content-source.js

(function () {
  if (window.__localStorageSyncSourceInjected) {
    return;
  }

  window.__localStorageSyncSourceInjected = true;

  safeSendMessage({ type: "TOKEN_SYNC_GET_SETTINGS" }, (response) => {
    const sourceDomains = response?.settings?.sourceDomains;
    const storageKeys = response?.settings?.storageKeys;

    if (!Array.isArray(sourceDomains) || !sourceDomains.includes(window.location.origin)) {
      return;
    }

    injectPageScript("page-source-bridge.js", () => {
      window.addEventListener("TOKEN_SYNC_SOURCE_STORAGE_CHANGED", (event) => {
        const key = event?.detail?.key;
        const value = event?.detail?.value;

        if (typeof key !== "string" || !key || typeof value !== "string" || !value) {
          return;
        }

        safeSendMessage({
          type: "TOKEN_SYNC_SOURCE_STORAGE_CHANGED",
          key,
          value
        });
      });

      window.dispatchEvent(
        new window.CustomEvent("TOKEN_SYNC_SOURCE_CONFIG", {
          detail: {
            storageKeys: Array.isArray(storageKeys) ? storageKeys : []
          }
        })
      );
    });
  });

  function injectPageScript(fileName, onLoad) {
    const script = document.createElement("script");
    script.src = chrome.runtime.getURL(fileName);
    script.async = false;
    script.onload = () => {
      onLoad?.();
      script.remove();
    };
    (document.head || document.documentElement).appendChild(script);
  }

  function safeSendMessage(message, callback) {
    try {
      if (!chrome?.runtime?.id) {
        callback?.(null);
        return;
      }

      chrome.runtime.sendMessage(message, (response) => {
        if (chrome.runtime.lastError) {
          callback?.(null);
          return;
        }

        callback?.(response);
      });
    } catch {
      callback?.(null);
    }
  }
})();