/*******************************************************************************
 * 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 dwtx.jface.resource.FontDescriptor;

import dwtx.jface.resource.DeviceResourceDescriptor;
import dwtx.jface.resource.ArrayFontDescriptor;

import dwt.graphics.Device;
import dwt.graphics.Font;
import dwt.graphics.FontData;
import dwt.widgets.Display;

import dwt.dwthelper.utils;

/**
 * Lightweight descriptor for a font. Creates the described font on demand.
 * Subclasses can implement different ways of describing a font. These objects
 * will be compared, so hashCode(...) and equals(...) must return something
 * meaningful.
 *
 * @since 3.1
 */
public abstract class FontDescriptor : DeviceResourceDescriptor {

    /**
     * Creates a FontDescriptor that describes an existing font. The resulting
     * descriptor depends on the Font. Disposing the Font while the descriptor
     * is still in use may throw a graphic disposed exception.
     *
     * @since 3.1
     *
     * @deprecated use {@link FontDescriptor#createFrom(Font)}
     *
     * @param font a font to describe
     * @param originalDevice must be the same Device that was passed into
     * the font's constructor when it was first created.
     * @return a newly created FontDescriptor.
     */
    public static FontDescriptor createFrom(Font font, Device originalDevice) {
        return new ArrayFontDescriptor(font);
    }

    /**
     * Creates a FontDescriptor that describes an existing font. The resulting
     * descriptor depends on the original Font, and disposing the original Font
     * while the descriptor is still in use may cause DWT to throw a graphic
     * disposed exception.
     *
     * @since 3.1
     *
     * @param font font to create
     * @return a newly created FontDescriptor that describes the given font
     */
    public static FontDescriptor createFrom(Font font) {
        return new ArrayFontDescriptor(font);
    }

    /**
     * Creates a new FontDescriptor given the an array of FontData that describes
     * the font.
     *
     * @since 3.1
     *
     * @param data an array of FontData that describes the font (will be passed into
     * the Font's constructor)
     * @return a FontDescriptor that describes the given font
     */
    public static FontDescriptor createFrom(FontData[] data) {
        return new ArrayFontDescriptor(data);
    }

    /**
     * Creates a new FontDescriptor given the associated FontData
     *
     * @param data FontData describing the font to create
     * @return a newly created FontDescriptor
     */
    public static FontDescriptor createFrom(FontData data) {
        return new ArrayFontDescriptor( [data] );
    }

    /**
     * Creates a new FontDescriptor given an OS-specific font name, height, and style.
     *
     * @see Font#Font(dwt.graphics.Device, java.lang.String, int, int)
     *
     * @param name os-specific font name
     * @param height height (pixels)
     * @param style a bitwise combination of NORMAL, BOLD, ITALIC
     * @return a new FontDescriptor
     */
    public static FontDescriptor createFrom(String name, int height, int style) {
        return createFrom(new FontData(name, height, style));
    }

    /**
     * Returns the set of FontData associated with this font. Modifying the elements
     * in the returned array has no effect on the original FontDescriptor.
     *
     * @return the set of FontData associated with this font
     * @since 3.3
     */
    public FontData[] getFontData() {
        Font tempFont = createFont(Display.getCurrent());
        FontData[] result = tempFont.getFontData();
        destroyFont(tempFont);
        return result;
    }

    /**
     * Returns an array of FontData containing copies of the FontData
     * from the original.
     *
     * @param original array to copy
     * @return a deep copy of the original array
     * @since 3.3
     */
    public static FontData[] copy(FontData[] original) {
        FontData[] result = new FontData[original.length];
        for (int i = 0; i < original.length; i++) {
            FontData next = original[i];

            result[i] = copy(next);
        }

        return result;
    }

    /**
     * Returns a copy of the original FontData
     *
     * @param next FontData to copy
     * @return a copy of the given FontData
     * @since 3.3
     */
    public static FontData copy(FontData next) {
        FontData result = new FontData(next.getName(), next.getHeight(), next.getStyle());
        result.setLocale(next.getLocale());
        return result;
    }

