import { isAnyArray } from 'is-any-array';
import max from 'ml-array-max';
import min from 'ml-array-min';

function rescale(input) {
  var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};

  if (!isAnyArray(input)) {
    throw new TypeError('input must be an array');
  } else if (input.length === 0) {
    throw new TypeError('input must not be empty');
  }

  var output;

  if (options.output !== undefined) {
    if (!isAnyArray(options.output)) {
      throw new TypeError('output option must be an array if specified');
    }

    output = options.output;
  } else {
    output = new Array(input.length);
  }

  var currentMin = min(input);
  var currentMax = max(input);

  if (currentMin === currentMax) {
    throw new RangeError('minimum and maximum input values are equal. Cannot rescale a constant array');
  }

  var _options$min = options.min,
      minValue = _options$min === void 0 ? options.autoMinMax ? currentMin : 0 : _options$min,
      _options$max = options.max,
      maxValue = _options$max === void 0 ? options.autoMinMax ? currentMax : 1 : _options$max;

  if (minValue >= maxValue) {
    throw new RangeError('min option must be smaller than max option');
  }

  var factor = (maxValue - minValue) / (currentMax - currentMin);

  for (var i = 0; i < input.length; i++) {
    output[i] = (input[i] - currentMin) * factor + minValue;
  }

  return output;
}

export { rescale as default };