use gpgme::{Context, Protocol};

/// Check if a GPG key matching 'email' exists
/// Returns the key ID if found, None otherwise
pub fn find_signing_key_for_email(
    email: &str,
) -> Result<Option<String>, Box<dyn std::error::Error>> {
    // Create a new GPG context
    let mut ctx = Context::from_protocol(Protocol::OpenPgp)?;

    // List all secret keys
    let keys = ctx.secret_keys()?;

    // Find a key that matches the email and can sign
    for key_result in keys {
        let key = key_result?;
        // Check if the key has signing capability
        if key.can_sign() {
            // Check user IDs for email match
            for user_id in key.user_ids() {
                if let Ok(userid_email) = user_id.email()
                    && userid_email.eq_ignore_ascii_case(email)
                    && let Ok(fingerprint) = key.fingerprint()
                {
                    return Ok(Some(fingerprint.to_string()));
                }
            }
        }
    }

    Ok(None)
}