import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashSet;

public class Client extends Thread {

	public static void main(String[] args) throws IOException, InterruptedException {
		
		int listenPort = 9009;
		String group = "public";
		
		
		if(args.length>=1)	//can change group with first command line argument
			group=args[0];
		if(args.length==2)	//can change port with second command line argument
			listenPort=Integer.parseInt(args[1]);		
		String server = "garyc.me:9009";
		
		ServerSocket ss= new ServerSocket(listenPort);
		ss.setSoTimeout(10000);	//only wait this many milliseconds for incoming connection
		System.out.println("Listening on port "+listenPort+". Please forward this port if necessary.\nNew files will show up in the 'incoming' directory");
		File incoming = new File("incoming");
		incoming.mkdir();	//create incoming dir
		File temp  = new File("temp");
		temp.mkdir();	//create temp dir
		File outgoing = new File("outgoing");	//create outgoing dir
		outgoing.mkdir();
		System.out.println("Place files in the 'outgoing' directory to send");		

		Socket serverSocket = new Socket(server.split(":")[0],Integer.parseInt(server.split(":")[1]));
		OutputStream serverOutputStream = serverSocket.getOutputStream();
		InputStream serverInputStream = serverSocket.getInputStream();
		serverOutputStream.write(("version:1;port:"+listenPort+";group:"+group+";").getBytes());
		String stats="";
		boolean idle = true;
		while (true){
			while(serverInputStream.available()>0){
				String[] serverData = readData(serverInputStream);
				if(serverData[0].equals("stats")){
					if(!stats.equals(serverData[1])){
						stats=serverData[1];
						String[] parts = stats.split(",");
						System.out.println("Currenly "+parts[1]+" users online in the '"+group+"' group ("+parts[0]+" globally)");
					}
				}
			}			
			///////////////////// Sender Part /////////////////////////
			File[] list = outgoing.listFiles();	//search outgoing directory for any files
			if(list.length>0){	//found file to send
				idle = false;
				serverOutputStream.write("status:busy;".getBytes());	//inform server we are busy
				serverOutputStream.flush();
				File file=list[0];	//get the first file in the list
				HashSet<String> sentTo = new HashSet<String>();	//list hosts we sent this file to already
				int sentCount = 0;	//number of times file was successfully sent
				if(file.isDirectory())	//trying to send directory
					System.out.println("\""+file.getName()+"\" is a directory. Skipping.");
				else	//is actually a file
				while(true){	//stop when we run out of hosts to send to
					while(serverInputStream.available()>0)	//drain server connection
						serverInputStream.read();
					serverOutputStream.write(("get:readyList;").getBytes());
					String[] serverData = readData(serverInputStream);
					String host=null;
					if(serverData[0].equals("readyList") && serverData.length==2){	//server sent readyList
						String[] hosts = serverData[1].split(",");
						for(int i=0;i<hosts.length;i++){
							if(!sentTo.contains(hosts[i])){
								host=hosts[i]; 
								break;
							}
						}
					}
					if(host==null){	//if we were unable to find ready receiver 
						if(sentTo.size()>0){	//if we sent this file to at least one host
							System.out.println("Sent file "+file.getName()+" to "+sentCount+" clients");
							break;	//go on to next file
						}
						//didnt send file
						break;	//try again later
					}
					sentTo.add(host);
					System.out.print("Sending file "+file.getName()+" to "+host.split("-")[0]+"...");
					Socket s;
					boolean error=false;
					try{
						s = new Socket(host.split("-")[0],Integer.parseInt(host.split("-")[1]));
						s.setSoTimeout(5000);
						
						sendFile(file , s.getOutputStream());

						s.close();
					}catch(Exception e){
						System.out.println("Connection error or duplicate file");
						error=true;
					}
					if(!error){
						System.out.println("Success!");
						sentCount++;
					}
				}
				if(sentTo.size()>0){	//if we actually attempted to send file
					File sent=new File("sent");
					sent.mkdir();
					File dest = new File(sent, file.getName());
					if(dest.exists())	//overwrite exitsing file
						dest.delete();
					dest = new File(sent, file.getName());
					file.renameTo(dest);
				}else{	//everyone is busy
					sleep((int)(Math.random()*5000));	//wait a random amount of time
				}
			}else if (!idle){
				System.out.println ("Done.");
				System.out.println("Place files in the \"outgoing\" directory to send");
				idle=true;
				serverOutputStream.write(("get:stats;").getBytes());
			}
			
			///////////////////// Receiver Part /////////////////////////
			serverOutputStream.write("status:ready;get:stats;".getBytes());	//inform server we are ready and want user stats
			serverOutputStream.flush();
			Socket s;
			try{
				s = ss.accept();	//this blocks while waiting for incoming connection
			}catch(java.net.SocketTimeoutException e){	//timeout
				continue;
			}
			serverOutputStream.write("status:busy;".getBytes());	//inform server we are busy
			serverOutputStream.flush();
			BufferedInputStream in = new BufferedInputStream(s.getInputStream());
			
			//input from sender should look like:
			//file:[file name]:[file size];[raw data]
			
			String[] input = readData(in);
			if(input[0].equals("file")){
				String filename=input[1];	//read filename from stream
				filename=filename.replace('/', '_');	//replace potentially dangerous characters
				filename=filename.replace('\\', '_');
				int size=Integer.parseInt(input[2]);
				File dest = new File (incoming, filename);
				System.out.print("Receiving file "+filename+" ("+size/1024+" KB) from "+s.getInetAddress().getHostAddress()+"...");
				if(dest.exists()){	//overwrite exitsing file
					System.out.println("already have file!");
					in.close();
					s.close();						
					continue;
				}
				
				File file = new File (temp, filename);
				BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(file));
				for(int i=0;i<size;i++)
					out.write(in.read());
				out.close();
				System.out.println("done!");
			
				file.renameTo(dest);	//move file from temp to incoming 
			}
			in.close();
			s.close();	
		}
	}
	
	//sends a file over the outputstream using custom protocol
	public static void sendFile(File file, OutputStream os) throws IOException {
		BufferedInputStream in = new BufferedInputStream(new FileInputStream(file));
		BufferedOutputStream out = new BufferedOutputStream(os);
		
		out.write(("file:"+file.getName()+":"+file.length()+";").getBytes());
		out.flush();
		byte[] buff = new byte[1024];
		byte[] bigbuff = new byte[1024*1024];
		int wrote=0;
		try {
			while(wrote < file.length()){
				if (file.length() - wrote >bigbuff.length){
					
					in.read(bigbuff);
					out.write(bigbuff);
					wrote += bigbuff.length;
				}
				if (file.length() - wrote >buff.length){
					in.read(buff);
					out.write(buff);
					wrote += buff.length;
				}
				out.write(in.read());
				wrote++;
			}
		} catch (IOException e) {
			in.close();
			out.write('0');
		}
		in.close();
		out.flush();
		out.close();
	}	
	
	//read a colon-separated "command" from input stream
	public static String[] readData(InputStream in) throws IOException{
		String out="";
		char c = ' ';
		while(true){	//forever
			c = (char)in.read();	//read a character from input stream
			if(c==';')	//stop when semicolon found
				break;
			out += c; 
		}		
		return out.split(":");
	}	

}