<?php

namespace App\Service;

use IDCI\Bundle\GraphQLClientBundle\Client\GraphQLApiClient;
use IDCI\Bundle\GraphQLClientBundle\Client\GraphQLApiClientRegistryInterface;
use Symfony\Contracts\HttpClient\HttpClientInterface;

/**
 * Fetches the last 365 days of contributions from the GitHub GraphQL API.
 *
 * Required token scopes: read:user
 */
class GitHubProvider implements ProviderInterface
{
    private const GRAPHQL_URL = 'https://api.github.com/graphql';

    public function __construct(
        private readonly HttpClientInterface $client,
        private readonly GraphQLApiClientRegistryInterface $registry,
        private readonly string $username,
        private readonly string $token,
    ) {}

    public function isConfigured(): bool
    {
        return $this->username !== '' && $this->token !== '';
    }

    /**
     * @return array<string, int>  date (Y-m-d) => contribution count
     */
    public function fetch(): array
    {
        $from = (new \DateTimeImmutable('-365 days'))->format('Y-m-d\T00:00:00\Z');
        $to   = (new \DateTimeImmutable())->format('Y-m-d\T23:59:59\Z');

        /** @var GraphQLApiClient $graphqlClient */
        $graphqlClient = $this->registry->get('github');

        $query = $graphqlClient->buildQuery(
            ['user' => ['login' => $this->username]],
            [
                'contributionsCollection' => [
                    '_parameters' => ['from' => $from, 'to' => $to],
                    'contributionCalendar' => [
                        'weeks' => [
                            'contributionDays' => ['date', 'contributionCount'],
                        ],
                    ],
                ],
            ]
        )->getGraphQLQuery();

        // GitHub's GraphQL API requires application/json — the bundle's built-in
        // transport sends form_params, so we use Symfony HttpClient here instead.
        $response = $this->client->request('POST', self::GRAPHQL_URL, [
            'headers' => [
                'Authorization' => "Bearer {$this->token}",
                'Content-Type'  => 'application/json',
            ],
            'json' => ['query' => $query],
        ]);

        $data = $response->toArray();

        if (isset($data['errors'])) {
            throw new \RuntimeException('GitHub GraphQL error: ' . json_encode($data['errors']));
        }

        $result = [];
        $weeks  = $data['data']['user']['contributionsCollection']['contributionCalendar']['weeks'] ?? [];

        foreach ($weeks as $week) {
            foreach ($week['contributionDays'] as $day) {
                if ($day['contributionCount'] > 0) {
                    $result[$day['date']] = $day['contributionCount'];
                }
            }
        }

        return $result;
    }
}