package edu.vt.marian.uip;

import java.io.*;
import java.net.*;
import java.util.*;
import java.text.DateFormat;

import edu.vt.marian.common.*;



/** 
    class name: uip_log_manager
    class description: this class is responsible for the uip_log management
	uses the services of class(es): debug
	designer(s): Jianxin Zhao (jxzhao@csgrad.cs.vt.edu)
	implementator(s): Xuelei Sun (xusun@csgrad.cs.vt.edu)
	finished time: December 8, 1998
	known bugs:
	JDK version: 1.1.5
	side effects:
*/

public class uip_log_manager
{

	public final static int OK = 0;
	public final static int WRITE_LOG_ERROR = -1;
	public final static int NO_WRITE = 1;
    public final static int NULL_FUNCTION = -2;

	/**
		this is for debug
	*/
	Debug debug;

	/**
		this is the log level flag
		0: null
		1: common log message
		2: function name
		3: function parameters
	*/
	private int logging_level = 0;

	/**
		this is the output stream
	*/
	private PrintWriter pw = null;

	/**
		this is the message separator string
	*/
	private String message_separator = "=================================================================================";

	/** these two variables are used to reduce the disk writing times
	*/
	private int writing_count = 0;
	private int writing_threhold = 20;


	/**
		method description:  this constructor create the uip_log_manager  
		uses the services of class(es): debug
		input parameter(s):  String dir, directory name of the uip_log_manager
                		     Debug debug, for debugging
		output parameter(s): none
		return value: none
		synchronization consideration: none
	*/
	public uip_log_manager(String dir, Debug debug)
	{
		//set debug
		this.debug = debug;

        //check the dir parameter
		if (dir == null)
		{
			debug.dumpTrace("class uip_log_manager, Method: constructor, null or empty directory named");
			return;
		}

		//open and read the config file
		BufferedReader in_config_file = null;
		try
		{
			//variables for the config file reading
			String line = null;
			StringTokenizer token_line = null;     
			String stoken = null;
			String s1 = null;

			//variables for temporary info read from the config file
			in_config_file = new BufferedReader(new FileReader(dir + "config"));

			line = in_config_file.readLine();
			while (line != null)
			{
				token_line = new StringTokenizer(line," ",false);
				if (token_line.countTokens() > 1) //in  case an empty line is encountered
				{
					//ignore empty lines and lines with only one token
					stoken = token_line.nextToken();
					if (!stoken.startsWith("#")) //ignore comments(begin with "#")
					{
						//for message seperator
						if (stoken.equals("message_separator"))
						{
							s1 = token_line.nextToken();
							message_separator = s1;
						}

						//for logging level
						else if (stoken.equals("logging_level"))
						{
							s1 = token_line.nextToken();
							try
							{
								logging_level = Integer.parseInt(s1);
							  
								if (logging_level < 0)
								{
									debug.dumpTrace("Class: uip_log_manger, Method constructor, invalid logging level" + Integer.toString(logging_level));
									logging_level = 0;
								}
							}
							catch (Exception e)
							{
								debug.dumpTrace("Class: uip_log_manger, Method: constructor, logging level is not an integer");
								logging_level = 0;
							}
						}//end logging_level				  

					}//end if not comments line

				} //end if token count > 1
				line = in_config_file.readLine();
			} //end while not null line
			
			in_config_file.close();
		}//end try open file	 
		catch (Exception e) 
		{
			debug.dumpTrace("Class: uip_log_manager, Method:constructor, error read config file.");
			try
			{
				in_config_file.close();
			}
			catch (Exception e1)
			{
                        	return;
            }
			return; 
		}


		//open the log file
		/*** Replaced by RKF 26May00.  Can this Calendar stuff be for real??
		Date current_time = new Date();
		String file_name = dir + Integer.toString(current_time.getYear() + 1900)
		 	+ "_" + Integer.toString(current_time.getMonth() + 1)
			+ "_" + Integer.toString(current_time.getDate() )
			+ "_" + Integer.toString(current_time.getHours())
			+ "_" + Integer.toString(current_time.getMinutes())
			+ "_" + Integer.toString(current_time.getSeconds());
		*/
		Calendar current_time = Calendar.getInstance();
		String file_name = dir + Integer.toString(current_time.get(Calendar.YEAR))
		 	+ "_" + Integer.toString(current_time.get(Calendar.MONTH) + 1)
			+ "_" + Integer.toString(current_time.get(Calendar.DAY_OF_MONTH) )
			+ "_" + Integer.toString(current_time.get(Calendar.HOUR_OF_DAY))
			+ "_" + Integer.toString(current_time.get(Calendar.MINUTE))
			+ "_" + Integer.toString(current_time.get(Calendar.SECOND));
		
