/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.oozie.service;

import org.apache.commons.logging.LogFactory;
import org.apache.log4j.LogManager;
import org.apache.log4j.PropertyConfigurator;
import org.apache.oozie.util.XLogFilter;
import org.apache.oozie.util.Instrumentable;
import org.apache.oozie.util.Instrumentation;
import org.apache.oozie.util.XLog;
import org.apache.oozie.util.XConfiguration;
import org.apache.oozie.BuildInfo;
import org.apache.oozie.ErrorCode;
import org.apache.hadoop.conf.Configuration;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Properties;
import java.util.Map;
import java.util.regex.Pattern;

/**
 * Built-in service that initializes and manages Logging via Log4j.
 * <p/>
 * Oozie Lo4gj default configuration file is <code>oozie-log4j.properties</code>.
 * <p/>
 * The file name can be changed by setting the Java System property <code>oozie.log4j.file</code>.
 * <p/>
 * The Log4j configuration files must be a properties file.
 * <p/>
 * The Log4j configuration file is first looked in the Oozie configuration directory see {@link ConfigurationService}.
 * If the file is not found there, it is looked in the classpath.
 * <p/>
 * If the Log4j configuration file is loaded from Oozie configuration directory, automatic reloading is enabled.
 * <p/>
 * If the Log4j configuration file is loaded from the classpath, automatic reloading is disabled.
 * <p/>
 * the automatic reloading interval is defined by the Java System property <code>oozie.log4j.reload</code>. The default
 * value is 10 seconds.
 * <p>
 * <p>
 * Unlike most of the other Services, XLogService isn't easily overridable because Services depends on XLogService being available
 */
public class XLogService implements Service, Instrumentable {
    private static final String INSTRUMENTATION_GROUP = "logging";

    /**
     * System property that indicates the logs directory.
     */
    public static final String OOZIE_LOG_DIR = "oozie.log.dir";

    /**
     * System property that indicates the log4j configuration file to load.
     */
    public static final String LOG4J_FILE = "oozie.log4j.file";

    /**
     * System property that indicates the reload interval of the configuration file.
     */
    public static final String LOG4J_RELOAD = "oozie.log4j.reload";

    /**
     * Default value for the log4j configuration file if {@link #LOG4J_FILE} is not set.
     */
    public static final String DEFAULT_LOG4J_PROPERTIES = "oozie-log4j.properties";

    /**
     * Default value for the reload interval if {@link #LOG4J_RELOAD} is not set.
     */
    public static final String DEFAULT_RELOAD_INTERVAL = "10";

    private XLog log;
    private long interval;
    private boolean fromClasspath;
    private String log4jFileName;
    private boolean logOverWS = true;

    private static final String STARTUP_MESSAGE = "{E}"
            + " ******************************************************************************* {E}"
            + "  STARTUP MSG: Oozie BUILD_VERSION [{0}] compiled by [{1}] on [{2}]{E}"
            + "  STARTUP MSG:       revision [{3}]@[{4}]{E}"
            + "*******************************************************************************";

    private String oozieLogPath;
    private String oozieLogName;
    private int oozieLogRotation = -1;

    public XLogService() {
    }
    
    public String getOozieLogPath() {
        return oozieLogPath;
    }
    
    public String getOozieLogName() {
        return oozieLogName;
    }

    /**
     * Initialize the log service.
     *
     * @param services services instance.
     * @throws ServiceException thrown if the log service could not be initialized.
     */
    public void init(Services services) throws ServiceException {
        String oozieHome = Services.getOozieHome();
        String oozieLogs = System.getProperty(OOZIE_LOG_DIR, oozieHome + "/logs");
        System.setProperty(OOZIE_LOG_DIR, oozieLogs);
        try {
            LogManager.resetConfiguration();
            log4jFileName = System.getProperty(LOG4J_FILE, DEFAULT_LOG4J_PROPERTIES);
            if (log4jFileName.contains("/")) {
                throw new ServiceException(ErrorCode.E0011, log4jFileName);
            }
            if (!log4jFileName.endsWith(".properties")) {
                throw new ServiceException(ErrorCode.E0012, log4jFileName);
            }
            String configPath = ConfigurationService.getConfigurationDirectory();
            File log4jFile = new File(configPath, log4jFileName);
            if (log4jFile.exists()) {
                fromClasspath = false;
            }
            else {
                ClassLoader cl = Thread.currentThread().getContextClassLoader();
                URL log4jUrl = cl.getResource(log4jFileName);
                if (log4jUrl == null) {
                    throw new ServiceException(ErrorCode.E0013, log4jFileName, configPath);
                }
                fromClasspath = true;
            }

