package jalview.datamodel;

/**
 * Holds the aligned column positions (base 0) for one codon in a nucleotide
 * sequence, and (optionally) its peptide translation. The object is immutable
 * once created.
 * 
 * Example: in "G-AT-C-GA" the aligned codons are (0, 2, 3) and (5, 7, 8).
 * 
 * JBPComment: Is this useful anywhere other than jalview.analysis.Dna ?
 * 
 * @author gmcarstairs
 *
 */
public final class AlignedCodon
{
  public final int pos1;

  public final int pos2;

  public final int pos3;

  public final String product;

  public AlignedCodon(int i, int j, int k)
  {
    this(i, j, k, null);
  }

  public AlignedCodon(int i, int j, int k, String prod)
  {
    pos1 = i;
    pos2 = j;
    pos3 = k;
    product = prod;
  }

  /**
   * Returns the column position for the given base (1, 2, 3).
   * 
   * @param base
   * @return
   * @throws IllegalArgumentException
   *           if an argument value other than 1, 2 or 3 is supplied
   */
  public int getBaseColumn(int base)
  {
    if (base < 1 || base > 3)
    {
      throw new IllegalArgumentException(Integer.toString(base));
    }
    return base == 1 ? pos1 : (base == 2 ? pos2 : pos3);
  }

  /**
   * Two aligned codons are equal if all their base positions are the same. We
   * don't care about the protein product. This test is required for correct
   * alignment of translated gapped dna alignments (the same codon positions in
   * different sequences occupy the same column in the translated alignment).
   */
  @Override
  public boolean equals(Object o)
  {
    /*
     * Equality with null value required for consistency with
     * Dna.compareCodonPos
     */
    if (o == null)
    {
      return true;
    }
    if (!(o instanceof AlignedCodon))
    {
      return false;
    }
    AlignedCodon ac = (AlignedCodon) o;
    return (pos1 == ac.pos1 && pos2 == ac.pos2 && pos3 == ac.pos3);
  }

  @Override
  public String toString()
  {
    StringBuilder sb = new StringBuilder();
    sb.append("[").append(pos1).append(", ").append(pos2).append(", ")
            .append(pos3).append("]");
    return sb.toString();
  }
}