alloy-eips 2.4.1

use crate::{
    eip4844::{
        Blob, BlobAndProofV2, BlobTransactionSidecar, Bytes48, BYTES_PER_BLOB,
        BYTES_PER_COMMITMENT, BYTES_PER_PROOF,
    },
    eip7594::{CELLS_PER_EXT_BLOB, EIP_7594_WRAPPER_VERSION},
};
use alloc::{boxed::Box, vec::Vec};
use alloy_primitives::{B128, B256};
use alloy_rlp::{BufMut, Decodable, Encodable, Header};

use super::{Decodable7594, Encodable7594};
use crate::eip4844::VersionedHashIter;
#[cfg(feature = "kzg")]
use crate::eip4844::{AsAlloy, AsCkzg, BlobTransactionValidationError};

/// This represents a set of blobs, and its corresponding commitments and proofs.
/// Proof type depends on the sidecar variant.
///
/// Its [`Encodable`] and [`Decodable`] implementations include an outer RLP list header. The
/// field-level [`Encodable7594`] and [`Decodable7594`] codecs omit that header.
#[derive(Clone, PartialEq, Eq, Hash, Debug, derive_more::From)]
#[cfg_attr(feature = "serde", derive(serde::Serialize))]
#[cfg_attr(feature = "serde", serde(untagged))]
#[cfg_attr(any(test, feature = "arbitrary"), derive(arbitrary::Arbitrary))]
pub enum BlobTransactionSidecarVariant {
    /// EIP-4844 style blob transaction sidecar.
    Eip4844(BlobTransactionSidecar),
    /// EIP-7594 style blob transaction sidecar with cell proofs.
    Eip7594(BlobTransactionSidecarEip7594),
}

impl Default for BlobTransactionSidecarVariant {
    fn default() -> Self {
        Self::Eip4844(BlobTransactionSidecar::default())
    }
}

impl BlobTransactionSidecarVariant {
    /// Returns true if this is a [`BlobTransactionSidecarVariant::Eip4844`].
    pub const fn is_eip4844(&self) -> bool {
        matches!(self, Self::Eip4844(_))
    }

    /// Returns true if this is a [`BlobTransactionSidecarVariant::Eip7594`].
    pub const fn is_eip7594(&self) -> bool {
        matches!(self, Self::Eip7594(_))
    }

    /// Returns the EIP-4844 sidecar if it is [`Self::Eip4844`].
    pub const fn as_eip4844(&self) -> Option<&BlobTransactionSidecar> {
        match self {
            Self::Eip4844(sidecar) => Some(sidecar),
            _ => None,
        }
    }

    /// Returns the EIP-7594 sidecar if it is [`Self::Eip7594`].
    pub const fn as_eip7594(&self) -> Option<&BlobTransactionSidecarEip7594> {
        match self {
            Self::Eip7594(sidecar) => Some(sidecar),
            _ => None,
        }
    }

    /// Converts into EIP-4844 sidecar if it is [`Self::Eip4844`].
    pub fn into_eip4844(self) -> Option<BlobTransactionSidecar> {
        match self {
            Self::Eip4844(sidecar) => Some(sidecar),
            _ => None,
        }
    }

    /// Converts the EIP-7594 sidecar if it is [`Self::Eip7594`].
    pub fn into_eip7594(self) -> Option<BlobTransactionSidecarEip7594> {
        match self {
            Self::Eip7594(sidecar) => Some(sidecar),
            _ => None,
        }
    }

    /// Get a reference to the blobs
    pub fn blobs(&self) -> &[Blob] {
        match self {
            Self::Eip4844(sidecar) => &sidecar.blobs,
            Self::Eip7594(sidecar) => &sidecar.blobs,
        }
    }

    /// Consume self and return the blobs
    pub fn into_blobs(self) -> Vec<Blob> {
        match self {
            Self::Eip4844(sidecar) => sidecar.blobs,
            Self::Eip7594(sidecar) => sidecar.blobs,
        }
    }

    /// Clears EIP-7594 blob payloads while retaining commitments and cell proofs.
    ///
    /// This prepares the sidecar for inclusion in an eth/72 `PooledTransactions` response as
    /// specified by [EIP-8070]. This has no effect on EIP-4844 sidecars.
    ///
    /// [EIP-8070]: https://eips.ethereum.org/EIPS/eip-8070
    pub fn clear_eip7594_blobs(&mut self) {
        if let Self::Eip7594(sidecar) = self {
            sidecar.clear_eip7594_blobs();
        }
    }

    /// Calculates a size heuristic for the in-memory size of the [BlobTransactionSidecarVariant].
    #[inline]
    pub const fn size(&self) -> usize {
        match self {
            Self::Eip4844(sidecar) => sidecar.size(),
            Self::Eip7594(sidecar) => sidecar.size(),
        }
    }

    /// Attempts to convert this sidecar into the EIP-7594 format using default KZG settings.
    ///
    /// This method converts an EIP-4844 sidecar to EIP-7594 by computing cell KZG proofs from
    /// the blob data. If the sidecar is already in EIP-7594 format, it returns itself unchanged.
    ///
    /// The conversion requires computing `CELLS_PER_EXT_BLOB` cell proofs for each blob using
    /// the KZG trusted setup. The default KZG settings are loaded from the environment.
    ///
    /// # Returns
    ///
    /// - `Ok(Self)` - The sidecar in EIP-7594 format (either converted or unchanged)
    /// - `Err(c_kzg::Error)` - If KZG proof computation fails
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use alloy_eips::eip7594::BlobTransactionSidecarVariant;
    /// # use alloy_eips::eip4844::BlobTransactionSidecar;
    /// # fn example(sidecar: BlobTransactionSidecarVariant) -> Result<(), c_kzg::Error> {
    /// // Convert an EIP-4844 sidecar to EIP-7594 format
    /// let eip7594_sidecar = sidecar.try_convert_into_eip7594()?;
    ///
    /// // Verify it's now in EIP-7594 format
    /// assert!(eip7594_sidecar.is_eip7594());
    /// # Ok(())
    /// # }
    /// ```
    #[cfg(feature = "kzg")]
    pub fn try_convert_into_eip7594(self) -> Result<Self, c_kzg::Error> {
        self.try_convert_into_eip7594_with_settings(
            crate::eip4844::env_settings::EnvKzgSettings::Default.get(),
        )
    }

    /// Attempts to convert this sidecar into the EIP-7594 format using custom KZG settings.
    ///
    /// This method converts an EIP-4844 sidecar to EIP-7594 by computing cell KZG proofs from
    /// the blob data using the provided KZG settings. If the sidecar is already in EIP-7594
    /// format, it returns itself unchanged.
    ///
    /// The conversion requires computing `CELLS_PER_EXT_BLOB` cell proofs for each blob using
    /// the provided KZG trusted setup parameters.
    ///
    /// Use this method when you need to specify custom KZG settings rather than using the
    /// defaults. For most use cases, [`try_convert_into_eip7594`](Self::try_convert_into_eip7594)
    /// is sufficient.
    ///
    /// # Arguments
    ///
    /// * `settings` - The KZG settings to use for computing cell proofs
    ///
    /// # Returns
    ///
    /// - `Ok(Self)` - The sidecar in EIP-7594 format (either converted or unchanged)
    /// - `Err(c_kzg::Error)` - If KZG proof computation fails
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use alloy_eips::eip7594::BlobTransactionSidecarVariant;
    /// # use alloy_eips::eip4844::BlobTransactionSidecar;
    /// # use alloy_eips::eip4844::env_settings::EnvKzgSettings;
    /// # fn example(sidecar: BlobTransactionSidecarVariant) -> Result<(), c_kzg::Error> {
    /// // Load custom KZG settings
    /// let kzg_settings = EnvKzgSettings::Default.get();
    ///
    /// // Convert using custom settings
    /// let eip7594_sidecar = sidecar.try_convert_into_eip7594_with_settings(kzg_settings)?;
    ///
    /// // Verify it's now in EIP-7594 format
    /// assert!(eip7594_sidecar.is_eip7594());
    /// # Ok(())
    /// # }
    /// ```
    #[cfg(feature = "kzg")]
    pub fn try_convert_into_eip7594_with_settings(
        self,
        settings: &c_kzg::KzgSettings,
    ) -> Result<Self, c_kzg::Error> {
        match self {
            Self::Eip4844(legacy) => legacy.try_into_7594(settings).map(Self::Eip7594),
            sidecar @ Self::Eip7594(_) => Ok(sidecar),
        }
    }

    /// Consumes this sidecar and returns a [`BlobTransactionSidecarEip7594`] using default KZG
    /// settings.
    ///
    /// This method converts an EIP-4844 sidecar to EIP-7594 by computing cell KZG proofs from
    /// the blob data. If the sidecar is already in EIP-7594 format, it extracts and returns the
    /// inner [`BlobTransactionSidecarEip7594`].
    ///
    /// Unlike [`try_convert_into_eip7594`](Self::try_convert_into_eip7594), this method returns
    /// the concrete [`BlobTransactionSidecarEip7594`] type rather than the enum variant.
    ///
    /// The conversion requires computing `CELLS_PER_EXT_BLOB` cell proofs for each blob using
    /// the KZG trusted setup. The default KZG settings are loaded from the environment.
    ///
    /// # Returns
    ///
    /// - `Ok(BlobTransactionSidecarEip7594)` - The sidecar in EIP-7594 format
    /// - `Err(c_kzg::Error)` - If KZG proof computation fails
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use alloy_eips::eip7594::BlobTransactionSidecarVariant;
    /// # use alloy_eips::eip4844::BlobTransactionSidecar;
    /// # fn example(sidecar: BlobTransactionSidecarVariant) -> Result<(), c_kzg::Error> {
    /// // Convert and extract the EIP-7594 sidecar
    /// let eip7594_sidecar = sidecar.try_into_eip7594()?;
    ///
    /// // Now we have the concrete BlobTransactionSidecarEip7594 type
    /// assert_eq!(eip7594_sidecar.blobs.len(), eip7594_sidecar.commitments.len());
    /// # Ok(())
    /// # }
    /// ```
    #[cfg(feature = "kzg")]
    pub fn try_into_eip7594(self) -> Result<BlobTransactionSidecarEip7594, c_kzg::Error> {
        self.try_into_eip7594_with_settings(
            crate::eip4844::env_settings::EnvKzgSettings::Default.get(),
        )
    }

