/////////////////////////////////////////////////////////////////////////////////
// Copyright 2019 StarkWare Industries Ltd.                                    //
//                                                                             //
// Licensed under the Apache License, Version 2.0 (the "License").             //
// You may not use this file except in compliance with the License.            //
// You may obtain a copy of the License at                                     //
//                                                                             //
// https://www.starkware.co/open-source-license/                               //
//                                                                             //
// Unless required by applicable law or agreed to in writing,                  //
// software distributed under the License is distributed on an "AS IS" BASIS,  //
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.    //
// See the License for the specific language governing permissions             //
// and limitations under the License.                                          //
/////////////////////////////////////////////////////////////////////////////////

import assert from 'assert';
import BN from 'bn.js';

/**
 Asserts input is equal to or greater than lowerBound and lower than upperBound.
 Assert message specifies inputName.
 input, lowerBound, and upperBound should be of type BN.
 inputName should be a string.
*/
function assertInRange(
  input: BN,
  lowerBound: BN,
  upperBound: BN,
  inputName = ''
) {
  const messageSuffix =
    inputName === '' ? 'invalid length' : `invalid ${inputName} length`;
  assert(
    input.gte(lowerBound) && input.lt(upperBound),
    `Message not signable, ${messageSuffix}.`
  );
}

class Range {
  constructor(public lowerBound: BN, public upperBound: BN) {}
}

/**
 Asserts that the input is within [lowerBound, upperBound) in at least one of the given ranges.
 Assert message specifies inputName.
 input should be of type BN.
 ranges should be a vector of Range objects.
 inputName should be a string.
*/
function assertInMultiRange(input: BN, ranges: Range[], inputName = '') {
  const messageSuffix =
    inputName === '' ? 'invalid length' : `invalid ${inputName} length`;
  for (let i = 0; i < ranges.length; i++) {
    if (input.gte(ranges[i].lowerBound) && input.lt(ranges[i].upperBound)) {
      return;
    }
  }
  assert(false, `Message not signable, ${messageSuffix}.`);
}

export {
  Range, // Class.
  assertInRange,
  assertInMultiRange // Function.
};