const express = require("express");
const fs = require("fs");
const path = require("path");

const app = express();
const PORT = process.env.PORT || 3000;
const BASE_FILE = path.join(__dirname, "data", "base.json");
const BASE_PATH = (process.env.BASE_PATH || "/").replace(/\/$/, "") || "/";

// Auth credentials from environment
const AUTH_LOGIN = process.env.SMS_LOGIN;
const AUTH_PASSWORD = process.env.SMS_PASSWORD;

// Router for all endpoints
const router = express.Router();

// Middleware
app.use(express.urlencoded({ extended: true }));
app.use(express.json());

// Ensure data directory and base.json exist
function ensureBaseFile() {
  const dataDir = path.dirname(BASE_FILE);
  if (!fs.existsSync(dataDir)) {
    fs.mkdirSync(dataDir, { recursive: true });
  }
  if (!fs.existsSync(BASE_FILE)) {
    fs.writeFileSync(BASE_FILE, JSON.stringify({ messages: [] }, null, 2));
  }
}

// Read messages from base.json
function readMessages() {
  ensureBaseFile();
  const data = fs.readFileSync(BASE_FILE, "utf8");
  return JSON.parse(data).messages;
}

// Write messages to base.json
function writeMessages(messages) {
  ensureBaseFile();
  fs.writeFileSync(BASE_FILE, JSON.stringify({ messages }, null, 2));
}

// POST /send-msg - receive and log SMS
router.post("/send", (req, res) => {
  const { login, psw, phones, mes } = req.body;

  if (!login || !psw || !phones || !mes) {
    return res.json({ error: "Отсутствуют обязательные параметры", error_code: 1 });
  }

  // Validate credentials
  if (login !== AUTH_LOGIN || psw !== AUTH_PASSWORD) {
    return res.json({ error: "Ошибка авторизации", error_code: 2 });
  }

  const message = {
    id: Date.now(),
    timestamp: new Date().toISOString(),
    login,
    phone: phones,
    message: mes,
  };

  const messages = readMessages();
  messages.push(message);
  writeMessages(messages);

  console.log(`[${message.timestamp}] SMS to ${phones}: ${mes}`);

  res.json({ id: message.id, cnt: 1 });
});

// GET /view-all-sms - view all logged messages
router.get("/view-all-sms", (req, res) => {
  const messages = readMessages();
  res.json({ messages });
});

// POST /clear-all-sms - clear all messages
router.post("/clear-all-sms", (req, res) => {
  writeMessages([]);
  console.log("All messages cleared");
  res.json({ status: "ok", message: "All messages cleared" });
});

// GET /balance - get account balance (SMSC API compatible)
router.get("/balance.php", (req, res) => {
  const { login, psw } = req.query;

  if (!login || !psw) {
    return res.json({ error: "Отсутствуют обязательные параметры", error_code: 1 });
  }

  if (login !== AUTH_LOGIN || psw !== AUTH_PASSWORD) {
    return res.json({ error: "Ошибка авторизации", error_code: 2 });
  }

  res.json({ balance: "1000.00" });
});

// Serve static files
router.use(express.static(path.join(__dirname, "public")));

// GET / - serve main page
router.get("/", (req, res) => {
  res.sendFile(path.join(__dirname, "public", "index.html"));
});

// Mount router at BASE_PATH
app.use(BASE_PATH, router);

// Initialize and start server
ensureBaseFile();
app.listen(PORT, () => {
  console.log(`SMS OTP Gateway running on port ${PORT}, base path: ${BASE_PATH}`);
});