/*-
 * ============LICENSE_START=======================================================
 * org.openecomp.aai
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * 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.
 * ============LICENSE_END=========================================================
 */

package org.openecomp.aai.logging;

import com.att.eelf.configuration.EELFLogger;
import com.att.eelf.configuration.EELFManager;
import org.json.JSONException;
import org.json.JSONObject;
import org.slf4j.MDC;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Iterator;
import java.util.UUID;
import java.util.concurrent.TimeUnit;

public class LoggingContext {

	public enum StatusCode {
		COMPLETE,
		ERROR
	}

	private static final EELFLogger LOGGER = EELFManager.getInstance().getLogger(LoggingContext.class);

	private static final String PREVIOUS_CONTEXT_KEY = "_PREVIOUS_CONTEXT";

	//ECOMP Specific Log Event Fields
	public static enum LoggingField {
		START_TIME("startTime"),
		REQUEST_ID("requestId"),
		SERVICE_INSTANCE_ID("serviceInstanceId"),
		SERVER_NAME("serverName"),
		SERVICE_NAME("serviceName"),
		PARTNER_NAME("partnerName"),
		STATUS_CODE("statusCode"),
		RESPONSE_CODE("responseCode"),
		RESPONSE_DESCRIPTION("responseDescription"),
		INSTANCE_UUID("instanceUUID"),
		SEVERITY("severity"),
		SERVER_IP_ADDRESS("serverIpAddress"),
		ELAPSED_TIME("elapsedTime"),
		SERVER("server"),
		CLIENT_IP_ADDRESS("clientIpAddress"),
		UNUSED("unused"),
		PROCESS_KEY("processKey"),
		CUSTOM_FIELD_1("customField1"),
		CUSTOM_FIELD_2("customField2"),
		CUSTOM_FIELD_3("customField3"),
		CUSTOM_FIELD_4("customField4"),
		
		//ECOMP Specific Metric Log Event Fields
		TARGET_ENTITY("targetEntity"),

		//A&AI Specific Log Event Fields
		COMPONENT("component"),
		STOP_WATCH_START("stopWatchStart");

		private final String text;

		private LoggingField(final String text) {
			this.text = text;
		}

		public String toString() {
			return text;
		}
	}


	public static void init() {
		LoggingContext.clear();
		LoggingContext.startTime();
		LoggingContext.server();
		LoggingContext.serverIpAddress();
	}

	private static void startTime() {
		MDC.put(LoggingField.START_TIME.toString(), LogFormatTools.getCurrentDateTime());
	}

	public static void requestId(UUID requestId) {
		MDC.put(LoggingField.REQUEST_ID.toString(), requestId.toString());
	}

	public static void requestId(String requestId) {
		try {
			MDC.put(LoggingField.REQUEST_ID.toString(), UUID.fromString(requestId).toString());
		} catch (IllegalArgumentException e) {
			final UUID generatedRequestUuid = UUID.randomUUID();
			MDC.put(LoggingField.REQUEST_ID.toString(), generatedRequestUuid.toString());
			LOGGER.warn("Unable to use UUID " + requestId + " (Not formatted properly). Using generated UUID=" + generatedRequestUuid);
		}
	}

	public static void serviceInstanceId(String serviceInstanceId) {
		MDC.put(LoggingField.SERVICE_INSTANCE_ID.toString(), serviceInstanceId);
	}

	public static void serverName(String serverName) {
		MDC.put(LoggingField.SERVER_NAME.toString(), serverName);
	}

	public static void serviceName(String serviceName) {
		MDC.put(LoggingField.SERVICE_NAME.toString(), serviceName);
	}

	public static void partnerName(String partnerName) {
		MDC.put(LoggingField.PARTNER_NAME.toString(), partnerName);
	}

	public static void statusCode(LoggingContext.StatusCode statusCode) {
		MDC.put(LoggingField.STATUS_CODE.toString(), statusCode.toString());
	}

	public static String responseCode() {
		return (String) MDC.get(LoggingField.RESPONSE_CODE.toString());
	}

	public static void responseCode(String responseCode) {
		MDC.put(LoggingField.RESPONSE_CODE.toString(), responseCode);
	}

	public static void responseDescription(String responseDescription) {
		MDC.put(LoggingField.RESPONSE_DESCRIPTION.toString(), responseDescription);
	}

	public static void instanceUuid(UUID instanceUuid) {
		MDC.put(LoggingField.INSTANCE_UUID.toString(), instanceUuid.toString());
	}

	public static void severity(int severity) {
		MDC.put(LoggingField.SEVERITY.toString(), String.valueOf(severity));
	}

	private static void serverIpAddress() {
		try {
			MDC.put(LoggingField.SERVER_IP_ADDRESS.toString(), InetAddress.getLocalHost().getHostAddress());
		} catch (UnknownHostException e) {
			LOGGER.warn("Unable to resolve server IP address - will not be displayed in logged events");
		}
	}