		try
		{
			pw = new PrintWriter(new FileWriter(file_name));
		}
		catch (IOException e0)
		{
			debug.dumpTrace("class uip_log_manager, Method: constructor, create log file failed");
			try
			{
				pw.close();
			}
			catch (Exception e1)
			{
				;
			}
			return;
		}
		
		//write the first creation message
		DateFormat df = DateFormat.getInstance();
		pw.println(message_separator);
		pw.println("time: " + df.format(current_time.getTime()));
		pw.println("from: uip_log_manger");
		pw.println("message: start logging, logging level " + Integer.toString(logging_level));
		pw.flush();
	
	} //end of constructor	


	/**
		method description:  this method provides the smooth exit  
		uses the services of class(es): debug
		input parameter(s):  String condition
		output parameter(s): none
		return value: 	OK
                		WRITE_LOG_ERROR
		synchronization consideration: synchronized
	*/
	public synchronized int exit(String condition)
	{
        Date current_time = new Date();
		pw.println(message_separator);
		pw.println("time: " + current_time.toString());
		pw.println("from: uip_log_manger");
		pw.println("message: exit under condition: " + condition);
		pw.flush();
		pw.close();
                     
		return OK;
	}//end exit

	/**
		method description:	this method write the common log message
		uses the services of class(es): debug
		input parameter(s):  String caller_desc, caller description string
                		     String message, log message string
		output parameter(s): none
		return value: 	OK
				NO_WRITE
                                WRITE_LOG_ERROR
		synchronization consideration: synchronized
	*/
	public synchronized int write_log(String caller_desc, String message)
	{
        	//check the logging level and parameters
		if (logging_level == 0)
		{
			return NO_WRITE;
		}

		if ( (caller_desc == null) || (message == null) )
		{
			debug.dumpTrace("class: uip_log_manager, Method: write_log, null caller description or message");
		}

        //write the common message
        Date current_time = new Date();
		pw.println(message_separator);
		pw.println("time: " + current_time.toString());
		pw.println("from: " + caller_desc);
		pw.println("message: " + message);

		// not write disk every time
		writing_count++;
		if (writing_count > writing_threhold)
		{
			writing_count = 0;
			pw.flush();
		}

		return OK;
	}//end write log


	/**
		method description:	this method write the function passed log message
		uses the services of class(es): rpc_function debug
		input parameter(s):  String caller_desc, caller description string
				     String message, log message string
                                     rpc_function rpc
		output parameter(s): none
		return value: 	OK
				NO_WRITE
                                WRITE_LOG_ERROR
		synchronization consideration: synchronized
	*/
	public synchronized int log_function_passed (String caller_desc, String message, rpc_function rf)
	{
	      	//check the logging level and parameters
		if (logging_level < 1)
		{
			return NO_WRITE;
		}

		if ( rf == null )
		{
			debug.dumpTrace("class: uip_log_manager, Method: log_function passed, null rpc function");
			return NULL_FUNCTION;
		}

		if ( (caller_desc == null) || (message == null) )
		{
			debug.dumpTrace("class: uip_log_manager, Method: write_log, null caller description or message");
		}

        //write the common message
        Date current_time = new Date();
		pw.println(message_separator);
		pw.println("time: " + current_time.toString());
		pw.println("from: " + caller_desc);
		pw.println("message: " + message);

        //write the function
		if ( rf.to_stream(logging_level, pw) != rf.OK )
		{
			debug.dumpTrace("class uip_log_manger, Method: exit, error write log message");
			try
            {
				pw.close();
			}
			catch (Exception e1)
			{
				;
			}
			return WRITE_LOG_ERROR;
        }

		// not write disk every time
		writing_count++;
		if (writing_count > writing_threhold)
		{
			writing_count = 0;
			pw.flush();
		}

		return OK;
	}//end log function passed
}