pokemon-stock-checker/chrome-extension/api-interceptor.js

// API Interceptor - Captures Pokemon Center API responses
// Injected into the page context to intercept fetch/XHR

(function() {
  'use strict';

  // Avoid double injection
  if (window.__pokemonMonitorInjected) return;
  window.__pokemonMonitorInjected = true;

  const API_PATTERNS = [
    '/tpci-ecommweb-api/product/',
    '/site/resourceapi/category/',
    '/tpci-ecommweb-api/review/',
    '/graphql',
  ];

  function isApiUrl(url) {
    return API_PATTERNS.some(pattern => url.includes(pattern));
  }

  function extractSkusFromData(data, skus = new Set()) {
    if (!data) return skus;

    if (typeof data === 'object') {
      // Look for SKU-like fields
      for (const key of ['sku', 'skuCode', 'productId', 'id', 'code']) {
        if (data[key] && typeof data[key] === 'string') {
          const value = data[key];
          // Pokemon Center SKUs: 699-17113, 191-85953, etc.
          if (/^\d{1,3}-\d{4,6}$/.test(value) || /^\d{5,}$/.test(value)) {
            skus.add(value);
          }
        }
      }

      // Recurse into nested objects/arrays
      for (const value of Object.values(data)) {
        if (typeof value === 'object') {
          extractSkusFromData(value, skus);
        }
      }
    }

    if (Array.isArray(data)) {
      for (const item of data) {
        extractSkusFromData(item, skus);
      }
    }

    return skus;
  }

  function sendToExtension(type, data) {
    window.postMessage({
      source: 'pokemon-api-interceptor',
      type: type,
      data: data
    }, '*');
  }

  // Intercept fetch
  const originalFetch = window.fetch;
  window.fetch = async function(...args) {
    const response = await originalFetch.apply(this, args);

    try {
      const url = typeof args[0] === 'string' ? args[0] : args[0]?.url || '';

      if (isApiUrl(url) && response.ok) {
        // Clone response so we can read it without consuming
        const clone = response.clone();
        const contentType = clone.headers.get('content-type') || '';

        if (contentType.includes('application/json')) {
          clone.json().then(data => {
            const skus = extractSkusFromData(data);

            sendToExtension('api-response', {
              url: url,
              timestamp: Date.now(),
              skuCount: skus.size,
              skus: Array.from(skus),
              preview: JSON.stringify(data).slice(0, 500)
            });
          }).catch(() => {});
        }
      }
    } catch (e) {
      // Silently ignore errors
    }

    return response;
  };

  // Intercept XMLHttpRequest
  const originalXhrOpen = XMLHttpRequest.prototype.open;
  const originalXhrSend = XMLHttpRequest.prototype.send;

  XMLHttpRequest.prototype.open = function(method, url, ...rest) {
    this._monitorUrl = url;
    return originalXhrOpen.apply(this, [method, url, ...rest]);
  };

  XMLHttpRequest.prototype.send = function(...args) {
    const xhr = this;
    const url = xhr._monitorUrl || '';

    if (isApiUrl(url)) {
      xhr.addEventListener('load', function() {
        try {
          if (xhr.status === 200) {
            const contentType = xhr.getResponseHeader('content-type') || '';
            if (contentType.includes('application/json')) {
              const data = JSON.parse(xhr.responseText);
              const skus = extractSkusFromData(data);

              sendToExtension('api-response', {
                url: url,
                timestamp: Date.now(),
                skuCount: skus.size,
                skus: Array.from(skus),
                preview: JSON.stringify(data).slice(0, 500)
              });
            }
          }
        } catch (e) {
          // Silently ignore
        }
      });
    }

    return originalXhrSend.apply(this, args);
  };

  console.log('[Pokemon Monitor] API interceptor active');

  // Also scan embedded page data for SKUs (handles server-side rendered pages)
  function scanPageForSkus() {
    const skus = new Set();

    // Method 1: Extract from product URLs in the page
    const productLinks = document.querySelectorAll('a[href*="/product/"]');
    productLinks.forEach(link => {
      const match = link.href.match(/\/product\/(\d{1,3}-\d{4,6})/);
      if (match) {
        skus.add(match[1]);
      }
    });

    // Method 2: Look for __NEXT_DATA__ (Next.js embedded data)
    const nextDataScript = document.getElementById('__NEXT_DATA__');
    if (nextDataScript) {
      try {
        const data = JSON.parse(nextDataScript.textContent);
        extractSkusFromData(data, skus);
      } catch (e) {}
    }

    // Method 3: Look for any script tags with JSON containing product data
    document.querySelectorAll('script[type="application/json"], script[type="application/ld+json"]').forEach(script => {
      try {
        const data = JSON.parse(script.textContent);
        extractSkusFromData(data, skus);
      } catch (e) {}
    });

    // Method 4: Look for data attributes on product elements
    document.querySelectorAll('[data-sku], [data-product-id], [data-product-sku]').forEach(el => {
      const sku = el.dataset.sku || el.dataset.productId || el.dataset.productSku;
      if (sku && /^\d{1,3}-\d{4,6}$/.test(sku)) {
        skus.add(sku);
      }
    });

    if (skus.size > 0) {
      console.log(`[Pokemon Monitor] Found ${skus.size} SKUs in page`);
      sendToExtension('api-response', {
        url: window.location.href,
        timestamp: Date.now(),
        skuCount: skus.size,
        skus: Array.from(skus),
        source: 'page-scan'
      });
    }
  }

  // Scan page after it loads
  if (document.readyState === 'complete') {
    setTimeout(scanPageForSkus, 1000);
  } else {
    window.addEventListener('load', () => setTimeout(scanPageForSkus, 1000));
  }

  // Re-scan when page content changes (for infinite scroll, etc.)
  let scanTimeout;
  const observer = new MutationObserver(() => {
    clearTimeout(scanTimeout);
    scanTimeout = setTimeout(scanPageForSkus, 2000);
  });

  // Start observing after initial load
  setTimeout(() => {
    observer.observe(document.body, { childList: true, subtree: true });
  }, 3000);
})();