module.exports = stringify;

function getSerialize (fn, decycle) {
  var seen = [], keys = [];
  decycle = decycle || function(key, value) {
    return '[Circular ' + getPath(value, seen, keys) + ']'
  };
  return function(key, value) {
    var ret = value;
    if (typeof value === 'object' && value) {
      if (seen.indexOf(value) !== -1)
        ret = decycle(key, value);
      else {
        seen.push(value);
        keys.push(key);
      }
    }
    if (fn) ret = fn(key, ret);
    return ret;
  }
}

function getPath (value, seen, keys) {
  var index = seen.indexOf(value);
  var path = [ keys[index] ];
  for (index--; index >= 0; index--) {
    if (seen[index][ path[0] ] === value) {
      value = seen[index];
      path.unshift(keys[index]);
    }
  }
  return '~' + path.join('.');
}

function stringify(obj, fn, spaces, decycle) {
  return JSON.stringify(obj, getSerialize(fn, decycle), spaces);
}

stringify.getSerialize = getSerialize;