/*
 * Copyright (c) 2004 Your Corporation. All Rights Reserved.
 */
package com.jetmaven.oa;

import org.apache.velocity.app.VelocityEngine;
import org.springframework.ui.velocity.VelocityEngineUtils;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedWriter;
import java.io.File;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

/**
 * @author <a href="mailto:youmail@yourdomain.com">yourname</a> Date: 2004-11-22
 */
public class ViewVelocityTemplateController implements Controller
{
    private VelocityEngine engine;
    private String encoding;

    public VelocityEngine getEngine()
    {
        return engine;
    }

    public void setEngine(VelocityEngine engine)
    {
        this.engine = engine;

    }

    public String getEncoding()
    {
        return encoding;
    }

    public void setEncoding(String encoding)
    {
        this.encoding = encoding;
    }

    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception
    {
        response.setContentType("text/html;charset=gb2312");
        String relativeUri = request.getRequestURI().replaceFirst(request.getContextPath(), "");
        File reportFilePath = new File(request.getSession(true).getServletContext().getRealPath(relativeUri));
        if (reportFilePath.exists())
        {
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(response.getOutputStream()));
            VelocityEngineUtils.mergeTemplate(engine, relativeUri, encoding, getVelocityContextFromRequest(request), writer);
            writer.flush();
            writer.close();
        } else
        {
            setError404(response);
        }
        return null;
    }

    /**
     * 从request中构建VelocityContext对象(提取request中的属性值)
     *
     * @param request HttpServletRequest变量
     * @return VelocityContext对象
     */
    private Map getVelocityContextFromRequest(HttpServletRequest request)
    {
        Map context = new HashMap();
        Enumeration allAttrKey = request.getAttributeNames();
        while (allAttrKey.hasMoreElements())
        {
            String attrKey = (String) allAttrKey.nextElement();
            context.put(attrKey, request.getAttribute(attrKey));
        }
        return context;
    }

    /**
     * 设置404错误，指定的vm文件未找到
     *
     * @param response web的response变量
     * @throws java.io.IOException 异常
     */
    private void setError404(HttpServletResponse response) throws IOException
    {
        response.setContentType("text/html;charset=gb2312");
        response.setStatus(404);
        response.getOutputStream().write("Error:404,File not Found!".getBytes());
    }
}