<?php

declare(strict_types=1);

namespace Pcm\GeocodeBundle\Service;

use Pcm\GeocodeBundle\Exception\ApiErrorException;
use Pcm\GeocodeBundle\Exception\NoResultsFoundException;
use Pcm\GeocodeBundle\Model\GeoCoordinates;
use Symfony\Contracts\HttpClient\HttpClientInterface;
use Symfony\Contracts\HttpClient\ResponseInterface;

/**
 * Find the geo-coordinates of a postcode
 */
final class Geocoder
{
    private const string API_URL = "https://nominatim.openstreetmap.org/search";

    public function __construct(private HttpClientInterface $client) {}

    /**
     * Find and return the geo-coordinates of a postcode
     *
     * @param string $postcode
     *
     * @return GeoCoordinates
     *
     * @throws NoResultsFoundException when no results were found for the provided postcode
     * @throws ApiErrorException when the API response contains an error
     */
    public function geocodePostcode(string $postcode): GeoCoordinates
    {
        $client = $this->createClient();
        $response = $this->makeApiRequest($client, $postcode);
        $data = $this->getDataFromResponse($response);

        if (array_key_exists('error', $data)) {
            throw new ApiErrorException($postcode, $data['error']['message']);
        }

        if (empty($data)) {
            throw new NoResultsFoundException($postcode, "No results found.");
        }

        return $this->createGeoCoordinates($data);
    }

    private function createClient(): HttpClientInterface
    {
        return $this->client->withOptions([
            'headers' => ["User-Agent" => "Geocode"]
        ]);
    }

    private function makeApiRequest(HttpClientInterface $client, string $postcode): ResponseInterface
    {
        return $client->request(
            method: 'GET',
            url: self::API_URL,
            options: [
                'query' => [
                    'format' => 'json',
                    'postalcode' => $postcode
                ]
            ]
        );
    }

    private function getDataFromResponse(ResponseInterface $response): array
    {
        return $response->toArray(false);
    }

    private function createGeoCoordinates(array $data): GeoCoordinates
    {
        $lat = $this->getLatitudeFromData($data);
        $long = $this->getLongitudeFromData($data);

        return new GeoCoordinates($lat, $long);
    }

    private function getLatitudeFromData(array $data): float
    {
        return (float) $data[0]['lat'];
    }

    private function getLongitudeFromData(array $data): float
    {
        return (float) $data[0]['lon'];
    }
}