const STORE_KEY = "stun_nav_store";
const DEFAULT_SETTINGS = {
  browserTitle: "家中服务导航",
  brand: "STUN NAV",
  title: "家中服务",
  subtitle: "聚合 Lucky STUN 最新入口，一处打开所有家中应用"
};

function json(payload, status = 200) {
  return new Response(JSON.stringify(payload), {
    status,
    headers: {
      "content-type": "application/json; charset=utf-8",
      "cache-control": "no-store"
    }
  });
}

function firstValue(...values) {
  return values.find((value) => value !== undefined && value !== null && String(value).trim() !== "");
}

function trimText(value, fallback, maxLength = 80) {
  const text = String(firstValue(value, fallback)).trim();
  return text.slice(0, maxLength);
}

function sanitizeSettings(input = {}) {
  return {
    browserTitle: trimText(input.browserTitle, DEFAULT_SETTINGS.browserTitle, 80),
    brand: trimText(input.brand, DEFAULT_SETTINGS.brand, 40),
    title: trimText(input.title, DEFAULT_SETTINGS.title, 80),
    subtitle: trimText(input.subtitle, DEFAULT_SETTINGS.subtitle, 140)
  };
}

function slugify(value) {
  return String(value || "")
    .trim()
    .toLowerCase()
    .replace(/[^a-z0-9\u4e00-\u9fa5_-]+/gi, "-")
    .replace(/^-+|-+$/g, "")
    .slice(0, 80);
}

function normalizeUrl(value) {
  const raw = String(value || "").trim();
  if (!raw) return "";
  if (/^https?:\/\//i.test(raw)) return raw;
  return `http://${raw}`;
}

function buildUrl(input) {
  const directUrl = firstValue(input.url, input.href, input.link, input.target);
  if (directUrl) return normalizeUrl(String(directUrl));

  const addr = firstValue(input.addr, input.address, input.external, input.stun_addr);
  if (addr) return normalizeUrl(`${input.scheme || input.protocol || "http"}://${addr}`);

  const host = firstValue(input.host, input.ip, input.stun_ip);
  const port = firstValue(input.port, input.stun_port);
  if (!host || !port) return "";

  const path = firstValue(input.path, input.pathname) || "";
  return normalizeUrl(`${input.scheme || input.protocol || "http"}://${host}:${port}${path}`);
}

function getKv(env = {}) {
  return env.STUN_NAV_KV || env.stun_nav_kv || globalThis.STUN_NAV_KV || globalThis.stun_nav_kv || globalThis.my_kv;
}

function getWebhookToken(env = {}) {
  return env.WEBHOOK_TOKEN || globalThis.WEBHOOK_TOKEN || "";
}

function getRequestToken(request, url) {
  const auth = request.headers.get("authorization") || "";
  if (auth.toLowerCase().startsWith("bearer ")) return auth.slice(7).trim();
  return request.headers.get("x-webhook-token") || url.searchParams.get("token") || "";
}

function queryToObject(search = "") {
  const query = {};
  const raw = String(search || "").replace(/^\?/, "");
  if (!raw) return query;

  for (const pair of raw.split("&")) {
    if (!pair) continue;
    const [key, ...valueParts] = pair.split("=");
    const name = decodeURIComponent(key.replace(/\+/g, " "));
    const value = decodeURIComponent(valueParts.join("=").replace(/\+/g, " "));
    query[name] = value;
  }

  return query;
}

function timingSafeEqual(a, b) {
  const left = String(a);
  const right = String(b);
  let diff = left.length ^ right.length;
  const length = Math.max(left.length, right.length);
  for (let index = 0; index < length; index += 1) {
    diff |= left.charCodeAt(index % left.length || 0) ^ right.charCodeAt(index % right.length || 0);
  }
  return diff === 0;
}

function isAuthorized(request, url, env) {
  const expected = getWebhookToken(env);
  if (!expected) return true;
  return timingSafeEqual(getRequestToken(request, url), expected);
}

async function readBody(request) {
  const raw = (await request.text()).trim();
  if (!raw) return {};

  const contentType = request.headers.get("content-type") || "";
  if (contentType.includes("application/json")) return JSON.parse(raw);
  if (contentType.includes("application/x-www-form-urlencoded")) {
    return Object.fromEntries(new URLSearchParams(raw));
  }

