package at.gv.egiz.eaaf.utils.springboot.ajp.logging;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.MDC;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.stereotype.Component;

@Component
@EnableConfigurationProperties(LoggingProperties.class)
public class MdcEnhancerFilter implements Filter {

  /**
   * Logging properties.
   */
  @Autowired
  private LoggingProperties loggingProperties;

  /**
   * {@inheritDoc}
   */
  @Override
  public void doFilter(final ServletRequest servletRequest, final ServletResponse servletResponse,
      final FilterChain filterChain) throws IOException, ServletException {
    final HttpServletRequest request = (HttpServletRequest) servletRequest;

    String key;
    String value;
    for (final String header : loggingProperties.getMdc().getHeaders()) {
      key = loggingProperties.getMdc().getHeaderPrefix() + header + loggingProperties.getMdc()
          .getHeaderPostfix();
      value = request.getHeader(header);
      if (!StringUtils.isEmpty(value)) {
        MDC.put(key, value);
      } else if (loggingProperties.getMdc().getNullValue() != null) {
        MDC.put(key, loggingProperties.getMdc().getNullValue());
      }
    }

    for (final String cookie : loggingProperties.getMdc().getCookies()) {
      key = loggingProperties.getMdc().getCookiePrefix() + cookie + loggingProperties.getMdc()
          .getCookiePostfix();
      value = getCookie(cookie, request.getCookies());
      if (!StringUtils.isEmpty(value)) {
        MDC.put(key, value);
      } else if (loggingProperties.getMdc().getNullValue() != null) {
        MDC.put(key, loggingProperties.getMdc().getNullValue());
      }
    }

    Object object;
    for (final String attribute : loggingProperties.getMdc().getSessionAttributes()) {
      key = loggingProperties.getMdc().getSessionAttributePrefix() + attribute + loggingProperties.getMdc()
          .getSessionAttributePostfix();
      object = request.getSession(true).getAttribute(attribute);
      if (object != null) {
        MDC.put(key, object.toString());
      } else if (loggingProperties.getMdc().getNullValue() != null) {
        MDC.put(key, loggingProperties.getMdc().getNullValue());
      }
    }

    try {
      filterChain.doFilter(servletRequest, servletResponse);
    } finally {
      for (final String header : loggingProperties.getMdc().getHeaders()) {
        MDC.remove(header);
      }
      for (final String cookie : loggingProperties.getMdc().getCookies()) {
        MDC.remove(cookie);
      }
      for (final String attribute : loggingProperties.getMdc().getSessionAttributes()) {
        MDC.remove(attribute);
      }
    }
  }

  private static String getCookie(final String cookie, final Cookie[] cookies) {
    if (cookies == null || StringUtils.isEmpty(cookie)) {
      return null;
    }
    for (final Cookie c : cookies) {
      if (c.getName().equals(cookie)) {
        return c.getValue();
      }
    }
    return null;
  }
}