITER;

    /**
     * The representation for no key.
     */
    public static const int NO_KEY = 0;

    /**
     * Creates an instance of <code>KeyStroke</code> given a natural key.
     *
     * @param naturalKey
     *            the natural key. The format of this integer is defined by
     *            whichever widget toolkit you are using; <code>NO_KEY</code>
     *            always means no natural key.
     * @return a key stroke. This key stroke will have no modifier keys.
     *         Guaranteed not to be <code>null</code>.
     * @see SWTKeySupport
     */
    public static final KeyStroke getInstance(int naturalKey) {
        return new KeyStroke(NO_KEY, naturalKey);
    }

    /**
     * Creates an instance of <code>KeyStroke</code> given a set of modifier keys
     * and a natural key.
     *
     * @param modifierKeys
     *            the modifier keys. The format of this integer is defined by
     *            whichever widget toolkit you are using; <code>NO_KEY</code>
     *            always means no modifier keys.
     * @param naturalKey
     *            the natural key. The format of this integer is defined by
     *            whichever widget toolkit you are using; <code>NO_KEY</code>
     *            always means no natural key.
     * @return a key stroke. Guaranteed not to be <code>null</code>.
     * @see SWTKeySupport
     */
    public static final KeyStroke getInstance(int modifierKeys,
            int naturalKey) {
        return new KeyStroke(modifierKeys, naturalKey);
    }

    /**
     * Creates an instance of <code>KeyStroke</code> by parsing a given a formal
     * string representation.
     *
     * @param string
     *            the formal string representation to parse.
     * @return a key stroke. Guaranteed not to be <code>null</code>.
     * @throws ParseException
     *             if the given formal string representation could not be parsed
     *             to a valid key stroke.
     */
    public static final KeyStroke getInstance(String string) {
        if (string is null) {
            throw new NullPointerException("Cannot parse a null string"); //$NON-NLS-1$
        }

        IKeyLookup lookup = KeyLookupFactory.getDefault();
        int modifierKeys = NO_KEY;
        int naturalKey = NO_KEY;
        int i = 0;

        auto tokens = tango.text.Util.delimit( string, KEY_DELIMITERS );
        foreach( idx, token; tokens ){

            if (i % 2 is 0) {
                if ( idx+1 < tokens.length ) {
                    token = token.toUpperCase();
                    int modifierKey = lookup.formalModifierLookup(token);
                    if (modifierKey is NO_KEY) {
                        throw new ParseException(
                                "Cannot create key stroke with duplicate or non-existent modifier key: " //$NON-NLS-1$
                                        ~ token);
                    }

                    modifierKeys |= modifierKey;

                } else if (token.length is 1) {
                    naturalKey = token.charAt(0);

                } else {
                    token = token.toUpperCase();
                    naturalKey = lookup.formalKeyLookup(token);
                }
            }

            i++;
        }

        return new KeyStroke(modifierKeys, naturalKey);
    }

    /**
     * An integer representation of the modifier keys; <code>NO_KEY</code>
     * means that there is no modifier key.
     */
    private const int modifierKeys;

    /**
     * The natural key for this key stroke. This value is <code>NO_KEY</code>
     * if the key stroke is incomplete (i.e., has no natural key).
     */
    private const int naturalKey;

    /**
     * Constructs an instance of <code>KeyStroke</code> given a set of
     * modifier keys and a natural key.
     *
     * @param modifierKeys
     *            the modifier keys. The format of this integer is defined by
     *            whichever widget toolkit you are using; <code>NO_KEY</code>
     *            always means no modifier keys.
     * @param naturalKey
     *            the natural key. The format of this integer is defined by
     *            whichever widget toolkit you are using; <code>NO_KEY</code>
     *            always means no natural key.
     * @see SWTKeySupport
     */
    private this(int modifierKeys, int naturalKey) {
        this.modifierKeys = modifierKeys;
        this.naturalKey = naturalKey;
    }

    /*
     * (non-Javadoc)
     *
     * @see java.lang.Comparable#compareTo(java.lang.Object)
     */
    public final int compareTo(Object object) {
        KeyStroke keyStroke = cast(KeyStroke) object;
        int compareTo = Util.compare(modifierKeys, keyStroke.modifierKeys);

        if (compareTo is 0) {
            compareTo = Util.compare(naturalKey, keyStroke.naturalKey);
        }

        return compareTo;
    }
    public override int opCmp( Object object ){
        return compareTo( object );
    }

    /*
     * (non-Javadoc)
     *
     * @see java.lang.Object#equals(java.lang.Object)
     */
    public final override int opEquals(Object object) {
        if (!(cast(KeyStroke)object )) {
            return false;
        }

        KeyStroke keyStroke = cast(KeyStroke) object;
        if (modifierKeys !is keyStroke.modifierKeys) {
            return false;
        }

        return (naturalKey is keyStroke.naturalKey);
    }

    /**
     * Formats this key stroke into the current default look.
     *
     * @return A string representation for this key stroke using the default
     *         look; never <code>null</code>.
     */
    public final String format() {
        return KeyFormatterFactory.getDefault().format(this);
    }

    /**
     * Returns the modifier keys for this key stroke.
     *
     * @return the bit mask of modifier keys; <code>NO_KEY</code> means that
     *         there is no modifier key.
     */
    public final int getModifierKeys() {
        return modifierKeys;
    }

    /**
     * Returns the natural key for this key stroke.
     *
     * @return The natural key for this key stroke. This value is
     *         <code>NO_KEY</code> if the key stroke is incomplete (i.e., has
     *         no natural key).
     */
    public final int getNaturalKey() {
        return naturalKey;
    }

    /*
     * (non-Javadoc)
     *
     * @see java.lang.Object#hashCode()
     */
    public final override hash_t toHash() {
        return modifierKeys << 4 + naturalKey;
    }

    /**
     * Returns whether or not this key stroke is complete. Key strokes are
     * complete iff they have a natural key which is not <code>NO_KEY</code>.
     *
     * @return <code>true</code>, iff the key stroke is complete.
     */
    public final bool isComplete() {
        return (naturalKey !is NO_KEY);
    }

    /**
     * Returns the formal string representation for this key stroke.
     *
     * @return The formal string representation for this key stroke. Guaranteed
     *         not to be <code>null</code>.
     * @see java.lang.Object#toString()
     */
    public final override String toString() {
        return KeyFormatterFactory.getFormalKeyFormatter().format(this);
    }
}