<?php
require_once dirname(__DIR__, 2) . '/vendor/autoload.php';

use Dotenv\Dotenv;

class DBHandlerSelect
{
    private static $instance = null;
    private $pdo;

    private function __construct()
    {
        $dotenv = Dotenv::createImmutable(dirname(__DIR__, 2));
        $dotenv->load();

        $host = $_ENV['DB_HOST'];
        $db = $_ENV['DB_DATABASE'];
        $user = $_ENV['DB_USERNAME'];
        $pass = $_ENV['DB_PASSWORD'];
        $charset = 'utf8mb4';

        $dsn = "mysql:host=$host;dbname=$db;charset=$charset";
        $options = [
            PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            PDO::ATTR_EMULATE_PREPARES   => false,
        ];

        try {
            $this->pdo = new PDO($dsn, $user, $pass, $options);
        } catch (PDOException $e) {
            die("Database connection failed: " . $e->getMessage());
        }
    }

    public static function getInstance()
    {
        if (self::$instance === null) {
            self::$instance = new DBHandlerSelect();
        }
        return self::$instance;
    }

    public function getConnection()
    {
        return $this->pdo;
    }
    // Ritorna tutte le righe di una SELECT parametrizzata
    public function select($sql, $params = [])
    {
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($params);
        return $stmt->fetchAll();
    }

    // Ritorna una sola riga (o null se non trova niente)
    public function selectOne($sql, $params = [])
    {
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($params);
        $row = $stmt->fetch();
        return $row === false ? null : $row;
    }

    // Conta le righe di una query (comodo per le card)
    public function count($sql, $params = [])
    {
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($params);
        return $stmt->rowCount();
    }

    // Inserisce una riga e ritorna l'id appena creato.
    // $data è un array associativo colonna => valore.
    public function insert($table, $data)
    {
        $cols  = array_keys($data);
        $place = array_fill(0, count($cols), '?');

        // i backtick proteggono nomi di tabella/colonna con trattini (es. `trf-details`)
        $colList = '`' . implode('`, `', $cols) . '`';
        $sql = "INSERT INTO `$table` ($colList) VALUES (" . implode(', ', $place) . ")";

        $stmt = $this->pdo->prepare($sql);
        $stmt->execute(array_values($data));

        return $this->pdo->lastInsertId();
    }
}