//! ASN.1 `OBJECT IDENTIFIER`

use crate::{

    asn1::AnyRef, ord::OrdIsValueOrd, DecodeValue, EncodeValue, Error, FixedTag, Header, Length,

    Reader, Result, Tag, Tagged, Writer,

};

use const_oid::ObjectIdentifier;

#[cfg(feature = "alloc")]

use super::Any;

impl<'a> DecodeValue<'a> for ObjectIdentifier {

    fn decode_value<R: Reader<'a>>(reader: &mut R, header: Header) -> Result<Self> {

        let mut buf = [0u8; ObjectIdentifier::MAX_SIZE];

        let slice = buf

            .get_mut(..header.length.try_into()?)

            .ok_or_else(|| Self::TAG.length_error())?;

Unexecuted instantiation: <const_oid::ObjectIdentifier as der::decode::DecodeValue>::decode_value::<der::reader::nested::NestedReader<der::reader::nested::NestedReader<der::reader::slice::SliceReader>>>::{closure#0}

Unexecuted instantiation: <const_oid::ObjectIdentifier as der::decode::DecodeValue>::decode_value::<der::reader::nested::NestedReader<der::reader::slice::SliceReader>>::{closure#0}

Unexecuted instantiation: <const_oid::ObjectIdentifier as der::decode::DecodeValue>::decode_value::<_>::{closure#0}

        let actual_len = reader.read_into(slice)?.len();

        debug_assert_eq!(actual_len, header.length.try_into()?);

        Ok(Self::from_bytes(slice)?)

    }

Unexecuted instantiation: <const_oid::ObjectIdentifier as der::decode::DecodeValue>::decode_value::<der::reader::nested::NestedReader<der::reader::nested::NestedReader<der::reader::slice::SliceReader>>>

Unexecuted instantiation: <const_oid::ObjectIdentifier as der::decode::DecodeValue>::decode_value::<der::reader::nested::NestedReader<der::reader::slice::SliceReader>>

Unexecuted instantiation: <const_oid::ObjectIdentifier as der::decode::DecodeValue>::decode_value::<_>

}

impl EncodeValue for ObjectIdentifier {

    fn value_len(&self) -> Result<Length> {

        Length::try_from(self.as_bytes().len())

    }

    fn encode_value(&self, writer: &mut impl Writer) -> Result<()> {

        writer.write(self.as_bytes())

    }

Unexecuted instantiation: <const_oid::ObjectIdentifier as der::encode::EncodeValue>::encode_value::<der::writer::slice::SliceWriter>

Unexecuted instantiation: <const_oid::ObjectIdentifier as der::encode::EncodeValue>::encode_value::<_>

}

impl FixedTag for ObjectIdentifier {

    const TAG: Tag = Tag::ObjectIdentifier;

}

impl OrdIsValueOrd for ObjectIdentifier {}

impl<'a> From<&'a ObjectIdentifier> for AnyRef<'a> {

    fn from(oid: &'a ObjectIdentifier) -> AnyRef<'a> {

        // Note: ensuring an infallible conversion is possible relies on the

        // invariant that `const_oid::MAX_LEN <= Length::max()`.

        //

        // The `length()` test below ensures this is the case.

        let value = oid

            .as_bytes()

            .try_into()

            .expect("OID length invariant violated");

        AnyRef::from_tag_and_value(Tag::ObjectIdentifier, value)

    }

}

#[cfg(feature = "alloc")]

impl From<ObjectIdentifier> for Any {

    fn from(oid: ObjectIdentifier) -> Any {

        AnyRef::from(&oid).into()

    }

}

impl TryFrom<AnyRef<'_>> for ObjectIdentifier {

    type Error = Error;

    fn try_from(any: AnyRef<'_>) -> Result<ObjectIdentifier> {

        any.tag().assert_eq(Tag::ObjectIdentifier)?;

        Ok(ObjectIdentifier::from_bytes(any.value())?)

    }

}

#[cfg(test)]

mod tests {

    use super::ObjectIdentifier;

    use crate::{Decode, Encode, Length};

    const EXAMPLE_OID: ObjectIdentifier = ObjectIdentifier::new_unwrap("1.2.840.113549");

    const EXAMPLE_OID_BYTES: &[u8; 8] = &[0x06, 0x06, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d];

    #[test]

    fn decode() {

        let oid = ObjectIdentifier::from_der(EXAMPLE_OID_BYTES).unwrap();

        assert_eq!(EXAMPLE_OID, oid);

    }

    #[test]

    fn encode() {

        let mut buffer = [0u8; 8];

        assert_eq!(

            EXAMPLE_OID_BYTES,

            EXAMPLE_OID.encode_to_slice(&mut buffer).unwrap()

        );

    }

    #[test]

    fn length() {

        // Ensure an infallible `From` conversion to `Any` will never panic

        assert!(ObjectIdentifier::MAX_SIZE <= Length::MAX.try_into().unwrap());

    }

}