package pad.prac1;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.util.Scanner;


public class EditableBufferedReader extends BufferedReader 
{
	/*
	 * MODE DEFINITIONS
	 */
	
	public static final int DEL_BACKWARD 	= 0;
	public static final int DEL_FORWARD 	= 1;
	public static final int INSERT 			= 0;
	public static final int OVERWRITE 		= 1;
	
	/*
	 * TYPE DEFINITIONS
	 */
	
	public static final int ESCAPE_SEQUENCE = 0;
	public static final int PRINTABLE 		= 1;
	public static final int NON_PRINTABLE 	= 2;
	
	/* KEY DEFINITIONS
	 * 
	 * ESC (0x1B) starts an escape sequence
	 * ESC+[+C (0x1B 0x5B 0x43) Cursor Forward
	 * ESC+[+D (0x1B 0x5B 0x44) Cursor Backward
	 * ESC+[+2+~ (0x1B 0x5B 0x32 0x7E) Insert
	 * ESC+[+3+~ (0x1B 0x5B 0x33 0x7E) Delete forward
	 * ESC+O+H (0x1B 0x4F 0x48) Home
	 * ESC+O+F (0x1B 0x4F 0x46) End
	 */
	
	public static final int RETURN_KEY 		= 0x0D;
	public static final int BACKSPACE 		= 0x08;
	public static final int BACKSPACE_DEL 	= 0x7F;
	public static final int ESC 			= 0x1B;
	public static final int ESC_SEQ 		= 0x5B;
	public static final int FORWARD 		= 0x43;
	public static final int BACKWARD		= 0x44;
	public static final int GOTO			= 0x48;
	public static final int DEL 			= 0x33;
	public static final int TILDE 			= 0x7E;
	public static final int HOME_END 		= 0x4F;
	public static final int HOME 			= 0x48;
	public static final int END 			= 0x46;
	public static final int INSERT_KEY		= 0x32;
	public static final int INS_SPACE		= 0x40;
	public static final int DEL_CHAR		= 0x50;
	public static final int EOF				= 0x04;
	public static final int LINE_FEED		= 0x0A;
	
	private Console console = new Console();
	private Line line = new Line(console);
	private boolean endOfFile 	= false;

	public EditableBufferedReader(Reader in)
	{
		super(in);
	}
	
	public EditableBufferedReader(Reader in, int sz)
	{
		super(in,sz);
	}
	
	private void setRaw() throws IOException, InterruptedException
	{
		String[] cmd = {"/bin/sh", "-c", "stty raw -echo </dev/tty"};
		Runtime.getRuntime().exec(cmd).waitFor();
	}
	
	private void unsetRaw() throws IOException, InterruptedException
	{
		String[] cmd = {"/bin/sh", "-c", "stty -raw echo </dev/tty"};
		Runtime.getRuntime().exec(cmd).waitFor();
	}
	
	private void parseKey() throws IOException
	{
		Scanner scanner = new Scanner(System.in);
        if(scanner.findWithinHorizon("(\\033)?", 0).length() > 0)
		{
			scanner.skip("(\\033)?");
			if(scanner.findWithinHorizon("(\\[)?", 0).length() > 0)
			{
				scanner.skip("(\\[)?");
	    		int character = (int)scanner.findWithinHorizon("(?s).{1}", 0).charAt(0);
	        	switch(character)
	        	{
			        case FORWARD:
						line.setCursorTo(line.getCursorPosition()+1);
					break;
						
					case BACKWARD:
						line.setCursorTo(line.getCursorPosition()-1);
					break;
					
					case DEL:
						line.delChar(DEL_FORWARD);
					break;
						
					case INSERT_KEY:
						line.toggleMode();
					break;
	        	}
	        	scanner.close();
	        	return;
    		}
			else if(scanner.findWithinHorizon("O?", 0).length() > 0)
			{
				scanner.skip("O?");
        		int character = (int)scanner.findWithinHorizon("(?s).{1}", 0).charAt(0);
            	switch(character)
            	{
    	        	case HOME:
    					line.setCursorTo(1);
    				break;
    					
    				case END:
    					line.setCursorTo(line.length()+1);
    				break;
            	}
            	scanner.close();
            	return;
			}
			scanner.close();
		}
        else
        {
        	int character = (int)scanner.findWithinHorizon("(?s).{1}", 0).charAt(0);
        	switch(character)
	        {
				case EOF:
					endOfFile = true;
				break;
				
				case BACKSPACE:
				case BACKSPACE_DEL:
					line.delChar(DEL_BACKWARD);
				break;
						
				case RETURN_KEY:
					character = LINE_FEED;
				default:
					line.addChar((char)character);
				break;
	        }
        	scanner.close();
	        return;
        }
	}
	
	public int read() throws IOException
	{
		return super.read();
	}
	
	public String readLine()
	{
		try 
		{
			setRaw();
		} 
		catch (Exception e) 
		{
			System.out.println("Couldn't set terminal in raw mode");
			return "";
		}
		try
		{
			while(!endOfFile)
			{
				parseKey();
			}
		}
		catch(Exception e)
		{
			System.out.println("Error reading line");
			return "";
		}
		try 
		{
			unsetRaw();
		} 
		catch (Exception e) 
		{
			System.out.println("Couldn't unset raw mode");
			return "";
		}
		System.out.println("");
		return line.toString();
	}
}