package rebelsky.exam3;

import java.io.PrintWriter;
import java.io.BufferedReader;

/**
 * Something that permits interactive testing of linear
 * structures.
 *
 * @author Samuel A. Rebelsky
 * @version 1.0 of November 2005
 */
public class LinearTester
{
  /**
   * Run an interfactive test of ls using in and and out for
   * input and output.
   */
  public static void test(LinearStructure<String> ls,
                          BufferedReader in,
                          PrintWriter out)
  {
    String command;    // The user's command

    boolean done = false;
    instructions(out);
    while (!done) {
      out.print("Command? "); out.flush();
      try {
        command = in.readLine().toLowerCase();
      }
      catch (Exception e) {
        out.println("I/O problems.  Stopping. " + e);
        command = "quit";
      }
      if (command.equals("help")) {
        instructions(out);
      }
      else if (command.equals("get")) {
        try {
          out.println("Got '" + ls.get() + "'");
        }
        catch (Exception e) {
          out.println("Failed to get a value because " + e);
        }
      } // get
      else if (command.equals("status")) {
        out.println("Size: " + ls.size());
        out.println("Empty? " + ls.isEmpty());
        out.println("Full? " + ls.isFull());
      }
      else if (command.equals("put")) {
        out.print("Put what? "); out.flush();
        try {
          String putme = in.readLine();
          ls.put(putme);
        }
        catch (Exception e) {
          out.println("Failed to put because " + e);
        }
      } // put
      else if (command.equals("quit")) {
        done = true;
      }
      else {
        out.println("Do not understand '" + command + "'");
        instructions(out);
      }   
    } // while
  } // test(LinearStructure<String>, BufferedReader, PrintWriter)

  /**
   * Print the instructions.
   */
  static void instructions(PrintWriter out)
  {
    out.println("quit - stop the program");
    out.println("help - print these instructions");
    out.println("status - get the status of the structure");
    out.println("get - get an element from the structure");
    out.println("put - add an element to the structure");
  } // instructions(PrintWriter)
} // LinearTester