import java.io.IOException;

import javax.management.remote.JMXServiceURL;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import se.lil.jm.JmxMon;
import se.lil.jm.Registry;

/**
 * Servlet implementation class JmxMonRESTgetData
 */
@WebServlet(description = "Calls getData on an existing JmxMon object or creates and calls it", urlPatterns = { "/JmxMonREST/getData" })
public class JmxMonRESTgetData extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public JmxMonRESTgetData() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("application/json");
		try {
			StringBuffer sb = new StringBuffer();
			int age = 0;
			if(request.getParameterMap().containsKey("age")) {
				try {
					age = Integer.parseInt(request.getParameter("age"));
				} catch (Exception e) {
					response.setStatus(400);
					response.getWriter().println("{\"error\":true,\"msg\":\"The specified age parameter is not a valid integer number\"}");
					return;
				}
			}
			
			if(request.getParameterMap().containsKey("connectionString")) {
				// We have a connection string, find the monitor or create it and call getData() on the monitor

				// Check that we have a valid connection string
				try {
					new JMXServiceURL(request.getParameter("connectionString"));
				} catch (Exception e) {
					// Error, we need a correct connection string
					response.setStatus(400);
					response.getWriter().println("{\"error\":true,\"msg\":\"connectionString is not a correct JMX Service URL\"}");
					return;
				}
				
				// Try to find the monitor in our list
				JmxMon monitor = Registry.findOrCreate(request.getParameter("connectionString"));
				
				// Call getData()
				boolean didUpdate = monitor.getData(age);
				String name = monitor.getServerName();
				if(didUpdate) {
					sb.append("{\"error\":false,\"msg\":\"Sucessfully collected data on instance '" + name + "'\"");
					sb.append(",\"ms\":"+monitor.getLastRTms()+"}");
				} else {
					response.setStatus(HttpServletResponse.SC_ACCEPTED);
					sb.append("{\"error\":false");
					sb.append(",\"msg\":\"Data does not need to be updated on instance '" + name + "' either because another thread did concurrently update the monitor and we just waited for it to complete, or because the age (if) specified was higher than the monitors data age.\"");
					sb.append(",\"age\":"+monitor.getAgeTs()+"}");
				}
				
			} else {
				// No input, just return the list of monitors
				sb.append("{\"count\":" + Registry.getList().size() + "}");
			}
			
			response.getWriter().println(sb.toString());
			
		} catch (Throwable e) {
			response.setStatus(500);
			Throwable lastCause = e.getCause();
			Throwable thisCause = e;
			while(lastCause != null) { thisCause = lastCause; lastCause = thisCause.getCause(); }
			//response.getWriter().println("{\"error\":true,\"msg\":\""+e.toString().replace("\n"," ").replace("\"","\\\"").trim()+"\"}");
			String rst = "{\"error\":true,\"msg\":\"" + e.toString() + ". Caused by: " + thisCause.toString() + "\"}";
			rst.replace("\n"," ").replace("\"","\\\"").trim();
			response.getWriter().println(rst);
			e.printStackTrace();
		}
	}
}