App\Core\Entity\PaginatedResult.php

<?php
/**
 * @author Florent HAZARD <f.hazard@sowapps.com>
 *
 * Paginate results from Doctrine QueryBuilder
 */

namespace App\Core\Entity;

use ArrayIterator;
use Doctrine\ORM\QueryBuilder;
use Iterator;
use OutOfBoundsException;

class PaginatedResult {
	
	protected Iterator $results;
	protected int $page;
	protected int $resultPerPage;
	protected int $count;
	protected int $pageDelta = 2;
	
	/**
	 * PaginatedResult constructor
	 *
	 * @param Iterator $results
	 * @param int $page
	 * @param int $resultPerPage
	 * @param int $count
	 */
	public function __construct(Iterator $results, int $page, int $resultPerPage, int $count) {
		$this->results = $results;
		$this->page = $page;
		$this->resultPerPage = $resultPerPage;
		$this->count = $count;
		
		if( $page > $this->getPageCount() ) {
			throw new OutOfBoundsException('Wrong page number');
		}
	}
	
	/**
	 * @return bool
	 */
	public function hasResults(): bool {
		return !!$this->count;
	}
	
	/**
	 * @return int
	 */
	public function getPageCount(): int {
		return max(ceil($this->count / $this->resultPerPage), 1);
	}
	
	/**
	 * @return Iterator
	 */
	public function getResults(): Iterator {
		return $this->results;
	}
	
	/**
	 * @return mixed|array
	 */
	public function getNext() {
		$results = $this->getResults();
		$results->next();
		return $results->current();
	}
	
	/**
	 * @return int
	 */
	public function getPage(): int {
		return $this->page;
	}
	
	/**
	 * @return int
	 */
	public function getResultPerPage(): int {
		return $this->resultPerPage;
	}
	
	/**
	 * @return int
	 */
	public function getCount(): int {
		return $this->count;
	}
	
	/**
	 * @return bool
	 */
	public function hasPreviousPage(): bool {
		return !$this->isFirstPage();
	}
	
	/**
	 * @return int
	 */
	public function isFirstPage(): int {
		return $this->page === 1;
	}
	
	/**
	 * @return bool
	 */
	public function hasNextPage(): bool {
		return !$this->isLastPage();
	}
	
	/**
	 * @return int
	 */
	public function isLastPage(): int {
		return $this->page === $this->getPageCount();
	}
	
	/**
	 * @return int
	 */
	public function getDeltaStart(): int {
		return (int) max($this->page - $this->pageDelta, 1);
	}
	
	/**
	 * @return int
	 */
	public function getDeltaEnd() {
		return (int) min($this->page + $this->pageDelta, $this->getPageCount());
	}
	
	public static function paginate(QueryBuilder $queryBuilder, int $page, int $resultPerPage, string $alias) {
		$counter = clone $queryBuilder;
		
		if( $page < 1 ) {
			throw new OutOfBoundsException('Wrong page number');
		}
		
		$counter->select('COUNT(' . $alias . '.id)');
		$count = $counter->getQuery()
			->getSingleScalarResult();
		
		$resultMax = $page * $resultPerPage;
		$resultMin = $resultMax - $resultPerPage;
		
		if( ($count - 1) >= $resultMin ) {
			$results = $queryBuilder
				->setMaxResults($resultPerPage)
				->setFirstResult($resultMin)
				->getQuery()
				->iterate();
		} else {
			$results = new ArrayIterator();
		}
		
		return new PaginatedResult($results, $page, $resultPerPage, $count);
	}
	
}