// Telegram Bot for Marvel Panel - Full featured
// User commands: link, usage, subscription, unlink
// Admin commands: user management, stats, broadcast

function apiUrl(env, method) {
  return `https://api.telegram.org/bot${env.TELEGRAM_BOT_TOKEN}/${method}`;
}

async function tg(env, method, params) {
  const r = await fetch(apiUrl(env, method), {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(params)
  });
  return r.json();
}

async function send(env, chatId, text, extra = {}) {
  return tg(env, "sendMessage", { chat_id: chatId, text, parse_mode: "HTML", ...extra });
}

function gb(b) { return (b / 1073741824).toFixed(2); }
function esc(s) {
  return String(s ?? "").replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
}

async function isAdmin(env, kv, chatId) {
  const admin = await kv.get("gw:admin_chat");
  return admin === String(chatId);
}

async function getUserByChat(kv, chatId) {
  const uuid = await kv.get("gw:tg:" + chatId);
  if (!uuid) return null;
  return kv.get("gw:user:" + uuid, "json");
}

function userInfoText(u) {
  const quota = u.quotaBytes ? gb(u.quotaBytes) + " GB" : "Unlimited";
  const used = gb(u.usedTotal || 0) + " GB";
  const remaining = u.quotaBytes ? gb(u.quotaBytes - (u.usedTotal || 0)) + " GB" : "Unlimited";
  const exp = u.expiresAt ? new Date(u.expiresAt).toLocaleDateString("en-GB") : "Never";
  const pct = u.quotaBytes ? Math.min(100, (u.usedTotal || 0) / u.quotaBytes * 100).toFixed(1) : "0";
  const filled = Math.round(pct / 10);
  const bar = "█".repeat(filled) + "░".repeat(10 - filled);
  return `<b>${esc(u.name)}</b>\n${bar} ${pct}%\n\nQuota: ${quota}\nUsed: ${used}\nRemaining: ${remaining}\nExpires: ${exp}`;
}

export default {
  async fetch(request, env) {
    const url = new URL(request.url);
    const kv = env.BK_KV;
    if (!env.TELEGRAM_BOT_TOKEN) return new Response("Bot token not configured", { status: 500 });
    if (!kv) return new Response("KV not bound", { status: 500 });

    if (url.pathname === "/webhook" && request.method === "POST") {
      const update = await request.json();
      const msg = update.message;
      if (!msg || !msg.text) return new Response("OK");
      const chatId = msg.chat.id;
      const text = msg.text.trim();
      const parts = text.split(/\s+/);
      const cmd = parts[0];
      const args = parts.slice(1);
      const admin = await isAdmin(env, kv, chatId);

      // ─── /start ───
      if (cmd === "/start") {
        await send(env, chatId,
          "👋 <b>Panel Bot</b>\n\n" +
          "Link your account:\n<code>/link YOUR_UUID</code>\n\n" +
          "<b>Commands:</b>\n/usage — quota &amp; expiry\n/sub — subscription link\n/unlink — remove link" +
          (admin ? "\n\n<b>Admin:</b>\n/users — list users\n/adduser name quotaGB days\n/deluser uuid\n/stats — overview\n/broadcast msg" : ""));
        return new Response("OK");
      }

      // ─── /claim (first user becomes admin) ───
      if (cmd === "/claim") {
        const existing = await kv.get("gw:admin_chat");
        if (existing) {
          await send(env, chatId, admin ? "✅ You are the admin." : "❌ Admin already claimed.");
        } else {
          await kv.put("gw:admin_chat", String(chatId));
          await send(env, chatId, "✅ You are now the admin.\n\n/users — list users\n/adduser name quotaGB days\n/deluser uuid\n/stats\n/broadcast message");
        }
        return new Response("OK");
      }

      // ─── /link ───
      if (cmd === "/link") {
        const uuid = args[0] ? args[0].trim() : "";
        if (!uuid) { await send(env, chatId, "Usage: <code>/link YOUR_UUID</code>"); return new Response("OK"); }
        const user = await kv.get("gw:user:" + uuid, "json");
        if (!user) { await send(env, chatId, "❌ User not found."); return new Response("OK"); }
        if (user.revoked) { await send(env, chatId, "❌ This account is revoked."); return new Response("OK"); }
        await kv.put("gw:tg:" + chatId, uuid);
        await kv.put("gw:tgrev:" + uuid, String(chatId));
        await send(env, chatId, `✅ Linked to <b>${esc(user.name)}</b>!\n\n${userInfoText(user)}`);
        return new Response("OK");
      }

      // ─── /unlink ───
      if (cmd === "/unlink") {
        const uuid = await kv.get("gw:tg:" + chatId);
        if (uuid) { await kv.delete("gw:tg:" + chatId); await kv.delete("gw:tgrev:" + uuid); }
        await send(env, chatId, "✅ Unlinked.");
        return new Response("OK");
      }

      // ─── /usage ───
      if (cmd === "/usage") {
        const user = await getUserByChat(kv, chatId);
        if (!user) { await send(env, chatId, "Not linked. Use <code>/link YOUR_UUID</code> first."); return new Response("OK"); }
        await send(env, chatId, "📊 " + userInfoText(user));
        return new Response("OK");
      }

