/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2022 iText Group NV
 * Authors: Bruno Lowagie, Balder Van Camp, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
 * details. You should have received a copy of the GNU Affero General Public
 * License along with this program; if not, see http://www.gnu.org/licenses or
 * write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License, a
 * covered work must retain the producer line in every PDF that is created or
 * manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing a
 * commercial license. Buying such a license is mandatory as soon as you develop
 * commercial activities involving the iText software without disclosing the
 * source code of your own applications. These activities include: offering paid
 * services to customers as an ASP, serving PDFs on the fly in a web
 * application, shipping iText with a closed source product.
 *
 * For more information, please contact iText Software Corp. at this address:
 * sales@itextpdf.com
 */
package com.itextpdf.tool.xml.css;

import com.itextpdf.text.Font;
import com.itextpdf.tool.xml.Tag;

/**
 * @author Emiel Ackermann
 */
public class FontSizeTranslator {

    public static final float DEFAULT_FONT_SIZE = 12f;

    /**
     *
     */
    private static CssUtils utils = CssUtils.getInstance();
    private static FontSizeTranslator myself;

    /**
     * @return Singleton instance of FontSizeTranslater.
     */
    public static synchronized FontSizeTranslator getInstance() {
        if (null == myself) {
            myself = new FontSizeTranslator();
        }
        return myself;
    }

    /**
     * Returns the css value of the style <b>font-size</b> in a pt-value. Possible font-size values:
     * <ul>
     * <li>a constant in px, in, cm, mm, pc, em or ex,</li>
     * <li>xx-small,</li>
     * <li>x-small,</li>
     * <li>small,</li>
     * <li>medium,</li>
     * <li>large,</li>
     * <li>x-large,</li>
     * <li>xx-large,</li>
     * <li>smaller (than tag's parent size),</li>
     * <li>larger (than tag's parent size),</li>
     * <li>a percentage (e.g font-size:250%) of tag's parent size,</li>
     * </ul>
     *
     * @param tag to get the font size of.
     *
     * @return float font size of the content of the tag in pt.
     */
    public float translateFontSize(final Tag tag) {
        float size = Font.UNDEFINED;
        if (tag.getCSS().get(CSS.Property.FONT_SIZE) != null) {
            String value = tag.getCSS().get(CSS.Property.FONT_SIZE);
            if (value.equalsIgnoreCase(CSS.Value.XX_SMALL)) {
                size = 6.75f;
            } else if (value.equalsIgnoreCase(CSS.Value.X_SMALL)) {
                size = 7.5f;
            } else if (value.equalsIgnoreCase(CSS.Value.SMALL)) {
                size = 9.75f;
            } else if (value.equalsIgnoreCase(CSS.Value.MEDIUM)) {
                size = 12f;
            } else if (value.equalsIgnoreCase(CSS.Value.LARGE)) {
                size = 13.5f;
            } else if (value.equalsIgnoreCase(CSS.Value.X_LARGE)) {
                size = 18f;
            } else if (value.equalsIgnoreCase(CSS.Value.XX_LARGE)) {
                size = 24f;
            } else if (value.equalsIgnoreCase(CSS.Value.SMALLER)) {
                if (tag.getParent() != null) {
                    float parentSize =
                        getFontSize(tag.getParent()); // if the font-size of the parent can be set in some memory the translation part is not needed anymore.
                    if (parentSize == Font.UNDEFINED) {
                        size = 9.75f;
                    } else if (parentSize <= 6.75f) {
                        size = parentSize - 1;
                    } else if (parentSize == 7.5f) {
                        size = 6.75f;
                    } else if (parentSize == 9.75f) {
                        size = 7.5f;
                    } else if (parentSize == 12f) {
                        size = 9.75f;
                    } else if (parentSize == 13.5f) {
                        size = 12f;
                    } else if (parentSize == 18f) {
                        size = 13.5f;
                    } else if (parentSize == 24f) {
                        size = 18f;
                    } else if (parentSize < 24f) {
                        size = parentSize * 0.85f;
                    } else if (parentSize >= 24) {
                        size = parentSize * 2 / 3;
                    }
                } else {
                    size = 9.75f;
                }
            } else if (value.equalsIgnoreCase(CSS.Value.LARGER)) {
                if (tag.getParent() != null) {
                    float parentSize = getFontSize(tag.getParent()); // if the font-size of the parent can be set in some memory the translation part is not needed anymore.
                    if (parentSize == Font.UNDEFINED) {
                        size = 13.5f;
                    } else if (parentSize == 6.75f) {
                        size = 7.5f;
                    } else if (parentSize == 7.5f) {
                        size = 9.75f;
                    } else if (parentSize == 9.75f) {
                        size = 12f;
                    } else if (parentSize == 12f) {
                        size = 13.5f;
                    } else if (parentSize == 13.5f) {
                        size = 18f;
                    } else if (parentSize == 18f) {
                        size = 24f;
                    } else {
                        size = parentSize * 1.5f;
                    }
                } else {
                    size = 13.5f;
                }
            } else if (utils.isMetricValue(value) || utils.isNumericValue(value)) {
                size = utils.parsePxInCmMmPcToPt(value);
            } else if (utils.isRelativeValue(value)) {
                float baseValue = Font.UNDEFINED;
                if (tag.getParent() != null) {
                    baseValue = getFontSize(tag.getParent());
                }
                if (baseValue == Font.UNDEFINED) {
                    baseValue = 12;
                }
                size = utils.parseRelativeValue(value, baseValue);
            }
        }
        return size;
    }

    /**
     * Retrieves the pt font size from {@link Tag#getCSS()} with {@link CSS.Property#FONT_SIZE} or returns default 12pt
     *
     * @param tag the tag to get the font-size from.
     *
     * @return the font size
     */
    public float getFontSize(final Tag tag) {
        String str = tag.getCSS().get(CSS.Property.FONT_SIZE);
        if (null != str) {
            return Float.parseFloat(str.replace("pt", ""));
        }
        return Font.UNDEFINED;
    }
}
