/* Copyright 2017 Mozilla Foundation
 *
 * 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
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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.
 */
'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.validateRangeRequestCapabilities = undefined;

var _util = require('../shared/util');

function validateRangeRequestCapabilities(_ref) {
  var getResponseHeader = _ref.getResponseHeader,
      isHttp = _ref.isHttp,
      rangeChunkSize = _ref.rangeChunkSize,
      disableRange = _ref.disableRange;

  (0, _util.assert)(rangeChunkSize > 0);
  var returnValues = {
    allowRangeRequests: false,
    suggestedLength: undefined
  };
  if (disableRange || !isHttp) {
    return returnValues;
  }
  if (getResponseHeader('Accept-Ranges') !== 'bytes') {
    return returnValues;
  }
  var contentEncoding = getResponseHeader('Content-Encoding') || 'identity';
  if (contentEncoding !== 'identity') {
    return returnValues;
  }
  var length = getResponseHeader('Content-Length');
  length = parseInt(length, 10);
  if (!(0, _util.isInt)(length)) {
    return returnValues;
  }
  returnValues.suggestedLength = length;
  if (length <= 2 * rangeChunkSize) {
    return returnValues;
  }
  returnValues.allowRangeRequests = true;
  return returnValues;
}
exports.validateRangeRequestCapabilities = validateRangeRequestCapabilities;