/**
 * Counts the number of empty lines between two AST nodes.
 *
 * Extracts the lines between the end of the left node and the start of the
 * right node, then counts only the completely empty lines (containing only
 * whitespace). This is used to determine if nodes are separated by newlines and
 * to enforce newline formatting rules.
 *
 * @example
 *
 * ```ts
 * // Source code:
 * // const a = 1;
 * //
 * // const b = 2;
 *
 * getLinesBetween(sourceCode, nodeA, nodeB)
 * // Returns: 1 (one empty line between nodes)
 * ```
 *
 * @example
 *
 * ```ts
 * // Source code:
 * // const a = 1;
 * // // comment
 * // const b = 2;
 *
 * getLinesBetween(sourceCode, nodeA, nodeB)
 * // Returns: 0 (no empty lines, comment line is not empty)
 * ```
 *
 * @param source - ESLint source code object containing the lines array.
 * @param left - Node or object containing the left/first node.
 * @param right - Node or object containing the right/second node.
 * @returns Number of empty lines between the two nodes.
 */
function getLinesBetween(source, left, right) {
  return source.lines
    .slice(left.node.loc.end.line, right.node.loc.start.line - 1)
    .filter(line => line.trim().length === 0).length
}
export { getLinesBetween }
