"use strict";

const CHROME_VERSION = "140.0.0.0";
const TARGET_HOSTS = [
  "netflix.com",
  "assets.nflxext.com"
];

function getOperatingSystem() {
  const ua = globalThis.navigator?.userAgent || "";
  const platform = globalThis.navigator?.platform || "";
  const userAgentDataPlatform = globalThis.navigator?.userAgentData?.platform || "";

  if (/Windows/i.test(ua) || /Win/i.test(platform) || /win/i.test(userAgentDataPlatform)) {
    return "win";
  }

  if (/Mac/i.test(ua) || /Mac/i.test(platform) || /mac/i.test(userAgentDataPlatform)) {
    return "mac";
  }

  if (/Linux/i.test(ua) || /Linux/i.test(platform) || /linux/i.test(userAgentDataPlatform)) {
    return "linux";
  }

  return "linux";
}

function getChromeLikeUserAgent() {
  const os = getOperatingSystem();

  switch (os) {
    case "mac":
      return `Mozilla/5.0 (Macintosh; Intel Mac OS X 14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/${CHROME_VERSION} Safari/537.36`;
    case "win":
      return `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/${CHROME_VERSION} Safari/537.36`;
    case "linux":
    default:
      return `Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/${CHROME_VERSION} Safari/537.36`;
  }
}

function isTargetHost(url) {
  try {
    const hostname = new URL(url).hostname.toLowerCase();

    return hostname === "netflix.com" ||
      hostname.endsWith(".netflix.com") ||
      hostname === "assets.nflxext.com" ||
      hostname.endsWith(".nflxext.com");
  } catch {
    return false;
  }
}

const browserApi = globalThis.browser || globalThis.chrome;

browserApi.webRequest.onBeforeSendHeaders.addListener(
  (details) => {
    if (!isTargetHost(details.url)) {
      return {};
    }

    const requestHeaders = details.requestHeaders ?? [];
    const userAgentValue = getChromeLikeUserAgent();
    let foundUserAgent = false;

    for (const header of requestHeaders) {
      if (header.name.toLowerCase() === "user-agent") {
        header.value = userAgentValue;
        foundUserAgent = true;
        break;
      }
    }

    if (!foundUserAgent) {
      requestHeaders.push({
        name: "User-Agent",
        value: userAgentValue
      });
    }

    return { requestHeaders };
  },
  {
    urls: [
      "*://netflix.com/*",
      "*://*.netflix.com/*",
      "*://assets.nflxext.com/*",
      "*://*.nflxext.com/*"
    ]
  },
  [
    "blocking",
    "requestHeaders"
  ]
);