  try {
    return JSON.parse(raw);
  } catch {
    return { url: raw };
  }
}

async function readStore(kv) {
  if (!kv) {
    throw new Error("KV namespace is not bound. Bind it with variable name STUN_NAV_KV.");
  }
  const data = (await kv.get(STORE_KEY, { type: "json" })) || {};
  return {
    settings: sanitizeSettings(data.settings || {}),
    services: Array.isArray(data.services) ? data.services : []
  };
}

async function writeStore(kv, data) {
  await kv.put(STORE_KEY, JSON.stringify({
    settings: sanitizeSettings(data.settings || {}),
    services: Array.isArray(data.services) ? data.services : []
  }));
}

function serviceFromWebhook(idFromPath, query, body) {
  const merged = { ...query, ...body };
  const name = firstValue(merged.name, merged.service, merged.title, idFromPath);
  const id = slugify(firstValue(merged.id, merged.key, idFromPath, name));
  const url = buildUrl(merged);
  const protocol = firstValue(merged.protocol, merged.scheme, "http");

  if (!id) return { error: "missing service id or name" };
  if (!url) return { error: "missing service url, addr, or host+port" };

  return {
    service: {
      id,
      name: String(name || id),
      url,
      group: String(firstValue(merged.group, merged.category, "默认")),
      protocol: String(protocol).replace(/:$/, ""),
      note: String(firstValue(merged.note, merged.description) || ""),
      updatedAt: new Date().toISOString()
    }
  };
}

async function listServices(kv) {
  const data = await readStore(kv);
  return json({
    ok: true,
    settings: data.settings,
    services: data.services.map((item) => ({
      id: item.id,
      name: item.name,
      url: item.url,
      group: item.group || "默认",
      note: item.note || "",
      updatedAt: item.updatedAt || item.createdAt || ""
    }))
  });
}

async function updateService(request, url, kv, idFromPath) {
  const body = request.method === "GET" ? {} : await readBody(request);
  const query = queryToObject(url.search);
  const result = serviceFromWebhook(idFromPath, query, body);
  if (result.error) return json({ ok: false, error: result.error }, 400);

  const data = await readStore(kv);
  const index = data.services.findIndex((item) => item.id === result.service.id);
  if (index >= 0) {
    data.services[index] = { ...data.services[index], ...result.service };
  } else {
    data.services.push({ createdAt: result.service.updatedAt, ...result.service });
  }

  data.services.sort((a, b) => `${a.group}${a.name}`.localeCompare(`${b.group}${b.name}`, "zh-Hans-CN"));
  await writeStore(kv, data);
  return json({ ok: true, service: result.service });
}

async function updateSettings(request, kv) {
  const body = await readBody(request);
  const data = await readStore(kv);
  data.settings = sanitizeSettings({ ...data.settings, ...body });
  await writeStore(kv, data);
  return json({ ok: true, settings: data.settings });
}

async function deleteService(kv, idFromPath) {
  const id = slugify(idFromPath);
  if (!id) return json({ ok: false, error: "missing service id" }, 400);

  const data = await readStore(kv);
  const before = data.services.length;
  data.services = data.services.filter((item) => item.id !== id);
  await writeStore(kv, data);
  return json({ ok: true, deleted: before !== data.services.length, id });
}

export async function onRequest({ request, env }) {
  try {
    const url = new URL(request.url);
    const kv = getKv(env);
    const path = url.pathname.replace(/^\/api\/?/, "");
    const parts = path.split("/").filter(Boolean).map(decodeURIComponent);

    if (request.method === "OPTIONS") return json({ ok: true });

    if (parts[0] === "services" && parts.length === 1 && request.method === "GET") {
      return await listServices(kv);
    }

    if (parts[0] === "webhook" && ["GET", "POST", "PUT", "PATCH"].includes(request.method)) {
      if (!isAuthorized(request, url, env)) return json({ ok: false, error: "invalid webhook token" }, 401);
      return await updateService(request, url, kv, parts[1] || "");
    }

    if (parts[0] === "settings" && ["POST", "PUT", "PATCH"].includes(request.method)) {
      if (!isAuthorized(request, url, env)) return json({ ok: false, error: "invalid webhook token" }, 401);
      return await updateSettings(request, kv);
    }

    if (parts[0] === "services" && parts[1] && request.method === "DELETE") {
      if (!isAuthorized(request, url, env)) return json({ ok: false, error: "invalid webhook token" }, 401);
      return await deleteService(kv, parts[1]);
    }

    return json({ ok: false, error: "not found" }, 404);
  } catch (error) {
    return json({ ok: false, error: error.message || "server error" }, 500);
  }
}