      // ─── /sub ───
      if (cmd === "/sub") {
        const uuid = await kv.get("gw:tg:" + chatId);
        if (!uuid) { await send(env, chatId, "Not linked. Use <code>/link YOUR_UUID</code> first."); return new Response("OK"); }
        const panelHost = env.PANEL_HOST || "shield-pixel-486.river-stone-88.workers.dev";
        await send(env, chatId, `🔗 <b>Subscription link:</b>\n<code>https://${panelHost}/sub/u/${uuid}</code>\n\nAdd it to v2rayNG under subscriptions.`);
        return new Response("OK");
      }

      // ─── Admin commands ───
      if (!admin) {
        await send(env, chatId, "Unknown command. Try /start");
        return new Response("OK");
      }

      // /users
      if (cmd === "/users") {
        const list = await kv.list({ prefix: "gw:user:" });
        if (!list.keys.length) { await send(env, chatId, "No users."); return new Response("OK"); }
        let out = `<b>👥 Users (${list.keys.length})</b>\n\n`;
        for (const k of list.keys.slice(0, 30)) {
          const u = await kv.get(k.name, "json");
          if (!u) continue;
          const pct = u.quotaBytes ? Math.round((u.usedTotal || 0) / u.quotaBytes * 100) : 0;
          const flag = u.revoked ? "🚫" : pct >= 90 ? "🔴" : pct >= 70 ? "🟡" : "🟢";
          const quotaStr = u.quotaBytes ? gb(u.quotaBytes) : "∞";
          out += `${flag} <b>${esc(u.name)}</b> — ${gb(u.usedTotal || 0)}/${quotaStr} GB\n<code>${u.uuid.slice(0, 8)}</code>\n\n`;
        }
        if (list.keys.length > 30) out += `…and ${list.keys.length - 30} more`;
        await send(env, chatId, out);
        return new Response("OK");
      }

      // /adduser name quotaGB days
      if (cmd === "/adduser") {
        const [name, quotaStr, daysStr] = args;
        if (!name) { await send(env, chatId, "Usage: <code>/adduser name quotaGB days</code>\nExample: <code>/adduser Ali 10 30</code>"); return new Response("OK"); }
        const uuid = crypto.randomUUID();
        const quotaGB = parseFloat(quotaStr) || 0;
        const days = parseFloat(daysStr) || 0;
        const user = {
          uuid, name,
          quotaBytes: quotaGB * 1073741824,
          usedTotal: 0,
          expiresAt: days > 0 ? Date.now() + days * 86400000 : 0,
          revoked: false, createdAt: Date.now()
        };
        await kv.put("gw:user:" + uuid, JSON.stringify(user));
        const panelHost = env.PANEL_HOST || "shield-pixel-486.river-stone-88.workers.dev";
        await send(env, chatId,
          `✅ User <b>${esc(name)}</b> created!\n\nUUID:\n<code>${uuid}</code>\n\nSub link:\n<code>https://${panelHost}/sub/u/${uuid}</code>`);
        return new Response("OK");
      }

      // /deluser uuid-prefix
      if (cmd === "/deluser") {
        const prefix = args[0];
        if (!prefix) { await send(env, chatId, "Usage: <code>/deluser uuid-prefix</code>"); return new Response("OK"); }
        const list = await kv.list({ prefix: "gw:user:" });
        const match = list.keys.find(k => k.name.replace("gw:user:", "").startsWith(prefix));
        if (!match) { await send(env, chatId, "❌ No user matches that prefix."); return new Response("OK"); }
        const uuid = match.name.replace("gw:user:", "");
        const u = await kv.get(match.name, "json");
        await kv.delete(match.name);
        const tgChat = await kv.get("gw:tgrev:" + uuid);
        if (tgChat) {
          await kv.delete("gw:tg:" + tgChat);
          await kv.delete("gw:tgrev:" + uuid);
          await send(env, tgChat, "⚠️ Your account has been removed by the admin.");
        }
        await send(env, chatId, `✅ Deleted <b>${esc(u && u.name ? u.name : uuid)}</b>`);
        return new Response("OK");
      }

      // /stats
      if (cmd === "/stats") {
        const list = await kv.list({ prefix: "gw:user:" });
        let totalQuota = 0, totalUsed = 0, revoked = 0, expired = 0;
        for (const k of list.keys) {
          const u = await kv.get(k.name, "json");
          if (!u) continue;
          totalQuota += u.quotaBytes || 0;
          totalUsed += u.usedTotal || 0;
          if (u.revoked) revoked++;
          if (u.expiresAt && Date.now() > u.expiresAt) expired++;
        }
        await send(env, chatId,
          `<b>📈 Stats</b>\n\nUsers: ${list.keys.length}\nRevoked: ${revoked}\nExpired: ${expired}\n\nTotal quota: ${gb(totalQuota)} GB\nTotal used: ${gb(totalUsed)} GB`);
        return new Response("OK");
      }

      // /broadcast message
      if (cmd === "/broadcast") {
        const message = text.slice("/broadcast".length).trim();
        if (!message) { await send(env, chatId, "Usage: <code>/broadcast your message</code>"); return new Response("OK"); }
        const list = await kv.list({ prefix: "gw:tgrev:" });
        let sent = 0;
        for (const k of list.keys) {
          const c = await kv.get(k.name);
          if (c) { await send(env, c, `📢 <b>Admin:</b>\n${esc(message)}`); sent++; }
        }
        await send(env, chatId, `✅ Broadcast sent to ${sent} linked users.`);
        return new Response("OK");
      }

      await send(env, chatId, "Unknown command. Try /start");
      return new Response("OK");
    }

    if (url.pathname === "/") return new Response("Panel Bot running. Webhook: /webhook");
    return new Response("Not found", { status: 404 });
  }
};