espresso_types/v0/impls/

header.rs

use std::{collections::HashSet, fmt};

use alloy::primitives::{B256, Keccak256};
use anyhow::{Context, bail, ensure};
use ark_serialize::CanonicalSerialize;
use base64::{Engine, prelude::BASE64_STANDARD};
use committable::{Commitment, Committable, RawCommitmentBuilder};
use either::Either;
use hotshot_query_service_types::{
    HeightIndexed, availability::QueryableHeader, explorer::traits::ExplorerHeader,
};
use hotshot_types::{
    data::{EpochNumber, VidCommitment, ViewNumber, vid_commitment},
    light_client::LightClientState,
    stake_table::HSStakeTable,
    traits::{
        BlockPayload, EncodeBytes, ValidatedState as _,
        block_contents::{BlockHeader, BuilderFee, GENESIS_VID_NUM_STORAGE_NODES},
        election::{Membership, MembershipSnapshot},
        node_implementation::NodeType,
        signature_key::BuilderSignatureKey,
    },
    utils::{BuilderCommitment, epoch_from_block_number, is_ge_epoch_root, is_last_block},
};
use jf_merkle_tree_compat::{AppendableMerkleTreeScheme, MerkleCommitment, MerkleTreeScheme};
use serde::{
    Deserialize, Deserializer, Serialize, Serializer,
    de::{self, MapAccess, SeqAccess, Visitor},
};
use serde_json::{Map, Value};
use thiserror::Error;
use time::OffsetDateTime;
use vbs::version::Version;
use versions::{DRB_AND_HEADER_UPGRADE_VERSION, EPOCH_REWARD_VERSION, EPOCH_VERSION};

use super::{
    instance_state::NodeState, state::ValidatedState, v0_1::IterableFeeInfo, v0_3::ChainConfig,
};
use crate::{
    BlockMerkleCommitment, FeeAccount, FeeAmount, FeeInfo, FeeMerkleCommitment, Header,
    L1BlockInfo, L1Snapshot, Leaf2, NamespaceId, NsIndex, NsTable, PayloadByteLen, SeqTypes,
    TimestampMillis, UpgradeType,
    eth_signature_key::BuilderSignature,
    v0::{
        header::{EitherOrVersion, VersionedHeader},
        impls::{StakeTableHash, distribute_block_reward},
    },
    v0_1::{self},
    v0_2,
    v0_3::{
        self, REWARD_MERKLE_TREE_V1_HEIGHT, RewardAmount, RewardMerkleCommitmentV1,
        RewardMerkleTreeV1,
    },
    v0_4::{self, RewardAccountV2, RewardMerkleCommitmentV2},
    v0_5::{self, LeaderCounts, MAX_VALIDATORS},
    v0_6::{self, REWARD_MERKLE_TREE_V2_HEIGHT, RewardMerkleTreeV2},
};

impl v0_1::Header {
    pub(crate) fn commit(&self) -> Commitment<Header> {
        let mut bmt_bytes = vec![];
        self.block_merkle_tree_root
            .serialize_with_mode(&mut bmt_bytes, ark_serialize::Compress::Yes)
            .unwrap();
        let mut fmt_bytes = vec![];
        self.fee_merkle_tree_root
            .serialize_with_mode(&mut fmt_bytes, ark_serialize::Compress::Yes)
            .unwrap();

        RawCommitmentBuilder::new(&Self::tag())
            .field("chain_config", self.chain_config.commit())
            .u64_field("height", self.height)
            .u64_field("timestamp", self.timestamp)
            .u64_field("l1_head", self.l1_head)
            .optional("l1_finalized", &self.l1_finalized)
            .constant_str("payload_commitment")
            .fixed_size_bytes(self.payload_commitment.as_ref())
            .constant_str("builder_commitment")
            .fixed_size_bytes(self.builder_commitment.as_ref())
            .field("ns_table", self.ns_table.commit())
            .var_size_field("block_merkle_tree_root", &bmt_bytes)
            .var_size_field("fee_merkle_tree_root", &fmt_bytes)
            .field("fee_info", self.fee_info.commit())
            .finalize()
    }
}

impl Committable for Header {
    fn commit(&self) -> Commitment<Self> {
        match self {
            Self::V1(header) => header.commit(),
            Self::V2(fields) => RawCommitmentBuilder::new(&Self::tag())
                .u64_field("version_major", 0)
                .u64_field("version_minor", 2)
                .field("fields", fields.commit())
                .finalize(),
            Self::V3(fields) => RawCommitmentBuilder::new(&Self::tag())
                .u64_field("version_major", 0)
                .u64_field("version_minor", 3)
                .field("fields", fields.commit())
                .finalize(),
            Self::V4(fields) => RawCommitmentBuilder::new(&Self::tag())
                .u64_field("version_major", 0)
                .u64_field("version_minor", 4)
                .field("fields", fields.commit())
                .finalize(),
            Self::V5(fields) => RawCommitmentBuilder::new(&Self::tag())
                .u64_field("version_major", 0)
                .u64_field("version_minor", 5)
                .field("fields", fields.commit())
                .finalize(),
            Self::V6(fields) => RawCommitmentBuilder::new(&Self::tag())
                .u64_field("version_major", 0)
                .u64_field("version_minor", 6)
                .field("fields", fields.commit())
                .finalize(),
        }
    }

