// file: crates/ksp-job-backfill-lib/src/conversion.rs
// version: 5

use sha2::Digest; // rust-rules: trait-import

const RAW_TRANSACTION_METHOD_CODE: &str = "getTransaction";
const RAW_TRANSACTION_OBSERVATION_CONTRACT_VERSION: u32 = 1;
const RAW_TRANSACTION_PROTOCOL_CODE: &str = "solana.http.json_rpc";

/// Complete in-memory RAW transaction acquisition ready for Store persistence.
#[derive(Debug)]
pub struct BackfillRawAcquisition {
    inner: Box<BackfillRawAcquisitionInner>,
}

#[derive(Debug)]
struct BackfillRawAcquisitionInner {
    acquisition: ksp_raw_transaction_lib::RawTransactionAcquisition,
}

impl crate::BackfillRawAcquisition {
    /// Returns the canonical RAW transaction produced through the source-neutral common layer.
    #[must_use]
    pub fn transaction(&self) -> &ksp_store_lib::RawTransaction {
        return self.inner.acquisition.transaction();
    }

    /// Returns the Backfill-owned acquisition observation linked by the common assembly layer.
    #[must_use]
    pub fn observation(&self) -> &ksp_store_lib::RawTransactionObservation {
        return self.inner.acquisition.observation();
    }

    /// Consumes the in-memory acquisition into the canonical transaction and its Backfill-owned observation.
    #[must_use]
    pub fn into_parts(self) -> (ksp_store_lib::RawTransaction, ksp_store_lib::RawTransactionObservation) {
        let inner = *self.inner;
        return inner.acquisition.into_parts();
    }
}

/// Result of hydrating one deterministic Backfill candidate through observed `getTransaction`.
#[derive(Debug)]
pub enum BackfillHydrationOutcome {
    /// The RPC returned one complete transaction and common conversion produced canonical RAW plus Backfill provenance.
    Available(crate::BackfillRawAcquisition),
    /// The RPC returned JSON `null`; only the canonical transaction identity exists and no provenance is fabricated.
    Missing(ksp_store_lib::RawTransactionReference),
}

impl crate::BackfillHydrationOutcome {
    /// Returns the network-scoped transaction identity represented by this hydration outcome.
    #[must_use]
    pub fn reference(&self) -> &ksp_store_lib::RawTransactionReference {
        return match self {
            Self::Available(acquisition) => acquisition.transaction().reference(),
            Self::Missing(reference) => reference,
        };
    }

    /// Returns whether `getTransaction` returned JSON `null`.
    #[must_use]
    pub const fn is_missing(&self) -> bool {
        return matches!(self, Self::Missing(_));
    }
}

/// Hydrates one candidate with the typed observed Transport path and converts it through the common RAW v1 layer.
///
/// The caller supplies the local receipt timestamp because wall-clock ownership remains outside this
/// pure conversion path. Transport retains endpoint selection and retry. Backfill retains campaign
/// provenance and observation-key ownership; the common crate owns signature parsing, RAW v1
/// canonicalization, content hashing and transaction/observation assembly.
pub async fn hydrate_backfill_candidate(
    transport: &ksp_onchain_transport_lib::HttpTransportPool,
    request: &crate::BackfillRequest,
    candidate: &crate::BackfillCandidate,
    received_at: ksp_store_lib::RawTimestamp,
) -> ksp_core_lib::Result<crate::BackfillHydrationOutcome> {
    let reference = canonical_reference(request, candidate);
    let reference = match reference {
        std::result::Result::Ok(reference) => reference,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let config = ksp_onchain_transport_lib::SolanaGetTransactionConfig::new(
        std::option::Option::Some(request.commitment().transport()),
        std::option::Option::Some(ksp_onchain_transport_lib::SolanaTransactionEncoding::Base64),
        std::option::Option::Some(0),
    );
    let observed = transport.get_transaction_observed(request.role(), candidate.identity().signature().as_str(), std::option::Option::Some(&config)).await;
    let observed = match observed {
        std::result::Result::Ok(observed) => observed,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let provider = observed.provider().as_str().to_owned();
    let endpoint = observed.endpoint_name().to_owned();
    let transaction = observed.into_value();
    let transaction = match transaction {
        std::option::Option::Some(transaction) => transaction,
        std::option::Option::None => return std::result::Result::Ok(crate::BackfillHydrationOutcome::Missing(reference)),
    };
    let fields = CanonicalTransactionFields {
        block_time: transaction.block_time(),
        meta: transaction.meta(),
        slot: transaction.slot(),
        transaction: transaction.transaction(),
        transaction_index: transaction.transaction_index(),
        version: transaction.version(),
    };
    let acquisition = convert_available_fields(request, reference, fields, provider.as_str(), endpoint.as_str(), received_at);
    return match acquisition {
        std::result::Result::Ok(acquisition) => std::result::Result::Ok(crate::BackfillHydrationOutcome::Available(acquisition)),
        std::result::Result::Err(error) => std::result::Result::Err(error),
    };
}

