/**
 * $Id$ 
 * 
 * Copyright (c) 2011-2012 Jens Elkner.
 * All Rights Reserved.
 *
 * This software is the proprietary information of Jens Elkner.
 * Use is subject to license terms.
 */
package org.opensolaris.opengrok.web;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.opensolaris.opengrok.history.Annotation;

/**
 * @author 	Jens Elkner
 * @version	$Revision$
 */
/* Apache 6.x doesn't support it:
@WebServlet(name="Annotation Servlet", 
    description="Provides annotations for a source file in compact JSON format",
    value= "/json/annotate/*")
*/
public class AnnotationServlet extends HttpServlet {
    private static final long serialVersionUID = -7799365322134860997L;
    private static final Logger logger =
        Logger.getLogger(AnnotationServlet.class.getName());
    
    static void sendProlog(PrintWriter out) {
        out.write("{\"data\":");
    }

    static void sendEpilog(PrintWriter out, boolean noDataSent, String[] errors)
        throws IOException 
    {
        if (noDataSent) {
            out.write("''");
        }
        if (errors != null && errors.length != 0) {
            out.write(',');
            Util.writeJsonArray(out, "errors", errors);
        }
        out.write('}');
    }

    private static void writeAnnos(PrintWriter out, Annotation a, PageConfig cfg) {
        String tmp = cfg.getConfig().getUserPage();
        out.write('{');
        
        if (tmp != null && tmp.length() > 0) {
            out.write("\"userPage\":{\"link\":");
            out.write(Util.jsStringLiteral(tmp));
            tmp = cfg.getConfig().getUserPageSuffix();
            if (tmp != null && tmp.length() > 0) {
                out.write(",\"suffix\":");
                out.write(Util.jsStringLiteral(tmp));
            }
            out.write("},");
        }
        out.write("\"a\":");
        out.write(a.toJson());
        out.write('}');
    }

    /** 
     * {@inheritDoc}
     */
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
        throws IOException 
    {
        PageConfig cfg = PageConfig.get(req);
        long flast = cfg.getLastModified()/1000 * 1000;
        long lmdate = cfg.getConfig().getLastModified();
        if (lmdate > flast) {
            flast = lmdate;
        }
        if (req.getDateHeader("If-Modified-Since") >= flast) {
            resp.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
            return;
        }
        resp.setDateHeader("Last-Modified", flast);
        resp.setCharacterEncoding("UTF-8");
        resp.setContentType("application/json");
        PrintWriter out = resp.getWriter();
        ArrayList<String> errors = new ArrayList<String>();
        int data = 0;
        try {
            sendProlog(out);
            if (cfg.resourceNotAvailable()) {
                errors.add("Resource ignored");
                return;
            }
            Annotation annotation = cfg.getAnnotation();
            if (annotation == null) {
                errors.add("Annotations not available");
                return;
            }
            writeAnnos(out, annotation, cfg);
            data++;
        } catch (Exception ex) {
            logger.log(Level.SEVERE, req.getRequestURI(), ex);
            errors.add(ex.getLocalizedMessage());
        } finally {
            sendEpilog(out, data == 0, errors.toArray(new String[errors.size()]));
            out.close();
        }
    }
            
}