/*
 * 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();
	}
}