use p256::ecdsa::{
    Signature, SigningKey, VerifyingKey,
    signature::{Signer, Verifier},
};
use rand_core::OsRng;

///
/// contains the ecdsa private key, the ecdsa public key and the username
///
pub struct CryptographicSignature {
    priv_key: SigningKey,
    pub pub_key: VerifyingKey,
    pub username: String,
}

impl CryptographicSignature {
    ///
    /// creates a CryptographicSignature
    ///
    pub fn new(username: String) -> CryptographicSignature {
        // generate a private key
        let priv_key = SigningKey::random(&mut OsRng);
        // extract the public key from the private key
        let pub_key = VerifyingKey::from(&priv_key);
        // return the new struct
        CryptographicSignature {
            priv_key: priv_key,
            pub_key: pub_key,
            username: username,
        }
    }
}

///
/// returns a string representing the pub_key as a String
///
pub fn formatPubKey(crypto_pair: CryptographicSignature) -> String  {
    let encoded_point = crypto_pair.pub_key.to_encoded_point(false);
    let pubkey_bytes = encoded_point.as_bytes();
    hex::encode(pubkey_bytes)
}

#[cfg(test)]
mod tests {
    // Note this useful idiom: importing names from outer (for mod tests) scope.
    use super::*;

    #[test]
    fn creating_cryptographic_signature() {
        let username = String::from("quoicoubeh");
        let crypto_pair = CryptographicSignature::new(username);
        let formatted_pubkey =formatPubKey(crypto_pair);
        println!("pubkey : {}",formatted_pubkey);
    }
}