/**
 * server.js — Node.js CRUD (Express + PostgreSQL).
 *
 * Переменные окружения:
 *   PGHOST, PGPORT, PGDATABASE, PGUSER, PGPASSWORD
 *   TABLE_NAME (по умолчанию crud_items)
 *   PORT (по умолчанию 3000)
 *
 * При старте: CREATE TABLE IF NOT EXISTS.
 */
const express = require("express");
const { Pool } = require("pg");
const path = require("path");

const VERSION = "1.0.0";
const TABLE_NAME = process.env.TABLE_NAME || "crud_items";
const PORT = process.env.PORT || 3000;

const pool = new Pool({
  host: process.env.PGHOST || "127.0.0.1",
  port: parseInt(process.env.PGPORT || "5432"),
  database: process.env.PGDATABASE || "postgres",
  user: process.env.PGUSER || "postgres",
  password: process.env.PGPASSWORD || "",
  ssl: process.env.PGSSLMODE === "require" ? { rejectUnauthorized: false } : false,
});

const app = express();
app.use(express.urlencoded({ extended: true }));
app.use(express.static(path.join(__dirname, "public")));
app.set("view engine", "ejs");
app.set("views", path.join(__dirname, "views"));

// --- Инициализация БД ---
async function initDB() {
  const client = await pool.connect();
  try {
    await client.query(`
      CREATE TABLE IF NOT EXISTS ${TABLE_NAME} (
        id    SERIAL PRIMARY KEY,
        value TEXT NOT NULL DEFAULT ''
      )
    `);
  } finally {
    client.release();
  }
}

// --- Главная страница (GET + POST) ---
app.get("/", async (req, res) => {
  try {
    let editRow = null;
    if (req.query.edit) {
      const result = await pool.query(
        `SELECT id, value FROM ${TABLE_NAME} WHERE id = $1`,
        [parseInt(req.query.edit)]
      );
      if (result.rows.length > 0) editRow = result.rows[0];
    }

    const result = await pool.query(
      `SELECT id, value FROM ${TABLE_NAME} ORDER BY id`
    );

    res.render("index", {
      table_name: TABLE_NAME,
      rows: result.rows,
      editRow,
      version: VERSION,
    });
  } catch (err) {
    res.status(500).send(err.message);
  }
});

app.post("/", async (req, res) => {
  try {
    const { action, value, id } = req.body;

    if (action === "create") {
      await pool.query(`INSERT INTO ${TABLE_NAME} (value) VALUES ($1)`, [value || ""]);
    } else if (action === "update") {
      await pool.query(`UPDATE ${TABLE_NAME} SET value = $1 WHERE id = $2`, [
        value || "",
        parseInt(id || 0),
      ]);
    } else if (action === "delete") {
      await pool.query(`DELETE FROM ${TABLE_NAME} WHERE id = $1`, [
        parseInt(id || 0),
      ]);
    }

    res.redirect("/");
  } catch (err) {
    res.status(500).send(err.message);
  }
});

// --- Старт ---
// Сервер стартует всегда, даже если PG недоступен.
// initDB — асинхронно, ошибка логируется но не роняет под.
initDB()
  .then(() => console.log("DB ready"))
  .catch((err) => console.error("DB init failed:", err.message));

app.listen(PORT, () => {
  console.log(`Node.js CRUD v${VERSION} — http://0.0.0.0:${PORT}`);
});