import java.util.*;
import java.io.*;
/**
 * Class to facilitate input and output from the command line.
 */

public class Terminal {
    static StreamTokenizer tokenizer = 
	new StreamTokenizer(new InputStreamReader(System.in));
    static PrintStream outFile = null;
    static String fileName;
    static int callDepth = 0;
    static String prefix = "";
    
    /**
     * Start a transcript file that logs all input and output
     * <br>The file is saved to the same directory as the project file
     * <br>Under Windows 95, use Cafe/Word/WordPad to view the text file
     * @param fn string to call transcript file
     * @return none
     */
    
    public static void recognizeAsLetter(char c) 
    {
    	tokenizer.wordChars(c,c);
    }
    
    public static void startTranscript(String fn) 
    {
        fileName = fn;
        try {
            outFile = new PrintStream(new FileOutputStream(fileName));
            outFile.println("----- Transcript file " + fileName + " started "
                            + new Date());
            System.out.println("----- Writing output to the file: " + 
			       fn + ". ");
        }
        catch (IOException e) {
            System.out.println("IOException in startTranscript opening " + 
			       fn + "\n" + e);
        }
    }
    
    public static void readInputFromFile(String fn) 
    {
    	try {
	    InputStream is = new FileInputStream(fileName);
	    Reader r = new BufferedReader(new InputStreamReader(is));
	    tokenizer = new StreamTokenizer(r);
	    println("----- Reading input from the file: " + fn + ". ");
        }
        catch (IOException e) {
            System.out.println("IOException in readInputFromFile opening " + 
			       fn + "\n" + e);
        }
    }
    
    
    /**
     * Stop the transcript file from logging input and output
     * @return none
     */
    public static void stopTranscript() 
    {
        outFile.println("----- Transcript file " + fileName + " closed "
                        + new Date());
        outFile.close();
        outFile = null;
    }
    
    static String getPrefix(int i) 
    {
        if (i > 0)
	    return("| " + getPrefix(i-1));
        else
	    return("");
    }
    
    /**
     * Print a string to the command line with a carriage return.
     * <br>Indentation added if printCall and printReturn are used.
     * @param s string to output
     * @return none
     */
    public static void println(String s) 
    {
        if (outFile != null) outFile.println(prefix + s);
        System.out.println(prefix + s);
    }
    
    /**
     * Print a string to the command line.  No indentation is added.
     * @param s string to output
     * @return none
     */
    public static void print(String s) 
    {
        if (outFile != null) outFile.print(s);
	System.out.print(s);
	System.out.flush();
    }
    
    /**
     * Prints the current indentation to the command line.
     * @return none
     */
    public static void indent() 
    {
        System.out.print(prefix);
        System.out.flush();
        if (outFile != null) outFile.print(prefix);
    }
    
    /**
     * Print procedure call information to the command line with a
     * <br>carriage return.  Indentation is increased for future println
     * <br>and indent calls.
     * @param s procedure call information to output
     * @return none
     */
    public static void printCall(String s) 
    {
        println(s);
        callDepth++;
        prefix = getPrefix(callDepth);
    }
    
    /**
     * Print a return value to the command line with a
     * <br>carriage return.  Indentation is decreased for future println
     * <br>and indent calls.
     * @param s string (the formatted return value) to output
     * @return none
     */
    public static void printReturn(String s) 
    {
        callDepth--;
        prefix = getPrefix(callDepth);
        println(s);
    }
    
    /**
     * Read a double from the command line
     * @return a double
     */
    public static double readDouble() 
    {
        scanTo(tokenizer.TT_NUMBER);
	if (outFile != null) outFile.println("" + tokenizer.nval);
        return (tokenizer.nval);
    }
    
    /**
     * Read a integer from the command line
     * @return a integer
     */
    public static int readInt() 
    {
        scanTo(tokenizer.TT_NUMBER);
        if (outFile != null) outFile.println("" + (int) tokenizer.nval);
        return ((int) tokenizer.nval); //use Math.trunc??
    }
    
    /**
     * Read a string from the command line
     * @return a string
     */
    public static String readWord() 
    {
        scanTo(tokenizer.TT_WORD);
        if (tokenizer.sval != null) 
	    {
		if (outFile != null) outFile.println("" + tokenizer.sval);
		return(tokenizer.sval);
	    } 
	else 
	    {
		if (outFile != null) outFile.println("" + 
						     ((char) tokenizer.ttype));
		return("" + ((char) tokenizer.ttype));
	    }
    }
    
    static void scanTo(int tt) 
    {
	// scans to a given token type:
	// TT_NUMBER or TT_WORD
        boolean found = false;
        try {
            while (!found) 
		{
		    int ttype = tokenizer.nextToken();
		    if (ttype == tt) 
			{
			    found = true;
			}
		    else if (ttype == tokenizer.TT_EOF) 
			{
			    println("End of File reached while scanning for input.");
			    found = true;
			}
		    else if (ttype == tokenizer.TT_EOL) 
			{
			    // skip over end of line
			}
		    else if ((tt == tokenizer.TT_WORD)
			     && (ttype != tokenizer.TT_NUMBER)) 
			{
			    found = true;
			}
		}
        }
	
        catch (IOException e) {
            println("IOException while scanning for input.");
        }
    }
}