package rebelsky.text;

/**
 * A simple representation of a multi-line block of text
 * surrounded by stars.
 *
 * @author Samuel A. Rebelsky
 * @author Everyone else in CSC152 2005S
 */
public class SurroundedText
  implements TextBlock
{

// +--------+--------------------------------------------------
// | Fields |
// +--------+

  /** 
   * The stuff that gets surrounded. 
   */
  TextBlock blob;


// +--------------+--------------------------------------------
// | Constructors |
// +--------------+

  /**
   * Surround a simple text block.
   *
   * @pre
   *   The block is not null
   * @exception Exception
   *   If the block is null.
   */
  public SurroundedText(TextBlock _blob)
    throws Exception
  {
    if (_blob == null)
      throw new Exception("Cannot surround null text");
    this.blob = _blob;
  } // SurroundedText(TextBlock)


// +----------------+------------------------------------------
// | Public Methods |
// +----------------+

  /**
   * Determine the width of the surrounded block.
   */
  public int getWidth()
  {
    return 4 + this.blob.getWidth();
  } // getWidth()

  /**
   * Determine the number of lines of the surrounded block.
   */
  public int getLines()
  {
    return 2 + this.blob.getLines();
  } // getLines()

  /**
   * Determine the nth line of this block.  Lines are numbered
   * starting with 0.  
   *
   * @exception Exception
   *   If an invalid line number is given.
   */
  public TextLine getLine(int n)
    throws Exception
  {
    if ( (n >= 1) && (n <= this.blob.getLines()) ) {
      return new TextLine("* " 
        + this.blob.getLine(n-1).atWidth(this.blob.getWidth()) 
        + " *");
    }
    else if ((n == 0) || (n == this.blob.getLines() + 1)) {
      String stars = "****";
      while (stars.length() < this.getWidth()) {
        stars = stars + stars;
      }
      return new TextLine(stars.substring(0,this.getWidth()));
    }
    else {
      throw new Exception("Invalid line number.");
    }
  } // getLine()

} // class SurroundedText