    /// Consumes this sidecar and returns a [`BlobTransactionSidecarEip7594`] using custom KZG
    /// settings.
    ///
    /// This method converts an EIP-4844 sidecar to EIP-7594 by computing cell KZG proofs from
    /// the blob data using the provided KZG settings. If the sidecar is already in EIP-7594
    /// format, it extracts and returns the inner [`BlobTransactionSidecarEip7594`].
    ///
    /// Unlike [`try_convert_into_eip7594_with_settings`](Self::try_convert_into_eip7594_with_settings),
    /// this method returns the concrete [`BlobTransactionSidecarEip7594`] type rather than the
    /// enum variant.
    ///
    /// The conversion requires computing `CELLS_PER_EXT_BLOB` cell proofs for each blob using
    /// the provided KZG trusted setup parameters.
    ///
    /// Use this method when you need to specify custom KZG settings rather than using the
    /// defaults. For most use cases, [`try_into_eip7594`](Self::try_into_eip7594) is sufficient.
    ///
    /// # Arguments
    ///
    /// * `settings` - The KZG settings to use for computing cell proofs
    ///
    /// # Returns
    ///
    /// - `Ok(BlobTransactionSidecarEip7594)` - The sidecar in EIP-7594 format
    /// - `Err(c_kzg::Error)` - If KZG proof computation fails
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use alloy_eips::eip7594::BlobTransactionSidecarVariant;
    /// # use alloy_eips::eip4844::BlobTransactionSidecar;
    /// # use alloy_eips::eip4844::env_settings::EnvKzgSettings;
    /// # fn example(sidecar: BlobTransactionSidecarVariant) -> Result<(), c_kzg::Error> {
    /// // Load custom KZG settings
    /// let kzg_settings = EnvKzgSettings::Default.get();
    ///
    /// // Convert and extract using custom settings
    /// let eip7594_sidecar = sidecar.try_into_eip7594_with_settings(kzg_settings)?;
    ///
    /// // Now we have the concrete BlobTransactionSidecarEip7594 type
    /// assert_eq!(eip7594_sidecar.blobs.len(), eip7594_sidecar.commitments.len());
    /// # Ok(())
    /// # }
    /// ```
    #[cfg(feature = "kzg")]
    pub fn try_into_eip7594_with_settings(
        self,
        settings: &c_kzg::KzgSettings,
    ) -> Result<BlobTransactionSidecarEip7594, c_kzg::Error> {
        match self {
            Self::Eip4844(legacy) => legacy.try_into_7594(settings),
            Self::Eip7594(sidecar) => Ok(sidecar),
        }
    }

    /// Verifies that the sidecar is valid. See relevant methods for each variant for more info.
    #[cfg(feature = "kzg")]
    pub fn validate(
        &self,
        blob_versioned_hashes: &[B256],
        proof_settings: &c_kzg::KzgSettings,
    ) -> Result<(), BlobTransactionValidationError> {
        match self {
            Self::Eip4844(sidecar) => sidecar.validate(blob_versioned_hashes, proof_settings),
            Self::Eip7594(sidecar) => sidecar.validate(blob_versioned_hashes, proof_settings),
        }
    }

    /// Returns the commitments of the sidecar.
    pub fn commitments(&self) -> &[Bytes48] {
        match self {
            Self::Eip4844(sidecar) => &sidecar.commitments,
            Self::Eip7594(sidecar) => &sidecar.commitments,
        }
    }

    /// Returns an iterator over the versioned hashes of the commitments.
    pub fn versioned_hashes(&self) -> VersionedHashIter<'_> {
        VersionedHashIter::new(self.commitments())
    }

    /// Returns the index of the versioned hash in the commitments vector.
    pub fn versioned_hash_index(&self, hash: &B256) -> Option<usize> {
        match self {
            Self::Eip4844(s) => s.versioned_hash_index(hash),
            Self::Eip7594(s) => s.versioned_hash_index(hash),
        }
    }

    /// Returns the blob corresponding to the versioned hash, if it exists.
    pub fn blob_by_versioned_hash(&self, hash: &B256) -> Option<&Blob> {
        match self {
            Self::Eip4844(s) => s.blob_by_versioned_hash(hash),
            Self::Eip7594(s) => s.blob_by_versioned_hash(hash),
        }
    }

    /// Outputs the RLP length of the [BlobTransactionSidecarVariant] fields, without a RLP header.
    #[doc(hidden)]
    pub fn rlp_encoded_fields_length(&self) -> usize {
        match self {
            Self::Eip4844(sidecar) => sidecar.rlp_encoded_fields_length(),
            Self::Eip7594(sidecar) => sidecar.rlp_encoded_fields_length(),
        }
    }

    /// Returns the [`Self::rlp_encode_fields`] RLP bytes.
    #[inline]
    #[doc(hidden)]
    pub fn rlp_encoded_fields(&self) -> Vec<u8> {
        let mut buf = Vec::with_capacity(self.rlp_encoded_fields_length());
        self.rlp_encode_fields(&mut buf);
        buf
    }

    /// Encodes the inner [BlobTransactionSidecarVariant] fields as RLP bytes, __without__ a RLP
    /// header.
    #[inline]
    #[doc(hidden)]
    pub fn rlp_encode_fields(&self, out: &mut dyn BufMut) {
        match self {
            Self::Eip4844(sidecar) => sidecar.rlp_encode_fields(out),
            Self::Eip7594(sidecar) => sidecar.rlp_encode_fields(out),
        }
    }

    /// RLP decode the fields of a [BlobTransactionSidecarVariant] based on the wrapper version.
    #[doc(hidden)]
    pub fn rlp_decode_fields(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
        Self::decode_7594(buf)
    }
}

impl Encodable for BlobTransactionSidecarVariant {
    /// Encodes the selected sidecar as an RLP list, including its outer header.
    fn encode(&self, out: &mut dyn BufMut) {
        match self {
            Self::Eip4844(sidecar) => sidecar.encode(out),
            Self::Eip7594(sidecar) => sidecar.encode(out),
        }
    }

    fn length(&self) -> usize {
        match self {
            Self::Eip4844(sidecar) => sidecar.rlp_encoded_length(),
            Self::Eip7594(sidecar) => sidecar.rlp_encoded_length(),
        }
    }
}

impl Decodable for BlobTransactionSidecarVariant {
    /// Decodes an RLP list, including its outer header.
    fn decode(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
        let header = Header::decode(buf)?;
        if !header.list {
            return Err(alloy_rlp::Error::UnexpectedString);
        }
        if buf.len() < header.payload_length {
            return Err(alloy_rlp::Error::InputTooShort);
        }
        let remaining = buf.len();
        let this = Self::rlp_decode_fields(buf)?;
        if buf.len() + header.payload_length != remaining {
            return Err(alloy_rlp::Error::UnexpectedLength);
        }

        Ok(this)
    }
}

impl Encodable7594 for BlobTransactionSidecarVariant {
    fn encode_7594_len(&self) -> usize {
        self.rlp_encoded_fields_length()
    }

    fn encode_7594(&self, out: &mut dyn BufMut) {
        self.rlp_encode_fields(out);
    }
}

impl Decodable7594 for BlobTransactionSidecarVariant {
    fn decode_7594(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
        if buf.first() == Some(&EIP_7594_WRAPPER_VERSION) {
            Ok(Self::Eip7594(Decodable7594::decode_7594(buf)?))
        } else {
            Ok(Self::Eip4844(Decodable7594::decode_7594(buf)?))
        }
    }
}

#[cfg(feature = "kzg")]
impl TryFrom<BlobTransactionSidecarVariant> for BlobTransactionSidecarEip7594 {
    type Error = c_kzg::Error;

    fn try_from(value: BlobTransactionSidecarVariant) -> Result<Self, Self::Error> {
        value.try_into_eip7594()
    }
}

#[cfg(feature = "serde")]
impl<'de> serde::Deserialize<'de> for BlobTransactionSidecarVariant {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        use core::fmt;

        #[derive(serde::Deserialize, fmt::Debug)]
        #[serde(field_identifier, rename_all = "camelCase")]
        enum Field {
            Blobs,
            Commitments,
            Proofs,
            CellProofs,
        }

        struct VariantVisitor;

        impl<'de> serde::de::Visitor<'de> for VariantVisitor {
            type Value = BlobTransactionSidecarVariant;

            fn expecting(&self, formatter: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
                formatter
                    .write_str("a valid blob transaction sidecar (EIP-4844 or EIP-7594 variant)")
            }

            fn visit_map<M>(self, mut map: M) -> Result<Self::Value, M::Error>
            where
                M: serde::de::MapAccess<'de>,
            {
                let mut blobs = None;
                let mut commitments = None;
                let mut proofs = None;
                let mut cell_proofs = None;

                while let Some(key) = map.next_key()? {
                    match key {
                        Field::Blobs => {
                            blobs = Some(crate::eip4844::deserialize_blobs_map(&mut map)?);
                        }
                        Field::Commitments => commitments = Some(map.next_value()?),
                        Field::Proofs => proofs = Some(map.next_value()?),
                        Field::CellProofs => cell_proofs = Some(map.next_value()?),
                    }
                }

                let blobs = blobs.ok_or_else(|| serde::de::Error::missing_field("blobs"))?;
                let commitments =
                    commitments.ok_or_else(|| serde::de::Error::missing_field("commitments"))?;

                match (cell_proofs, proofs) {
                    (Some(cp), None) => {
                        Ok(BlobTransactionSidecarVariant::Eip7594(BlobTransactionSidecarEip7594 {
                            blobs,
                            commitments,
                            cell_proofs: cp,
                        }))
                    }
                    (None, Some(pf)) => {
                        Ok(BlobTransactionSidecarVariant::Eip4844(BlobTransactionSidecar {
                            blobs,
                            commitments,
                            proofs: pf,
                        }))
                    }
                    (None, None) => {
                        Err(serde::de::Error::custom("Missing 'cellProofs' or 'proofs'"))
                    }
                    (Some(_), Some(_)) => Err(serde::de::Error::custom(
                        "Both 'cellProofs' and 'proofs' cannot be present",
                    )),
                }
            }
        }

        const FIELDS: &[&str] = &["blobs", "commitments", "proofs", "cellProofs"];
        deserializer.deserialize_struct("BlobTransactionSidecarVariant", FIELDS, VariantVisitor)
    }
}

