// $Id$

/**
 * @file
 * Override Drupal tabledrag methods to add support for nested fieldgroups.
 */

/**
 * Determine the valid indentations interval for the row at a given position
 * in the table.
 *
 * @param prevRow
 *   DOM object for the row before the tested position
 *   (or null for first position in the table).
 * @param nextRow
 *   DOM object for the row after the tested position
 *   (or null for last position in the table).
 */
Drupal.tableDrag.prototype.row.prototype.validIndentInterval = function (prevRow, nextRow) {
  var minIndent, maxIndent;

  // Minimum indentation:
  // Do not orphan the next row.
  minIndent = nextRow ? $('.indentation', nextRow).size() : 0;

  // Maximum indentation:
  if (!prevRow || ($(prevRow).is('.tabledrag-leaf') && !$('.indentation', prevRow).size() < $('.indentation', this.element).size())) {
    // Do not indent the first row in the table or 'root' rows.
    if (!prevRow) {
      maxIndent = 0;
    }
    else {
      maxIndent = $('.indentation', prevRow).size();
    }
  }
  else {
    // Do not go deeper than as a child of the previous row.
    maxIndent = $('.indentation', prevRow).size() + ($(prevRow).is('.tabledrag-leaf') ? 0 : 1);
    // Limit by the maximum allowed depth for the table.
    if (this.maxDepth) {
      maxIndent = Math.min(maxIndent, this.maxDepth - (this.groupDepth - this.indents));
    }
  }

  return {'min':minIndent, 'max':maxIndent};
}