export interface SessionCredential {
    tenantId?: string;
    clientId?: string;
    scopes?: string[];
}

export function resolveCredential(req: any): SessionCredential {
    const headerTenant = req.header('x-tenant-id');
    const headerClientId = req.header('x-client-id');
    const headerScopes = req.header('x-graph-scopes');

    if (headerTenant || headerClientId || headerScopes) {
        return {
            tenantId: headerTenant,
            clientId: headerClientId,
            scopes: headerScopes ? headerScopes.split(' ') : undefined,
        };
    }

    // fallback to ENV
    return {
        tenantId: process.env.TENANT_ID,
        clientId: process.env.CLIENT_ID,
        scopes: (process.env.GRAPH_SCOPES || '').split(' ').filter(Boolean),
    };
}