/// This represents a set of blobs, and its corresponding commitments and cell proofs.
///
/// A well-formed sidecar has one commitment per blob and `CELLS_PER_EXT_BLOB` cell proofs per
/// blob. Public fields and [`Self::new`] do not enforce these cardinalities or validate proofs.
/// With the `kzg` feature, prefer `try_from_blobs_with_settings` or call `validate` before
/// use.
///
/// Its [`Encodable`] and [`Decodable`] implementations include an outer RLP list header. The
/// field-level [`Encodable7594`] and [`Decodable7594`] codecs omit that header.
#[derive(Clone, Default, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(any(test, feature = "arbitrary"), derive(arbitrary::Arbitrary))]
#[cfg_attr(feature = "serde", serde(rename_all = "camelCase"))]
pub struct BlobTransactionSidecarEip7594 {
    /// The blob data.
    #[cfg_attr(feature = "serde", serde(deserialize_with = "crate::eip4844::deserialize_blobs"))]
    pub blobs: Vec<Blob>,
    /// The blob commitments.
    pub commitments: Vec<Bytes48>,
    /// List of cell proofs for all blobs in the sidecar, including the proofs for the extension
    /// indices, for a total of `CELLS_PER_EXT_BLOB` proofs per blob (`CELLS_PER_EXT_BLOB` is the
    /// number of cells for an extended blob, defined in
    /// [the consensus specs](https://github.com/ethereum/consensus-specs/tree/9d377fd53d029536e57cfda1a4d2c700c59f86bf/specs/fulu/polynomial-commitments-sampling.md#cells))
    pub cell_proofs: Vec<Bytes48>,
}

impl core::fmt::Debug for BlobTransactionSidecarEip7594 {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        f.debug_struct("BlobTransactionSidecarEip7594")
            .field("blobs", &self.blobs.len())
            .field("commitments", &self.commitments)
            .field("cell_proofs", &self.cell_proofs)
            .finish()
    }
}

impl BlobTransactionSidecarEip7594 {
    /// Constructs a sidecar without validating cardinalities, commitments, or cell proofs.
    pub const fn new(
        blobs: Vec<Blob>,
        commitments: Vec<Bytes48>,
        cell_proofs: Vec<Bytes48>,
    ) -> Self {
        Self { blobs, commitments, cell_proofs }
    }

    /// Recovers a sidecar from a common set of EIP-7594 cells for every blob.
    ///
    /// `cell_mask` identifies the cells supplied for each commitment. `cells` must be flattened in
    /// blob-major order: all selected cells for `commitments[0]`, followed by all selected cells
    /// for `commitments[1]`, and so on. At least half of the 128 extended blob cells must be
    /// selected. The recovered sidecar contains the complete blob data and all 128 cell proofs.
    ///
    /// Recovery authenticates each reconstructed blob by recomputing and comparing its
    /// commitment. It does not verify proofs for the input cells; callers accepting untrusted
    /// cells and proofs should batch-verify them before recovery when early rejection is useful.
    ///
    /// This uses the default KZG settings.
    #[cfg(feature = "kzg")]
    pub fn try_recover_from_cells(
        commitments: Vec<Bytes48>,
        cell_mask: BlobCellMask,
        cells: &[crate::eip7594::Cell],
    ) -> Result<Self, BlobCellRecoveryError> {
        use crate::eip4844::env_settings::EnvKzgSettings;

        Self::try_recover_from_cells_with_settings(
            commitments,
            cell_mask,
            cells,
            EnvKzgSettings::Default.get(),
        )
    }

    /// Recovers a sidecar from EIP-7594 cells using custom KZG settings.
    ///
    /// See [`Self::try_recover_from_cells`] for the expected cell layout and verification
    /// boundary.
    #[cfg(feature = "kzg")]
    pub fn try_recover_from_cells_with_settings(
        commitments: Vec<Bytes48>,
        cell_mask: BlobCellMask,
        cells: &[crate::eip7594::Cell],
        settings: &c_kzg::KzgSettings,
    ) -> Result<Self, BlobCellRecoveryError> {
        let cells_per_blob = cell_mask.count();
        if !commitments.is_empty() && cells_per_blob < CELLS_PER_EXT_BLOB / 2 {
            return Err(BlobCellRecoveryError::InsufficientCells {
                provided: cells_per_blob,
                required: CELLS_PER_EXT_BLOB / 2,
            });
        }

        let expected_cells = commitments
            .len()
            .checked_mul(cells_per_blob)
            .ok_or(BlobCellRecoveryError::CellCountOverflow)?;
        if cells.len() != expected_cells {
            return Err(BlobCellRecoveryError::CellCountMismatch {
                provided: cells.len(),
                expected: expected_cells,
            });
        }
        if commitments.is_empty() {
            return Ok(Self::new(Vec::new(), commitments, Vec::new()));
        }

        let cell_indices =
            cell_mask.selected_indices().map(|index| index as u64).collect::<Vec<_>>();
        let mut blobs = Vec::with_capacity(commitments.len());
        let cell_proof_capacity = commitments
            .len()
            .checked_mul(CELLS_PER_EXT_BLOB)
            .ok_or(BlobCellRecoveryError::CellCountOverflow)?;
        let mut cell_proofs = Vec::with_capacity(cell_proof_capacity);

        for (blob_index, (blob_cells, expected_commitment)) in
            cells.chunks_exact(cells_per_blob).zip(&commitments).enumerate()
        {
            let ckzg_cells = crate::eip7594::Cell::slice_as_ckzg(blob_cells);
            let (recovered_cells, recovered_proofs) =
                settings.recover_cells_and_kzg_proofs(&cell_indices, ckzg_cells)?;
            let blob = reconstruct_blob(recovered_cells.as_ref());

            let commitment = settings.blob_to_kzg_commitment(blob.as_ckzg())?;
            let commitment = Bytes48::from_ckzg(commitment.to_bytes());
            if commitment != *expected_commitment {
                return Err(BlobCellRecoveryError::CommitmentMismatch { blob_index });
            }

            blobs.push(blob);
            cell_proofs
                .extend_from_slice(c_kzg::KzgProof::slice_as_alloy(recovered_proofs.as_ref()));
        }

        Ok(Self::new(blobs, commitments, cell_proofs))
    }

    /// Clears blob payloads while retaining commitments and cell proofs.
    ///
    /// This prepares the sidecar for inclusion in an eth/72 `PooledTransactions` response as
    /// specified by [EIP-8070].
    ///
    /// [EIP-8070]: https://eips.ethereum.org/EIPS/eip-8070
    pub fn clear_eip7594_blobs(&mut self) {
        self.blobs.clear();
    }

    /// Calculates a size heuristic for the in-memory size of the [BlobTransactionSidecarEip7594].
    #[inline]
    pub const fn size(&self) -> usize {
        self.blobs.capacity() * BYTES_PER_BLOB
            + self.commitments.capacity() * BYTES_PER_COMMITMENT
            + self.cell_proofs.capacity() * BYTES_PER_PROOF
    }

    /// Shrinks the sidecar vectors to fit their current contents.
    #[inline]
    pub fn shrink_to_fit(&mut self) {
        self.blobs.shrink_to_fit();
        self.commitments.shrink_to_fit();
        self.cell_proofs.shrink_to_fit();
    }

    /// Tries to create a new [`BlobTransactionSidecarEip7594`] from the hex encoded blob str.
    ///
    /// See also [`Blob::from_hex`](c_kzg::Blob::from_hex)
    #[cfg(all(feature = "kzg", any(test, feature = "arbitrary")))]
    pub fn try_from_blobs_hex<I, B>(blobs: I) -> Result<Self, c_kzg::Error>
    where
        I: IntoIterator<Item = B>,
        B: AsRef<str>,
    {
        let mut converted = Vec::new();
        for blob in blobs {
            converted.push(crate::eip4844::utils::hex_to_blob(blob)?);
        }
        Self::try_from_blobs(converted)
    }

    /// Tries to create a new [`BlobTransactionSidecarEip7594`] from the given blob
    /// bytes.
    ///
    /// See also [`Blob::from_bytes`](c_kzg::Blob::from_bytes)
    #[cfg(all(feature = "kzg", any(test, feature = "arbitrary")))]
    pub fn try_from_blobs_bytes<I, B>(blobs: I) -> Result<Self, c_kzg::Error>
    where
        I: IntoIterator<Item = B>,
        B: AsRef<[u8]>,
    {
        let mut converted = Vec::new();
        for blob in blobs {
            converted.push(crate::eip4844::utils::bytes_to_blob(blob)?);
        }
        Self::try_from_blobs(converted)
    }

    /// Tries to create a new [`BlobTransactionSidecarEip7594`] from the given
    /// blobs and KZG settings.
    #[cfg(feature = "kzg")]
    pub fn try_from_blobs_with_settings(
        blobs: Vec<Blob>,
        settings: &c_kzg::KzgSettings,
    ) -> Result<Self, c_kzg::Error> {
        if let [blob] = blobs.as_slice() {
            let blob = blob.as_ckzg();
            let commitment = settings.blob_to_kzg_commitment(blob)?;
            let (_cells, kzg_proofs) = settings.compute_cells_and_kzg_proofs(blob)?;
            let commitments = vec![Bytes48::from_ckzg(commitment.to_bytes())];
            let proofs = c_kzg::KzgProof::boxed_slice_as_alloy(kzg_proofs).into();
            return Ok(Self::new(blobs, commitments, proofs));
        }

        let mut commitments = Vec::with_capacity(blobs.len());
        let mut proofs = Vec::with_capacity(blobs.len() * CELLS_PER_EXT_BLOB);
        for blob in &blobs {
            let blob = blob.as_ckzg();
            let commitment = settings.blob_to_kzg_commitment(blob)?;
            let (_cells, kzg_proofs) = settings.compute_cells_and_kzg_proofs(blob)?;

            commitments.push(Bytes48::from_ckzg(commitment.to_bytes()));
            proofs.extend_from_slice(c_kzg::KzgProof::slice_as_alloy(kzg_proofs.as_ref()));
        }

