package rebelsky.text;

/**
 * A simple representation of a line or part of a line of text.
 * TextLines are much like Strings, but we make them a different
 * class for convenience (e.g., in case we want to add capabilities).
 *
 * @author Samuel A. Rebelsky
 * @author Everyone else in CSC152 2005S
 */
public class TextLine
  implements TextBlock
{

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

  /** The contents of the line. */
  String contents;

  /** A collection of spaces used for padding. */
  String spaces;

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

  /** Build a new TextLine from a string. */
  public TextLine(String _contents)
  {
    this.contents = _contents;
    this.spaces = " ";
  } // TextLine(String)


// +-------------------+---------------------------------------
// | TextBlock Methods |
// +-------------------+

  /** Get the width of this line. */
  public int getWidth()
  {
    return this.contents.length();
  } // getWidth()

  /** Get the number of lines in this block. */
  public int getLines()
  {
    return 1;
  } // getLines()

  /** Get a line of this block. */
  public TextLine getLine(int n)
    throws Exception
  {
    if (n == 0)
      return this;
    else
      throw new Exception("This block has only 1 line.");
  } // getLine(int)


// +---------------+-------------------------------------------
// | Other Methods |
// +---------------+

  /** Get the text on this line. */
  public String toString()
  {
    return this.contents;
  } // toString()

  /** Change the text on this line. */
  public void setContents(String newcontents)
  {
    this.contents = newcontents;
  } // setContents(String)

  /** Get this line represented as a specific width. */
  public String atWidth(int width)
  {
    // Remember the length of this line, since we use it
    // many times in the code to follow.
    int len = this.contents.length();
    if (len >= width)
      return this.contents.substring(0,width);
    else {
      while (len + this.spaces.length() < width) 
        this.spaces = this.spaces + this.spaces;
      return this.contents + this.spaces.substring(0, width-len);
    }
  } // atWidth(int)
} // class TextLine