package luan.host;

import java.io.File;
import java.io.IOException;
import java.util.Map;
import java.util.HashMap;
import java.util.TimeZone;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.NCSARequestLog;
import org.eclipse.jetty.server.handler.AbstractHandler;
import org.eclipse.jetty.server.handler.ResourceHandler;
import org.eclipse.jetty.server.handler.HandlerList;
import org.eclipse.jetty.server.handler.RequestLogHandler;
import org.eclipse.jetty.server.handler.DefaultHandler;
import org.eclipse.jetty.server.handler.HandlerCollection;
import luan.Luan;
import luan.LuanState;
import luan.LuanException;
import luan.LuanTable;
import luan.LuanFunction;
import luan.modules.IoLuan;
import luan.modules.JavaLuan;
import luan.modules.PackageLuan;
import luan.modules.http.jetty.LuanHandler;
import luan.modules.http.jetty.AuthenticationHandler;
import luan.modules.http.jetty.NotFound;


public class WebHandler extends AbstractHandler {
	private static final Logger logger = LoggerFactory.getLogger(WebHandler.class);

	private static class Site {
		final Handler handler;
		final LuanHandler luanHandler;

		Site(Handler handler,LuanHandler luanHandler) {
			this.handler = handler;
			this.luanHandler = luanHandler;
		}
	}

	public static String allowJavaFileName = "allow_java";  // change for security
	private static final String tz = TimeZone.getDefault().getID();
	private static final Map<String,Site> siteMap = new HashMap<String,Site>();
	private static String sitesDir = null;
	private static Server server = null;

	public static boolean isServing() {
		return sitesDir != null;
	}

	public WebHandler(String dir,Server server) {
		if( sitesDir != null )
			throw new RuntimeException("already set");
		if( !new File(dir).exists() )
			throw new RuntimeException();
		this.sitesDir = dir;
		this.server = server;
	}

	public void handle(String target,Request baseRequest,HttpServletRequest request,HttpServletResponse response) 
		throws IOException, ServletException
	{
		String domain = baseRequest.getServerName();
//		System.out.println("handle "+domain);
		Site site = getSite(domain);
		if( site != null ) {
			site.handler.handle(target,baseRequest,request,response);
		}
	}

	public static Object runLuan(String domain,String sourceText,String sourceName) throws LuanException {
		return getSite(domain).luanHandler.runLuan(sourceText,sourceName);
	}

	public static Object callSite(String domain,String fnName,Object... args) throws LuanException {
		return getSite(domain).luanHandler.call_rpc(fnName,args);
	}

	private static Site getSite(String domain) {
		synchronized(siteMap) {
			Site site = siteMap.get(domain);
			if( site == null ) {
				if( sitesDir==null )
					throw new NullPointerException("sitesDir");
				File dir = new File(sitesDir,domain);
				if( !dir.exists() /* && !recover(dir) */ )
					return null;
				site = newSite(dir.toString(),domain);
				siteMap.put(domain,site);
			}
			return site;
		}
	}
/*
	private static boolean recover(File dir) {
		File backups = new File(dir.getParentFile().getParentFile(),"backups");
		if( !backups.exists() )
			return false;
		String name = dir.getName();
		File from = null;
		for( File backup : backups.listFiles() ) {
			File d = new File(backup,"current/"+name);
			if( d.exists() && (from==null || from.lastModified() < d.lastModified()) )
				from = d;
		}
		if( from == null )
			return false;
		if( !from.renameTo(dir) )
			throw new RuntimeException("couldn't rename "+from+" to "+dir);
		logger.info("recovered "+name+" from "+from);
		return true;
	}
*/
	static LuanTable initLuan(LuanState luan,String dir,String domain) {
		LuanTable init;
		try {
			init = (LuanTable)luan.eval(
				"local Luan = require 'luan:Luan.luan'\n"
				+"local f = Luan.load_file 'classpath:luan/host/Init.luan'\n"
				+"return f('"+dir+"','"+domain+"')\n"
			);
		} catch(LuanException e) {
			throw new RuntimeException(e);
		}
		File allowJavaFile = new File(dir,"site/private/"+allowJavaFileName);
		if( !allowJavaFile.exists() ) {
			JavaLuan.setSecurity( luan, javaSecurity );
			IoLuan.setSecurity( luan, ioSecurity(dir) );
		}
		return init;
	}

	private static Site newSite(String dir,String domain) {
		LuanState luan = new LuanState();
		LuanTable init = initLuan(luan,dir,domain);
		String password = (String)init.rawGet("password");

		AuthenticationHandler authenticationHandler = new AuthenticationHandler("/private/");
		authenticationHandler.setPassword(password);
		String loggerRoot = (String)init.rawGet("logger_root");
		LuanHandler luanHandler = new LuanHandler(luan,loggerRoot);

		ResourceHandler resourceHandler = new ResourceHandler();
		resourceHandler.setResourceBase(dir+"/site");
		resourceHandler.setDirectoriesListed(true);
		resourceHandler.setAliases(true);

		NotFound notFoundHandler = new NotFound(luanHandler);
		DefaultHandler defaultHandler = new DefaultHandler();

		HandlerList handlers = new HandlerList();
		handlers.setHandlers(new Handler[]{authenticationHandler,luanHandler,resourceHandler,notFoundHandler,defaultHandler});

		String logDir = dir+"/site/private/local/logs/web";
		new File(logDir).mkdirs();
		NCSARequestLog log = new NCSARequestLog(logDir+"/yyyy_mm_dd.log");
		log.setExtended(false);
		log.setLogTimeZone(tz);
		RequestLogHandler logHandler = new RequestLogHandler();
		logHandler.setRequestLog(log);

		HandlerCollection hc = new HandlerCollection();
		hc.setHandlers(new Handler[]{handlers,logHandler});
//		hc.setServer(getServer());

		try {
			hc.start();
		} catch(Exception e) {
			throw new RuntimeException(e);
		}
		return new Site(hc,luanHandler);
	}

	public static void removeHandler(String domain) throws Exception {
		synchronized(siteMap) {
			Site site = siteMap.remove(domain);
			if( site != null ) {
				site.handler.stop();
				site.handler.destroy();
			}
		}
	}

	public static void loadHandler(String domain) {
		getSite(domain);
	}

	public static Server server() {
		return server;
	}

	private static final IoLuan.Security ioSecurity(String dir) {
		final String siteDir = dir + "/site/";
		return new IoLuan.Security() {
			public void check(LuanState luan,String name) throws LuanException {
				if( name.startsWith("file:") ) {
					if( name.contains("..") )
						throw new LuanException("Security violation - '"+name+"' contains '..'");
					if( !name.startsWith("file:"+siteDir) )
						throw new LuanException("Security violation - '"+name+"' outside of site dir");
				}
				else if( name.startsWith("classpath:luan/host/") ) {
					throw new LuanException("Security violation");
				}
				else if( name.startsWith("os:") || name.startsWith("bash:") ) {
					throw new LuanException("Security violation");
				}
			}
		};
	}

	private static final JavaLuan.Security javaSecurity = new JavaLuan.Security() {
		public void check(LuanState luan,String name) throws LuanException {
			if( !name.startsWith("luan:") )
				throw new LuanException("Security violation - only luan:* modules can load Java");
			if( name.equals("luan:logging/Logging") )
				throw new LuanException("Security violation - cannot reload Logging");
		}
	};
}