/// Decodes one validated Base58 signature through the source-neutral common parser while preserving Backfill error semantics.
pub(crate) fn decode_backfill_signature(signature: &crate::BackfillSignature) -> ksp_core_lib::Result<ksp_store_lib::RawTransactionSignature> {
    let parsed = ksp_raw_transaction_lib::parse_raw_transaction_signature(signature.as_str());
    return match parsed {
        std::result::Result::Ok(signature) => std::result::Result::Ok(signature),
        std::result::Result::Err(_) => std::result::Result::Err(conversion_error("signature")),
    };
}

struct CanonicalTransactionFields<'a> {
    block_time: std::option::Option<i64>,
    meta: &'a ksp_onchain_transport_lib::SolanaWireField<serde_json::Value>,
    slot: u64,
    transaction: &'a ksp_onchain_transport_lib::SolanaEncodedTransaction,
    transaction_index: &'a ksp_onchain_transport_lib::SolanaWireField<u32>,
    version: &'a ksp_onchain_transport_lib::SolanaWireField<ksp_onchain_transport_lib::SolanaTransactionVersion>,
}

fn canonical_reference(request: &crate::BackfillRequest, candidate: &crate::BackfillCandidate) -> ksp_core_lib::Result<ksp_store_lib::RawTransactionReference> {
    if candidate.identity().network() != request.network() {
        return std::result::Result::Err(conversion_error("candidate.network"));
    }
    let signature = crate::decode_backfill_signature(candidate.identity().signature());
    let signature = match signature {
        std::result::Result::Ok(signature) => signature,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    return std::result::Result::Ok(ksp_store_lib::RawTransactionReference::new(candidate.identity().network().clone(), signature));
}

fn convert_available_fields(
    request: &crate::BackfillRequest,
    reference: ksp_store_lib::RawTransactionReference,
    fields: CanonicalTransactionFields<'_>,
    provider: &str,
    endpoint: &str,
    received_at: ksp_store_lib::RawTimestamp,
) -> ksp_core_lib::Result<crate::BackfillRawAcquisition> {
    let transaction = canonical_transaction(&reference, fields);
    let transaction = match transaction {
        std::result::Result::Ok(transaction) => transaction,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let provenance = build_provenance(request, provider, endpoint, received_at);
    let provenance = match provenance {
        std::result::Result::Ok(provenance) => provenance,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let observation_key = observation_key(request, transaction.reference(), provider, endpoint);
    let acquisition = ksp_raw_transaction_lib::assemble_raw_transaction_acquisition(transaction, observation_key, provenance);
    return std::result::Result::Ok(crate::BackfillRawAcquisition { inner: Box::new(BackfillRawAcquisitionInner { acquisition }) });
}

fn canonical_transaction(
    reference: &ksp_store_lib::RawTransactionReference,
    fields: CanonicalTransactionFields<'_>,
) -> ksp_core_lib::Result<ksp_store_lib::RawTransaction> {
    let transaction_data = match fields.transaction {
        ksp_onchain_transport_lib::SolanaEncodedTransaction::Binary { data, encoding }
            if *encoding == ksp_onchain_transport_lib::SolanaTransactionBinaryEncoding::Base64 =>
        {
            data.clone()
        },
        ksp_onchain_transport_lib::SolanaEncodedTransaction::Binary { .. }
        | ksp_onchain_transport_lib::SolanaEncodedTransaction::LegacyBinary(_)
        | ksp_onchain_transport_lib::SolanaEncodedTransaction::Json(_) => {
            return std::result::Result::Err(conversion_error("transaction.encoding"));
        },
    };
    let meta = map_wire_field(fields.meta, |value| return value.clone());
    let version = map_wire_field(fields.version, |value| {
        return match value {
            ksp_onchain_transport_lib::SolanaTransactionVersion::Legacy => ksp_raw_transaction_lib::RawTransactionVersion::Legacy,
            ksp_onchain_transport_lib::SolanaTransactionVersion::Number(number) => ksp_raw_transaction_lib::RawTransactionVersion::Number(*number),
        };
    });
    let transaction_index = map_wire_field(fields.transaction_index, |value| return *value);
    let material = ksp_raw_transaction_lib::RawTransactionMaterial::binary_base64(
        reference.network().clone(),
        reference.signature(),
        fields.slot,
        fields.block_time,
        transaction_data,
        meta,
        version,
        transaction_index,
    );
    let canonical = ksp_raw_transaction_lib::canonicalize_raw_transaction(material);
    return match canonical {
        std::result::Result::Ok(transaction) => std::result::Result::Ok(transaction),
        std::result::Result::Err(_) => std::result::Result::Err(conversion_error("common.canonicalization")),
    };
}

