<?php
function refreshOutlookToken(PDO $pdo, int $praticien_id): ?string {
    $stmt = $pdo->prepare("SELECT refresh_token FROM outlook_tokens WHERE praticien_id = ?");
    $stmt->execute([$praticien_id]);
    $refresh_token = $stmt->fetchColumn();

    if (!$refresh_token) return null;

    $client_id = '8328e538-3cee-4731-9122-8b7fd6f461a9';
    $client_secret = 'xKY8Q~dygFtWlM62--4t0RVkAlFI3f5uspwOedkL';
    $token_url = 'https://login.microsoftonline.com/consumers/oauth2/v2.0/token';

    $data = [
        'client_id' => $client_id,
        'client_secret' => $client_secret,
        'refresh_token' => $refresh_token,
        'grant_type' => 'refresh_token',
        'scope' => 'offline_access User.Read Calendars.ReadWrite'
    ];

    $options = [
        'http' => [
            'method' => 'POST',
            'header' => "Content-type: application/x-www-form-urlencoded",
            'content' => http_build_query($data),
        ],
    ];

    $response = file_get_contents($token_url, false, stream_context_create($options));
    $tokens = json_decode($response, true);

    if (!isset($tokens['access_token'])) {
        return null;
    }

    $access_token = $tokens['access_token'];
    $refresh_token = $tokens['refresh_token'] ?? $refresh_token;
    $expires_at = time() + $tokens['expires_in'];

    $pdo->prepare("UPDATE outlook_tokens SET access_token = ?, refresh_token = ?, expires_at = ? WHERE praticien_id = ?")
        ->execute([$access_token, $refresh_token, $expires_at, $praticien_id]);

    return $access_token;
}