	public static void elapsedTime(long elapsedTime, TimeUnit timeUnit) {
		MDC.put(LoggingField.ELAPSED_TIME.toString(), String.valueOf(TimeUnit.MILLISECONDS.convert(elapsedTime, timeUnit)));
	}

	private static void server() {
		try {
			MDC.put(LoggingField.SERVER.toString(),  InetAddress.getLocalHost().getCanonicalHostName());
		} catch (UnknownHostException e) {
			LOGGER.warn("Unable to resolve server IP address - hostname will not be displayed in logged events");
		}
	}

	public static void clientIpAddress(InetAddress clientIpAddress) {
		MDC.put(LoggingField.CLIENT_IP_ADDRESS.toString(), clientIpAddress.getHostAddress());
	}

	public static void clientIpAddress(String clientIpAddress) {
		try {
			MDC.put(LoggingField.CLIENT_IP_ADDRESS.toString(), InetAddress.getByName(clientIpAddress).getHostAddress());
		} catch (UnknownHostException e) {
			//Ignore, will not be thrown since InetAddress.getByName(String) only
			//checks the validity of the passed in string
		}
	}

	public static void unused(String unused) {
		LOGGER.warn("Using field '" + LoggingField.UNUSED + "' (seems like this should go unused...)");
		MDC.put(LoggingField.UNUSED.toString(), unused);
	}

	public static void processKey(String processKey) {
		MDC.put(LoggingField.PROCESS_KEY.toString(), processKey);
	}

	public static void customField1(String customField1) {
		MDC.put(LoggingField.CUSTOM_FIELD_1.toString(), customField1);
	}

	public static void customField2(String customField2) {
		MDC.put(LoggingField.CUSTOM_FIELD_2.toString(), customField2);
	}

	public static void customField3(String customField3) {
		MDC.put(LoggingField.CUSTOM_FIELD_3.toString(), customField3);
	}

	public static void customField4(String customField4) {
		MDC.put(LoggingField.CUSTOM_FIELD_4.toString(), customField4);
	}

	public static void component(String component) {
		MDC.put(LoggingField.COMPONENT.toString(), component);
	}

	public static void targetEntity(String targetEntity) {
		MDC.put(LoggingField.TARGET_ENTITY.toString(), targetEntity);
	}

	public static void stopWatchStart() {
		MDC.put(LoggingField.STOP_WATCH_START.toString(), String.valueOf(System.nanoTime()));
	}

	public static double stopWatchStop() {
		final long stopWatchEnd = System.nanoTime();
		final Long stopWatchStart = Long.valueOf(MDC.get(LoggingField.STOP_WATCH_START.toString()));

		if (stopWatchStart == null) throw new StopWatchNotStartedException();

		MDC.remove(LoggingField.STOP_WATCH_START.toString());

		final double elapsedTimeMillis = (stopWatchEnd - stopWatchStart) / 1000.0 / 1000.0;

		LoggingContext.elapsedTime((long) elapsedTimeMillis, TimeUnit.MILLISECONDS);

		return elapsedTimeMillis;
	}

	public static void put(String key, String value) {
		MDC.put(key, value);
	}

	public static void clear() {
		MDC.clear();
	}

	public static void remove(String key) {
		MDC.remove(key);
	}

	public static void save() {
		final JSONObject context = new JSONObject();

		for (LoggingField field : LoggingField.values()) {
			if (field == LoggingField.ELAPSED_TIME) continue;

			try {
				context.put(field.toString(), MDC.get(field.toString()));
			} catch (JSONException e) {
				//Ignore - only occurs when the key is null (which can't happen)
				//			or the value is invalid (everything is converted to a string
				//			before it get put() to the MDC)
			}
		}

		MDC.put("_PREVIOUS_CONTEXT", context.toString());
	}

	public static void restore() {
		
		final String rawPreviousContext = MDC.get(PREVIOUS_CONTEXT_KEY);
	
		if (rawPreviousContext == null) {
			throw new LoggingContextNotExistsException();
		}

		try {
			final JSONObject previousContext = new JSONObject(rawPreviousContext);

			@SuppressWarnings("unchecked")
			final Iterator<String> keys = previousContext.keys();
	
			while (keys.hasNext()) {
				final String key = keys.next();

				try {
					MDC.put(key, previousContext.getString(key));
				} catch (JSONException e) {
					//Ignore, only occurs when the key is null (cannot happen)
					//			or the value is invalid (they are all strings)
				}
			}
	
			MDC.remove(PREVIOUS_CONTEXT_KEY);
		} catch (JSONException e) {
			//Ignore, the previousContext is serialized from a JSONObject
		}
	}
}