            if (fromClasspath) {
                ClassLoader cl = Thread.currentThread().getContextClassLoader();
                URL log4jUrl = cl.getResource(log4jFileName);
                PropertyConfigurator.configure(log4jUrl);
            }
            else {
                interval = Long.parseLong(System.getProperty(LOG4J_RELOAD, DEFAULT_RELOAD_INTERVAL));
                PropertyConfigurator.configureAndWatch(log4jFile.toString(), interval * 1000);
            }

            log = new XLog(LogFactory.getLog(getClass()));

            log.info(XLog.OPS, STARTUP_MESSAGE, BuildInfo.getBuildInfo().getProperty(BuildInfo.BUILD_VERSION),
                    BuildInfo.getBuildInfo().getProperty(BuildInfo.BUILD_USER_NAME), BuildInfo.getBuildInfo()
                            .getProperty(BuildInfo.BUILD_TIME), BuildInfo.getBuildInfo().getProperty(
                            BuildInfo.BUILD_VC_REVISION), BuildInfo.getBuildInfo().getProperty(BuildInfo.BUILD_VC_URL));

            String from = (fromClasspath) ? "CLASSPATH" : configPath;
            String reload = (fromClasspath) ? "disabled" : Long.toString(interval) + " sec";
            log.info("Log4j configuration file [{0}]", log4jFileName);
            log.info("Log4j configuration file loaded from [{0}]", from);
            log.info("Log4j reload interval [{0}]", reload);

            XLog.Info.reset();
            XLog.Info.defineParameter(USER);
            XLog.Info.defineParameter(GROUP);
            XLogFilter.reset();
            XLogFilter.defineParameter(USER);
            XLogFilter.defineParameter(GROUP);

            // Getting configuration for oozie log via WS
            ClassLoader cl = Thread.currentThread().getContextClassLoader();
            InputStream is = (fromClasspath) ? cl.getResourceAsStream(log4jFileName) : new FileInputStream(log4jFile);
            extractInfoForLogWebService(is);
        }
        catch (IOException ex) {
            throw new ServiceException(ErrorCode.E0010, ex.getMessage(), ex);
        }
    }

    private void extractInfoForLogWebService(InputStream is) throws IOException {
        logOverWS = true;
        Properties props = new Properties();
        props.load(is);

