HtmCache

/*
 * This program is free software: you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program. If
 * not, see <http://www.gnu.org/licenses/>.
 */
package com.l2dc.gameserver.cache;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.util.Arrays;
import java.util.HashSet;
import java.util.concurrent.ConcurrentHashMap;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.l2dc.Config;
import com.l2dcproject.commons.util.ResourceUtil;
import com.l2dc.gameserver.model.actor.instance.L2PcInstance;
import com.l2dc.gameserver.templates.htm.HtmTemplateEngine;
import com.l2dc.gameserver.util.Util;

/**
 * @author Layane
 *
 */
public class HtmCache
{
    private static final Logger LOG = LoggerFactory.getLogger(HtmCache.class);

    private final ConcurrentHashMap<String, String> _cache = new ConcurrentHashMap<String, String>();

    private static final String[] VALID_TAGS = { "column", "unknown", "ul", "u",
        "tt", "tr", "title", "textcode", "textarea", "td", "table", "sup", "sub",
        "strike", "spin", "select", "right", "pre", "p", "option", "ol", "multiedit",
        "li", "left", "input", "img", "i", "html", "h7", "h6", "h5", "h4", "h3", "h2",
        "h1", "font", "extend", "edit", "comment", "combobox", "center", "button", "br",
        "br1", "body", "bar", "address", "a", "sel", "list", "var", "fore", "readonl",
        "rows", "valign", "fixwidth", "bordercolorli", "bordercolorda", "bordercolor",
        "border", "bgcolor", "background", "align", "valu", "readonly", "multiple",
        "selected", "typ", "type", "maxlength", "checked", "src", "y", "x", "querydelay",
        "noscrollbar", "imgsrc", "b", "fg", "size", "face", "color", "deffon", "deffixedfont",
        "width", "value", "tooltip", "name", "min", "max", "height", "disabled", "align",
        "msg", "link", "href", "action", "head", "tbody", "!--" };

    private final static HashSet<String> VALID_TAGS_SET = new HashSet<String>(301);

    static
    {
        VALID_TAGS_SET.addAll(Arrays.asList(VALID_TAGS));
    }

    private int _loadedFiles;
    private long _bytesBuffLen;

    /**
     *
     * @return
     */
    public static HtmCache getInstance()
    {
        return SingletonHolder.INSTANCE;
    }

    private HtmCache()
    {
        init(Config.DATAPACK_ROOT);
    }

    /**
     *
     */
    public void reload()
    {
        HtmTemplateEngine.getInstance().reload();
        init(Config.DATAPACK_ROOT);
    }

    /**
     *
     * @param f
     */
    public void init(File f)
    {
        if (!Config.LAZY_CACHE)
        {
            LOG.info("Html cache start...");
            parseDir(f);
            LOG.info("Cache[HTML]: {} megabytes on {} files loaded", String.format("%.3f", getMemoryUsage()), getLoadedFiles());
        }
        else
        {
            _cache.clear();
            _loadedFiles = 0;
            _bytesBuffLen = 0;
            LOG.info("Cache[HTML]: Running lazy cache");
        }
    }

    /**
     *
     * @param f
     */
    public void reloadPath(File f)
    {
        parseDir(f);
        LOG.info("Cache[HTML]: Reloaded specified path");
    }

    /**
     *
     * @return
     */
    public double getMemoryUsage()
    {
        return ((float) _bytesBuffLen / 1048576);
    }

    /**
     *
     * @return
     */
    public int getLoadedFiles()
    {
        return _loadedFiles;
    }

    private static class HtmFilter implements FileFilter
    {
        public HtmFilter()
        {
        }

        @Override
        public boolean accept(File file)
        {
            if (!file.isDirectory())
            {
                return (file.getName().endsWith(".htm") || file.getName().endsWith(".html"));
            }
            return true;
        }
    }

    private void parseDir(File dir)
    {
        final FileFilter filter = new HtmFilter();
        final File[] files = dir.listFiles(filter);

        for (File file : files)
        {
            if (!file.isDirectory())
                loadFile(file);
            else
                parseDir(file);
        }
    }

