/**
 * Telegram Local Polling Bridge
 * 
 * This script runs locally in Node and pulls messages from the Telegram Bot API,
 * forwarding them to the NestJS API webhook container. This lets you test the 
 * bot locally without needing public tunneling tools like Ngrok!
 * 
 * Usage:
 *   node scripts/telegram-poll.js
 */

import { readFileSync } from "node:fs";
import { resolve, dirname } from "node:path";
import { fileURLToPath } from "node:url";

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
const envPath = resolve(__dirname, "../infra/.env");

// 1. Simple Env Loader
function loadEnv() {
  try {
    const raw = readFileSync(envPath, "utf8");
    for (const line of raw.split("\n")) {
      const trimmed = line.trim();
      if (!trimmed || trimmed.startsWith("#")) continue;
      const eqIdx = trimmed.indexOf("=");
      if (eqIdx === -1) continue;
      const key = trimmed.slice(0, eqIdx).trim();
      const val = trimmed.slice(eqIdx + 1).trim();
      if (!process.env[key]) {
        process.env[key] = val;
      }
    }
  } catch (err) {
    console.warn("Could not load infra/.env file. Using system environment variables.");
  }
}

loadEnv();

const token = process.env.TELEGRAM_BOT_TOKEN;
if (!token) {
  console.error("❌ ERROR: TELEGRAM_BOT_TOKEN is not set in infra/.env");
  process.exit(1);
}

const API_URL = `https://api.telegram.org/bot${token}`;
const WEBHOOK_URL = `http://localhost:3001/api/webhooks/telegram`;

async function main() {
  console.log("🚀 Starting Telegram bot local polling bridge...");
  console.log(`🤖 Targeting webhook: ${WEBHOOK_URL}`);
  
  // Clear any existing remote webhook registration so polling is allowed
  try {
    const response = await fetch(`${API_URL}/deleteWebhook`);
    const resJson = await response.json();
    if (resJson.ok) {
      console.log("✅ Cleared any active remote webhook registrations.");
    }
  } catch (err) {
    console.error("⚠️ Failed to delete webhook registration:", err.message);
  }

  let offset = 0;
  while (true) {
    try {
      const response = await fetch(`${API_URL}/getUpdates?offset=${offset}&timeout=15`);
      const data = await response.json();
      
      if (!data.ok) {
        console.error("❌ Telegram API returned error:", data.description);
        await new Promise((resolve) => setTimeout(resolve, 5000));
        continue;
      }

      if (data.result && data.result.length > 0) {
        for (const update of data.result) {
          offset = update.update_id + 1;
          console.log(`\n📥 Received Telegram update_id: ${update.update_id}`);
          
          try {
            const postResponse = await fetch(WEBHOOK_URL, {
              method: "POST",
              headers: {
                "Content-Type": "application/json",
              },
              body: JSON.stringify(update),
            });
            
            const postResult = await postResponse.json();
            console.log(`📤 Forwarded to webhook. API response code: ${postResponse.status}`, postResult);
          } catch (postErr) {
            console.error("❌ Failed to forward update to local API webhook:", postErr.message);
          }
        }
      }
    } catch (err) {
      console.error("⚠️ Connection error during polling:", err.message);
      await new Promise((resolve) => setTimeout(resolve, 5000));
    }
  }
}

main().catch((err) => {
  console.error("💥 Fatal error:", err);
  process.exit(1);
});