        Ok(Self::new(blobs, commitments, proofs))
    }

    /// Tries to create a new [`BlobTransactionSidecarEip7594`] from the given
    /// blobs.
    ///
    /// This uses the global/default KZG settings, see also
    /// [`EnvKzgSettings::Default`](crate::eip4844::env_settings::EnvKzgSettings).
    #[cfg(feature = "kzg")]
    pub fn try_from_blobs(blobs: Vec<Blob>) -> Result<Self, c_kzg::Error> {
        use crate::eip4844::env_settings::EnvKzgSettings;

        Self::try_from_blobs_with_settings(blobs, EnvKzgSettings::Default.get())
    }

    /// Computes the EIP-7594 cells for all blobs using the default KZG settings.
    ///
    /// The returned cells use the same blob-major flattened layout as [`Self::cell_proofs`]:
    /// every blob contributes one contiguous [`CELLS_PER_EXT_BLOB`]-cell chunk. For blob index
    /// `i` and cell index `j`, the cell is at `i * CELLS_PER_EXT_BLOB + j`.
    ///
    /// In other words, the layout is `[blob0_cell0, ..., blob0_cell127, blob1_cell0, ...]`.
    #[cfg(feature = "kzg")]
    pub fn compute_cells(&self) -> Result<Vec<crate::eip7594::Cell>, c_kzg::Error> {
        use crate::eip4844::env_settings::EnvKzgSettings;

        self.compute_cells_with_settings(EnvKzgSettings::Default.get())
    }

    /// Computes the EIP-7594 cells for all blobs using the given KZG settings.
    ///
    /// The returned cells use the same blob-major flattened layout as [`Self::cell_proofs`]:
    /// every blob contributes one contiguous [`CELLS_PER_EXT_BLOB`]-cell chunk. For blob index
    /// `i` and cell index `j`, the cell is at `i * CELLS_PER_EXT_BLOB + j`.
    ///
    /// In other words, the layout is `[blob0_cell0, ..., blob0_cell127, blob1_cell0, ...]`.
    #[cfg(feature = "kzg")]
    pub fn compute_cells_with_settings(
        &self,
        settings: &c_kzg::KzgSettings,
    ) -> Result<Vec<crate::eip7594::Cell>, c_kzg::Error> {
        if let [blob] = self.blobs.as_slice() {
            let blob_cells = settings.compute_cells(blob.as_ckzg())?;
            return Ok(c_kzg::Cell::boxed_slice_as_alloy(blob_cells).into());
        }

        let mut cells = Vec::with_capacity(self.blobs.len() * CELLS_PER_EXT_BLOB);
        for blob in &self.blobs {
            let blob_cells = settings.compute_cells(blob.as_ckzg())?;
            cells.extend_from_slice(c_kzg::Cell::slice_as_alloy(blob_cells.as_ref()));
        }
        Ok(cells)
    }

    /// Computes the EIP-7594 cells for all blobs and returns only the cells selected by
    /// `cell_mask`.
    ///
    /// The returned cells keep the blob-major order from [`Self::compute_cells`] but omit cells
    /// whose indices are not selected by `cell_mask`.
    ///
    /// This uses the default KZG settings.
    #[cfg(feature = "kzg")]
    pub fn compute_matching_cells(
        &self,
        cell_mask: BlobCellMask,
    ) -> Result<Vec<crate::eip7594::Cell>, c_kzg::Error> {
        use crate::eip4844::env_settings::EnvKzgSettings;

        self.compute_matching_cells_with_settings(cell_mask, EnvKzgSettings::Default.get())
    }

    /// Computes the EIP-7594 cells for all blobs with the given KZG settings and returns only the
    /// cells selected by `cell_mask`.
    ///
    /// The returned cells keep the blob-major order from [`Self::compute_cells_with_settings`] but
    /// omit cells whose indices are not selected by `cell_mask`.
    #[cfg(feature = "kzg")]
    pub fn compute_matching_cells_with_settings(
        &self,
        cell_mask: BlobCellMask,
        settings: &c_kzg::KzgSettings,
    ) -> Result<Vec<crate::eip7594::Cell>, c_kzg::Error> {
        let cells = self.compute_cells_with_settings(settings)?;
        Ok(cell_mask
            .matching_cells_from_computed_cells(&cells)
            .expect("computed cells must contain full extended blob cell chunks"))
    }

    /// Verifies that the versioned hashes are valid for this sidecar's blob data, commitments, and
    /// proofs.
    ///
    /// Takes as input the [KzgSettings](c_kzg::KzgSettings), which should contain the parameters
    /// derived from the KZG trusted setup.
    ///
    /// This ensures that the blob transaction payload has the expected number of blob data
    /// elements, commitments, and proofs. The cells are constructed from each blob and verified
    /// against the commitments and proofs.
    ///
    /// Returns [BlobTransactionValidationError::InvalidProof] if any blob KZG proof in the response
    /// fails to verify, or if the versioned hashes in the transaction do not match the actual
    /// commitment versioned hashes.
    #[cfg(feature = "kzg")]
    pub fn validate(
        &self,
        blob_versioned_hashes: &[B256],
        proof_settings: &c_kzg::KzgSettings,
    ) -> Result<(), BlobTransactionValidationError> {
        // Ensure the versioned hashes and commitments have the same length.
        if blob_versioned_hashes.len() != self.commitments.len() {
            return Err(c_kzg::Error::MismatchLength(format!(
                "There are {} versioned commitment hashes and {} commitments",
                blob_versioned_hashes.len(),
                self.commitments.len()
            ))
            .into());
        }

        let blobs_len = self.blobs.len();
        let expected_cell_proofs_len = blobs_len * CELLS_PER_EXT_BLOB;
        if self.cell_proofs.len() != expected_cell_proofs_len {
            return Err(c_kzg::Error::MismatchLength(format!(
                "There are {} cell proofs and {} blobs. Expected {} cell proofs.",
                self.cell_proofs.len(),
                blobs_len,
                expected_cell_proofs_len
            ))
            .into());
        }

        // calculate versioned hashes by zipping & iterating
        for (versioned_hash, commitment) in
            blob_versioned_hashes.iter().zip(self.commitments.iter())
        {
            // calculate & verify versioned hash
            let calculated_versioned_hash =
                crate::eip4844::kzg_to_versioned_hash(commitment.as_slice());
            if *versioned_hash != calculated_versioned_hash {
                return Err(BlobTransactionValidationError::WrongVersionedHash {
                    have: *versioned_hash,
                    expected: calculated_versioned_hash,
                });
            }
        }

        // Repeat cell ranges for each blob.
        let cell_indices =
            Vec::from_iter((0..blobs_len).flat_map(|_| 0..CELLS_PER_EXT_BLOB as u64));

        // Repeat commitments for each cell.
        let mut commitments = Vec::with_capacity(blobs_len * CELLS_PER_EXT_BLOB);
        for commitment in &self.commitments {
            commitments.extend(core::iter::repeat_n(*commitment, CELLS_PER_EXT_BLOB));
        }

        let cells = if let [blob] = self.blobs.as_slice() {
            let cells: Box<[c_kzg::Cell]> = proof_settings.compute_cells(blob.as_ckzg())?;
            cells.into()
        } else {
            let mut cells = Vec::with_capacity(blobs_len * CELLS_PER_EXT_BLOB);
            for blob in &self.blobs {
                let blob_cells = proof_settings.compute_cells(blob.as_ckzg())?;
                cells.extend_from_slice(blob_cells.as_ref());
            }
            cells
        };

        let res = proof_settings.verify_cell_kzg_proof_batch(
            Bytes48::slice_as_ckzg(&commitments),
            &cell_indices,
            &cells,
            Bytes48::slice_as_ckzg(self.cell_proofs.as_slice()),
        )?;

        res.then_some(()).ok_or(BlobTransactionValidationError::InvalidProof)
    }

    /// Returns an iterator over the versioned hashes of the commitments.
    pub fn versioned_hashes(&self) -> VersionedHashIter<'_> {
        VersionedHashIter::new(&self.commitments)
    }

    /// Returns the index of the versioned hash in the commitments vector.
    pub fn versioned_hash_index(&self, hash: &B256) -> Option<usize> {
        self.commitments.iter().position(|commitment| {
            crate::eip4844::kzg_to_versioned_hash(commitment.as_slice()) == *hash
        })
    }

    /// Returns the blob corresponding to the versioned hash, if it exists.
    pub fn blob_by_versioned_hash(&self, hash: &B256) -> Option<&Blob> {
        self.versioned_hash_index(hash).and_then(|index| self.blobs.get(index))
    }

    /// Returns the requested cells and proofs for the blob at `blob_index`, if it exists.
    ///
    /// This uses the default KZG settings.
    #[cfg(feature = "kzg")]
    pub fn blob_cells_and_proofs(
        &self,
        blob_index: usize,
        cell_mask: BlobCellMask,
    ) -> Result<Option<crate::eip4844::BlobCellsAndProofsV1>, c_kzg::Error> {
        use crate::eip4844::env_settings::EnvKzgSettings;

        self.blob_cells_and_proofs_with_settings(
            blob_index,
            cell_mask,
            EnvKzgSettings::Default.get(),
        )
    }

    /// Returns the requested cells and proofs for the blob at `blob_index`, if it exists.
    #[cfg(feature = "kzg")]
    pub fn blob_cells_and_proofs_with_settings(
        &self,
        blob_index: usize,
        cell_mask: BlobCellMask,
        settings: &c_kzg::KzgSettings,
    ) -> Result<Option<crate::eip4844::BlobCellsAndProofsV1>, c_kzg::Error> {
        let Some(blob) = self.blobs.get(blob_index) else { return Ok(None) };

        let proof_start = blob_index * CELLS_PER_EXT_BLOB;
        let Some(proofs) = self.cell_proofs.get(proof_start..proof_start + CELLS_PER_EXT_BLOB)
        else {
            return Ok(None);
        };

        if cell_mask.count() == 0 {
            return Ok(Some(crate::eip4844::BlobCellsAndProofsV1::default()));
        }

        let cells = settings.compute_cells(blob.as_ckzg())?;