fn map_wire_field<T, U, F>(field: &ksp_onchain_transport_lib::SolanaWireField<T>, mut map_value: F) -> ksp_raw_transaction_lib::RawTransactionWireField<U>
where
    F: FnMut(&T) -> U,
{
    return match field {
        ksp_onchain_transport_lib::SolanaWireField::Omitted => ksp_raw_transaction_lib::RawTransactionWireField::Omitted,
        ksp_onchain_transport_lib::SolanaWireField::Null => ksp_raw_transaction_lib::RawTransactionWireField::Null,
        ksp_onchain_transport_lib::SolanaWireField::Value(value) => ksp_raw_transaction_lib::RawTransactionWireField::Value(map_value(value)),
    };
}

fn build_provenance(
    request: &crate::BackfillRequest,
    provider: &str,
    endpoint: &str,
    received_at: ksp_store_lib::RawTimestamp,
) -> ksp_core_lib::Result<ksp_store_lib::RawAcquisitionProvenance> {
    let provider = match provenance_code(provider, "provenance.provider") {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let protocol = match provenance_code(RAW_TRANSACTION_PROTOCOL_CODE, "provenance.protocol") {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let method = match provenance_code(RAW_TRANSACTION_METHOD_CODE, "provenance.method") {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let endpoint = match provenance_code(endpoint, "provenance.endpoint") {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let commitment = match provenance_code(request.commitment().code(), "provenance.commitment") {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let capture_session = match provenance_code(request.job_id().as_str(), "provenance.capture_session") {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let provenance = ksp_store_lib::RawAcquisitionProvenance::new(provider, protocol, method, ksp_store_lib::RawAcquisitionOrigin::Backfill, received_at)
        .with_endpoint_id(endpoint)
        .with_commitment(commitment)
        .with_capture_session_id(capture_session);
    return std::result::Result::Ok(provenance);
}

fn provenance_code(value: &str, field: &'static str) -> ksp_core_lib::Result<ksp_store_lib::RawProvenanceCode> {
    let code = ksp_store_lib::RawProvenanceCode::new(value);
    return match code {
        std::result::Result::Ok(code) => std::result::Result::Ok(code),
        std::result::Result::Err(_) => std::result::Result::Err(conversion_error(field)),
    };
}

fn observation_key(
    request: &crate::BackfillRequest,
    reference: &ksp_store_lib::RawTransactionReference,
    provider: &str,
    endpoint: &str,
) -> ksp_store_lib::RawObservationKey {
    let mut hasher = sha2::Sha256::new();
    hasher.update(b"ksp.job.backfill.raw_transaction_observation.v1\0");
    hash_bytes(&mut hasher, request.job_id().as_str().as_bytes());
    hash_bytes(&mut hasher, request.scope_fingerprint().as_bytes());
    hash_bytes(&mut hasher, reference.signature().as_bytes());
    hash_bytes(&mut hasher, provider.as_bytes());
    hash_bytes(&mut hasher, endpoint.as_bytes());
    hash_bytes(&mut hasher, request.commitment().code().as_bytes());
    hasher.update(RAW_TRANSACTION_OBSERVATION_CONTRACT_VERSION.to_be_bytes());
    let bytes: [u8; 32] = hasher.finalize().into();
    return ksp_store_lib::RawObservationKey::new(bytes);
}

fn hash_bytes(hasher: &mut sha2::Sha256, value: &[u8]) {
    hasher.update((value.len() as u64).to_be_bytes());
    hasher.update(value);
}

fn conversion_error(field: &'static str) -> ksp_core_lib::Error {
    return ksp_core_lib::Error::new(crate::ERROR_CODE_BACKFILL_RAW_CONVERSION_INVALID, "invalid deterministic Backfill RAW conversion")
        .with_context("field", field);
}

#[cfg(test)]
#[path = "../unit_tests/conversion.rs"]
mod tests;