//Dstl (c) Crown Copyright 2017
package uk.gov.dstl.baleen.core.web.servlets;

import java.io.IOException;
import java.time.LocalDateTime;
import java.time.temporal.ChronoUnit;

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

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

/**
 * Provides a status message for users to check the API is available.
 *
 * Accessing this resource requires no permissions (and no authentication).
 *
 * 
 *
 */
public class StatusServlet extends AbstractApiServlet {
	private static final Logger LOGGER = LoggerFactory.getLogger(StatusServlet.class);
	private static final long serialVersionUID = 1L;
	private final transient BaleenStatus status;

	/**
	 * Short status message.
	 *
	 * 
	 *
	 */
	public static class BaleenStatus {
		private String name = "Baleen";
		private String version = "2.4.0";
		private String status = "ok";
		private LocalDateTime timestamp;

		/**
		 * Constructor for BaleenStatus, which also sets the timestamp at which
		 * this message is valid
		 */
		public BaleenStatus() {
			timestamp = LocalDateTime.now();
		}

		/**
		 * Get the name of this instance
		 *
		 * @return The name of this instance
		 */
		public String getName() {
			return name;
		}

		/**
		 * Set the name of this instance
		 *
		 * @param name
		 *            The name of this instance
		 */
		public void setName(String name) {
			this.name = name;
		}

		/**
		 * Get the version of this instance
		 *
		 * @return The version of this instance
		 */
		public String getVersion() {
			return version;
		}

		/**
		 * Set the version of this instance
		 *
		 * @param version
		 *            The version of this instance
		 */
		public void setVersion(String version) {
			this.version = version;
		}

		/**
		 * Get the status of this instance
		 *
		 * @return The status of this instance
		 */
		public String getStatus() {
			return status;
		}

		/**
		 * Set the status of this instance
		 *
		 * @param status
		 *            The status of this instance
		 */
		public void setStatus(String status) {
			this.status = status;
		}
		
		/**
		 * Get the uptime
		 * 
		 * @return The time, in seconds, since this StatusMessage was created
		 */
		public long getUptime() {
			return ChronoUnit.SECONDS.between(timestamp, LocalDateTime.now());
		}
	}

	/**
	 * New instance.
	 *
	 */
	public StatusServlet() {
		this(new BaleenStatus());
	}

	/**
	 * New instance with a specific status
	 * 
	 * @param status Status to use
	 */
	public StatusServlet(BaleenStatus status) {
		super(LOGGER, StatusServlet.class);
		this.status = status;
	}

	@Override
	protected void get(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		respondWithJson(resp, status);
	}

}