use crate::SignatureError;
use p256::ecdsa::SigningKey;
use p256::ecdsa::VerifyingKey;
use p256::elliptic_curve::group::GroupEncoding;
use signature::Signer;
use signature::Verifier;
use sui_sdk_types::types::Secp256r1PublicKey;
use sui_sdk_types::types::Secp256r1Signature;
use sui_sdk_types::types::SignatureScheme;
use sui_sdk_types::types::SimpleSignature;
use sui_sdk_types::types::UserSignature;

pub struct Secp256r1PrivateKey(SigningKey);

impl std::fmt::Debug for Secp256r1PrivateKey {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_tuple("Secp256r1PrivateKey")
            .field(&"__elided__")
            .finish()
    }
}

#[cfg(test)]
impl proptest::arbitrary::Arbitrary for Secp256r1PrivateKey {
    type Parameters = ();
    type Strategy = proptest::strategy::BoxedStrategy<Self>;
    fn arbitrary_with(_: Self::Parameters) -> Self::Strategy {
        use proptest::strategy::Strategy;

        proptest::arbitrary::any::<[u8; Self::LENGTH]>()
            .prop_map(Self::new)
            .boxed()
    }
}

impl Secp256r1PrivateKey {
    /// The length of an secp256r1 private key in bytes.
    pub const LENGTH: usize = 32;

    pub fn new(bytes: [u8; Self::LENGTH]) -> Self {
        Self(SigningKey::from_bytes(&bytes.into()).unwrap())
    }

    pub fn scheme(&self) -> SignatureScheme {
        SignatureScheme::Secp256r1
    }

    pub fn verifying_key(&self) -> Secp256r1VerifyingKey {
        let verifying_key = self.0.verifying_key();
        Secp256r1VerifyingKey(*verifying_key)
    }

    pub fn public_key(&self) -> Secp256r1PublicKey {
        Secp256r1PublicKey::new(self.0.verifying_key().as_ref().to_bytes().into())
    }

    pub fn generate<R>(mut rng: R) -> Self
    where
        R: rand_core::RngCore + rand_core::CryptoRng,
    {
        let mut buf: [u8; Self::LENGTH] = [0; Self::LENGTH];
        rng.fill_bytes(&mut buf);
        Self::new(buf)
    }

    #[cfg(feature = "pem")]
    #[cfg_attr(doc_cfg, doc(cfg(feature = "pem")))]
    /// Deserialize PKCS#8 private key from ASN.1 DER-encoded data (binary format).
    pub fn from_der(bytes: &[u8]) -> Result<Self, SignatureError> {
        p256::pkcs8::DecodePrivateKey::from_pkcs8_der(bytes)
            .map(Self)
            .map_err(SignatureError::from_source)
    }

    #[cfg(feature = "pem")]
    #[cfg_attr(doc_cfg, doc(cfg(feature = "pem")))]
    /// Serialize this private key as DER-encoded PKCS#8
    pub fn to_der(&self) -> Result<Vec<u8>, SignatureError> {
        use p256::pkcs8::EncodePrivateKey;

        self.0
            .to_pkcs8_der()
            .map_err(SignatureError::from_source)
            .map(|der| der.as_bytes().to_owned())
    }

    #[cfg(feature = "pem")]
    #[cfg_attr(doc_cfg, doc(cfg(feature = "pem")))]
    /// Deserialize PKCS#8-encoded private key from PEM.
    pub fn from_pem(s: &str) -> Result<Self, SignatureError> {
        p256::pkcs8::DecodePrivateKey::from_pkcs8_pem(s)
            .map(Self)
            .map_err(SignatureError::from_source)
    }

    #[cfg(feature = "pem")]
    #[cfg_attr(doc_cfg, doc(cfg(feature = "pem")))]
    /// Serialize this private key as PEM-encoded PKCS#8
    pub fn to_pem(&self) -> Result<String, SignatureError> {
        use pkcs8::EncodePrivateKey;

        self.0
            .to_pkcs8_pem(pkcs8::LineEnding::default())
            .map_err(SignatureError::from_source)
            .map(|pem| (*pem).to_owned())
    }