        Ok(Some(Self::blob_cells_and_proofs_from_computed_cells(cell_mask, cells.as_ref(), proofs)))
    }

    /// Returns the requested cells and proofs from precomputed cells.
    #[cfg(feature = "kzg")]
    fn blob_cells_and_proofs_from_computed_cells(
        cell_mask: BlobCellMask,
        cells: &[c_kzg::Cell],
        proofs: &[Bytes48],
    ) -> crate::eip4844::BlobCellsAndProofsV1 {
        // The response needs two owned vectors, and `count()` exactly matches
        // `selected_indices()`, so this avoids reallocations while staying simple.
        let mut blob_cells = Vec::with_capacity(cell_mask.count());
        let mut selected_proofs = Vec::with_capacity(cell_mask.count());
        for cell_index in cell_mask.selected_indices() {
            blob_cells
                .push(cells.get(cell_index).map(|cell| crate::eip7594::Cell::new(cell.to_bytes())));
            selected_proofs.push(proofs.get(cell_index).copied());
        }

        crate::eip4844::BlobCellsAndProofsV1 { blob_cells, proofs: selected_proofs }
    }

    /// Matches versioned hashes and returns an iterator of (index, [`BlobAndProofV2`]) pairs
    /// where index is the position in `versioned_hashes` that matched the versioned hash in the
    /// sidecar.
    ///
    /// This is used for the `engine_getBlobsV2` RPC endpoint of the engine API
    pub fn match_versioned_hashes<'a>(
        &'a self,
        versioned_hashes: &'a [B256],
    ) -> impl Iterator<Item = (usize, BlobAndProofV2)> + 'a {
        self.versioned_hashes().enumerate().flat_map(move |(i, blob_versioned_hash)| {
            versioned_hashes.iter().enumerate().filter_map(move |(j, target_hash)| {
                if blob_versioned_hash == *target_hash {
                    let maybe_blob = self.blobs.get(i);
                    let proof_range = i * CELLS_PER_EXT_BLOB..(i + 1) * CELLS_PER_EXT_BLOB;
                    let maybe_proofs = self
                        .cell_proofs
                        .get(proof_range)
                        .filter(|proofs| proofs.len() == CELLS_PER_EXT_BLOB);
                    if let Some((blob, proofs)) = maybe_blob.copied().zip(maybe_proofs) {
                        return Some((
                            j,
                            BlobAndProofV2 { blob: Box::new(blob), proofs: proofs.to_vec() },
                        ));
                    }
                }
                None
            })
        })
    }

    /// Matches versioned hashes and returns (index, [`crate::eip4844::BlobCellsAndProofsV1`])
    /// pairs where index is the position in `versioned_hashes` that matched the versioned hash in
    /// the sidecar.
    ///
    /// This is used for the `engine_getBlobsV4` RPC endpoint of the engine API.
    ///
    /// This uses the default KZG settings.
    #[cfg(feature = "kzg")]
    pub fn match_versioned_hashes_cells<'a>(
        &'a self,
        versioned_hashes: &'a [B256],
        cell_mask: BlobCellMask,
    ) -> Result<
        impl Iterator<Item = (usize, crate::eip4844::BlobCellsAndProofsV1)> + 'a,
        c_kzg::Error,
    > {
        use crate::eip4844::env_settings::EnvKzgSettings;

        self.match_versioned_hashes_cells_with_settings(
            versioned_hashes,
            cell_mask,
            EnvKzgSettings::Default.get(),
        )
    }

    /// Matches versioned hashes and returns (index, [`crate::eip4844::BlobCellsAndProofsV1`])
    /// pairs where index is the position in `versioned_hashes` that matched the versioned hash in
    /// the sidecar.
    #[cfg(feature = "kzg")]
    pub fn match_versioned_hashes_cells_with_settings<'a>(
        &'a self,
        versioned_hashes: &'a [B256],
        cell_mask: BlobCellMask,
        settings: &c_kzg::KzgSettings,
    ) -> Result<
        impl Iterator<Item = (usize, crate::eip4844::BlobCellsAndProofsV1)> + 'a,
        c_kzg::Error,
    > {
        let mut matches = Vec::new();
        let mut cells_and_proofs_by_blob =
            Vec::<(usize, crate::eip4844::BlobCellsAndProofsV1)>::new();

        for (blob_index, commitment) in self.commitments.iter().enumerate() {
            let blob_versioned_hash = crate::eip4844::kzg_to_versioned_hash(commitment.as_slice());
            for (matched_index, target_hash) in versioned_hashes.iter().enumerate() {
                if blob_versioned_hash != *target_hash {
                    continue;
                }

                let Some(blob) = self.blobs.get(blob_index) else { continue };
                let proof_start = blob_index * CELLS_PER_EXT_BLOB;
                let Some(proofs) =
                    self.cell_proofs.get(proof_start..proof_start + CELLS_PER_EXT_BLOB)
                else {
                    continue;
                };

                let cells_and_proofs = if cell_mask.count() == 0 {
                    crate::eip4844::BlobCellsAndProofsV1::default()
                } else if let Some((_, cells_and_proofs)) =
                    cells_and_proofs_by_blob.iter().find(|(index, _)| *index == blob_index)
                {
                    cells_and_proofs.clone()
                } else {
                    let cells = settings.compute_cells(blob.as_ckzg())?;
                    let cells_and_proofs = Self::blob_cells_and_proofs_from_computed_cells(
                        cell_mask,
                        cells.as_ref(),
                        proofs,
                    );
                    cells_and_proofs_by_blob.push((blob_index, cells_and_proofs.clone()));
                    cells_and_proofs
                };

                matches.push((matched_index, cells_and_proofs));
            }
        }

        Ok(matches.into_iter())
    }

    /// Outputs the RLP length of [BlobTransactionSidecarEip7594] fields without a RLP header.
    #[doc(hidden)]
    pub fn rlp_encoded_fields_length(&self) -> usize {
        // wrapper version + blobs + commitments + cell proofs
        1 + self.blobs.length() + self.commitments.length() + self.cell_proofs.length()
    }

    /// Encodes the inner [BlobTransactionSidecarEip7594] fields as RLP bytes, __without__ a
    /// RLP header.
    ///
    /// This encodes the fields in the following order:
    /// - `wrapper_version`
    /// - `blobs`
    /// - `commitments`
    /// - `cell_proofs`
    #[inline]
    #[doc(hidden)]
    pub fn rlp_encode_fields(&self, out: &mut dyn BufMut) {
        // Put version byte.
        out.put_u8(EIP_7594_WRAPPER_VERSION);
        // Encode the blobs, commitments, and cell proofs
        self.blobs.encode(out);
        self.commitments.encode(out);
        self.cell_proofs.encode(out);
    }

    /// Creates an RLP header for the [BlobTransactionSidecarEip7594].
    fn rlp_header(&self) -> Header {
        Header { list: true, payload_length: self.rlp_encoded_fields_length() }
    }

    /// Calculates the length of the [BlobTransactionSidecarEip7594] when encoded as
    /// RLP.
    pub fn rlp_encoded_length(&self) -> usize {
        self.rlp_header().length() + self.rlp_encoded_fields_length()
    }

    /// Encodes the [BlobTransactionSidecarEip7594] as RLP bytes.
    pub fn rlp_encode(&self, out: &mut dyn BufMut) {
        self.rlp_header().encode(out);
        self.rlp_encode_fields(out);
    }

    /// RLP decode the fields of a [BlobTransactionSidecarEip7594].
    #[doc(hidden)]
    pub fn rlp_decode_fields(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
        Ok(Self {
            blobs: Decodable::decode(buf)?,
            commitments: Decodable::decode(buf)?,
            cell_proofs: Decodable::decode(buf)?,
        })
    }

    /// Decodes the [BlobTransactionSidecarEip7594] from RLP bytes.
    pub fn rlp_decode(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
        let header = Header::decode(buf)?;
        if !header.list {
            return Err(alloy_rlp::Error::UnexpectedString);
        }
        if buf.len() < header.payload_length {
            return Err(alloy_rlp::Error::InputTooShort);
        }
        let remaining = buf.len();

        let this = Self::decode_7594(buf)?;
        if buf.len() + header.payload_length != remaining {
            return Err(alloy_rlp::Error::UnexpectedLength);
        }

        Ok(this)
    }
}

/// An error that can occur while recovering blobs from EIP-7594 cells.
#[cfg(feature = "kzg")]
#[derive(Debug)]
pub enum BlobCellRecoveryError {
    /// Fewer than half of the extended blob cells were selected.
    InsufficientCells {
        /// The number of cells supplied for each blob.
        provided: usize,
        /// The minimum number of cells required for recovery.
        required: usize,
    },
    /// The flattened cell slice does not match the commitments and cell mask.
    CellCountMismatch {
        /// The number of cells supplied.
        provided: usize,
        /// The number of cells implied by the commitments and cell mask.
        expected: usize,
    },
    /// The expected cell count cannot be represented as a `usize`.
    CellCountOverflow,
    /// A reconstructed blob does not match its supplied commitment.
    CommitmentMismatch {
        /// The index of the blob whose commitment did not match.
        blob_index: usize,
    },
    /// An error returned by [`c_kzg`].
    Kzg(c_kzg::Error),
}

#[cfg(feature = "kzg")]
impl core::fmt::Display for BlobCellRecoveryError {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        match self {
            Self::InsufficientCells { provided, required } => {
                write!(f, "need at least {required} cells per blob for recovery, got {provided}")
            }
            Self::CellCountMismatch { provided, expected } => {
                write!(f, "expected {expected} cells, got {provided}")
            }
            Self::CellCountOverflow => f.write_str("the expected cell count overflows usize"),
            Self::CommitmentMismatch { blob_index } => {
                write!(f, "reconstructed blob {blob_index} does not match its commitment")
            }
            Self::Kzg(err) => write!(f, "KZG error: {err:?}"),
        }
    }
}

#[cfg(feature = "kzg")]
impl core::error::Error for BlobCellRecoveryError {}

#[cfg(feature = "kzg")]
impl From<c_kzg::Error> for BlobCellRecoveryError {
    fn from(source: c_kzg::Error) -> Self {
        Self::Kzg(source)
    }
}

