var balancedMatch = balanced;
function balanced(a, b, str) {
  if (a instanceof RegExp) a = maybeMatch(a, str);
  if (b instanceof RegExp) b = maybeMatch(b, str);
  var r = range(a, b, str);
  return r && {
    start: r[0],
    end: r[1],
    pre: str.slice(0, r[0]),
    body: str.slice(r[0] + a.length, r[1]),
    post: str.slice(r[1] + b.length)
  };
}
function maybeMatch(reg, str) {
  var m = str.match(reg);
  return m ? m[0] : null;
}
balanced.range = range;
function range(a, b, str) {
  var begs, beg, left, right, result;
  var ai = str.indexOf(a);
  var bi = str.indexOf(b, ai + 1);
  var i = ai;
  if (ai >= 0 && bi > 0) {
    if (a === b) {
      return [ai, bi];
    }
    begs = [];
    left = str.length;
    while (i >= 0 && !result) {
      if (i == ai) {
        begs.push(i);
        ai = str.indexOf(a, i + 1);
      } else if (begs.length == 1) {
        result = [begs.pop(), bi];
      } else {
        beg = begs.pop();
        if (beg < left) {
          left = beg;
          right = bi;
        }
        bi = str.indexOf(b, i + 1);
      }
      i = ai < bi && ai >= 0 ? ai : bi;
    }
    if (begs.length) {
      result = [left, right];
    }
  }
  return result;
}

export { balancedMatch };
