<?php

namespace App\Services;

use GuzzleHttp\Client;
use GuzzleHttp\Exception\ClientException;
use InvalidArgumentException;
use SimpleXMLElement;

/**
 * @method object get($uri, ...$args)
 * @method object post($uri, ...$data)
 * @method object put($uri, ...$data)
 * @method object patch($uri, ...$data)
 * @method object head($uri, ...$data)
 * @method object delete($uri)
 */
abstract class ApiClient
{
    protected $responseFormat = 'json';

    /**
     * The GuzzleHttp client to talk to the API.
     */
    protected $client;

    /**
     * The query parameter name for the key.
     * For example, Last.fm use api_key, like this:
     * https://ws.audioscrobbler.com/2.0?method=artist.getInfo&artist=Kamelot&api_key=API_KEY.
     *
     * @var string
     */
    protected $keyParam = 'key';

    public function __construct(Client $client)
    {
        $this->client = $client;
    }

    /**
     * Make a request to the API.
     *
     * @param string  $method    The HTTP method
     * @param string  $uri       The API URI (segment)
     * @param bool    $appendKey Whether to automatically append the API key into the URI.
     *                           While it's usually the case, some services (like Last.fm) requires
     *                           an "API signature" of the request. Appending an API key will break the request.
     * @param mixed[] $params    An array of parameters
     *
     * @return mixed|SimpleXMLElement|null
     */
    public function request(string $method, string $uri, bool $appendKey = true, array $params = [])
    {
        try {
            $body = (string) $this->getClient()
                ->$method($this->buildUrl($uri, $appendKey), ['form_params' => $params])
                ->getBody();

            if ($this->responseFormat === 'json') {
                return json_decode($body);
            }

            if ($this->responseFormat === 'xml') {
                return simplexml_load_string($body);
            }

            return $body;
        } catch (ClientException $e) {
            return;
        }
    }

    /**
     * Make an HTTP call to the external resource.
     *
     * @param string  $method The HTTP method
     * @param mixed[] $args   An array of parameters
     *
     * @throws InvalidArgumentException
     *
     * @return mixed|null|SimpleXMLElement
     */
    public function __call(string $method, array $args)
    {
        if (count($args) < 1) {
            throw new InvalidArgumentException('Magic request methods require a URI and optional options array');
        }

        $uri = $args[0];
        $opts = isset($args[1]) ? $args[1] : [];
        $appendKey = isset($args[2]) ? $args[2] : true;

        return $this->request($method, $uri, $appendKey, $opts);
    }

    /**
     * Turn a URI segment into a full API URL.
     *
     * @param bool $appendKey Whether to automatically append the API key into the URL.
     */
    public function buildUrl(string $uri, bool $appendKey = true): string
    {
        if (!starts_with($uri, ['http://', 'https://'])) {
            if ($uri[0] !== '/') {
                $uri = "/$uri";
            }

            $uri = $this->getEndpoint().$uri;
        }

        if ($appendKey) {
            if (parse_url($uri, PHP_URL_QUERY)) {
                $uri .= "&{$this->keyParam}=".$this->getKey();
            } else {
                $uri .= "?{$this->keyParam}=".$this->getKey();
            }
        }

        return $uri;
    }

    public function getClient(): Client
    {
        return $this->client;
    }

    abstract public function getKey(): ?string;

    abstract public function getSecret(): ?string;

    abstract public function getEndpoint(): string;
}