    #[cfg(feature = "pem")]
    pub(crate) fn from_p256(private_key: SigningKey) -> Self {
        Self(private_key)
    }
}

impl Signer<Secp256r1Signature> for Secp256r1PrivateKey {
    fn try_sign(&self, message: &[u8]) -> Result<Secp256r1Signature, SignatureError> {
        let signature: p256::ecdsa::Signature = self.0.try_sign(message)?;
        Ok(Secp256r1Signature::new(signature.to_bytes().into()))
    }
}

impl Signer<SimpleSignature> for Secp256r1PrivateKey {
    fn try_sign(&self, msg: &[u8]) -> Result<SimpleSignature, SignatureError> {
        <Self as Signer<Secp256r1Signature>>::try_sign(self, msg).map(|signature| {
            SimpleSignature::Secp256r1 {
                signature,
                public_key: self.public_key(),
            }
        })
    }
}

impl Signer<UserSignature> for Secp256r1PrivateKey {
    fn try_sign(&self, msg: &[u8]) -> Result<UserSignature, SignatureError> {
        <Self as Signer<SimpleSignature>>::try_sign(self, msg).map(UserSignature::Simple)
    }
}

#[derive(Debug)]
pub struct Secp256r1VerifyingKey(VerifyingKey);

impl Secp256r1VerifyingKey {
    pub fn new(public_key: &Secp256r1PublicKey) -> Result<Self, SignatureError> {
        VerifyingKey::try_from(public_key.inner().as_ref()).map(Self)
    }

    pub fn public_key(&self) -> Secp256r1PublicKey {
        Secp256r1PublicKey::new(self.0.as_ref().to_bytes().into())
    }

    #[cfg(feature = "pem")]
    #[cfg_attr(doc_cfg, doc(cfg(feature = "pem")))]
    /// Deserialize public key from ASN.1 DER-encoded data (binary format).
    pub fn from_der(bytes: &[u8]) -> Result<Self, SignatureError> {
        p256::pkcs8::DecodePublicKey::from_public_key_der(bytes)
            .map(Self)
            .map_err(SignatureError::from_source)
    }

    #[cfg(feature = "pem")]
    #[cfg_attr(doc_cfg, doc(cfg(feature = "pem")))]
    /// Serialize this public key as DER-encoded data
    pub fn to_der(&self) -> Result<Vec<u8>, SignatureError> {
        use pkcs8::EncodePublicKey;

        self.0
            .to_public_key_der()
            .map_err(SignatureError::from_source)
            .map(|der| der.into_vec())
    }

    #[cfg(feature = "pem")]
    #[cfg_attr(doc_cfg, doc(cfg(feature = "pem")))]
    /// Deserialize public key from PEM.
    pub fn from_pem(s: &str) -> Result<Self, SignatureError> {
        p256::pkcs8::DecodePublicKey::from_public_key_pem(s)
            .map(Self)
            .map_err(SignatureError::from_source)
    }

    #[cfg(feature = "pem")]
    #[cfg_attr(doc_cfg, doc(cfg(feature = "pem")))]
    /// Serialize this public key into PEM
    pub fn to_pem(&self) -> Result<String, SignatureError> {
        use pkcs8::EncodePublicKey;

        self.0
            .to_public_key_pem(pkcs8::LineEnding::default())
            .map_err(SignatureError::from_source)
    }

    #[cfg(feature = "pem")]
    pub(crate) fn from_p256(verifying_key: VerifyingKey) -> Self {
        Self(verifying_key)
    }
}

impl Verifier<Secp256r1Signature> for Secp256r1VerifyingKey {
    fn verify(&self, message: &[u8], signature: &Secp256r1Signature) -> Result<(), SignatureError> {
        let signature = p256::ecdsa::Signature::from_bytes(signature.inner().into())?;
        self.0.verify(message, &signature)
    }
}

impl Verifier<SimpleSignature> for Secp256r1VerifyingKey {
    fn verify(&self, message: &[u8], signature: &SimpleSignature) -> Result<(), SignatureError> {
        let SimpleSignature::Secp256r1 {
            signature,
            public_key,
        } = signature
        else {
            return Err(SignatureError::from_source("not a secp256r1 signature"));
        };

        if public_key.inner() != self.public_key().inner() {
            return Err(SignatureError::from_source(
                "public_key in signature does not match",
            ));
        }