    fn tag() -> String {
        // We use the tag "BLOCK" since blocks are identified by the hash of their header. This will
        // thus be more intuitive to users than "HEADER".
        "BLOCK".into()
    }
}

impl Serialize for Header {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        match self {
            Self::V1(header) => header.serialize(serializer),
            Self::V2(fields) => VersionedHeader {
                version: EitherOrVersion::Version(Version { major: 0, minor: 2 }),
                fields: fields.clone(),
            }
            .serialize(serializer),
            Self::V3(fields) => VersionedHeader {
                version: EitherOrVersion::Version(Version { major: 0, minor: 3 }),
                fields: fields.clone(),
            }
            .serialize(serializer),
            Self::V4(fields) => VersionedHeader {
                version: EitherOrVersion::Version(Version { major: 0, minor: 4 }),
                fields: fields.clone(),
            }
            .serialize(serializer),
            Self::V5(fields) => VersionedHeader {
                version: EitherOrVersion::Version(Version { major: 0, minor: 5 }),
                fields: fields.clone(),
            }
            .serialize(serializer),
            Self::V6(fields) => VersionedHeader {
                version: EitherOrVersion::Version(Version { major: 0, minor: 6 }),
                fields: fields.clone(),
            }
            .serialize(serializer),
        }
    }
}

impl<'de> Deserialize<'de> for Header {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        struct HeaderVisitor;

        impl<'de> Visitor<'de> for HeaderVisitor {
            type Value = Header;

            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
                formatter.write_str("Header")
            }

            fn visit_seq<V>(self, mut seq: V) -> Result<Self::Value, V::Error>
            where
                V: SeqAccess<'de>,
            {
                let chain_config_or_version: EitherOrVersion = seq
                    .next_element()?
                    .ok_or_else(|| de::Error::missing_field("chain_config"))?;

                match chain_config_or_version {
                    // For v0.1, the first field in the sequence of fields is the first field of the struct, so we call a function to get the rest of
                    // the fields from the sequence and pack them into the struct.
                    EitherOrVersion::Left(cfg) => Ok(Header::V1(
                        v0_1::Header::deserialize_with_chain_config(cfg.into(), seq)?,
                    )),
                    EitherOrVersion::Right(commit) => Ok(Header::V1(
                        v0_1::Header::deserialize_with_chain_config(commit.into(), seq)?,
                    )),
                    // For all versions > 0.1, the first "field" is not actually part of the `Header` struct.
                    // We just delegate directly to the derived deserialization impl for the appropriate version.
                    EitherOrVersion::Version(Version { major: 0, minor: 2 }) => Ok(Header::V2(
                        seq.next_element()?
                            .ok_or_else(|| de::Error::missing_field("fields"))?,
                    )),
                    EitherOrVersion::Version(Version { major: 0, minor: 3 }) => Ok(Header::V3(
                        seq.next_element()?
                            .ok_or_else(|| de::Error::missing_field("fields"))?,
                    )),
                    EitherOrVersion::Version(Version { major: 0, minor: 4 }) => Ok(Header::V4(
                        seq.next_element()?
                            .ok_or_else(|| de::Error::missing_field("fields"))?,
                    )),
                    EitherOrVersion::Version(Version { major: 0, minor: 5 }) => Ok(Header::V5(
                        seq.next_element()?
                            .ok_or_else(|| de::Error::missing_field("fields"))?,
                    )),
                    EitherOrVersion::Version(Version { major: 0, minor: 6 }) => Ok(Header::V6(
                        seq.next_element()?
                            .ok_or_else(|| de::Error::missing_field("fields"))?,
                    )),
                    EitherOrVersion::Version(v) => {
                        Err(serde::de::Error::custom(format!("invalid version {v:?}")))
                    },
                }
            }

            fn visit_map<V>(self, mut map: V) -> Result<Header, V::Error>
            where
                V: MapAccess<'de>,
            {
                // insert all the fields in the serde_map as the map may have out of order fields.
                let mut serde_map: Map<String, Value> = Map::new();

                while let Some(key) = map.next_key::<String>()? {
                    serde_map.insert(key.trim().to_owned(), map.next_value()?);
                }

                if let Some(v) = serde_map.get("version") {
                    let fields = serde_map
                        .get("fields")
                        .ok_or_else(|| de::Error::missing_field("fields"))?;

