import java.io.File;
import java.io.FileInputStream;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.text.DecimalFormat;
import java.util.Vector;


public class LogReader {
	private File filename;//要處理的文件
	private LogDealer   logdealer;//負責輸出數據. 
	
	public File getFilename() {
		return filename;
	}
	public void setFilename(File filename) {
		this.filename = filename;
	}
	public LogDealer getLogdealer() {
		return logdealer;
	}
	public void setLogdealer(LogDealer logdealer) {
		this.logdealer = logdealer;
	}
	/**
	 * 把日志文件映射成內存緩沖
	 * @param File f日志文件
	 * @return MappedByteBuffer 內存映射緩沖。
	 * @throws 考慮異常
	 * */
	private MappedByteBuffer  mappedFile2Buffer(File f) throws Exception{		
		FileInputStream fis=new FileInputStream(f);
		FileChannel fc=fis.getChannel();				
		return fc.map(FileChannel.MapMode.READ_ONLY, 0, f.length());
	}
	/**
	 * 讀取所有登錄日志，并按登入與登出分類放入數據結構
	 * @param  MappedByteBuffer buffer     日志文件的內存緩沖
	 *         Vector<LogRecord> logins    日志的登入數據
	 *         Vector<LogRecord> logouts   日志的登出數據
	 * @return void
	 * @throws 考慮異常        
	 * */
	private void readLog(MappedByteBuffer buffer,
			Vector<LogRecord> logins,Vector<LogRecord> logouts){
		int len=buffer.capacity()/372;//記錄條數
		for(int i=0;i<len;i++){//循環讀取數據			
			buffer.position(i*372);
			byte[]  busername=new byte[32];
			buffer.get(busername);//讀取用戶名
			String username=new String(busername).trim();
			if(username.startsWith(".")){continue;}
			LogRecord log=new LogRecord();
			log.setUsername(username);			
			buffer.get(new byte[4]);//跳4字節
			byte[] bdevice=new byte[32];//讀取設備類型
			buffer.get(bdevice);
			log.setDevice(new String(bdevice).trim());			
			log.setPid(buffer.getInt());//進程ID			
			short type=buffer.getShort();//登錄類型			
			buffer.get(new byte[6]);//跳6個字節
			log.setVisittime(buffer.getInt());//登錄時間
			buffer.get(new byte[30]);//跳30字節
			byte[] buserip=new byte[257];//客戶IP
			buffer.get(buserip);
			log.setUserip(new String(buserip).trim());
			//分類存放到數據結構.
			if(type==7){/*登入*/	logins.add(log);}
			if(type==8){/*登出*/	logouts.add(log);}
		}
		buffer.clear();
		buffer=null;
	}
	/**
	 * 把登錄數據按一個登入一個登出匹配成一條完整的登錄過程記錄。
	 * @param  Vector<LogRecord> logins		日志的登入數據
	 *         Vector<LogRecord> logouts	日志的登出數據
	 * @return Vector<MatchedRecord> 所有完整的登入/登出記錄
	 * @throws 考慮異常        
	 * */
	private Vector<MatchedRecord> match(Vector<LogRecord> logins,Vector<LogRecord> logouts){
		Vector<MatchedRecord> re=new Vector<MatchedRecord>();/** 循環匹配查找.找到:就得到匹配數據* 找不到:就表示在線**/
		int num=logins.size();		
		NEXT:for(int i=0;i<num;i++){
			LogRecord login=logins.get(0);
			MatchedRecord matched=new MatchedRecord();
			matched.setUsername(login.getUsername());matched.setDevice(login.getDevice());
			matched.setUserip(login.getUserip());matched.setLogintime(login.getVisittime());
			for(int j=0;j<logouts.size();j++){				
				LogRecord logout=logouts.get(j);				
				if(login.equals(logout)){//匹配										
					matched.setLogouttime(logout.getVisittime());//匹配成功,則生成一條登錄數據					
					long duration=logout.getVisittime()-login.getVisittime();
					int days=(int)(duration/(24*60*60));
					duration=(int)(duration-days*(24*60*60));
					int hours=(int)(duration/(60*60));
					duration=(int)(duration-hours*(60*60));
					int minutes=(int)(duration/60);
					String sduration="";
					if(days>0){sduration+="<+"+days+">";}
					DecimalFormat format=new DecimalFormat("00");
					sduration+=format.format(hours)+":"+format.format(minutes);
					matched.setDuration(sduration);					
					logouts.remove(logout);/*刪除該登出數據*/logins.remove(login);//刪除該登入數據
					re.add(matched);continue NEXT;}}			 
			matched.setLogouttime(0);//沒有匹配成功，表示在線。
			matched.setDuration("仍然在登錄狀態");
			logins.remove(login);
			re.add(matched);}
		return re;
	}
	/**
	 * 得到所有的登錄歷史數據
	 * @param  無
	 * @return void
	 * @throws 考慮異常
	 * */
	public  void collect()throws Exception{
		MappedByteBuffer buffer=mappedFile2Buffer(filename);
		Vector<LogRecord> logins=new Vector<LogRecord>();
		Vector<LogRecord> logouts=new Vector<LogRecord>();
		readLog(buffer, logins, logouts);
		Vector<MatchedRecord> matched=match(logins,logouts);
		
		logdealer.deal(matched);
	}
}