<?php

namespace App\Services\Graph;

use Illuminate\Http\Client\RequestException;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Http;
use RuntimeException;

/**
 * Client Microsoft Graph minimal (flux client credentials, permissions « application »).
 * Permissions requises, avec consentement administrateur : User.Read.All, GroupMember.Read.All.
 */
class GraphClient
{
    public function __construct(private readonly string $tenantId) {}

    public function token(): string
    {
        return Cache::remember("graph-token:{$this->tenantId}", now()->addMinutes(50), function () {
            $res = Http::asForm()->timeout(config('signature.graph.timeout'))
                ->post("https://login.microsoftonline.com/{$this->tenantId}/oauth2/v2.0/token", [
                    'client_id' => config('signature.graph.client_id'),
                    'client_secret' => config('signature.graph.client_secret'),
                    'scope' => 'https://graph.microsoft.com/.default',
                    'grant_type' => 'client_credentials',
                ]);
            if (! $res->successful()) {
                throw new RuntimeException('Jeton Graph refusé : '.$res->json('error_description', $res->body()));
            }

            return $res->json('access_token');
        });
    }

    /** GET sur une URL relative (/users…) ou absolue (@odata.nextLink). */
    public function get(string $url, array $headers = []): array
    {
        $full = str_starts_with($url, 'https://') ? $url : config('signature.graph.base_url').$url;

        $res = Http::withToken($this->token())
            ->withHeaders($headers)
            ->timeout(config('signature.graph.timeout'))
            // Nouvel essai sur limitation (429) ou indisponibilité temporaire de Graph.
            ->retry(3, 2000, fn ($e) => $e instanceof RequestException && in_array($e->response->status(), [429, 503, 504], true), throw: false)
            ->get($full);

        if (! $res->successful()) {
            throw new RuntimeException("Graph {$res->status()} sur {$url} : ".$res->body());
        }

        return $res->json();
    }

    /**
     * Parcourt toutes les pages d'une collection.
     * Retourne [éléments, deltaLink|null].
     */
    public function all(string $url, array $headers = []): array
    {
        $items = [];
        $delta = null;
        $next = $url;
        while ($next) {
            $page = $this->get($next, $headers);
            array_push($items, ...($page['value'] ?? []));
            $next = $page['@odata.nextLink'] ?? null;
            $delta = $page['@odata.deltaLink'] ?? $delta;
        }

        return [$items, $delta];
    }
}