#[cfg(feature = "kzg")]
fn reconstruct_blob(recovered_cells: &[c_kzg::Cell; CELLS_PER_EXT_BLOB]) -> Blob {
    // `RecoverCells` returns cells in the canonical EIP-7594 order. The first half is the
    // original blob data; the remaining cells are the extension used for sampling and proofs.
    // The KZG backend performs the recovery, while this wrapper only materializes the original
    // blob cells.
    let mut blob = [0u8; BYTES_PER_BLOB];
    for (cell_index, cell) in recovered_cells.iter().take(CELLS_PER_EXT_BLOB / 2).enumerate() {
        let start = cell_index * crate::eip7594::BYTES_PER_CELL;
        let end = start + crate::eip7594::BYTES_PER_CELL;
        blob[start..end].copy_from_slice(cell.as_alloy().as_slice());
    }
    Blob::new(blob)
}

impl Encodable for BlobTransactionSidecarEip7594 {
    /// Encodes the sidecar as an RLP list, including its outer header.
    fn encode(&self, out: &mut dyn BufMut) {
        self.rlp_encode(out);
    }

    fn length(&self) -> usize {
        self.rlp_encoded_length()
    }
}

impl Decodable for BlobTransactionSidecarEip7594 {
    /// Decodes an RLP list, including its outer header.
    fn decode(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
        Self::rlp_decode(buf)
    }
}

impl Encodable7594 for BlobTransactionSidecarEip7594 {
    fn encode_7594_len(&self) -> usize {
        self.rlp_encoded_fields_length()
    }

    fn encode_7594(&self, out: &mut dyn BufMut) {
        self.rlp_encode_fields(out);
    }
}

impl Decodable7594 for BlobTransactionSidecarEip7594 {
    fn decode_7594(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
        let wrapper_version: u8 = Decodable::decode(buf)?;
        if wrapper_version != EIP_7594_WRAPPER_VERSION {
            return Err(alloy_rlp::Error::Custom("invalid wrapper version"));
        }
        Self::rlp_decode_fields(buf)
    }
}

/// Cell indices requested by `engine_getBlobsV4`.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash)]
pub struct BlobCellMask {
    value: u128,
}

impl BlobCellMask {
    /// Creates a mask from the Engine API 16-byte, big-endian bitarray.
    #[inline]
    pub fn new(indices_bitarray: B128) -> Self {
        Self { value: u128::from(indices_bitarray) }
    }

    /// Creates a mask from the raw bit representation.
    #[inline]
    pub const fn from_bits(value: u128) -> Self {
        Self { value }
    }

    /// Returns the raw bit representation.
    #[inline]
    pub const fn bits(self) -> u128 {
        self.value
    }

    /// Returns the number of selected cells.
    #[inline]
    pub const fn count(self) -> usize {
        self.value.count_ones() as usize
    }

    /// Returns true if the given cell index is selected.
    #[inline]
    pub const fn contains(self, index: usize) -> bool {
        index < CELLS_PER_EXT_BLOB && self.value & (1u128 << index) != 0
    }

    /// Iterates selected cell indices in ascending order.
    #[inline]
    pub fn selected_indices(self) -> impl Iterator<Item = usize> {
        let mut bits = self.value;
        core::iter::from_fn(move || {
            if bits == 0 {
                return None;
            }

            let index = bits.trailing_zeros() as usize;
            bits &= bits - 1;
            Some(index)
        })
    }

    /// Returns the selected cells from precomputed blob-major flattened cells.
    ///
    /// The `cells` slice must use the layout returned by `compute_cells`: each blob contributes
    /// one contiguous [`CELLS_PER_EXT_BLOB`]-cell chunk, so `cells.len()` must be evenly divisible
    /// by [`CELLS_PER_EXT_BLOB`] (128). This method returns `None` if `cells` ends with an
    /// incomplete chunk.
    ///
    /// The returned cells keep the same chunk order and include only the cell indices selected by
    /// this mask.
    pub fn matching_cells_from_computed_cells(
        self,
        cells: &[crate::eip7594::Cell],
    ) -> Option<Vec<crate::eip7594::Cell>> {
        let (chunks, remainder) = cells.as_chunks::<CELLS_PER_EXT_BLOB>();
        if !remainder.is_empty() {
            return None;
        }

        let mut matching_cells = Vec::with_capacity(chunks.len() * self.count());
        for blob_cells in chunks {
            for cell_index in self.selected_indices() {
                let cell = blob_cells
                    .get(cell_index)
                    .expect("cell mask index must be within extended blob cells");
                matching_cells.push(*cell);
            }
        }

        Some(matching_cells)
    }
}

/// Bincode-compatible [`BlobTransactionSidecarVariant`] serde implementation.
#[cfg(all(feature = "serde", feature = "serde-bincode-compat"))]
pub mod serde_bincode_compat {
    use crate::eip4844::{Blob, Bytes48};
    use alloc::{borrow::Cow, vec::Vec};
    use serde::{Deserialize, Deserializer, Serialize, Serializer};
    use serde_with::{DeserializeAs, SerializeAs};

    /// Bincode-compatible [`super::BlobTransactionSidecarVariant`] serde implementation.
    ///
    /// Intended to use with the [`serde_with::serde_as`] macro in the following way:
    /// ```rust
    /// use alloy_eips::eip7594::{serde_bincode_compat, BlobTransactionSidecarVariant};
    /// use serde::{Deserialize, Serialize};
    /// use serde_with::serde_as;
    ///
    /// #[serde_as]
    /// #[derive(Serialize, Deserialize)]
    /// struct Data {
    ///     #[serde_as(as = "serde_bincode_compat::BlobTransactionSidecarVariant")]
    ///     sidecar: BlobTransactionSidecarVariant,
    /// }
    /// ```
    #[derive(Debug, Serialize, Deserialize)]
    pub struct BlobTransactionSidecarVariant<'a> {
        /// The blob data (common to both variants).
        pub blobs: Cow<'a, Vec<Blob>>,
        /// The blob commitments (common to both variants).
        pub commitments: Cow<'a, Vec<Bytes48>>,
        /// The blob proofs (EIP-4844 only).
        pub proofs: Option<Cow<'a, Vec<Bytes48>>>,
        /// The cell proofs (EIP-7594 only).
        pub cell_proofs: Option<Cow<'a, Vec<Bytes48>>>,
    }

    impl<'a> From<&'a super::BlobTransactionSidecarVariant> for BlobTransactionSidecarVariant<'a> {
        fn from(value: &'a super::BlobTransactionSidecarVariant) -> Self {
            match value {
                super::BlobTransactionSidecarVariant::Eip4844(sidecar) => Self {
                    blobs: Cow::Borrowed(&sidecar.blobs),
                    commitments: Cow::Borrowed(&sidecar.commitments),
                    proofs: Some(Cow::Borrowed(&sidecar.proofs)),
                    cell_proofs: None,
                },
                super::BlobTransactionSidecarVariant::Eip7594(sidecar) => Self {
                    blobs: Cow::Borrowed(&sidecar.blobs),
                    commitments: Cow::Borrowed(&sidecar.commitments),
                    proofs: None,
                    cell_proofs: Some(Cow::Borrowed(&sidecar.cell_proofs)),
                },
            }
        }
    }

    impl<'a> BlobTransactionSidecarVariant<'a> {
        fn try_into_inner(self) -> Result<super::BlobTransactionSidecarVariant, &'static str> {
            match (self.proofs, self.cell_proofs) {
                (Some(proofs), None) => Ok(super::BlobTransactionSidecarVariant::Eip4844(
                    crate::eip4844::BlobTransactionSidecar {
                        blobs: self.blobs.into_owned(),
                        commitments: self.commitments.into_owned(),
                        proofs: proofs.into_owned(),
                    },
                )),
                (None, Some(cell_proofs)) => Ok(super::BlobTransactionSidecarVariant::Eip7594(
                    super::BlobTransactionSidecarEip7594 {
                        blobs: self.blobs.into_owned(),
                        commitments: self.commitments.into_owned(),
                        cell_proofs: cell_proofs.into_owned(),
                    },
                )),
                (None, None) => Err("Missing both 'proofs' and 'cell_proofs'"),
                (Some(_), Some(_)) => Err("Both 'proofs' and 'cell_proofs' cannot be present"),
            }
        }
    }

    impl<'a> From<BlobTransactionSidecarVariant<'a>> for super::BlobTransactionSidecarVariant {
        fn from(value: BlobTransactionSidecarVariant<'a>) -> Self {
            value.try_into_inner().expect("Invalid BlobTransactionSidecarVariant")
        }
    }

    impl SerializeAs<super::BlobTransactionSidecarVariant> for BlobTransactionSidecarVariant<'_> {
        fn serialize_as<S>(
            source: &super::BlobTransactionSidecarVariant,
            serializer: S,
        ) -> Result<S::Ok, S::Error>
        where
            S: Serializer,
        {
            BlobTransactionSidecarVariant::from(source).serialize(serializer)
        }
    }

    impl<'de> DeserializeAs<'de, super::BlobTransactionSidecarVariant>
        for BlobTransactionSidecarVariant<'de>
    {
        fn deserialize_as<D>(
            deserializer: D,
        ) -> Result<super::BlobTransactionSidecarVariant, D::Error>
        where
            D: Deserializer<'de>,
        {
            let value = BlobTransactionSidecarVariant::deserialize(deserializer)?;
            value.try_into_inner().map_err(serde::de::Error::custom)
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    #[cfg(feature = "kzg")]
    use crate::eip4844::{
        builder::{SidecarBuilder, SimpleCoder},
        env_settings::EnvKzgSettings,
    };

    #[test]
    fn clear_eip7594_blobs_preserves_metadata() {
        let commitments = vec![Bytes48::repeat_byte(0x01)];
        let cell_proofs = vec![Bytes48::repeat_byte(0x02); CELLS_PER_EXT_BLOB];
        let sidecar = BlobTransactionSidecarEip7594::new(
            vec![Blob::repeat_byte(0x03)],
            commitments.clone(),
            cell_proofs.clone(),
        );
        let mut variant = BlobTransactionSidecarVariant::Eip7594(sidecar);

        variant.clear_eip7594_blobs();

        let sidecar = variant.as_eip7594().unwrap();
        assert!(sidecar.blobs.is_empty());
        assert_eq!(sidecar.commitments, commitments);
        assert_eq!(sidecar.cell_proofs, cell_proofs);
    }

