PlatformIO_Esp32C3_BedCooler/data/www/components/temperature-card.js

class TemperatureCard extends HTMLElement {
  constructor() {
    super();
    this.source = null;
  }

  connectedCallback() {
    this.innerHTML = `
      <style>
        :host{display:block}section{height:100%;box-sizing:border-box}.liveValue{font-size:34px;font-weight:700;line-height:1.15;margin-top:10px}.secondaryValue{font-size:18px;font-weight:600;margin-top:2px}.state{display:inline-flex;align-items:center;gap:6px;margin-top:6px}.dot{width:9px;height:9px;border-radius:50%;background:#b3261e}.dot.on{background:#188038}
      </style>
      <section>
        <h3>Live temperature</h3>
        <div class="muted">Server-Sent Events</div>
        <div class="liveValue"><span id="temperatureC">--</span>&deg;C</div>
        <div class="secondaryValue"><span id="temperatureF">--</span>&deg;F</div>
        <div class="muted state"><span id="dot" class="dot"></span><span id="state">Disconnected</span></div>
      </section>`;
    window.addEventListener('app:login', event => this.start(event.detail.token));
    window.addEventListener('beforeunload', () => this.stop());
    if (window.App && window.App.token()) this.start(window.App.token());
  }

  disconnectedCallback() {
    this.stop();
  }

  setState(text, connected) {
    this.querySelector('#state').textContent = text;
    this.querySelector('#dot').classList.toggle('on', !!connected);
  }

  start(token) {
    this.stop();
    if (!token || !window.EventSource) {
      this.setState('Unavailable', false);
      return;
    }
    this.setState('Connecting', false);
    this.source = new EventSource('/api/temperature/events?token=' + encodeURIComponent(token));
    this.source.addEventListener('open', () => this.setState('Connected', true));
    this.source.addEventListener('temperature', event => {
      try {
        const json = JSON.parse(event.data);
        const connected = !!json.sensorConnected && json.temperatureC !== null && json.temperatureF !== null;
        this.querySelector('#temperatureC').textContent = connected ? Number(json.temperatureC).toFixed(2) : '--';
        this.querySelector('#temperatureF').textContent = connected ? Number(json.temperatureF).toFixed(2) : '--';
        this.setState(connected ? 'Connected' : 'Sensor unavailable', connected);
      } catch (error) {
        this.setState('Invalid event', false);
      }
    });
    this.source.addEventListener('error', () => this.setState('Reconnecting', false));
  }

  stop() {
    if (this.source) this.source.close();
    this.source = null;
  }
}

customElements.define('temperature-card', TemperatureCard);