icydb-core 0.201.0

//! Module: db::schema::authored_projection
//! Responsibility: bind generated authored field inputs to accepted field and catalog authority.
//! Does not own: runtime value projection, persisted encoding, or mutation execution.
//! Boundary: stable generated field slots -> admitted owned values.
use crate::{
    db::{
        data::encode_input_value_for_accepted_field_contract,
        schema::{
            AcceptedFieldPersistenceContract, AcceptedRowDecodeContract,
            enum_catalog::{AdmittedOwnedValue, ValueAdmissionBudget, ValueAdmissionError},
        },
    },
    traits::AuthoredFieldProjection,
    value::InputValue,
};

/// Failure to bind or admit one generated authored field slot.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub(in crate::db) enum AuthoredFieldAdmissionError {
    MissingFieldContract { slot: usize },
    FieldNotGenerated { slot: usize },
    MissingAuthoredValue { slot: usize },
    PersistenceEncoding { slot: usize },
    Admission(ValueAdmissionError),
}

/// Accepted-schema binding for one generated entity's authored field projection.
pub(in crate::db) struct AcceptedAuthoredFieldProjection<'a> {
    row_contract: &'a AcceptedRowDecodeContract,
}

impl<'a> AcceptedAuthoredFieldProjection<'a> {
    #[must_use]
    pub(in crate::db) const fn new(row_contract: &'a AcceptedRowDecodeContract) -> Self {
        Self { row_contract }
    }

    pub(in crate::db) fn admit_field<E>(
        &self,
        entity: &E,
        slot: usize,
        budget: &mut ValueAdmissionBudget,
    ) -> Result<AdmittedOwnedValue, AuthoredFieldAdmissionError>
    where
        E: AuthoredFieldProjection,
    {
        let (encoding, input) = self.authored_field_input(entity, slot)?;
        encoding
            .admission_contract()
            .normalize_and_admit(input, budget)
            .map_err(AuthoredFieldAdmissionError::Admission)
    }

    pub(in crate::db) fn encode_field<E>(
        &self,
        entity: &E,
        slot: usize,
        budget: &mut ValueAdmissionBudget,
    ) -> Result<Vec<u8>, AuthoredFieldAdmissionError>
    where
        E: AuthoredFieldProjection,
    {
        let (encoding, input) = self.authored_field_input(entity, slot)?;

        encode_input_value_for_accepted_field_contract(encoding, input, budget)
            .map_err(|_| AuthoredFieldAdmissionError::PersistenceEncoding { slot })
    }

    fn authored_field_input<E>(
        &self,
        entity: &E,
        slot: usize,
    ) -> Result<(AcceptedFieldPersistenceContract<'_>, InputValue), AuthoredFieldAdmissionError>
    where
        E: AuthoredFieldProjection,
    {
        let field = self
            .row_contract
            .field_for_slot(slot)
            .ok_or(AuthoredFieldAdmissionError::MissingFieldContract { slot })?;
        if !field.generated() {
            return Err(AuthoredFieldAdmissionError::FieldNotGenerated { slot });
        }
        let input = entity
            .get_input_value_by_index(slot)
            .ok_or(AuthoredFieldAdmissionError::MissingAuthoredValue { slot })?;
        let encoding = AcceptedFieldPersistenceContract::new(
            self.row_contract.enum_catalog_handle(),
            field.decode_contract(),
        )
        .map_err(|_| {
            AuthoredFieldAdmissionError::Admission(ValueAdmissionError::InvalidAcceptedContract)
        })?;

        Ok((encoding, input))
    }
}