function injectTradingViewWidget(targetSelector, config = {}) {
  const target = document.querySelector(targetSelector);
  if (!target) {
    console.warn(`[TradingView] Target "${targetSelector}" not found.`);
    return;
  }

  if (target.querySelector('.tradingview-widget-container')) {
    console.warn('[TradingView] Widget already injected, skipping.');
    return;
  }

  const defaults = {
    symbol: 'TVC:GOLD',
    colorTheme: 'dark',
    isTransparent: false,
    locale: 'en',
    width: '350'
  };

  const settings = { ...defaults, ...config };

  const wrapper = document.createElement('div');
  wrapper.className = 'tradingview-widget-container';
  wrapper.setAttribute('data-tv-injected', 'true');

  const widgetDiv = document.createElement('div');
  widgetDiv.className = 'tradingview-widget-container__widget';

  const credit = document.createElement('div');
  credit.className = 'tradingview-widget-copyright';
  credit.innerHTML = `<a href="https://www.tradingview.com/symbols/GOLD/?exchange=TVC"
    rel="noopener nofollow" target="_blank">
    <span class="blue-text">GOLD quote</span></a>
    <span class="trademark"> by TradingView</span>`;

  const script = document.createElement('script');
  script.type = 'text/javascript';
  script.src = 'https://s3.tradingview.com/external-embedding/embed-widget-single-quote.js';
  script.async = true;
  script.innerHTML = JSON.stringify(settings);

  script.addEventListener('error', () => {
    console.error('[TradingView] Failed to load widget script.');
  });

  wrapper.append(widgetDiv, credit, script);
  target.appendChild(wrapper);
}

document.addEventListener('DOMContentLoaded', () => {
  injectTradingViewWidget('#widget-container', {
    colorTheme: 'light',
    width: '400'
  });
});