package assignment2;

import java.io.*;
import java.util.*;

public class FTPserver2 {


	static int isValidUser = 0;
	static int isUPPairValid = 0;
	static int isPortValid = 0;
	static int fileCount = 0;




	static void parse(String input) {
		String token;


		StringTokenizer tokenizedLine = new StringTokenizer(input, " \r\n", true);


		if (tokenizedLine.hasMoreTokens()) {
			token = tokenizedLine.nextToken();


			if (token.equalsIgnoreCase("user")) {
				if (tokenizedLine.hasMoreTokens()) {
					token = tokenizedLine.nextToken();

					String user = "";
					while (token.equals(" ")) {
						user += token;
						token = tokenizedLine.nextToken();
					}


					while(tokenizedLine.hasMoreTokens() && !token.equals("\r")) {
						user += token;
						token = tokenizedLine.nextToken();
					}


					char[] userChar = user.toCharArray();
					for (int i = 0; i < userChar.length; i++) {
						if ((int) userChar[i] <= 127) {
							continue;
						}
						else {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
					}


					if (token.equals("\r")) {
						if (tokenizedLine.hasMoreTokens()) {
							if (tokenizedLine.nextToken().equals("\n")) {
								if (user.equals(" ")) {
									System.out.println("501 Syntax error in parameter.");
									return;
								}
								else if (user.length() > 0 && isValidUser == 0) {
									System.out.println("331 Guest access OK, send password.");
									isValidUser = 1;
								}
								else if (user.length() > 0 && isValidUser == 1) {
									System.out.println("503 Bad sequence of commands.");
								}
								else {
									System.out.println("500 Syntax error, command unrecognized.");
									return;
								}
							}

							else {
								System.out.println("501 Syntax error in parameter.");
								return;
							}
						}
						else {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
					}
					else {
						if (token.equals("\n")) {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
						else {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
					}
				}
				else {
					System.out.println("500 Syntax error, command unrecognized.");
				}
			}

			else if (token.equalsIgnoreCase("pass")) {
				if (tokenizedLine.hasMoreTokens()) {
					token = tokenizedLine.nextToken();

					String pass = "";
					while (token.equals(" ")) {
						pass += token;
						token = tokenizedLine.nextToken();
					}


					while (tokenizedLine.hasMoreTokens() && !token.equals("\r")) {
						pass += token;
						token = tokenizedLine.nextToken();
					}

					char[] passChar = pass.toCharArray();
					for (int i = 0; i < passChar.length; i++) {
						if ((int) passChar[i] <= 127) {
							continue;
						}
						else {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
					}

					if (token.equals("\r")) {
						if (tokenizedLine.hasMoreTokens()) {
							if (tokenizedLine.nextToken().equals("\n")) {
								if (pass.equals(" ")) {
									System.out.println("501 Syntax error in parameter.");
									return;
								}
								else if (pass.length() > 0) {
									if (isValidUser == 1) {
										System.out.println("230 Guest login OK.");
										isUPPairValid = 1;
									}
									else {
										System.out.println("503 Bad sequence of commands.");
									}
								}
								else {
									System.out.println("500 Syntax error, command unrecognized.");
									return;
								}
							}
							else {
								System.out.println("501 Syntax error in parameter.");
								return;
							}
						}
						else {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
					}
					else {
						if (token.equals("\n")) {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
						else {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
					}
				}
				else {
					System.out.println("500 Syntax error, command unrecognized.");
				}
			}


			else if (token.equalsIgnoreCase("type")) {
				token = tokenizedLine.nextToken();
				while (token.equals(" ")) {
					token = tokenizedLine.nextToken();
				}
				if (tokenizedLine.hasMoreTokens()) {
					if (token.equals("A") || token.equals("I")) {
						if (tokenizedLine.hasMoreTokens()) {
							if (tokenizedLine.nextToken().equals("\r")) {
								if (tokenizedLine.hasMoreTokens()) {
									if (tokenizedLine.nextToken().equals("\n")) {
										if (isValidUser == 1 && isUPPairValid == 1) {
											System.out.println("200 Type set to " + token + ".");
										}
										else if ((isValidUser == 1 && isUPPairValid == 0)) {
											System.out.println("503 Bad sequence of commands.");
										}
										else {
											System.out.println("530 Not logged in.");
										}
									}
									else {
										System.out.println("501 Syntax error in parameter.");
									}
								}
								else {
									System.out.println("501 Syntax error in parameter.");
								}
							}
							else {
								System.out.println("501 Syntax error in parameter.");
							}
						}
						else {
							System.out.println("501 Syntax error in parameter.");
						}
					}
					else {
						System.out.println("501 Syntax error in parameter.");
					}
				}
				else {
					System.out.println("500 Syntax error, command unrecognized.");
				}
			}


