package com.digi.config.util;

import com.digi.config.core.ControlledItem;
import com.digi.config.core.ControlledItemImpl;
import java.io.*;
import java.util.*;
import java.text.*;


/**
 * Defines an entry in the system log. Log entries are compound messages. At a minimum,
 * they include a primary text message. They can optionally include a detail message
 * a severity, and a service ID.
 *
 * Although it is possible for users to create SystemLogEntry's directly, typically
 * users will use the static helper methods found in the SystemLog class. See the
 * SystemLog class for details on how to do logging from a program.
 *
 * When SystemLogEntry objects are created users pass in a msg key. This key is used
 * to look up the primary text from the message property file. The msg key is also
 * used to look up the associated detail text, severity and service ID. The
 * associated field keys are produced by appending the following tags to the primary
 * msg key:
 *    _DETAILS  - key to the second level detailed text message
 *    _SEVERITY - key to the message severity (see below for valid values)
 *    _ID       - key to the message service id.
 *
 * The associated fields are optional, if they are not found in the message file,
 * then they will default to empty or (in the case of severity ) to the value passed
 * in on the constructor.
 *
 * Here is an example of a message stored in the Message file:
 *    MyMsg          = My normal parameterized {0} message.
 *    MyMsg_DETAILS  = My detailed parameterized {0} message that includes all the gory details \nand potential user actions.
 *    MyMsg_SEVERITY = 1
 *    MyMsg_ID       = common_023
 *
 *
 * The potential severity values are:
 *    0  DEBUG
 *    1  INFORMATION
 *    2  WARNING
 *    3  ERROR
 *    4  FATAL
 *
 * Detail messages can be multi-line with the \n seperator char delineating lines.
 *
 *
 * See the following classes for more information:
 *    SystemLog
 *    SystemLogEntry
 *    SystemLogCtlr
 *
 */
public class SystemLogEntry extends ControlledItemImpl implements ControlledItem {

    //==============================================================================
    //=                  Severity Constants
    //==============================================================================
    public final static int MSG_LEVEL_DEBUG      =0;
    public final static int MSG_LEVEL_INFORMATION=1;
    public final static int MSG_LEVEL_WARNING    =2;
    public final static int MSG_LEVEL_ERROR      =3;
    public final static int MSG_LEVEL_FATAL      =4;

    private final static long serialVersionUID=4795284070894478266L;

    //==============================================================================
    //=                  Instance Fields
    //==============================================================================

    /** The first level message text */
    private String baseMsg;

    /** The second level message */
    private String detailedMsg;

    /** The message severity */
    private int severity;

    /** The message service ID */
    private String serviceID;

    /** Exception Information */
    private ExceptionInfo exceptionInfo;

    /** Time that the Entry was created */
    private Calendar creationTime;

    /** The system that the Entry was created on */
    private String systemName;



    /**
     * Constructs a SystemLogEntry from a resource message and the specified
     * message parameters.
     *
     * If the resource bundle contains the optional detailed message then
     * that message will be created and attached to this entry.
     *
     * If the resource bundle contains the optional severity message then
     * it will be extracted and will override an passed in severity for this entry.
     *
     * @param msgId The id of the message in the resource bundle
     * @param msgParams The parameters of the message
     * @param detailedMsgParams The parameters of the optional detailed message.
     * @param severity The severity assigned to the entry
     */
    public SystemLogEntry(String msgId, Serializable[] msgParams, Serializable[] detailedMsgParams, int severity)
    throws MissingResourceException {
        this(msgId, msgParams, detailedMsgParams, severity, null);
    }



    /**
     * Constructs a SystemLogEntry from a resource message and the specified
     * message parameters.
     *
     * If the resource bundle contains the optional detailed message then
     * that message will be created and attached to this entry.
     *
     * If the resource bundle contains the optional severity message then
     * it will be extracted and will override an passed in severity for this entry.
     *
     * @param msgId The id of the message in the resource bundle
     * @param msgParams The parameters of the message
     * @param detailedMsgParams The parameters of the optional detailed message.
     * @param severity The severity assigned to the entry
     * @param t the exception info to be attached to the log entry (may be null)
     */
    public SystemLogEntry(String msgId, Serializable[] msgParams, Serializable[] detailedMsgParams, int severity, Throwable t) 
    throws MissingResourceException {

