Slince\Shopify\Common\CursorBasedPagination

Complexity

Total Complexity

13

Size/Duplication

Total Lines	129
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	5

Importance

Changes

0

8 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	0	7	1
A	current()	0	6	1
A	next()	0	8	2
A	hasNext()	0	4	1
A	prev()	0	7	2
A	hasPrev()	0	4	1
A	fetchResource()	0	10	1
A	extractHeaderLink()	0	21	4

<?php

namespace Slince\Shopify\Common;

use GuzzleHttp\Psr7\Request;
use Psr\Http\Message\ResponseInterface;
use Slince\Shopify\Client;
use Slince\Shopify\Common\Manager\ManagerInterface;
use Slince\Shopify\Common\Model\ModelInterface;
use Slince\Shopify\Exception\RuntimeException;

class CursorBasedPagination
{
    const LINK_REGEX = '/<(.*page_info=([a-z0-9\-]+).*)>; rel="?{type}"?/i';

    /**
     * @var string
     */
    protected $resource;

    /**
     * @var array
     */
    protected $query;

    /**
     * @var ManagerInterface
     */
    protected $manager;

    /**
     * @var Client
     */
    protected $client;

    /**
     * @var array
     */
    protected $links = [];

    public function __construct(ManagerInterface $manager, $resource, $query)
    {
        $this->manager = $manager;
        $this->client = $manager->getClient();
        $this->resource = $resource;
        $this->query = $query;
    }

    /**
     * Gets the current page data.
     *
     * @return ModelInterface[]
     */
    public function current()
    {
        $data = $this->client->get($this->resource, $this->query);
        $this->links = $this->extractHeaderLink($this->client->getLastResponse());
        return $this->manager->createMany(reset($data));
    }

    /**
     * Get the next page of data.
     *
     * @return ModelInterface[]
     */
    public function next()
    {
        if (!$this->hasNext()) {
            throw new RuntimeException("There's no next page");
        }

        return $this->fetchResource($this->links['next']);
    }

    /**
     * Checks whether has next page.
     *
     * @return bool
     */
    public function hasNext()
    {
        return !empty($this->links['next']);
    }

    /**
     * Get the previous page of data.
     *
     * @return ModelInterface[]
     */
    public function prev()
    {
        if (!$this->hasNext()) {
            throw new RuntimeException("There's no previous page");
        }
        return $this->fetchResource($this->links['previous']);
    }

    /**
     * Checks whether has previous page.
     *
     * @return bool
     */
    public function hasPrev()
    {
        return !empty($this->links['previous']);
    }

    protected function fetchResource($url)
    {
        $request = new Request('GET', $url, [
            'Content-Type' => 'application/json',
        ]);
        $response = $this->client->sendRequest($request);
        $data = \GuzzleHttp\json_decode((string)$response->getBody(), true);
        $this->links = $this->extractHeaderLink($this->client->getLastResponse());
        return $this->manager->createMany(reset($data));
    }

    protected function extractHeaderLink(ResponseInterface $response)
    {
        if (!$response->hasHeader('Link')) {
            return [];
        }
        $links = [
            'next'     => null,
            'previous' => null,
        ];
        foreach (array_keys($links) as $type) {
            $matched = preg_match(
                str_replace('{type}', $type, static::LINK_REGEX),
                $response->getHeader('Link')[0],
                $matches
            );
            if ($matched) {
                $links[$type] = $matches[1];
            }
        }
        return $links;
    }
}