			else if (token.equalsIgnoreCase("syst")) {
				if (tokenizedLine.hasMoreTokens()) {
					if (tokenizedLine.nextToken().equals("\r")) {
						if (tokenizedLine.hasMoreTokens()) {
							if (tokenizedLine.nextToken().equals("\n")) {
								if (isValidUser == 1 && isUPPairValid == 1) {
									System.out.println("215 UNIX Type: L8.");
								}
								else if ((isValidUser == 1 && isUPPairValid == 0)) {
									System.out.println("503 Bad sequence of commands.");
								}
								else {
									System.out.println("530 Not logged in.");
								}
							}
							else {
								System.out.println("501 Syntax error in parameter.");
							}
						}
						else {
							System.out.println("501 Syntax error in parameter.");
						}
					}
					else {
						System.out.println("501 Syntax error in parameter.");
					}
				}
				else {
					System.out.println("500 Syntax error, command unrecognized.");
				}

			}


			else if (token.equalsIgnoreCase("noop")) {
				if (tokenizedLine.hasMoreTokens()) {
					if (tokenizedLine.nextToken().equals("\r")) {
						if (tokenizedLine.hasMoreTokens()) {
							if (tokenizedLine.nextToken().equals("\n")) {
								if (isValidUser == 1 && isUPPairValid == 1) {
									System.out.println("200 Command OK.");
								}
								else if ((isValidUser == 1 && isUPPairValid == 0)) {
									System.out.println("503 Bad sequence of commands.");
								}
								else {
									System.out.println("530 Not logged in.");
								}
							}
							else {
								System.out.println("501 Syntax error in parameter.");
							}
						}
						else {
							System.out.println("501 Syntax error in parameter.");
						}
					}
					else {
						System.out.println("501 Syntax error in parameter.");
					}
				}
				else {
					System.out.println("500 Syntax error, command unrecognized.");
				}
			}

			else if (token.equalsIgnoreCase("port")) {
				if (tokenizedLine.hasMoreTokens()) {
					token = tokenizedLine.nextToken();

					String host = "";
					while (token.equals(" ")) {
						host += token;
						token = tokenizedLine.nextToken();
					}


					while (tokenizedLine.hasMoreTokens() && !token.equals("\r")) {
						host += token;
						token = tokenizedLine.nextToken();
					}

					char[] hostChar = host.toCharArray();

					for (int i = 0; i < hostChar.length; i++) {
						if ((int) hostChar[i] <= 255 && (int) hostChar[i] > 0) {
							continue;
						}
						else {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
					}

					if (token.equals("\r")) {
						if (tokenizedLine.hasMoreTokens()) {
							if (tokenizedLine.nextToken().equals("\n")) {
								String address = "";
								int portNum = 0;

								String[] split = host.split(",");
								if (split.length == 6) {
									if (isValidUser == 1 && isUPPairValid == 1) {
										for (int i = 0; i < 4; i++) {
											if (i < 4) {
												address += split[i]+ ".";
											}
											else {
												address += split[i];
											}
										}

										String pa1 = split[4];
										String pa2 = split[5];
										int port1 = Integer.parseInt(pa1);
										int port2 = Integer.parseInt(pa2);
										portNum = (port1 * 256) + port2;
										System.out.println("200 Port command successful (" + address + "," + portNum + ".");
										isPortValid = 1;
									}
									else if ((isValidUser == 1 && isUPPairValid == 0)) {
										System.out.println("503 Bad sequence of commands.");
									}
									else {
										System.out.println("530 Not logged in.");
									}
								}
								else {
									System.out.println("501 Syntax error in parameter.");
								}
							}
							else {
								System.out.println("501 Syntax error in parameter.");
							}
						}
						else {
							System.out.println("501 Syntax error in parameter.");
						}
					}
					else {
						System.out.println("501 Syntax error in parameter.");
					}
				}
				else {
					System.out.println("500 Syntax error, command unrecognized.");
				}
			}