        Configuration conf = new XConfiguration();
        for (Map.Entry entry : props.entrySet()) {
            conf.set((String) entry.getKey(), (String) entry.getValue());
        }
        String logFile = conf.get("log4j.appender.oozie.File");
        if (logFile == null) {
            log.warn("Oozie WS log will be disabled, missing property 'log4j.appender.oozie.File' for 'oozie' "
                    + "appender");
            logOverWS = false;
        }
        else {
            logFile = logFile.trim();
            int i = logFile.lastIndexOf("/");
            if (i == -1) {
                log.warn("Oozie WS log will be disabled, log file is not an absolute path [{0}] for 'oozie' appender",
                        logFile);
                logOverWS = false;
            }
            else {
                String appenderClass = conf.get("log4j.appender.oozie");
                if (appenderClass == null) {
                    log.warn("Oozie WS log will be disabled, missing property [log4j.appender.oozie]");
                    logOverWS = false;
                }
                else if (appenderClass.equals("org.apache.log4j.DailyRollingFileAppender")) {
                    String pattern = conf.get("log4j.appender.oozie.DatePattern");
                    if (pattern == null) {
                        log.warn("Oozie WS log will be disabled, missing property [log4j.appender.oozie.DatePattern]");
                        logOverWS = false;
                    }
                    else {
                        pattern = pattern.trim();
                        if (pattern.endsWith("HH")) {
                            oozieLogRotation = 60 * 60;
                        }
                        else if (pattern.endsWith("dd")) {
                                oozieLogRotation = 60 * 60 * 24;
                        }
                        else {
                            log.warn("Oozie WS log will be disabled, DatePattern [{0}] should end with 'HH' or 'dd'",
                                    pattern);
                            logOverWS = false;
                        }
                        if (oozieLogRotation > 0) {
                            oozieLogPath = logFile.substring(0, i);
                            oozieLogName = logFile.substring(i + 1);
                        }
                    }
                }
                else if (appenderClass.equals("org.apache.log4j.rolling.RollingFileAppender")) {
                    String pattern = conf.get("log4j.appender.oozie.RollingPolicy.FileNamePattern");
                    if (pattern == null) {
                        log.warn("Oozie WS log will be disabled, missing property "
                                + "[log4j.appender.oozie.RollingPolicy.FileNamePattern]");
                        logOverWS = false;
                    }
                    else {
                        pattern = pattern.trim();
                        if (pattern.matches(Pattern.quote(logFile) + ".*-%d\\{yyyy-MM-dd-HH\\}(\\.gz)?")) {
                            oozieLogRotation = 60 * 60;
                        }
                        else {
                            log.warn("Oozie WS log will be disabled, RollingPolicy.FileNamePattern [{0}] should end with " 
                                    + "'-%d{yyyy-MM-dd-HH}' or '-%d{yyyy-MM-dd-HH}.gz' and also start with the value of "
                                    + "log4j.appender.oozie.File [{1}]", pattern, logFile);
                            logOverWS = false;
                        }
                        if (oozieLogRotation > 0) {
                            oozieLogPath = logFile.substring(0, i);
                            oozieLogName = logFile.substring(i + 1);
                        }
                    }
                }
                else {
                    log.warn("Oozie WS log will be disabled, log4j.appender.oozie [" + appenderClass + "] should be "
                            + "either org.apache.log4j.DailyRollingFileAppender or org.apache.log4j.rolling.RollingFileAppender "
                            + "to enable it");
                    logOverWS = false;
                }
            }
        }
    }

    /**
     * Destroy the log service.
     */
    public void destroy() {
        LogManager.shutdown();
        XLog.Info.reset();
        XLogFilter.reset();
    }

    /**
     * Group log info constant.
     */
    public static final String USER = "USER";

    /**
     * Group log info constant.
     */
    public static final String GROUP = "GROUP";

    /**
     * Return the public interface for log service.
     *
     * @return {@link XLogService}.
     */
    public Class<? extends Service> getInterface() {
        return XLogService.class;
    }

    /**
     * Instruments the log service.
     * <p/>
     * It sets instrumentation variables indicating the config file, reload interval and if loaded from the classpath.
     *
     * @param instr instrumentation to use.
     */
    public void instrument(Instrumentation instr) {
        instr.addVariable(INSTRUMENTATION_GROUP, "config.file", new Instrumentation.Variable<String>() {
            public String getValue() {
                return log4jFileName;
            }
        });
        instr.addVariable(INSTRUMENTATION_GROUP, "reload.interval", new Instrumentation.Variable<Long>() {
            public Long getValue() {
                return interval;
            }
        });
        instr.addVariable(INSTRUMENTATION_GROUP, "from.classpath", new Instrumentation.Variable<Boolean>() {
            public Boolean getValue() {
                return fromClasspath;
            }
        });
        instr.addVariable(INSTRUMENTATION_GROUP, "log.over.web-service", new Instrumentation.Variable<Boolean>() {
            public Boolean getValue() {
                return logOverWS;
            }
        });
    }

    boolean getLogOverWS() {
        return logOverWS;
    }

    int getOozieLogRotation() {
        return oozieLogRotation;
    }

    String getLog4jProperties() {
        return log4jFileName;
    }

    boolean getFromClasspath() {
        return fromClasspath;
    }

}