/* AuDynaMediar.java

	Purpose:
		
	Description:
		
	History:
		Fri Jan 11 19:14:17     2008, Created by tomyeh

Copyright (C) 2008 Potix Corporation. All Rights Reserved.

{{IS_RIGHT
	This program is distributed under LGPL Version 2.1 in the hope that
	it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.zk.au.http;

import java.io.IOException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

import org.zkoss.lang.Exceptions;
import org.zkoss.mesg.Messages;
import org.zkoss.util.media.Media;
import org.zkoss.web.servlet.http.Https;
import org.zkoss.zk.mesg.MZk;
import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.ComponentNotFoundException;
import org.zkoss.zk.ui.Desktop;
import org.zkoss.zk.ui.Execution;
import org.zkoss.zk.ui.Executions;
import org.zkoss.zk.ui.Session;
import org.zkoss.zk.ui.Sessions;
import org.zkoss.zk.ui.WebApp;
import org.zkoss.zk.ui.ext.render.DynamicMedia;
import org.zkoss.zk.ui.http.ExecutionImpl;
import org.zkoss.zk.ui.sys.ComponentCtrl;
import org.zkoss.zk.ui.sys.DesktopCtrl;
import org.zkoss.zk.ui.sys.UiEngine;
import org.zkoss.zk.ui.sys.WebAppCtrl;
import org.zkoss.zk.ui.util.Configuration;

/**
 * The AU processor used to response the content for {@link DynamicMedia#getMedia}
 * 
 * @author tomyeh
 * @since 3.0.2
 */
public class AuDynaMediar implements AuExtension {
	private static final Logger log = LoggerFactory.getLogger(AuDynaMediar.class);

	private ServletContext _ctx;

	public AuDynaMediar() {
	}

	public void init(DHtmlUpdateServlet servlet) {
		_ctx = servlet.getServletContext();
	}

	public void destroy() {
	}

	/** Retrieves the media from {@link DynamicMedia#getMedia}.
	 */
	public void service(HttpServletRequest request, HttpServletResponse response, String pi)
			throws ServletException, IOException {
		//		if (log.isDebugEnabled()) log.debug("View "+pi);
		final Session sess = Sessions.getCurrent(false);
		if (sess == null) {
			response.sendError(HttpServletResponse.SC_GONE, Messages.get(MZk.PAGE_NOT_FOUND, pi));
			return;
		}

		int j = pi.indexOf('/', 1) + 1;
		int k = pi.indexOf('/', j);
		if (j <= 0 || k <= 0)
			throw new ServletException("Wrong path info: " + pi);

		final String dtid = pi.substring(j, k);
		final int l = pi.indexOf('/', ++k);
		final String uuid = l >= 0 ? pi.substring(k, l) : pi.substring(k);

		Media media;
		boolean download = false;
		try {
			final WebApp wapp = sess.getWebApp();
			final WebAppCtrl wappc = (WebAppCtrl) wapp;
			final UiEngine uieng = wappc.getUiEngine();
			final Desktop desktop = wappc.getDesktopCache(sess).getDesktop(dtid);
			final DesktopCtrl desktopCtrl = (DesktopCtrl) desktop;

			final Execution oldexec = Executions.getCurrent();
			final Execution exec = new ExecutionImpl(_ctx, request, response, desktop, null);
			uieng.activate(exec);

			final Configuration config = wapp.getConfiguration();
			boolean err = false;
			try {
				config.invokeExecutionInits(exec, oldexec);
				desktopCtrl.invokeExecutionInits(exec, oldexec);

				media = desktopCtrl.getDownloadMedia(uuid, false);
				if (media != null) {
					download = true; //yes, it is for download
				} else {
					final Component comp = desktop.getComponentByUuidIfAny(uuid);
					if (comp == null) { // B65-ZK-1599
						response.sendError(HttpServletResponse.SC_GONE,
								Messages.get(MZk.PAGE_NOT_FOUND, pi + " - " + uuid));
						log.debug("Failed to load media, " + pi);
						return;
					}
					final Object cc = ((ComponentCtrl) comp).getExtraCtrl();
					if (!(cc instanceof DynamicMedia))
						throw new ServletException(
								DynamicMedia.class + " must be implemented by getExtraCtrl() of " + comp);
					int m = l >= 0 ? pi.indexOf('/', l + 1) : -1;
					if (m < 0)
						m = l;
					media = ((DynamicMedia) cc).getMedia(m >= 0 ? pi.substring(m) : "");
					if (media == null) {
						response.sendError(HttpServletResponse.SC_GONE,
								Messages.get(MZk.PAGE_NOT_FOUND, pi + " - " + comp));
						return;
					}
				}
			} catch (Throwable ex) {
				err = true;

				final List<Throwable> errs = new LinkedList<Throwable>();
				errs.add(ex);
				desktopCtrl.invokeExecutionCleanups(exec, oldexec, errs);
				config.invokeExecutionCleanups(exec, oldexec, errs);

				final StringBuffer errmsg = new StringBuffer(100);
				if (!errs.isEmpty()) {
					for (Iterator it = errs.iterator(); it.hasNext();) {
						final Throwable t = (Throwable) it.next();
						log.error("Failed to load media, " + pi, t);
						errmsg.append('\n').append(Exceptions.getMessage(t));
					}
				}

				response.sendError(HttpServletResponse.SC_GONE,
						Messages.get(MZk.PAGE_FAILED, new Object[] { pi, errmsg, "" }));
				return;
			} finally {
				if (!err) {
					desktopCtrl.invokeExecutionCleanups(exec, oldexec, null);
					config.invokeExecutionCleanups(exec, oldexec, null);
				}
				uieng.deactivate(exec);
			}
		} catch (ComponentNotFoundException ex) {
			//possible because view might be as late as origin comp is gone
			response.sendError(HttpServletResponse.SC_GONE, Messages.get(MZk.UPDATE_OBSOLETE_PAGE, uuid));
			return;
		}

		Https.write(request, response, media, download, false);
		//see bug 2691017 for why not repeatable
		//FUTURE: support last-modified
	}
}