        <Self as Verifier<Secp256r1Signature>>::verify(self, message, signature)
    }
}

impl Verifier<UserSignature> for Secp256r1VerifyingKey {
    fn verify(&self, message: &[u8], signature: &UserSignature) -> Result<(), SignatureError> {
        let UserSignature::Simple(signature) = signature else {
            return Err(SignatureError::from_source("not a secp256r1 signature"));
        };

        <Self as Verifier<SimpleSignature>>::verify(self, message, signature)
    }
}

#[derive(Default, Clone, Debug)]
pub struct Secp256r1Verifier {}

impl Secp256r1Verifier {
    pub fn new() -> Self {
        Self {}
    }
}

impl Verifier<SimpleSignature> for Secp256r1Verifier {
    fn verify(&self, message: &[u8], signature: &SimpleSignature) -> Result<(), SignatureError> {
        let SimpleSignature::Secp256r1 {
            signature,
            public_key,
        } = signature
        else {
            return Err(SignatureError::from_source("not a secp256r1 signature"));
        };

        let verifying_key = Secp256r1VerifyingKey::new(public_key)?;

        verifying_key.verify(message, signature)
    }
}

impl Verifier<UserSignature> for Secp256r1Verifier {
    fn verify(&self, message: &[u8], signature: &UserSignature) -> Result<(), SignatureError> {
        let UserSignature::Simple(signature) = signature else {
            return Err(SignatureError::from_source("not a secp256r1 signature"));
        };

        <Self as Verifier<SimpleSignature>>::verify(self, message, signature)
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use crate::SuiSigner;
    use crate::SuiVerifier;
    use sui_sdk_types::types::PersonalMessage;
    use test_strategy::proptest;

    #[cfg(target_arch = "wasm32")]
    use wasm_bindgen_test::wasm_bindgen_test as test;

    // TODO need to export proptest impl from core crate
    // #[proptest]
    // fn transaction_signing(signer: Secp256r1PrivateKey, transaction: Transaction) {
    //     let signature = signer.sign_transaction(&transaction).unwrap();
    //     let verifier = signer.public_key();
    //     verifier
    //         .verify_transaction(&transaction, &signature)
    //         .unwrap();
    // }

    #[proptest]
    fn personal_message_signing(signer: Secp256r1PrivateKey, message: Vec<u8>) {
        let message = PersonalMessage(message.into());
        let signature = signer.sign_personal_message(&message).unwrap();
        let verifying_key = signer.verifying_key();
        verifying_key
            .verify_personal_message(&message, &signature)
            .unwrap();

        let verifier = Secp256r1Verifier::default();
        verifier
            .verify_personal_message(&message, &signature)
            .unwrap();
    }

    #[test]
    fn personal_message_signing_fixture() {
        let key = [
            167, 44, 116, 0, 51, 221, 254, 179, 210, 44, 93, 196, 125, 155, 85, 94, 29, 41, 13, 60,
            59, 132, 69, 84, 176, 217, 77, 49, 25, 113, 118, 125,
        ];
        let signer = Secp256r1PrivateKey::new(key);

        let message = PersonalMessage(b"hello".into());
        let sig = signer.sign_personal_message(&message).unwrap();
        let external_sig = "AlqWPdkIE2bZAUquKv2Tdh9i+Ih+rVSQXH/YsgvwkmeOJR0YLjL/kadivoPtiQkvZBQ1ZI8eDZxe8SaLniwoT88Dh+/vAuGf1UrouFTdefpBEWn3apy8x3EexN5c5ESzGDc=";
        let b64 = sig.to_base64();
        assert_eq!(external_sig, b64);
    }
}