paginacao_usando_template_method_pattern.php

paginacao_usando_template_method_pattern.php

<?php

include 'conexao.php';

abstract class Paginator {

    private \PDO $pdo;
    private int $pagina;
    private int $limit;

    public function __construct(\PDO $pdo, int $pagina = 1, $limit = 5) {
        $this->pdo = $pdo;
        $this->pagina = $pagina;
        $this->limit = $limit;
    }

    public function getPagina(): int {
        return $this->pagina;
    }

    public function getLimit(): int {
        return $this->limit;
    }

    protected abstract function getPaginateQuery(string $query, string $order = 'id'): string;

    public function getPaginateStatement(string $query): \PDOStatement {
        $query = $this->getPaginateQuery($query);
        $statement = $this->pdo->prepare($query);
        $statement->bindValue(':offset', (int) $this->getOffSet(), \PDO::PARAM_INT);
        $statement->bindValue(':limit', (int) $this->limit, \PDO::PARAM_INT);
        return $statement;
    }

    public function getOffSet() {
        return ($this->pagina - 1) * $this->limit;
    }

    public function getTotal(string $query) {
        $query_total = $this->pdo->query("SELECT COUNT(*) FROM ($query) q");
        return (int) $query_total->fetchColumn();
    }

}

class MySQLPaginator extends Paginator {

    protected function getPaginateQuery(string $query, string $order = 'id'): string {
        return "$query ORDER BY $order LIMIT :limit OFFSET :offset";
    }

}

class AnsiPaginator extends Paginator {

    protected function getPaginateQuery(string $query, string $order = 'id'): string {
        return "$query ORDER BY $order OFFSET :offset ROWS FETCH NEXT :limit ROWS ONLY";
    }

}

class HtmlUtil {

    private static function montaLinha(array $row, $tag = 'td') {
        return "<tr>" . implode('', array_map(function($row) use ($tag) {
                            return "<$tag>" . $row . "</$tag>";
                        }, $row)) . "</tr>";
    }

    public static function getTable(\PDOStatement $statement, array $header = []) {
        $statement->execute();
        $table = "<table border>";
        $table .= (!empty($header)) ? self::montaLinha($header, 'th') : '';
        while ($row = $statement->fetch()) {
            $table .= self::montaLinha($row);
        }
        return "$table </table>";
    }

    public static function getPaginationLinks(int $pagina, int $limit, int $total): string {
        $links = (($pagina - 1) > 0) ? "<a href='?pagina=" . ($pagina - 1) . "'>Anterior</a>" : "Anterior";
        $links .= "&nbsp";
        return $links.= (($pagina) * $limit < $total) ? "<a href='?pagina=" . ($pagina + 1) . "'>Próximo</a>" : "Próximo";
    }

}

$pagina = (isset($_REQUEST['pagina'])) ? $_REQUEST['pagina'] : 1;
$mySql = new \MySQLPaginator(Conexao::getInstance()->getPdo(), $pagina);
$query = "SELECT * FROM livro";
$statement = $mySql->getPaginateStatement("SELECT livro.id, livro.titulo, livro.preco, livro.isbn FROM livro");
echo HtmlUtil::getTable($statement, ['ID','Título','Preço', 'ISBN']);
echo HtmlUtil::getPaginationLinks($pagina, $mySql->getLimit(), $mySql->getTotal($query));