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use async_trait::async_trait;
pub mod one_or_many;
pub mod uri;

// one type of VM (e.g. a JWK) should be able to verify multiple types of things (payloads)
// in multiple ways/contexts (context properties), so generic over those. but each impl should
// have one concrete err type, so associated
#[async_trait]
pub trait VerificationMethod<SP, C> {
    type Error;
    async fn verify(&self, signed_payload: SP, context_properties: C) -> Result<(), Self::Error>;
}

// can return an attached or detached signature
#[async_trait]
pub trait SigningMethod<P, C, O> {
    type Error;
    async fn sign(&self, payload: P, context_properties: C) -> Result<O, Self::Error>;
}

#[async_trait]
pub trait ProofConstruction<P, C, I, O, S> {
    type Error;
    async fn prepare(payload: P, context_properties: C) -> Result<I, Self::Error>;
    fn complete(payload: P, context_properties: C, proof: S) -> Result<O, Self::Error>;
}

#[async_trait]
pub trait Verifiable<V, C> {
    type Error;
    async fn verify_with(&self, vm: V, c: C) -> Result<(), Self::Error>;
}

// #[async_trait]
// impl<'a, V, C, P> Verifiable<&'a V, C> for P
// where
//     V: VerificationMethod<&'a P, C> + Sync,
//     P: 'a + Send + Sync,
//     C: Send,
// {
//     type Error = V::Error;
//     async fn verify_with(&self, vm: &'a V, c: C) -> Result<(), Self::Error> {
//         vm.verify(&self, c).await
//     }
// }

pub trait Authenticated {
    type Id;
    fn authenticator(&self) -> Self::Id;
}

#[async_trait]
pub trait VerificationMethodRegistry<I> {
    type Error;
    type VM;
    async fn get_method(&self, id: I) -> Result<Option<Self::VM>, Self::Error>;
}

pub enum VDRError<R, V> {
    Registry(R),
    IdUnresolvable,
    Verification(V),
}

// impl VerificationMethod for all registries of VerificationMethods which can verify P
// #[async_trait]
// impl<V, P, C> VerificationMethod<P, C> for V
// where
//     V: VerificationMethodRegistry<P::Id> + Sync,
//     V::VM: VerificationMethod<P, C> + Send + Sync,
//     P: Authenticated + Send,
//     P::Id: Send,
//     C: Send,
// {
//     type Error = VDRError<
//         <V as VerificationMethodRegistry<P::Id>>::Error,
//         <V::VM as VerificationMethod<P, C>>::Error,
//     >;
//     async fn verify(&self, payload: P, context_properties: C) -> Result<(), Self::Error> {
//         let a = payload.authenticator();
//         let vm = self
//             .get_method(a)
//             .await
//             .map_err(Self::Error::Registry)?
//             .ok_or(Self::Error::IdUnresolvable)?;
//         vm.verify(payload, context_properties)
//             .await
//             .map_err(Self::Error::Verification)
//     }
// }

pub trait SemanticallyVerifiable<P> {
    type Error;
    fn verify_claims(&self, policy: P) -> Result<(), Self::Error>;
}

pub trait ChronologicallyVerifiable<T> {
    fn valid_now(&self) -> bool;
    fn valid_at(&self, time: T) -> bool;
}

#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {
        let result = 2 + 2;
        assert_eq!(result, 4);
    }
}