// File: UserInterface.java
//
// Author: Andrew H. Fagg
// 11/15/2
//
// User interaction with the file system.
//
// To Do:
//  nothing 
//

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

public class UserInterface {

    public UserInterface(FileSystem fs) {
	boolean flag = true;
	String str;
	int elem;
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String[] args;

	try{
	    // Loop for each line
	    while(flag) {

		System.out.print("\n> ");
		// Read the next line from the user
		do {
		    str = br.readLine();
		    if(str == null) {
			// Exit cleanly (useful when a file is the input)
			System.exit(0);
		    };
		    //System.out.println(str);
		}while(str.length() == 0);

		// Split the line into arguments that do not contain spaces
		//  the first substring is our command
		args = str.split("\\s+");

		try {
		    // Make sure there is a command
		    if(args.length > 0) {

			// Help
			if(args[0].equals("?") || args[0].equals("h")) {
			    System.out.println("?                          - Help");
			    System.out.println("append <fname1> <fname2>   - appends the contents of <fname1> onto <fname2>");
			    System.out.println("b                          - show the free block status");
			    System.out.println("c <fname>                  - create a file");
			    System.out.println("cat <fname>                - show the contents of the file");
			    System.out.println("export <fname1> <fname2>   - copy from external file <fname1> to Disk <fnam2>");
			    System.out.println("format                     - format the file system");
			    System.out.println("import <fname1> <fname2>   - copy from Disk <fname1> to external file <fnam2>");
			    System.out.println("h                          - Help");
			    System.out.println("ls <name>                  - list file/directory <name>");
			    System.out.println("mkdir <name>               - create a directory");
			    System.out.println("mv <fname1> <fname2>       - move a file");
			    System.out.println("rm <fname>                 - remove a file");
			    System.out.println("rmdir <name>               - remove a directory");
			    System.out.println("q                          - quit");

			}else if(args[0].equals("ls")) {

			    // List file/directory
			    
			    if(args.length == 1) {
				// Nothing specified - list the root directory
				fs.list("");
			    }else{
				fs.list(args[1]);
			    };
			}else if(args[0].equals("c")) {

			    // Create a file
			    if(args.length == 2) {
				fs.create(args[1]);
				System.out.println("File created.");
			    }else {
				System.out.println("Usage: c <fname>");
			    };
			}else if(args[0].equals("rm")) {

			    // Remove a file
			    if(args.length == 2) {
				fs.delete(args[1]);
				System.out.println("File deleted.");
			    }else {
				System.out.println("Usage: rm <fname>");
			    };
			}else if(args[0].equals("rmdir")) {

			    // Remove a directory
			    if(args.length == 2) {
				fs.deleteDir(args[1]);
				System.out.println("Directory deleted.");
			    }else {
				System.out.println("Usage: rmdir <fname>");
			    };
			}else if(args[0].equals("mkdir")) {

			    // Create a directory
			    if(args.length == 2) {
				fs.createDir(args[1]);
				System.out.println("Directory created.");
			    }else {
				System.out.println("Usage: mkdir <fname>");
			    };
			}else if(args[0].equals("format")) {

			    // Format the file system
			    if(args.length == 1) {
				fs.format();
				System.out.println("File sytem formatted.");
			    }else {
				System.out.println("Usage: format");
			    };
			}else if(args[0].equals("a")) {

			    // Append a few bytes to a file (a test command)
			    if(args.length == 2) {
				byte buf[] = new byte[]{'a', 'b', 'c', 'd'};
				fs.append(args[1], buf, buf.length);
			    }else {
				System.out.println("Usage: a <fname>");
			    };
			}else if(args[0].equals("cat")) {

			    // Show the contents of a file
			    if(args.length == 2) {
				byte[] bytes = fs.read(args[1]);
				if(bytes != null){
				    // Yes - there are bytes to be shown
				    String outstring = new String(bytes);
				    System.out.println(outstring);
				};
			    }else {
				System.out.println("Usage: cat <fname>");
			    };
			}else if(args[0].equals("b")) {

			    // Display the free blocks
			    fs.free_block.display();
			}else if(args[0].equals("q")) {

			    // Quit
			    flag = false;
			}else if(args[0].equals("import")) {

			    // Import a file
			    if(args.length == 3) {
				fs.fileImport(args[1], args[2]);
			    }else if(args.length == 2) {
				fs.fileImport(args[1], args[1]);
			    }else {
				System.out.println("Usage: import <fname1> [<fname2>]");
			    }
			}else if(args[0].equals("export")) {

			    // Export a file
			    if(args.length == 3) {
				fs.fileExport(args[1], args[2]);
			    }else if(args.length == 2) {
				fs.fileExport(args[1], args[1]);
			    }else {
				System.out.println("Usage: export <fname1> [<fname2>]");
			    }
			}else if(args[0].equals("cp")) {

			    // Copy a file
			    if(args.length == 3) {
				fs.fileCopy(args[1], args[2]);
			    }else {
				System.out.println("Usage: cp <fname1> <fname2>");
			    }
			}else if(args[0].equals("append")) {

			    // Append a file
			    if(args.length == 3) {
				fs.fileAppend(args[1], args[2]);
			    }else {
				System.out.println("Usage: append <fname1> <fname2>");
			    }
			}else if(args[0].equals("mv")) {

			    // Move a file
			    if(args.length == 3) {
				fs.move(args[1], args[2]);
			    }else {
				System.out.println("Usage: mv <fname1> <fname2>");
			    }
			}else if(args[0].equals("echo")) {
			    System.out.println(str);
			}else if(args[0].startsWith("#")) {
			    // Ignore these lines
			}else {

			    // Don't understand the command
			    System.out.println("?????");
			};
		    };
		}catch(FileSystemException e) {
		    System.out.println(e);
		};
	    };
	}catch(IOException e){System.out.println("ClientInteraction: IO error");};
    };

    public static void main(String args[]) {
	// Create the file system object
	FileSystem fs = new FileSystem();

	// Comment this back in if you want some additional debuggin information
	//fs.disk.debug_flag = true;

	// Start the user interface
	UserInterface ui = new UserInterface(fs);
    };
};