    /**
     * Returns a FontDescriptor that is equivalent to the reciever, but uses
     * the given style bits.
     *
     * <p>Does not modify the reciever.</p>
     *
     * @param style a bitwise combination of DWT.NORMAL, DWT.ITALIC and DWT.BOLD
     * @return a new FontDescriptor with the given style
     *
     * @since 3.3
     */
    public final FontDescriptor setStyle(int style) {
        FontData[] data = getFontData();

        for (int i = 0; i < data.length; i++) {
            FontData next = data[i];

            next.setStyle(style);
        }

        // Optimization: avoid holding onto extra instances by returning the reciever if
        // if it is exactly the same as the result
        FontDescriptor result = new ArrayFontDescriptor(data);
        if (result.opEquals(this)) {
            return this;
        }

        return result;
    }

    /**
     * <p>Returns a FontDescriptor that is equivalent to the reciever, but
     * has the given style bits, in addition to any styles the reciever already has.</p>
     *
     * <p>Does not modify the reciever.</p>
     *
     * @param style a bitwise combination of DWT.NORMAL, DWT.ITALIC and DWT.BOLD
     * @return a new FontDescriptor with the given additional style bits
     * @since 3.3
     */
    public final FontDescriptor withStyle(int style) {
        FontData[] data = getFontData();

        for (int i = 0; i < data.length; i++) {
            FontData next = data[i];

            next.setStyle(next.getStyle() | style);
        }

        // Optimization: avoid allocating extra instances by returning the reciever if
        // if it is exactly the same as the result
        FontDescriptor result = new ArrayFontDescriptor(data);
        if (result.opEquals(this)) {
            return this;
        }

        return result;
    }

    /**
     * <p>Returns a new FontDescriptor that is equivalent to the reciever, but
     * has the given height.</p>
     *
     * <p>Does not modify the reciever.</p>
     *
     * @param height a height, in points
     * @return a new FontDescriptor with the height, in points
     * @since 3.3
     */
    public final FontDescriptor setHeight(int height) {
        FontData[] data = getFontData();

        for (int i = 0; i < data.length; i++) {
            FontData next = data[i];

            next.setHeight(height);
        }

        // Optimization: avoid holding onto extra instances by returning the reciever if
        // if it is exactly the same as the result
        FontDescriptor result = new ArrayFontDescriptor(data);
        if (result.opEquals(this)) {
            return this;
        }

        return result;
    }

    /**
     * <p>Returns a FontDescriptor that is equivalent to the reciever, but whose height
     * is larger by the given number of points.</p>
     *
     * <p>Does not modify the reciever.</p>
     *
     * @param heightDelta a change in height, in points. Negative values will return smaller
     * fonts.
     * @return a FontDescriptor whose height differs from the reciever by the given number
     * of points.
     * @since 3.3
     */
    public final FontDescriptor increaseHeight(int heightDelta) {
        if (heightDelta is 0) {
            return this;
        }
        FontData[] data = getFontData();

        for (int i = 0; i < data.length; i++) {
            FontData next = data[i];

            next.setHeight(next.getHeight() + heightDelta);
        }

        return new ArrayFontDescriptor(data);
    }

    /**
     * Creates the Font described by this descriptor.
     *
     * @since 3.1
     *
     * @param device device on which to allocate the font
     * @return a newly allocated Font (never null)
     * @throws DeviceResourceException if unable to allocate the Font
     */
    public abstract Font createFont(Device device);

    /**
     * Deallocates anything that was allocated by createFont, given a font
     * that was allocated by an equal FontDescriptor.
     *
     * @since 3.1
     *
     * @param previouslyCreatedFont previously allocated font
     */
    public abstract void destroyFont(Font previouslyCreatedFont);

    /* (non-Javadoc)
     * @see dwtx.jface.resource.DeviceResourceDescriptor#create(dwt.graphics.Device)
     */
    public override final Object createResource(Device device) {
        return createFont(device);
    }

    /* (non-Javadoc)
     * @see dwtx.jface.resource.DeviceResourceDescriptor#destroy(java.lang.Object)
     */
    public override final void destroyResource(Object previouslyCreatedObject) {
        destroyFont(cast(Font)previouslyCreatedObject);
    }
}