                    let version = serde_json::from_value::<EitherOrVersion>(v.clone())
                        .map_err(de::Error::custom)?;
                    let result = match version {
                        EitherOrVersion::Version(Version { major: 0, minor: 2 }) => Ok(Header::V2(
                            serde_json::from_value(fields.clone()).map_err(de::Error::custom)?,
                        )),
                        EitherOrVersion::Version(Version { major: 0, minor: 3 }) => Ok(Header::V3(
                            serde_json::from_value(fields.clone()).map_err(de::Error::custom)?,
                        )),
                        EitherOrVersion::Version(Version { major: 0, minor: 4 }) => Ok(Header::V4(
                            serde_json::from_value(fields.clone()).map_err(de::Error::custom)?,
                        )),
                        EitherOrVersion::Version(Version { major: 0, minor: 5 }) => Ok(Header::V5(
                            serde_json::from_value(fields.clone()).map_err(de::Error::custom)?,
                        )),
                        EitherOrVersion::Version(Version { major: 0, minor: 6 }) => Ok(Header::V6(
                            serde_json::from_value(fields.clone()).map_err(de::Error::custom)?,
                        )),
                        EitherOrVersion::Version(v) => {
                            Err(de::Error::custom(format!("invalid version {v:?}")))
                        },
                        chain_config => Err(de::Error::custom(format!(
                            "expected version, found chain_config {chain_config:?}"
                        ))),
                    };
                    return result;
                }

                Ok(Header::V1(
                    serde_json::from_value(serde_map.into()).map_err(de::Error::custom)?,
                ))
            }
        }

        // List of all possible fields of all versions of the `Header`.
        // serde's `deserialize_struct` works by deserializing to a struct with a specific list of fields.
        // The length of the fields list we provide is always going to be greater than the length of the target struct.
        // In our case, we are deserializing to either a V1 Header or a VersionedHeader for versions > 0.1.
        // We use serde_json and bincode serialization in the sequencer.
        // Fortunately, serde_json ignores fields parameter and only cares about our Visitor implementation.
        // -  https://docs.rs/serde_json/1.0.120/serde_json/struct.Deserializer.html#method.deserialize_struct
        // Bincode uses the length of the fields list, but the bincode deserialization only cares that the length of the fields
        // is an upper bound of the target struct's fields length.
        // -  https://docs.rs/bincode/1.3.3/src/bincode/de/mod.rs.html#313
        // This works because the bincode deserializer only consumes the next field when `next_element` is called,
        // and our visitor calls it the correct number of times.
        // This would, however, break if the bincode deserializer implementation required an exact match of the field's length,
        // consuming one element for each field.
        let fields: &[&str] = &[
            "fields",
            "chain_config",
            "version",
            "height",
            "timestamp",
            "l1_head",
            "l1_finalized",
            "payload_commitment",
            "builder_commitment",
            "ns_table",
            "block_merkle_tree_root",
            "fee_merkle_tree_root",
            "fee_info",
            "builder_signature",
        ];

        deserializer.deserialize_struct("Header", fields, HeaderVisitor)
    }
}

impl Header {
    pub fn version(&self) -> Version {
        match self {
            Self::V1(_) => Version { major: 0, minor: 1 },
            Self::V2(_) => Version { major: 0, minor: 2 },
            Self::V3(_) => Version { major: 0, minor: 3 },
            Self::V4(_) => Version { major: 0, minor: 4 },
            Self::V5(_) => Version { major: 0, minor: 5 },
            Self::V6(_) => Version { major: 0, minor: 6 },
        }
    }
    #[allow(clippy::too_many_arguments)]
    pub(crate) fn create(
        chain_config: ChainConfig,
        height: u64,
        timestamp: u64,
        timestamp_millis: u64,
        l1_head: u64,
        l1_finalized: Option<L1BlockInfo>,
        payload_commitment: VidCommitment,
        builder_commitment: BuilderCommitment,
        ns_table: NsTable,
        fee_merkle_tree_root: FeeMerkleCommitment,
        block_merkle_tree_root: BlockMerkleCommitment,
        reward_merkle_tree_root_v1: RewardMerkleCommitmentV1,
        reward_merkle_tree_root_v2: RewardMerkleCommitmentV2,
        fee_info: Vec<FeeInfo>,
        builder_signature: Vec<BuilderSignature>,
        total_reward_distributed: Option<RewardAmount>,
        version: Version,
        next_stake_table_hash: Option<StakeTableHash>,
        leader_counts: Option<LeaderCounts>,
    ) -> Self {
        // Ensure FeeInfo contains at least 1 element
        assert!(!fee_info.is_empty(), "Invalid fee_info length: 0");

