openmct/example/generator/StateGeneratorProvider.js

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 * Open MCT, Copyright (c) 2014-2024, United States Government
 * as represented by the Administrator of the National Aeronautics and Space
 * Administration. All rights reserved.
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 * Open MCT is licensed under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
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 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
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export default function StateGeneratorProvider() {}

function pointForTimestamp(timestamp, duration, name) {
  return {
    name: name,
    utc: Math.floor(timestamp / duration) * duration,
    value: Math.floor(timestamp / duration) % 2
  };
}

StateGeneratorProvider.prototype.supportsSubscribe = function (domainObject) {
  return domainObject.type === 'example.state-generator';
};

StateGeneratorProvider.prototype.subscribe = function (domainObject, callback) {
  var duration = domainObject.telemetry.duration * 1000;

  var interval = setInterval(function () {
    var now = Date.now();
    var datum = pointForTimestamp(now, duration, domainObject.name);
    datum.value = String(datum.value);
    callback(datum);
  }, duration);

  return function () {
    clearInterval(interval);
  };
};

StateGeneratorProvider.prototype.supportsRequest = function (domainObject, options) {
  return domainObject.type === 'example.state-generator';
};

StateGeneratorProvider.prototype.request = function (domainObject, options) {
  var start = options.start;
  var end = Math.min(Date.now(), options.end); // no future values
  var duration = domainObject.telemetry.duration * 1000;
  if (options.strategy === 'latest' || options.size === 1) {
    start = end;
  }

  var data = [];
  while (start <= end && data.length < 5000) {
    data.push(pointForTimestamp(start, duration, domainObject.name));
    start += duration;
  }

  return Promise.resolve(data);
};