lucifer/webui/src/Helpers/lights.js

import {randId} from "./random";
import {notNullish, nullish} from "./null";
import {fetchGet} from "./fetcher";

const localData = {};
const callbacks = [];

export function subscribeToLight(lightId, callback) {
  const callbackId = randId();

  callbacks.push({callbackId, lightId, callback});

  if (lightId >= 0) {
    if (notNullish(localData[lightId])) {
      dispatch(localData[lightId]);
    }

    fetchOne(lightId);
  } else {
    const list = [];
    for (let key in localData) {
      if (localData.hasOwnProperty(key) && notNullish(localData[key])) {
        list.push(localData[key]);
      }
    }
    dispatch(list);

    fetchAll();
  }
}

function fetchAll() {
  fetchGet(`/light/`).then(({data, error}) => {
    if (error === null) {
      handleLights(data);
    }
  });
}

function fetchOne(id) {
  fetchGet(`/light/${id}`).then(({data, error}) => {
    if (error === null) {
      handleLight(data);
    }
  });
}

function handleLights(lights) {
  lights.forEach(l => handleLight(l));

  for (let key in localData) {
    if (localData.hasOwnProperty(key) && nullish(lights.find(l => l.id === key))) {
      delete localData[key];
    }
  }

  dispatch(lights);
}

function handleLight(light) {
  localData[light.id] = light;

  dispatch(light);
}

function dispatch(data) {
  if (Array.isArray(data)) {
    callbacks
      .filter(c => c !== null)
      .filter(c => c.lightId === -1)
      .forEach(c => c.callback(data));
  } else {
    callbacks
      .filter(c => c !== null)
      .filter(c => c.lightId === data.id)
      .forEach(c => c.callback(data));
  }
}