        match (version.major, version.minor) {
            (0, 1) => Self::V1(v0_1::Header {
                chain_config: v0_1::ResolvableChainConfig::from(v0_1::ChainConfig::from(
                    chain_config,
                )),
                height,
                timestamp,
                l1_head,
                l1_finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                fee_info: fee_info[0], // NOTE this is asserted to exist above
                builder_signature: builder_signature.first().copied(),
            }),
            (0, 2) => Self::V2(v0_2::Header {
                chain_config: v0_1::ResolvableChainConfig::from(v0_1::ChainConfig::from(
                    chain_config,
                )),
                height,
                timestamp,
                l1_head,
                l1_finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                fee_info: fee_info[0], // NOTE this is asserted to exist above
                builder_signature: builder_signature.first().copied(),
            }),
            (0, 3) => Self::V3(v0_3::Header {
                chain_config: chain_config.into(),
                height,
                timestamp,
                l1_head,
                l1_finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                fee_info: fee_info[0], // NOTE this is asserted to exist above
                builder_signature: builder_signature.first().copied(),
                reward_merkle_tree_root: reward_merkle_tree_root_v1,
            }),
            (0, 4) => Self::V4(v0_4::Header {
                chain_config: chain_config.into(),
                height,
                timestamp,
                timestamp_millis: TimestampMillis::from_millis(timestamp_millis),
                l1_head,
                l1_finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                fee_info: fee_info[0], // NOTE this is asserted to exist above
                builder_signature: builder_signature.first().copied(),
                reward_merkle_tree_root: reward_merkle_tree_root_v2,
                total_reward_distributed: total_reward_distributed.unwrap_or_default(),
                next_stake_table_hash,
            }),
            (0, 5) => Self::V5(v0_5::Header {
                chain_config: chain_config.into(),
                height,
                timestamp,
                timestamp_millis: TimestampMillis::from_millis(timestamp_millis),
                l1_head,
                l1_finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                fee_info: fee_info[0], // NOTE this is asserted to exist above
                builder_signature: builder_signature.first().copied(),
                reward_merkle_tree_root: reward_merkle_tree_root_v2,
                total_reward_distributed: total_reward_distributed.unwrap_or_default(),
                next_stake_table_hash,
                leader_counts: leader_counts.expect("leader_counts required for V5 header"),
            }),
            // V6 header format is used for v0.6 (new protocol).
            (0, 6) => {
                let fields = v0_6::Header {
                    chain_config: chain_config.into(),
                    height,
                    timestamp,
                    timestamp_millis: TimestampMillis::from_millis(timestamp_millis),
                    l1_head,
                    l1_finalized,
                    payload_commitment,
                    builder_commitment,
                    ns_table,
                    block_merkle_tree_root,
                    fee_merkle_tree_root,
                    fee_info: fee_info[0],
                    builder_signature: builder_signature.first().copied(),
                    reward_merkle_tree_root: reward_merkle_tree_root_v2,
                    total_reward_distributed: total_reward_distributed.unwrap_or_default(),
                    next_stake_table_hash,
                    leader_counts: leader_counts.expect("leader_counts required for V6 header"),
                };
                Self::V6(fields)
            },
            // This case should never occur
            // but if it does, we must panic
            // because we don't have the versioned types for this version
            _ => panic!("invalid version: {version}"),
        }
    }

    pub fn next_stake_table_hash(&self) -> Option<StakeTableHash> {
        match self {
            Self::V4(fields) => fields.next_stake_table_hash,
            Self::V5(fields) | Self::V6(fields) => fields.next_stake_table_hash,
            _ => None,
        }
    }

    /// Get the leader counts for V5+ headers.
    /// Returns None for earlier versions.
    pub fn leader_counts(&self) -> Option<&LeaderCounts> {
        match self {
            Self::V5(fields) | Self::V6(fields) => Some(&fields.leader_counts),
            _ => None,
        }
    }

    pub fn set_next_stake_table_hash(&mut self, hash: StakeTableHash) -> bool {
        match self {
            Self::V4(fields) => {
                fields.next_stake_table_hash = Some(hash);
                true
            },
            Self::V5(fields) | Self::V6(fields) => {
                fields.next_stake_table_hash = Some(hash);
                true
            },
            _ => false,
        }
    }
}

// Getter for a field which is the same across all versions.
macro_rules! field {
    ($obj:ident.$name:ident) => {
        match $obj {
            Self::V1(data) => &data.$name,
            Self::V2(data) => &data.$name,
            Self::V3(data) => &data.$name,
            Self::V4(data) => &data.$name,
            Self::V5(data) => &data.$name,
            Self::V6(data) => &data.$name,
        }
    };
}

macro_rules! field_mut {
    ($obj:ident.$name:ident) => {
        match $obj {
            Self::V1(data) => &mut data.$name,
            Self::V2(data) => &mut data.$name,
            Self::V3(data) => &mut data.$name,
            Self::V4(data) => &mut data.$name,
            Self::V5(data) => &mut data.$name,
            Self::V6(data) => &mut data.$name,
        }
    };
}

impl Header {
    #[allow(clippy::too_many_arguments)]
    fn from_info(
        payload_commitment: VidCommitment,
        builder_commitment: BuilderCommitment,
        ns_table: NsTable,
        parent_leaf: &Leaf2,
        mut l1: L1Snapshot,
        l1_deposits: &[FeeInfo],
        builder_fee: Vec<BuilderFee<SeqTypes>>,
        mut timestamp: u64,
        mut timestamp_millis: u64,
        mut state: ValidatedState,
        chain_config: ChainConfig,
        version: Version,
        total_reward_distributed: Option<RewardAmount>,
        next_stake_table_hash: Option<StakeTableHash>,
        leader_counts: Option<LeaderCounts>,
    ) -> anyhow::Result<Self> {
        ensure!(
            version.major == 0,
            "Invalid major version {}",
            version.major
        );

