//! Error type mapping from soliton::error::Error to Python exceptions.

use pyo3::create_exception;
use pyo3::exceptions::PyException;
use pyo3::prelude::*;

// Each soliton error variant gets a dedicated Python exception class,
// all inheriting from SolitonError.
create_exception!(
    soliton,
    SolitonError,
    PyException,
    "Base exception for all soliton errors."
);
create_exception!(
    soliton,
    InvalidLengthError,
    SolitonError,
    "Wrong-size parameter."
);
create_exception!(
    soliton,
    InvalidDataError,
    SolitonError,
    "Structurally invalid content."
);
create_exception!(soliton, AeadError, SolitonError, "AEAD decryption failed.");
create_exception!(
    soliton,
    VerificationError,
    SolitonError,
    "Signature verification failed."
);
create_exception!(
    soliton,
    BundleVerificationError,
    SolitonError,
    "Pre-key bundle verification failed."
);
create_exception!(
    soliton,
    DecapsulationError,
    SolitonError,
    "KEM decapsulation failed."
);
create_exception!(
    soliton,
    DuplicateMessageError,
    SolitonError,
    "Replayed or already-seen message."
);
create_exception!(
    soliton,
    ChainExhaustedError,
    SolitonError,
    "Counter-space exhausted."
);
create_exception!(
    soliton,
    UnsupportedVersionError,
    SolitonError,
    "Unsupported blob version."
);
create_exception!(
    soliton,
    UnsupportedCryptoVersionError,
    SolitonError,
    "Unrecognized crypto version."
);
create_exception!(
    soliton,
    InternalError,
    SolitonError,
    "Internal invariant violated."
);

/// Convert a soliton::error::Error into the appropriate Python exception.
pub fn to_py_err(e: soliton::error::Error) -> PyErr {
    use soliton::error::Error;
    match e {
        Error::InvalidLength { .. } => InvalidLengthError::new_err(e.to_string()),
        Error::InvalidData => InvalidDataError::new_err(e.to_string()),
        Error::AeadFailed => AeadError::new_err(e.to_string()),
        Error::VerificationFailed => VerificationError::new_err(e.to_string()),
        Error::BundleVerificationFailed => BundleVerificationError::new_err(e.to_string()),
        Error::DecapsulationFailed => DecapsulationError::new_err(e.to_string()),
        Error::DuplicateMessage => DuplicateMessageError::new_err(e.to_string()),
        Error::ChainExhausted => ChainExhaustedError::new_err(e.to_string()),
        Error::UnsupportedVersion => UnsupportedVersionError::new_err(e.to_string()),
        Error::UnsupportedCryptoVersion => UnsupportedCryptoVersionError::new_err(e.to_string()),
        Error::Internal => InternalError::new_err(e.to_string()),
        _ => SolitonError::new_err(e.to_string()),
    }
}

pub fn register(m: &Bound<'_, PyModule>) -> PyResult<()> {
    m.add("SolitonError", m.py().get_type::<SolitonError>())?;
    m.add(
        "InvalidLengthError",
        m.py().get_type::<InvalidLengthError>(),
    )?;
    m.add("InvalidDataError", m.py().get_type::<InvalidDataError>())?;
    m.add("AeadError", m.py().get_type::<AeadError>())?;
    m.add("VerificationError", m.py().get_type::<VerificationError>())?;
    m.add(
        "BundleVerificationError",
        m.py().get_type::<BundleVerificationError>(),
    )?;
    m.add(
        "DecapsulationError",
        m.py().get_type::<DecapsulationError>(),
    )?;
    m.add(
        "DuplicateMessageError",
        m.py().get_type::<DuplicateMessageError>(),
    )?;
    m.add(
        "ChainExhaustedError",
        m.py().get_type::<ChainExhaustedError>(),
    )?;
    m.add(
        "UnsupportedVersionError",
        m.py().get_type::<UnsupportedVersionError>(),
    )?;
    m.add(
        "UnsupportedCryptoVersionError",
        m.py().get_type::<UnsupportedCryptoVersionError>(),
    )?;
    m.add("InternalError", m.py().get_type::<InternalError>())?;
    Ok(())
}