func claimRewards(userId: String) async throws -> ClaimResponse {
    let url = URL(string: "https://yejzycmzbcwjsapmkwrq.supabase.co/functions/v1/referrer-claim")!
    var request = URLRequest(url: url)
    request.httpMethod = "POST"
    request.setValue(apiKey, forHTTPHeaderField: "x-api-key")
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
    
    let body = ["uid": userId]
    request.httpBody = try JSONEncoder().encode(body)
    
    let (data, _) = try await URLSession.shared.data(for: request)
    return try JSONDecoder().decode(ClaimResponse.self, from: data)
}

// Display claimed rewards
func showClaimedRewards(_ response: ClaimResponse) {
    let alert = UIAlertController(
        title: "🎉 Rewards Claimed!",
        message: response.message,
        preferredStyle: .alert
    )
    
    for reward in response.claimed_rewards {
        alert.addAction(UIAlertAction(title: "Copy \(reward.code)", style: .default) { _ in
            UIPasteboard.general.string = reward.code
            UIApplication.shared.open(URL(string: reward.store_url)!)
        })
    }
    
    alert.addAction(UIAlertAction(title: "Done", style: .cancel))
    present(alert, animated: true)
}