        // Increment height.
        let parent_header = parent_leaf.block_header();
        let height = parent_header.height() + 1;

        // Ensure the timestamp does not decrease. We can trust `parent.timestamp` because `parent`
        // has already been voted on by consensus. If our timestamp is behind, either f + 1 nodes
        // are lying about the current time, or our clock is just lagging.
        if timestamp < parent_header.timestamp() {
            tracing::warn!(
                "Espresso timestamp {timestamp} behind parent {}, local clock may be out of sync",
                parent_header.timestamp()
            );
            timestamp = parent_header.timestamp();
        }

        if timestamp_millis < parent_header.timestamp_millis() {
            tracing::warn!(
                "Espresso timestamp {timestamp} behind parent {}, local clock may be out of sync",
                parent_header.timestamp_millis()
            );
            timestamp_millis = parent_header.timestamp_millis();
        }

        // Ensure the L1 block references don't decrease. Again, we can trust `parent.l1_*` are
        // accurate.
        if l1.head < parent_header.l1_head() {
            tracing::warn!(
                "L1 head {} behind parent {}, L1 client may be lagging",
                l1.head,
                parent_header.l1_head()
            );
            l1.head = parent_header.l1_head();
        }
        if l1.finalized < parent_header.l1_finalized() {
            tracing::warn!(
                "L1 finalized {:?} behind parent {:?}, L1 client may be lagging",
                l1.finalized,
                parent_header.l1_finalized()
            );
            l1.finalized = parent_header.l1_finalized();
        }

        // Enforce that the sequencer block timestamp is not behind the L1 block timestamp. This can
        // only happen if our clock is badly out of sync with L1.
        if let Some(l1_block) = &l1.finalized {
            let l1_timestamp = l1_block.timestamp.to::<u64>();
            if timestamp < l1_timestamp {
                tracing::warn!(
                    "Espresso timestamp {timestamp} behind L1 timestamp {l1_timestamp}, local \
                     clock may be out of sync"
                );
                timestamp = l1_timestamp;
            }

            let l1_timestamp_millis = l1_timestamp * 1_000;

            if timestamp_millis < l1_timestamp_millis {
                tracing::warn!(
                    "Espresso timestamp_millis {timestamp_millis} behind L1 timestamp \
                     {l1_timestamp_millis}, local clock may be out of sync"
                );
                timestamp_millis = l1_timestamp_millis;
            }
        }

        state
            .block_merkle_tree
            .push(parent_header.commit())
            .context("missing blocks frontier")?;
        let block_merkle_tree_root = state.block_merkle_tree.commitment();

        // Insert the new L1 deposits
        for fee_info in l1_deposits {
            state
                .insert_fee_deposit(*fee_info)
                .context(format!("missing fee account {}", fee_info.account()))?;
        }

        // TODO(abdul): builder is unfunded error
        if version < versions::NEW_PROTOCOL_VERSION {
            for BuilderFee {
                fee_account,
                fee_signature,
                fee_amount,
            } in &builder_fee
            {
                ensure!(
                    fee_account.validate_fee_signature(fee_signature, *fee_amount, &ns_table)
                        || fee_account.validate_fee_signature_with_vid_commitment(
                            fee_signature,
                            *fee_amount,
                            &ns_table,
                            &payload_commitment
                        ),
                    "invalid builder signature"
                );

                let fee_info = FeeInfo::new(*fee_account, *fee_amount);
                state
                    .charge_fee(fee_info, chain_config.fee_recipient)
                    .context(format!("invalid builder fee {fee_info:?}"))?;
            }
        }

        let fee_info = FeeInfo::from_builder_fees(builder_fee.clone());

        let builder_signature: Vec<BuilderSignature> =
            builder_fee.iter().map(|e| e.fee_signature).collect();

        let fee_merkle_tree_root = state.fee_merkle_tree.commitment();