    /**
     *
     * @param file
     * @return
     */
    public String loadFile(File file)
    {
        final String relpath = Util.getRelativePath(Config.DATAPACK_ROOT, file);

        final HtmFilter filter = new HtmFilter();

        if (file.exists() && filter.accept(file) && !file.isDirectory())
        {
            String content;
            FileInputStream fis = null;

            try
            {
                fis = new FileInputStream(file);
                BufferedInputStream bis = new BufferedInputStream(fis);
                final int bytes = bis.available();
                final byte[] raw = new byte[bytes];

                bis.read(raw);
                bis.close();
                content = new String(raw, "UTF-8");
                content = content.replaceAll("\r\n", "\n");
                content = HtmTemplateEngine.getInstance().prepare(content, file.getAbsolutePath());

                String oldContent = _cache.get(relpath);

                if (oldContent == null)
                {
                    _bytesBuffLen += bytes;
                    _loadedFiles++;
                }
                else
                {
                    _bytesBuffLen = _bytesBuffLen - oldContent.length() + bytes;
                }

                if(!Config.LAZY_CACHE)
                    validate(file.getPath(), content);

                _cache.put(relpath, content);

                return content;
            }
            catch (Exception e)
            {
                LOG.error("Cache[HTML]: Problem with htm file {}", file.getAbsolutePath(), e);
            }
            finally
            {
                ResourceUtil.closeInputStream(fis);
            }
        }

        return null;
    }

    /**
     *
     * @param path
     * @param player
     * @return
     */
    public String getHtmForce(String path, L2PcInstance player)
    {
        String content = getHtm(path, player);

        if (content == null)
        {
            content = "<html><body>My text is missing:<br>" + path + "</body></html>";
            LOG.warn("Cache[HTML]: Missing HTML page: {}", path);
        }

        return content;
    }

    /**
     *
     * @param path
     * @param player
     * @return
     */
    public String getHtm(String path, L2PcInstance player)
    {
        return getHtm(path, player, null);
    }

    /**
     *
     * @param path
     * @param player
     * @param htmlPrefix - Temp parameter for community board caching, should be removed asap
     * @return
     */
    public String getHtm(String path, L2PcInstance player, String htmlPrefix)
    {
        String newPath = null;
        String content;
        if (player != null)
        {
            newPath = player.getHtmlPrefix() + path;
            content = getHtm(newPath);
            if (content != null)
                return HtmTemplateEngine.getInstance().parse(content, player, path);
        } else if(htmlPrefix != null && !htmlPrefix.isEmpty()) {
            newPath = htmlPrefix + path;
            content = getHtm(newPath);
            if (content != null)
                return content;
        }

        content = getHtm(path);
        if (content != null && newPath != null)
            _cache.put(newPath, content);

        return HtmTemplateEngine.getInstance().parse(content, player, path);
    }

    private String getHtm(String path)
    {
        if (path == null || path.isEmpty())
            return ""; // avoid possible NPE

        String content = _cache.get(path);

        if (Config.LAZY_CACHE && content == null)
            content = loadFile(new File(Config.DATAPACK_ROOT, path));

        return content;
    }

    /**
     *
     * @param path
     * @return
     */
    public boolean contains(String path)
    {
        return _cache.containsKey(path);
    }

    /**
     * Check if an HTM exists and can be loaded
     *
     * @param path
     *            The path to the HTM
     * @return
     * */
    public boolean isLoadable(String path)
    {
        File file = new File(Config.DATAPACK_ROOT, path);
        HtmFilter filter = new HtmFilter();

        if (file.exists() && filter.accept(file) && !file.isDirectory())
            return true;

        return false;
    }

    private void validate(String filename, String html)
    {
        outer: for (int begin = 0; (begin = html.indexOf('<', begin)) != -1; begin++)
        {
            int end;
            for (end = begin; end < html.length(); end++)
            {
                if (html.charAt(end) == '>' || html.charAt(end) == ' ')
                    break;
                // some special quest-replaced tag
                if (end == begin + 1 && html.charAt(end) == '?')
                    continue outer;
            }
            end++;
            String tag = html.substring(begin + 1, end - 1).toLowerCase().replaceAll("/", "");
            if (!VALID_TAGS_SET.contains(tag))
            {
                LOG.info("Cache[HTML]: Invalid tag used: '{}' at pos {} {}", new Object[] {tag, (begin + 1), filename});
            }
        }
    }


    @SuppressWarnings("synthetic-access")
    private static class SingletonHolder
    {
        protected static final HtmCache INSTANCE = new HtmCache();
    }
}