<?php

function graphql_query(string $endpoint, string $query, array $variables = [], ?string $token = null): array
{
    $headers = ['Content-Type: application/json', 'User-Agent: Unknow Agent'];
    if (null !== $token) {
        $headers[] = "Authorization: bearer $token";
        $headers[] = "X-Access-Token: $token";
    }

    if (false === $data = @file_get_contents($endpoint, false, stream_context_create([
        'http' => [
            'method' => 'POST',
            'header' => $headers,
            'content' => json_encode(['query' => $query, 'variables' => $variables]),
        ]
    ]))) {
        $error = error_get_last();
        throw new \ErrorException($error['message'], $error['type']);
    }

    echo $data;
    //return json_decode($data, true);
}

$query = <<<'GRAPHQL'
query StakeBalances($available: Boolean = false, $vault: Boolean = false) {
   user {
    id
    name
    balances {
        available @include(if: $available) {
            currency
            amount
        }
        vault @include (if: $vault) {
            currency
            amount
        }
    }
  }
}
GRAPHQL;

graphql_query("https://api.stake.com/graphql", $query, ['vault' => false, 'available' => true],"token");