        let header = match (version.major, version.minor) {
            (0, 1) => Self::V1(v0_1::Header {
                chain_config: v0_1::ResolvableChainConfig::from(v0_1::ChainConfig::from(
                    chain_config,
                )),
                height,
                timestamp,
                l1_head: l1.head,
                l1_finalized: l1.finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                fee_info: fee_info[0],
                builder_signature: builder_signature.first().copied(),
            }),
            (0, 2) => Self::V2(v0_2::Header {
                chain_config: v0_1::ResolvableChainConfig::from(v0_1::ChainConfig::from(
                    chain_config,
                )),
                height,
                timestamp,
                l1_head: l1.head,
                l1_finalized: l1.finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                fee_info: fee_info[0],
                builder_signature: builder_signature.first().copied(),
            }),
            (0, 3) => Self::V3(v0_3::Header {
                chain_config: chain_config.into(),
                height,
                timestamp,
                l1_head: l1.head,
                l1_finalized: l1.finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                reward_merkle_tree_root: state.reward_merkle_tree_v1.commitment(),
                fee_info: fee_info[0],
                builder_signature: builder_signature.first().copied(),
            }),
            (0, 4) => Self::V4(v0_4::Header {
                chain_config: chain_config.into(),
                height,
                timestamp,
                timestamp_millis: TimestampMillis::from_millis(timestamp_millis),
                l1_head: l1.head,
                l1_finalized: l1.finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                reward_merkle_tree_root: state.reward_merkle_tree_v2.commitment(),
                fee_info: fee_info[0],
                builder_signature: builder_signature.first().copied(),
                total_reward_distributed: total_reward_distributed.unwrap_or_default(),
                next_stake_table_hash,
            }),
            (0, 5) => Self::V5(v0_5::Header {
                chain_config: chain_config.into(),
                height,
                timestamp,
                timestamp_millis: TimestampMillis::from_millis(timestamp_millis),
                l1_head: l1.head,
                l1_finalized: l1.finalized,
                payload_commitment,
                builder_commitment,
                ns_table,
                block_merkle_tree_root,
                fee_merkle_tree_root,
                reward_merkle_tree_root: state.reward_merkle_tree_v2.commitment(),
                fee_info: fee_info[0],
                builder_signature: builder_signature.first().copied(),
                total_reward_distributed: total_reward_distributed.unwrap_or_default(),
                next_stake_table_hash,
                leader_counts: leader_counts.expect("leader_counts is required for V5 headers"),
            }),
            // V6 header format is used for v0.6 (new protocol).
            (0, 6) => {
                let fields = v0_6::Header {
                    chain_config: chain_config.into(),
                    height,
                    timestamp,
                    timestamp_millis: TimestampMillis::from_millis(timestamp_millis),
                    l1_head: l1.head,
                    l1_finalized: l1.finalized,
                    payload_commitment,
                    builder_commitment,
                    ns_table,
                    block_merkle_tree_root,
                    fee_merkle_tree_root,
                    reward_merkle_tree_root: state.reward_merkle_tree_v2.commitment(),
                    fee_info: fee_info[0],
                    builder_signature: builder_signature.first().copied(),
                    total_reward_distributed: total_reward_distributed.unwrap_or_default(),
                    next_stake_table_hash,
                    leader_counts: leader_counts.expect("leader_counts is required for V6 headers"),
                };
                Self::V6(fields)
            },
            // This case should never occur
            // but if it does, we must panic
            // because we don't have the versioned types for this version
            _ => panic!("invalid version: {version}"),
        };
        Ok(header)
    }

    /// Calculate the per-validator leader counts for the current block.
    ///
    /// The array is sized to [`MAX_VALIDATORS`] (100) because only the top 100
    /// validators by stake are selected into the active set via
    /// `select_active_validator_set()`. `leader_index` is a position within
    /// that set, so it is always in the range 0..100.
    pub fn calculate_leader_counts(
        parent_header: &Header,
        height: u64,
        leader_index: usize,
        epoch_height: u64,
    ) -> LeaderCounts {
        let mut leader_counts = [0u16; MAX_VALIDATORS];

        // Get parent's leader counts
        let parent_counts = parent_header.leader_counts();

        // If parent was the last block of an epoch, current block is epoch start
        let is_epoch_start = is_last_block(height.saturating_sub(1), epoch_height);

        if is_epoch_start || parent_counts.is_none() {
            leader_counts[leader_index] = 1;
        } else if let Some(parent_counts) = parent_counts {
            leader_counts = *parent_counts;
            leader_counts[leader_index] += 1;
        }

        leader_counts
    }

    /// Look up the proposing leader's index in the active validator set for this view.
    ///
    /// Returns `None` for protocol versions before [`EPOCH_REWARD_VERSION`] (V5),
    /// since per-epoch reward tracking was not yet active.
    ///
    /// The returned index is a position in the epoch's stake table (0..MAX_VALIDATORS)
    /// and is used to increment that leader's count in [`LeaderCounts`].
    pub async fn get_leader_index(
        version: Version,
        height: u64,
        view_number: u64,
        instance_state: &NodeState,
    ) -> anyhow::Result<Option<usize>> {
        // Leader counts are only tracked from V5 onward.
        if version < EPOCH_REWARD_VERSION {
            return Ok(None);
        }

        let epoch_height = instance_state
            .epoch_height
            .context("epoch height not in instance state for V6")?;
        let epoch = EpochNumber::new(epoch_from_block_number(height, epoch_height));

        let coordinator = instance_state.coordinator.clone();
        coordinator
            .membership_for_epoch(Some(epoch))
            .map_err(|e| anyhow::anyhow!("failed to get epoch membership: {e}"))?;

