import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Arrays;

public class Server{

	public static void main(String[] args) {
		ServerSocket server = null;
		Socket client = null;
		int port = 6789;
		InputStream in = null;
		OutputStream out = null;

		try {
			server = new ServerSocket(port);

			System.out.println("Awayting connection");

			if (server != null) {
				client = server.accept();
			}

			System.out.println("Connected with client");

			in = client.getInputStream();

			out = client.getOutputStream();

			BufferedReader clientReader = null;

			if (in != null) {
				clientReader = new BufferedReader(new InputStreamReader(in));
			}

			if (clientReader != null) {
				String line;
				while ((line = clientReader.readLine()) != null) {

					// Client request file list
					if (line.equals("list")) {
						System.out.println("Sending client file list");
						String[] fileList = new File("server").list();
						PrintWriter output = new PrintWriter(out, true);

						// Print formated fileList to stream
						for (int i = 0; i < fileList.length; i++) {
							output.println(i + ". " + fileList[i]);
						}
						output.println("-end-");
						System.out.println("File list sent");
					} // End file list

					// Client downloading file
					if (line.equals("get")) {
						String fileName = clientReader.readLine();

						System.out.println("Client requested - " + fileName);

						File file = new File("server\\" + fileName);

						System.out.println("File length " + file.length());
						FileInputStream fis = new FileInputStream(file);
						byte[] buffer = new byte[4096];

						// Send file length to client
						PrintWriter output = new PrintWriter(out, true);
						output.println(file.length());

						int count;
						while ((count = fis.read(buffer)) > 0) {
							System.out.println("writing " + count + " bytes");
							if (count < 4096) {
								buffer = Arrays.copyOf(buffer, count);
							}
							out.write(buffer);
							out.flush();
						}
						System.out.println("flush to stream");

						fis.close();
					}

					// Client upload file
					if (line.equals("put")){
						boolean error = false;
						String fileName = clientReader.readLine();

						System.out.println("Client uploading - "+fileName);
						String errorCheck = clientReader.readLine();
						int fileSize = -1;
						if (!errorCheck.equals("-CLIENT ERROR-")){
							fileSize = (int) Float.parseFloat(errorCheck);
						}else{
							error = true;
							String errorLine;
							while((errorLine = clientReader.readLine()) != null){
								if (errorLine.equals("-end-")){
									break;
								}else{
									System.out.println(errorLine);
								}
							}
						}

						if(!error){
							System.out.println("file size "+fileSize);

							File file = new File("server\\" + fileName);

							FileOutputStream fos = new FileOutputStream(file);
							DataInputStream dis = new DataInputStream(client.getInputStream());

							byte[] buffer = new byte[4096];
							int readBytes = 0;
							int count;
							while((count=dis.read(buffer)) > 0){
								System.out.println("Reading "+count+" Bytes");
								if (count < 4096){
									buffer = Arrays.copyOf(buffer, count);
								}
								fos.write(buffer);
								fos.flush();

								readBytes += count;
								System.out.println("Read a total of " + readBytes + " bytes");
								if (readBytes == fileSize) {
									break;
								}
								buffer = new byte[4096];
							}
							System.out.println("Flush to file");
							fos.close();

						}


					}

					// Client request exit
					if (line.equals("exit")) {
						System.out.println("Client request exit -> exiting");
						break;
					}
				}
			}

			if (clientReader != null) {
				clientReader.close();
			}

			if (in != null) {
				in.close();
			}

			if (out != null) {
				out.close();
			}
		} catch (NumberFormatException e) {
			e.printStackTrace();
			sendError(e, out);
		} catch (FileNotFoundException e) {
			e.printStackTrace();
			sendError(e, out);
		} catch (IOException e) {
			e.printStackTrace();
			sendError(e, out);
		} catch (Exception e) {
			e.printStackTrace();
			sendError(e, out);
		}

	}

	public static void sendError(Exception e, OutputStream out) {
		PrintWriter pw = new PrintWriter(out, true);
		pw.println("-SERVER ERROR-");
		e.printStackTrace(pw);
		pw.println("-end-");
	}

}