    #[test]
    fn clear_eip7594_blobs_ignores_eip4844_variant() {
        let sidecar = BlobTransactionSidecar::new(
            vec![Blob::repeat_byte(0x01)],
            vec![Bytes48::repeat_byte(0x02)],
            vec![Bytes48::repeat_byte(0x03)],
        );
        let mut variant = BlobTransactionSidecarVariant::Eip4844(sidecar.clone());

        variant.clear_eip7594_blobs();

        assert_eq!(variant, BlobTransactionSidecarVariant::Eip4844(sidecar));
    }

    #[test]
    fn sidecar_variant_rlp_roundtrip() {
        let mut encoded = Vec::new();

        // 4844
        let empty_sidecar_4844 =
            BlobTransactionSidecarVariant::Eip4844(BlobTransactionSidecar::default());
        empty_sidecar_4844.encode(&mut encoded);
        assert_eq!(
            empty_sidecar_4844,
            BlobTransactionSidecarVariant::decode(&mut &encoded[..]).unwrap()
        );

        let sidecar_4844 = BlobTransactionSidecarVariant::Eip4844(BlobTransactionSidecar::new(
            vec![Blob::default()],
            vec![Bytes48::ZERO],
            vec![Bytes48::ZERO],
        ));
        encoded.clear();
        sidecar_4844.encode(&mut encoded);
        assert_eq!(sidecar_4844, BlobTransactionSidecarVariant::decode(&mut &encoded[..]).unwrap());

        // 7594
        let empty_sidecar_7594 =
            BlobTransactionSidecarVariant::Eip7594(BlobTransactionSidecarEip7594::default());
        encoded.clear();
        empty_sidecar_7594.encode(&mut encoded);
        assert_eq!(
            empty_sidecar_7594,
            BlobTransactionSidecarVariant::decode(&mut &encoded[..]).unwrap()
        );

        let sidecar_7594 =
            BlobTransactionSidecarVariant::Eip7594(BlobTransactionSidecarEip7594::new(
                vec![Blob::default()],
                vec![Bytes48::ZERO],
                core::iter::repeat_n(Bytes48::ZERO, CELLS_PER_EXT_BLOB).collect(),
            ));
        encoded.clear();
        sidecar_7594.encode(&mut encoded);
        assert_eq!(sidecar_7594, BlobTransactionSidecarVariant::decode(&mut &encoded[..]).unwrap());
    }

    #[test]
    #[cfg(feature = "serde")]
    fn sidecar_variant_json_deserialize_sanity() {
        let mut eip4844 = BlobTransactionSidecar::default();
        eip4844.blobs.push(Blob::repeat_byte(0x2));

        let json = serde_json::to_string(&eip4844).unwrap();
        let variant: BlobTransactionSidecarVariant = serde_json::from_str(&json).unwrap();
        assert!(variant.is_eip4844());
        let jsonvariant = serde_json::to_string(&variant).unwrap();
        assert_eq!(json, jsonvariant);

        let mut eip7594 = BlobTransactionSidecarEip7594::default();
        eip7594.blobs.push(Blob::repeat_byte(0x4));
        let json = serde_json::to_string(&eip7594).unwrap();
        let variant: BlobTransactionSidecarVariant = serde_json::from_str(&json).unwrap();
        assert!(variant.is_eip7594());
        let jsonvariant = serde_json::to_string(&variant).unwrap();
        assert_eq!(json, jsonvariant);
    }

    #[test]
    fn rlp_7594_roundtrip() {
        let mut encoded = Vec::new();

        let sidecar_4844 = BlobTransactionSidecar::default();
        sidecar_4844.encode_7594(&mut encoded);
        assert_eq!(sidecar_4844, Decodable7594::decode_7594(&mut &encoded[..]).unwrap());

        let sidecar_variant_4844 = BlobTransactionSidecarVariant::Eip4844(sidecar_4844);
        assert_eq!(sidecar_variant_4844, Decodable7594::decode_7594(&mut &encoded[..]).unwrap());
        encoded.clear();
        sidecar_variant_4844.encode_7594(&mut encoded);
        assert_eq!(sidecar_variant_4844, Decodable7594::decode_7594(&mut &encoded[..]).unwrap());

        let sidecar_7594 = BlobTransactionSidecarEip7594::default();
        encoded.clear();
        sidecar_7594.encode_7594(&mut encoded);
        assert_eq!(sidecar_7594, Decodable7594::decode_7594(&mut &encoded[..]).unwrap());

        let sidecar_variant_7594 = BlobTransactionSidecarVariant::Eip7594(sidecar_7594);
        assert_eq!(sidecar_variant_7594, Decodable7594::decode_7594(&mut &encoded[..]).unwrap());
        encoded.clear();
        sidecar_variant_7594.encode_7594(&mut encoded);
        assert_eq!(sidecar_variant_7594, Decodable7594::decode_7594(&mut &encoded[..]).unwrap());
    }

    #[test]
    #[cfg(feature = "kzg")]
    fn validate_7594_sidecar() {
        let sidecar =
            SidecarBuilder::<SimpleCoder>::from_slice(b"Blobs are fun!").build_7594().unwrap();
        let versioned_hashes = sidecar.versioned_hashes().collect::<Vec<_>>();

        sidecar.validate(&versioned_hashes, EnvKzgSettings::Default.get()).unwrap();
    }

    #[test]
    #[cfg(feature = "kzg")]
    fn compute_cells_for_7594_sidecar() {
        let settings = EnvKzgSettings::Default.get();
        let sidecar = BlobTransactionSidecarEip7594::try_from_blobs_with_settings(
            vec![Blob::repeat_byte(0x01), Blob::repeat_byte(0x02)],
            settings,
        )
        .unwrap();

        let cells = sidecar.compute_cells_with_settings(settings).unwrap();
        assert_eq!(cells.len(), sidecar.blobs.len() * CELLS_PER_EXT_BLOB);
        assert_eq!(sidecar.compute_cells().unwrap(), cells);

        let cell_mask = BlobCellMask::from_bits((1u128 << 0) | (1u128 << 7));
        let matching_cells =
            sidecar.compute_matching_cells_with_settings(cell_mask, settings).unwrap();
        let expected_matching_cells = cells
            .as_chunks::<CELLS_PER_EXT_BLOB>()
            .0
            .iter()
            .flat_map(|blob_cells| [blob_cells[0], blob_cells[7]])
            .collect::<Vec<_>>();
        assert_eq!(
            cell_mask.matching_cells_from_computed_cells(&cells),
            Some(expected_matching_cells.clone())
        );
        assert_eq!(matching_cells, expected_matching_cells);
        assert_eq!(sidecar.compute_matching_cells(cell_mask).unwrap(), expected_matching_cells);
        assert!(sidecar.compute_matching_cells(BlobCellMask::default()).unwrap().is_empty());

        for (blob_index, blob) in sidecar.blobs.iter().enumerate() {
            let expected_cells = settings.compute_cells(blob.as_ckzg()).unwrap();
            let start = blob_index * CELLS_PER_EXT_BLOB;
            let end = start + CELLS_PER_EXT_BLOB;

            for (cell, expected_cell) in cells[start..end].iter().zip(expected_cells.iter()) {
                assert_eq!(*cell, crate::eip7594::Cell::new(expected_cell.to_bytes()));
            }
        }
    }

    #[cfg(feature = "kzg")]
    fn sparse_cells_for_mask(
        sidecar: &BlobTransactionSidecarEip7594,
        cell_mask: BlobCellMask,
        settings: &c_kzg::KzgSettings,
    ) -> Vec<crate::eip7594::Cell> {
        let cells = sidecar.compute_cells_with_settings(settings).unwrap();
        cell_mask.matching_cells_from_computed_cells(&cells).unwrap()
    }

    #[test]
    #[cfg(feature = "kzg")]
    fn recover_sidecar_from_complete_cells() {
        let settings = EnvKzgSettings::Default.get();
        assert_eq!(
            BlobTransactionSidecarEip7594::try_recover_from_cells_with_settings(
                Vec::new(),
                BlobCellMask::default(),
                &[],
                settings,
            )
            .unwrap(),
            BlobTransactionSidecarEip7594::default()
        );

        let sidecar = BlobTransactionSidecarEip7594::try_from_blobs_with_settings(
            vec![Blob::repeat_byte(0x01), Blob::repeat_byte(0x02)],
            settings,
        )
        .unwrap();
        let cells = sidecar.compute_cells_with_settings(settings).unwrap();
        let cell_mask = BlobCellMask::from_bits(u128::MAX);

        let recovered = BlobTransactionSidecarEip7594::try_recover_from_cells_with_settings(
            sidecar.commitments.clone(),
            cell_mask,
            &cells,
            settings,
        )
        .unwrap();
        assert_eq!(recovered, sidecar);

        assert_eq!(
            BlobTransactionSidecarEip7594::try_recover_from_cells(
                recovered.commitments.clone(),
                cell_mask,
                &cells,
            )
            .unwrap(),
            recovered
        );
    }

    /// Multiple blobs are recovered from a shared, non-contiguous set containing the minimum
    /// number of cells required for each blob.
    #[test]
    #[cfg(feature = "kzg")]
    fn recover_sparse_blobs_from_minimum_cells() {
        let settings = EnvKzgSettings::Default.get();
        let sidecar = BlobTransactionSidecarEip7594::try_from_blobs_with_settings(
            vec![Blob::repeat_byte(0x01), Blob::repeat_byte(0x02), Blob::repeat_byte(0x03)],
            settings,
        )
        .unwrap();

        let cell_mask = BlobCellMask::from_bits(
            (0..CELLS_PER_EXT_BLOB).step_by(2).fold(0, |mask, index| mask | (1u128 << index)),
        );
        assert_eq!(cell_mask.count(), CELLS_PER_EXT_BLOB / 2);
        let sparse_cells = sparse_cells_for_mask(&sidecar, cell_mask, settings);

        let recovered = BlobTransactionSidecarEip7594::try_recover_from_cells_with_settings(
            sidecar.commitments.clone(),
            cell_mask,
            &sparse_cells,
            settings,
        )
        .unwrap();

        assert_eq!(recovered.blobs, sidecar.blobs);
        assert_eq!(recovered.commitments, sidecar.commitments);
        assert_eq!(recovered.cell_proofs, sidecar.cell_proofs);
    }