        // Resolve the leader for this view and find their index in the stake table.
        let snapshot = coordinator
            .membership()
            .snapshot(epoch)
            .with_context(|| format!("no committee for epoch {epoch:?}"))?;

        let leader = snapshot
            .leader(ViewNumber::new(view_number))
            .with_context(|| format!("leader for epoch {epoch:?} not found"))?;

        let index = snapshot.validator_index(&leader).with_context(|| {
            format!("Leader {leader} not found in stake table for epoch {epoch}")
        })?;

        Ok(Some(index))
    }

    /// Distribute per epoch rewards at epoch boundaries.
    ///
    /// Rewards are calculated in the background during an epoch and applied
    /// atomically at the epoch boundary (the last block of each epoch).
    ///
    /// The flow for a given block at `height` in epoch E:
    ///
    /// - E ≤ first_epoch + 1 : no rewards exist yet, return zero.
    /// - if the previous epoch's calculation hasn't started,
    ///   kick it off in the background so it's ready by the boundary. Return zero rewards.
    /// - Epoch boundary (last block of E): apply the previous epoch's
    ///   (E-1) reward result to `validated_state.reward_merkle_tree_v2`, verify
    ///   the resulting root against `header_root` if provided, then start the
    ///   background calculation for the current epoch E. `header_root` is `None`
    ///   during proposal (the leader is building the header) and `Some` during
    ///   validation.
    ///
    /// If the previous epoch's result is missing at the boundary (e.g. after a
    /// restart or catchup), the function fetches the epoch's leaf, recovers the
    /// leader counts and stake table, computes rewards synchronously, and applies
    /// them before proceeding.
    ///
    /// # Returns
    /// `(total_rewards_applied, changed_accounts)` — the total reward amount
    /// distributed and the set of accounts whose balances changed.
    pub async fn handle_epoch_rewards(
        height: u64,
        leader_counts: &LeaderCounts,
        instance_state: &NodeState,
        validated_state: &mut ValidatedState,
        header_root: Option<RewardMerkleCommitmentV2>,
    ) -> anyhow::Result<(RewardAmount, HashSet<RewardAccountV2>)> {
        let epoch_height = instance_state
            .epoch_height
            .context("epoch_height not configured")?;
        ensure!(epoch_height > 0, "epoch_height must be > 0");
        let epoch = EpochNumber::new(epoch_from_block_number(height, epoch_height));
        let prev_epoch = EpochNumber::new(*epoch - 1);
        let coordinator = instance_state.coordinator.clone();
        let first_epoch = coordinator
            .membership()
            .first_epoch()
            .context("first_epoch not available")?;

        // No rewards data exists for the first two epochs.
        if epoch <= first_epoch + 1 {
            return Ok((RewardAmount::default(), HashSet::new()));
        }

        let mut reward_calculator = instance_state.epoch_rewards_calculator.lock().await;

        // Eagerly start the previous epoch's reward calculation if it hasn't
        // been kicked off yet, so the result is ready by the epoch boundary.
        if epoch > first_epoch + 2 && !reward_calculator.is_calculating(prev_epoch) {
            tracing::info!(%epoch, %prev_epoch, "triggering catchup reward calculation");
            reward_calculator.spawn_background_task(
                prev_epoch,
                epoch_height,
                validated_state.reward_merkle_tree_v2.clone(),
                instance_state.clone(),
                coordinator.clone(),
                None,
            );
        }

        if !is_last_block(height, epoch_height) {
            return Ok((RewardAmount::default(), HashSet::new()));
        }

        tracing::info!(%height, %epoch, %prev_epoch, "epoch boundary: applying rewards");

        let (epoch_rewards_applied, changed_accounts) = if let Some(result) =
            reward_calculator.get_result(prev_epoch).await
        {
            tracing::info!(
                %epoch,
                prev_epoch = %result.epoch,
                total = %result.total_distributed.0,
                "applying epoch rewards"
            );
            validated_state.reward_merkle_tree_v2 = result.reward_tree.clone();
            (result.total_distributed, result.changed_accounts)
        } else if prev_epoch <= first_epoch + 1 {
            // Previous epoch is too early to have rewards.
            (RewardAmount::default(), HashSet::new())
        } else {
            // the background result is missing
            // Fetch the previous epoch's leaf and compute rewards synchronously.
            let prev_epoch_last_block = *prev_epoch * epoch_height;
            if let Err(err) = coordinator.membership_for_epoch(Some(prev_epoch)) {
                tracing::info!(%prev_epoch, "stake table missing for prev_epoch, triggering catchup: {err:#}");
                coordinator
                    .wait_for_catchup(prev_epoch)
                    .await
                    .context(format!("failed to catch up for prev_epoch={prev_epoch}"))?;
            }

            let prev_snapshot = coordinator
                .membership()
                .snapshot(prev_epoch)
                .with_context(|| format!("no committee for prev_epoch={prev_epoch}"))?;

            let stake_table = HSStakeTable::from_iter(prev_snapshot.stake_table());
            let success_threshold = prev_snapshot.success_threshold();

