const START_DATE = '2018-05-24';
const TIME_STEP = 5 * 60; // secs

const SatellitesView = Kapsule({
  props: {
    satData: { default: [] },
    onTimeChange: { default: () => {}}
  },

  init(domNode, state) {
    const frameView = SatellitesFrame()(domNode);

    const timeStep = TIME_STEP * 1000;
    let time = new Date(START_DATE);
    const ticker = new FrameTicker.default();
    ticker.onTick.add(() => {
      time = new Date(+time + timeStep);
      state.onTimeChange(time);
      frameView
        .satellites(getSatPositions(state.satData, time))
        .time(time);
    });

    //

    function getSatPositions(sats, posTime) {
      const gmst = satellite.gstime(posTime); // Get sidereal time
      return sats
        .map(sat => {
          // x,y,z position / velocity
          const location = satellite.propagate(sat.satrec, posTime);

          if (!location.position) return null; // can't compute satellite pos

          // lat, lng, height
          sat.coords = satellite.eciToGeodetic(location.position, gmst);
          return sat;
        })
        .filter(d => d); // filter out nulls
    }
  },

  update(state) {}
});