        // Get the base message form the msgRb
        baseMsg = getLocalizedMessage(msgId, msgParams, null);

        // Get the severity from the msgRb
        try {
            severity=Integer.parseInt(ConfigResource.getMsgRbStringForce(msgId+"_SEVERITY"));
        } catch (MissingResourceException e) {
            // no severity in the msgRb... default to passed in severity
        } catch (Exception e) {
            // bad value in the resource file, warn and then default to passed in severity
            SystemLog.log("InvalidResource", new Serializable[] { msgId+"_SEVERITY"});
        }
        this.severity=severity;

        // Get the serviceID from the msgRb
        try {
            serviceID=ConfigResource.getMsgRbStringForce(msgId+"_ID");
        } catch (MissingResourceException e) {
            // no serviceID in the msgRb... default to blank
            serviceID="";
        }

        // Get the detailed message from the msgRb
        try {
            if (ConfigResource.getMsgRbStringForce(msgId+"_DETAILS")!=null) {
                detailedMsg=getLocalizedMessage(msgId+"_DETAILS", detailedMsgParams, null);
            }
        } catch (MissingResourceException e) {
            // If it doesn't exist thats OK... this is an optional message.
            detailedMsg=null;
        }

        // If exception information was passed in, then record it
        if (t!=null) {
            exceptionInfo=new ExceptionInfo(t);
        }

        // Record the creation time
        creationTime=Calendar.getInstance();

        // Record the system name
        try {
            systemName=java.net.InetAddress.getLocalHost().getHostName();
        } catch (java.net.UnknownHostException e) {
            systemName="Unknown";
        }
    }

    static private String getLocalizedMessage(String msgId, Serializable[] msgParams, Locale locale) {
        String formatString = ConfigResource.getMsgRbString(msgId);
        MessageFormat messageFormat = new MessageFormat(formatString);
        StringBuffer result = new StringBuffer();
        if (locale==null) {
            locale = Locale.getDefault();
        }
        messageFormat.setLocale(locale);
        messageFormat.format(msgParams, result, new FieldPosition(0));
        return result.toString();
    }








    /**
     * Returns the localized primary message text for this entry
     */
    public String getMsg() {
//        String name = systemName+"              ";
//        return name.substring(0,11)+" "+baseMsg.getLocalizedText(null);
        return baseMsg;
    }

    /**
     * Returns the localized 2nd level message text for this entry
     */
    public String getDetailedMsg() {
        if (detailedMsg!=null) {
            return detailedMsg;
        }
        return null;
    }

    /**
     * Returns the severity associated with this entry
     */
    public int getSeverity() {
        return severity;
    }


    /**
     * Indicates if there is a detailed messages within this entry
     */
    public boolean hasDetailedMsg() {
        return(detailedMsg!=null);
    }

    /**
     * Return the SystemLogEntry text
     */
    public String toString() {
        return "SystemLogEntry = " +getMsg()+"::" +getDetailedMsg();
    }

    /**
     * Returns any associated exception information
     */
    public ExceptionInfo getExceptionInfo() {
        return exceptionInfo;
    }

    /**
     * Returns the time the log entry was created
     */
    public Calendar getCreationTime() {
        return creationTime;
    }

    /**
     * Returns the name of the system the log entry was created on
     */
    public String getSystemName() {
        return systemName;
    }

    /**
     * Returns the service ID associated with the log message
     */
    public String getServiceId() {
        return this.serviceID;
    }


    /**
     * Contains localized and serializable information about an exception that occured
     */
    public class ExceptionInfo implements Serializable {
        public String name;
        public String message;
        public String callStack;

        public ExceptionInfo(Throwable t) {
            name=t.getClass().getName();
            message=t.getMessage();
            StringWriter sw=new StringWriter();
            PrintWriter pw=new PrintWriter(sw);
            t.printStackTrace(pw);
            callStack=sw.getBuffer().toString();
        }
    }


}