    /// A sparse set above the minimum cell count follows the same recovery path.
    #[test]
    #[cfg(feature = "kzg")]
    fn recover_sparse_blobs_with_more_than_minimum_cells() {
        let settings = EnvKzgSettings::Default.get();
        let sidecar = BlobTransactionSidecarEip7594::try_from_blobs_with_settings(
            vec![Blob::repeat_byte(0x01), Blob::repeat_byte(0x02)],
            settings,
        )
        .unwrap();

        let cell_mask = BlobCellMask::from_bits(
            ((1u128 << (CELLS_PER_EXT_BLOB / 2)) - 1) | (1u128 << (CELLS_PER_EXT_BLOB - 1)),
        );
        assert_eq!(cell_mask.count(), CELLS_PER_EXT_BLOB / 2 + 1);
        let sparse_cells = sparse_cells_for_mask(&sidecar, cell_mask, settings);

        let recovered = BlobTransactionSidecarEip7594::try_recover_from_cells_with_settings(
            sidecar.commitments.clone(),
            cell_mask,
            &sparse_cells,
            settings,
        )
        .unwrap();

        assert_eq!(recovered.blobs, sidecar.blobs);
        assert_eq!(recovered.cell_proofs, sidecar.cell_proofs);
    }

    #[test]
    #[cfg(feature = "kzg")]
    fn recover_sparse_blobs_rejects_insufficient_cells() {
        let settings = EnvKzgSettings::Default.get();
        let cell_mask = BlobCellMask::from_bits((1u128 << (CELLS_PER_EXT_BLOB / 2 - 1)) - 1);
        let cells = vec![crate::eip7594::Cell::repeat_byte(0); cell_mask.count()];

        let err = BlobTransactionSidecarEip7594::try_recover_from_cells_with_settings(
            vec![Bytes48::ZERO],
            cell_mask,
            &cells,
            settings,
        )
        .unwrap_err();
        assert!(matches!(
            err,
            BlobCellRecoveryError::InsufficientCells {
                provided,
                required,
            } if provided == CELLS_PER_EXT_BLOB / 2 - 1
                && required == CELLS_PER_EXT_BLOB / 2
        ));
    }

    #[test]
    #[cfg(feature = "kzg")]
    fn recover_sparse_blobs_rejects_mismatched_cell_count() {
        let settings = EnvKzgSettings::Default.get();
        let cell_mask = BlobCellMask::from_bits((1u128 << (CELLS_PER_EXT_BLOB / 2)) - 1);
        let cells = vec![crate::eip7594::Cell::repeat_byte(0); cell_mask.count() - 1];

        let err = BlobTransactionSidecarEip7594::try_recover_from_cells_with_settings(
            vec![Bytes48::ZERO, Bytes48::ZERO],
            cell_mask,
            &cells,
            settings,
        )
        .unwrap_err();
        assert!(matches!(
            err,
            BlobCellRecoveryError::CellCountMismatch {
                provided,
                expected,
            } if provided == CELLS_PER_EXT_BLOB / 2 - 1 && expected == CELLS_PER_EXT_BLOB
        ));
    }

    #[test]
    #[cfg(feature = "kzg")]
    fn recover_sparse_blobs_rejects_commitment_mismatch() {
        let settings = EnvKzgSettings::Default.get();
        let sidecar = BlobTransactionSidecarEip7594::try_from_blobs_with_settings(
            vec![Blob::repeat_byte(0x01)],
            settings,
        )
        .unwrap();
        let cell_mask = BlobCellMask::from_bits((1u128 << (CELLS_PER_EXT_BLOB / 2)) - 1);
        let sparse_cells = sparse_cells_for_mask(&sidecar, cell_mask, settings);

        let err = BlobTransactionSidecarEip7594::try_recover_from_cells_with_settings(
            vec![Bytes48::ZERO],
            cell_mask,
            &sparse_cells,
            settings,
        )
        .unwrap_err();
        assert!(matches!(err, BlobCellRecoveryError::CommitmentMismatch { blob_index: 0 }));
    }

    /// A cell that no longer matches the commitment must not produce a sidecar.
    #[test]
    #[cfg(feature = "kzg")]
    fn recover_sparse_blobs_rejects_corrupted_cells() {
        let settings = EnvKzgSettings::Default.get();
        let sidecar = BlobTransactionSidecarEip7594::try_from_blobs_with_settings(
            vec![Blob::repeat_byte(0x01), Blob::repeat_byte(0x02), Blob::repeat_byte(0x03)],
            settings,
        )
        .unwrap();
        let cell_mask = BlobCellMask::from_bits((1u128 << (CELLS_PER_EXT_BLOB / 2)) - 1);
        let mut sparse_cells = sparse_cells_for_mask(&sidecar, cell_mask, settings);
        sparse_cells[0][0] ^= 0xff;

        assert!(BlobTransactionSidecarEip7594::try_recover_from_cells_with_settings(
            sidecar.commitments,
            cell_mask,
            &sparse_cells,
            settings,
        )
        .is_err());
    }

    #[test]
    fn blob_cell_mask_selects_indices() {
        let selected = (1u128 << 0) | (1u128 << 7);
        let mask = BlobCellMask::new(B128::from(selected));

        assert_eq!(mask.bits(), selected);
        assert_eq!(mask.count(), 2);
        assert!(mask.contains(0));
        assert!(mask.contains(7));
        assert!(!mask.contains(1));
        assert_eq!(mask.selected_indices().collect::<Vec<_>>(), vec![0, 7]);

        let cells = (0..CELLS_PER_EXT_BLOB * 2)
            .map(|i| crate::eip7594::Cell::repeat_byte(i as u8))
            .collect::<Vec<_>>();
        assert_eq!(
            mask.matching_cells_from_computed_cells(&cells),
            Some(vec![
                cells[0],
                cells[7],
                cells[CELLS_PER_EXT_BLOB],
                cells[CELLS_PER_EXT_BLOB + 7]
            ])
        );
        assert_eq!(mask.matching_cells_from_computed_cells(&cells[..cells.len() - 1]), None);
    }

    #[test]
    fn match_versioned_hashes_skips_incomplete_proof_chunks() {
        let sidecar = BlobTransactionSidecarEip7594::new(
            vec![Blob::repeat_byte(0x01)],
            vec![Bytes48::repeat_byte(0x02)],
            vec![Bytes48::repeat_byte(0x03)],
        );
        let versioned_hash = sidecar.versioned_hashes().next().unwrap();

        let matches = sidecar.match_versioned_hashes(&[versioned_hash]).collect::<Vec<_>>();
        assert!(matches.is_empty());
    }

    #[test]
    #[cfg(feature = "kzg")]
    fn match_versioned_hashes_cells_for_7594_sidecar() {
        let settings = EnvKzgSettings::Default.get();
        let sidecar = BlobTransactionSidecarEip7594::try_from_blobs_with_settings(
            vec![Blob::repeat_byte(0x01), Blob::repeat_byte(0x02)],
            settings,
        )
        .unwrap();
        let versioned_hashes = sidecar.versioned_hashes().collect::<Vec<_>>();
        let cell_mask = BlobCellMask::from_bits((1u128 << 0) | (1u128 << 7));

        let cells_and_proofs =
            sidecar.blob_cells_and_proofs_with_settings(0, cell_mask, settings).unwrap().unwrap();
        assert_eq!(cells_and_proofs.blob_cells.len(), 2);
        assert_eq!(cells_and_proofs.proofs.len(), 2);
        assert_eq!(
            cells_and_proofs.proofs,
            vec![Some(sidecar.cell_proofs[0]), Some(sidecar.cell_proofs[7])]
        );

        let expected_cells = settings.compute_cells(sidecar.blobs[0].as_ckzg()).unwrap();
        assert_eq!(
            cells_and_proofs.blob_cells,
            vec![
                Some(crate::eip7594::Cell::new(expected_cells[0].to_bytes())),
                Some(crate::eip7594::Cell::new(expected_cells[7].to_bytes()))
            ]
        );

        let request = vec![versioned_hashes[0], B256::ZERO, versioned_hashes[0]];
        let matches = sidecar
            .match_versioned_hashes_cells_with_settings(&request, cell_mask, settings)
            .unwrap()
            .collect::<Vec<_>>();
        assert_eq!(matches.len(), 2);
        assert_eq!(matches[0], (0, cells_and_proofs.clone()));
        assert_eq!(matches[1], (2, cells_and_proofs.clone()));

        let default_matches = sidecar
            .match_versioned_hashes_cells(&[versioned_hashes[0]], cell_mask)
            .unwrap()
            .collect::<Vec<_>>();
        assert_eq!(default_matches, vec![(0, cells_and_proofs)]);
    }

    #[test]
    #[cfg(feature = "kzg")]
    fn match_versioned_hashes_cells_only_computes_matched_blobs() {
        let settings = EnvKzgSettings::Default.get();
        let mut sidecar = BlobTransactionSidecarEip7594::try_from_blobs_with_settings(
            vec![Blob::repeat_byte(0x01)],
            settings,
        )
        .unwrap();
        let versioned_hash = sidecar.versioned_hashes().next().unwrap();
        let cell_mask = BlobCellMask::from_bits(1);

        let invalid_blob = Blob::repeat_byte(0xff);
        assert!(settings.compute_cells(invalid_blob.as_ckzg()).is_err());

        sidecar.blobs.push(invalid_blob);
        sidecar.commitments.push(Bytes48::ZERO);
        sidecar.cell_proofs.extend(core::iter::repeat_n(Bytes48::ZERO, CELLS_PER_EXT_BLOB));

        let cells_and_proofs =
            sidecar.blob_cells_and_proofs_with_settings(0, cell_mask, settings).unwrap().unwrap();
        let matches = sidecar
            .match_versioned_hashes_cells_with_settings(&[versioned_hash], cell_mask, settings)
            .unwrap()
            .collect::<Vec<_>>();
        assert_eq!(matches, vec![(0, cells_and_proofs)]);
    }
}