			else if (token.equalsIgnoreCase("retr")) {
				if (tokenizedLine.hasMoreTokens()) {
					token = tokenizedLine.nextToken();


					if(!token.equals(" ")) {
						// Need to change the error
						System.out.println("ERROR -- command");
					}
					// String path = "";
					while (token.equals(" ")) {
						// path += token;
						token = tokenizedLine.nextToken();
					}

					while(token.charAt(0) == '/' || token.charAt(0) == '\\') {
						token = tokenizedLine.nextToken();
					}

					String path = "";
					while (tokenizedLine.hasMoreTokens() && !token.equals("\r")) {
						path += token;
						token = tokenizedLine.nextToken();
					}


					char[] pathChar = path.toCharArray();
					for (int i = 0; i < pathChar.length; i++) {
						if ((int) pathChar[i] <= 127 && (int) pathChar[i] >= 0) {
							continue;
						}
						else {
							System.out.println("501 Syntax error in parameter.");
							return;
						}
					}

					if (token.equals("\r")) {
						if (tokenizedLine.hasMoreTokens()) {
							if (tokenizedLine.nextToken().equals("\n")) {
								if (path.length() > 0) {
									System.out.println("150 File status okay.");
									fileCount++;

									try {
										copyFile(path);
									}
									catch (IOException e) {
										e.printStackTrace();
										System.out.println("550 File not found or access denied.");
									}
									return;
								}
								else {
									System.out.println("");
								}
							}

						}
					}
				}
			}
			else if (token.equalsIgnoreCase("quit")) {
				if (tokenizedLine.hasMoreTokens()) {
					if (tokenizedLine.nextToken().equals("\r")) {
						if (tokenizedLine.hasMoreTokens()) {
							if (tokenizedLine.nextToken().equals("\n")) {
								if (isValidUser == 1 && isUPPairValid == 1) {
									System.out.println("200 Command OK.");
								}
								else if ((isValidUser == 1 && isUPPairValid == 0)) {
									System.out.println("503 Bad sequence of commands.");
								}
								else {
									System.out.println("530 Not logged in.");
								}
							}
							else {
								System.out.println("501 Syntax error in parameter.");
							}
						}
						else {
							System.out.println("501 Syntax error in parameter.");
						}
					}
					else {
						System.out.println("501 Syntax error in parameter.");
					}
				}
				else {
					System.out.println("500 Syntax error, command unrecognized.");
				}
			}
			else if (isUPPairValid == 0) {
				System.out.println("530 Not logged in.");
			}
			else {
				System.out.println("500 Syntax error, command unrecognized.");
			}
		}
		else {
			System.out.println("500 Syntax error, command unrecognized.");
		}
	}

	private static void copyFile(String str) throws IOException {
		String file = "retr_files/file" + fileCount;
		FileInputStream in = null;
		FileOutputStream out = null;


		try {
			in = new FileInputStream(str);
			out = new FileOutputStream(file);

			int x;

			while((x = in.read()) != -1) {
				out.write(x);
			}

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

			if(out != null) {
				out.close();
			}
		} catch(IOException e) {
			e.printStackTrace();
		}
	}


	public static void main(String[] args) throws IOException {
		// Create a buffered reader to read in the lines
		BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
		// Store the lines in an ArrayList
		ArrayList<String> nexts = new ArrayList<String>();
		String next = "";
		int i = 0;
		i = input.read();

		// While the buffer is still open
		while(i != -1) {
			// Cast the integer to a char
			next += (char) i;
			if((char) i == '\r') {
				// While the newline isn't encountered, add to the list, reset
				i = input.read();
				if((char) i == '\n') {
					next += (char) i;
					nexts.add(next);
					next = "";
					i = input.read();
				} else {
					nexts.add(next);
					next = "";
				}

			} else if((char) i =='\n') {
				nexts.add(next);
				next = "";
				i = input.read();
			} else {
				i = input.read();
			}
		}

		for(int j = 0; j < nexts.size(); j++) {
			// Parsing each
			next = nexts.get(j);
			System.out.print(next);
			parse(next);
		}
	}
}