package com.loomis.jsf.servlet;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;

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

import com.loomis.jsf.component.resources.Resources;

public class ResourceServlet extends HttpServlet {
	public static final String RESOURCE_REQUEST_KEY = "resourcePath";
	
	private static final String ASSUMED_DIR_PREFIX = Resources.RESOURCE_DIR;
	private static Map<String, String> resourceMap;
	
	public static String generateResourceURL(String resourcePath) {
		return "/resources?" + RESOURCE_REQUEST_KEY + "=" + resourcePath;
	}
	
	private synchronized void loadResource(String resourcePath) {
		InputStream is = getClass().getResourceAsStream(ASSUMED_DIR_PREFIX + resourcePath);

		if (is == null) {

			return;
		}

		BufferedReader br = new BufferedReader(new InputStreamReader(is));

		try {
			String line = null;
			StringBuffer resourceBuf = new StringBuffer();

			while ((line = br.readLine()) != null) {
				resourceBuf.append(line + "\n");
			}

			getResourceMap().put(resourcePath, resourceBuf.toString());
		} catch (Exception e) {
			e.printStackTrace();
		} finally {

			try {
				br.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
	
	public void doWork(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		String resourcePath = request.getParameter(RESOURCE_REQUEST_KEY);
		
		if (!getResourceMap().containsKey(resourcePath)) {
			loadResource(resourcePath);
		}

		String resource = getResourceMap().get(resourcePath);

		if (resource == null) {
			return;
		}

		PrintWriter out = null;

		response.setContentType("text/plain;charset=UTF-8");

		out = response.getWriter();
		out.print(resource);

		if (out != null) {
			out.close();
		}
	}
	
	private static Map<String, String> getResourceMap() {
		if (resourceMap == null) {
			resourceMap = new HashMap<String, String>();
		}
		
		return resourceMap;
	}
	
	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doWork(request, response);
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doWork(request, response);
	}

}