/*
 * Copyright 2008-2019 by Emeric Vernat
 *
 *     This file is part of Java Melody.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.bull.javamelody.internal.model;

import java.io.Serializable;
import java.util.Date;

import javax.servlet.http.HttpServletRequest;

/**
 * Objet correspondant à une erreur dans filtre http ou dans logs à un instant t, avec son message, sa stackTrace
 * éventuelle et son utilisateur courant s'il est défini.
 * @author Emeric Vernat
 */
public class CounterError implements Serializable {
	public static final String REQUEST_KEY = "javamelody.request";
	private static final long serialVersionUID = 5690702786722045646L;
	@SuppressWarnings("all")
	private static final ThreadLocal<HttpServletRequest> HTTP_SERVLET_REQUEST_CONTEXT = new ThreadLocal<>();

	/**
	 * Max size of error message.
	 */
	private static final int MESSAGE_MAX_LENGTH = 1000;
	/**
	 * Max size of error stack-trace.
	 */
	private static final int STACKTRACE_MAX_LENGTH = 50000;

	private final long time;
	private final String remoteUser;
	private final String httpRequest;
	private final String message;
	private final String stackTrace;

	public CounterError(String message, String stackTrace) {
		super();
		assert message != null;
		this.time = System.currentTimeMillis();

		if (message.length() > MESSAGE_MAX_LENGTH) {
			// avoid possible memory errors as javamelody store 100 errors in memory
			this.message = message.substring(0, MESSAGE_MAX_LENGTH);
		} else {
			this.message = message;
		}

		if (stackTrace != null && stackTrace.length() > STACKTRACE_MAX_LENGTH) {
			this.stackTrace = stackTrace.substring(0, STACKTRACE_MAX_LENGTH);
		} else {
			this.stackTrace = stackTrace;
		}
		final HttpServletRequest currentRequest = getCurrentRequest();
		if (currentRequest == null) {
			this.remoteUser = null;
			this.httpRequest = null;
		} else {
			// unbindRequest pour éviter StackOverflowError dans le cas où getRemoteUser()
			// fait un log warn ou error. Par exemple, dans le cas d'un SSO comme
			// com.pixelpark.seraph.SSOAuthenticator.getUser (cf issue 24).
			unbindRequest();
			try {
				this.httpRequest = (String) currentRequest.getAttribute(REQUEST_KEY);
				this.remoteUser = currentRequest.getRemoteUser();
			} finally {
				bindRequest(currentRequest);
			}
		}
	}

	/**
	 * Définit la requête http (peut être nulle) pour le thread courant.
	 * @param request HttpServletRequest
	 */
	public static void bindRequest(HttpServletRequest request) {
		if (request != null) {
			HTTP_SERVLET_REQUEST_CONTEXT.set(request);
		}
	}

	/**
	 * Retourne la requête http pour le thread courant ou null si elle n'a pas été définie.
	 * @return HttpServletRequest
	 */
	private static HttpServletRequest getCurrentRequest() {
		return HTTP_SERVLET_REQUEST_CONTEXT.get();
	}

	/**
	 * Enlève le lien entre la requête http et le thread courant.
	 */
	public static void unbindRequest() {
		HTTP_SERVLET_REQUEST_CONTEXT.remove();
	}

	long getTime() {
		return time;
	}

	public Date getDate() {
		return new Date(time);
	}

	public String getRemoteUser() {
		return remoteUser;
	}

	public String getHttpRequest() {
		return httpRequest;
	}

	public String getMessage() {
		return message;
	}

	public String getStackTrace() {
		return stackTrace;
	}

	/** {@inheritDoc} */
	@Override
	public String toString() {
		return getClass().getSimpleName() + "[message=" + getMessage() + ']';
	}
}
