openmct/example/generator/StateGeneratorProvider.js

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 * Open MCT, Copyright (c) 2014-2023, United States Government
 * as represented by the Administrator of the National Aeronautics and Space
 * Administration. All rights reserved.
 *
 * 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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 * http://www.apache.org/licenses/LICENSE-2.0.
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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
 * under the License.
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define([], function () {
  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);
  };

  return StateGeneratorProvider;
});