            let prev_epoch_leaf = instance_state
                .state_catchup
                .as_ref()
                .fetch_leaf(prev_epoch_last_block, stake_table, success_threshold)
                .await
                .with_context(|| {
                    format!(
                        "failed to fetch leaf at height {prev_epoch_last_block} for prev_epoch \
                         {prev_epoch}"
                    )
                })?;
            let prev_epoch_header = prev_epoch_leaf.block_header();

            if prev_epoch_header.version() >= EPOCH_REWARD_VERSION {
                tracing::warn!(
                    %epoch,
                    %prev_epoch,
                    "missing epoch rewards at boundary, spawning calculation now"
                );

                if !reward_calculator.is_calculating(prev_epoch) {
                    // Pick the reward tree to build on
                    // use the local tree if its
                    // root matches what the previous epoch's header committed to,
                    // otherwise start from an empty tree because catchup will fill it
                    let expected_root = prev_epoch_header.reward_merkle_tree_root().right();
                    let actual_root = validated_state.reward_merkle_tree_v2.commitment();
                    let reward_tree = if expected_root == Some(actual_root) {
                        validated_state.reward_merkle_tree_v2.clone()
                    } else {
                        tracing::warn!(
                            %epoch,
                            %prev_epoch,
                            ?expected_root,
                            ?actual_root,
                            "reward merkle tree root mismatch, using empty tree for catchup"
                        );
                        RewardMerkleTreeV2::new(REWARD_MERKLE_TREE_V2_HEIGHT)
                    };

                    reward_calculator.spawn_background_task(
                        prev_epoch,
                        epoch_height,
                        reward_tree,
                        instance_state.clone(),
                        coordinator.clone(),
                        prev_epoch_header.leader_counts().copied(),
                    );
                }

                let result = reward_calculator
                    .get_result(prev_epoch)
                    .await
                    .context(format!(
                        "failed to calculate missing rewards for epoch {prev_epoch}"
                    ))?;

                tracing::info!(
                    %epoch,
                    %prev_epoch,
                    total = %result.total_distributed.0,
                    "applied delayed epoch rewards"
                );

                validated_state.reward_merkle_tree_v2 = result.reward_tree.clone();
                (result.total_distributed, result.changed_accounts)
            } else {
                tracing::info!(%epoch, %prev_epoch, "no rewards for pre-V5 epoch");
                (RewardAmount::default(), HashSet::new())
            }
        };

        // Verify the reward tree root matches the proposed header, if available.
        let calculated_root = validated_state.reward_merkle_tree_v2.commitment();
        if let Some(header_root) = header_root
            && calculated_root != header_root
        {
            bail!(
                "reward merkle tree root mismatch, using new merkle tree. Header root: \
                 {header_root}, Calculated root: {calculated_root}"
            );
        }

        // Kick off the background calculation for the current epoch so it's
        // ready on the next epoch boundary.
        reward_calculator.spawn_background_task(
            epoch,
            epoch_height,
            validated_state.reward_merkle_tree_v2.clone(),
            instance_state.clone(),
            coordinator,
            Some(*leader_counts),
        );

        Ok((epoch_rewards_applied, changed_accounts))
    }

    async fn get_chain_config(
        validated_state: &ValidatedState,
        instance_state: &NodeState,
    ) -> anyhow::Result<ChainConfig> {
        let validated_cf = validated_state.chain_config;
        let instance_cf = instance_state.chain_config;

        if validated_cf.commit() == instance_cf.commit() {
            return Ok(instance_cf);
        }

        match validated_cf.resolve() {
            Some(cf) => Ok(cf),
            None => {
                tracing::info!("fetching chain config {} from peers", validated_cf.commit());

                instance_state
                    .state_catchup
                    .as_ref()
                    .fetch_chain_config(validated_cf.commit())
                    .await
            },
        }
    }
}

impl Header {
    /// A commitment to a ChainConfig or a full ChainConfig.
    pub fn chain_config(&self) -> v0_3::ResolvableChainConfig {
        match self {
            Self::V1(fields) => v0_3::ResolvableChainConfig::from(&fields.chain_config),
            Self::V2(fields) => v0_3::ResolvableChainConfig::from(&fields.chain_config),
            Self::V3(fields) => fields.chain_config,
            Self::V4(fields) => fields.chain_config,
            Self::V5(fields) => fields.chain_config,
            Self::V6(fields) => fields.chain_config,
        }
    }

    pub fn height(&self) -> u64 {
        *field!(self.height)
    }

    pub fn height_mut(&mut self) -> &mut u64 {
        &mut *field_mut!(self.height)
    }

    pub fn timestamp_internal(&self) -> u64 {
        match self {
            Self::V1(fields) => fields.timestamp,
            Self::V2(fields) => fields.timestamp,
            Self::V3(fields) => fields.timestamp,
            Self::V4(fields) => fields.timestamp,
            Self::V5(fields) => fields.timestamp,
            Self::V6(fields) => fields.timestamp,
        }
    }

    pub fn timestamp_millis_internal(&self) -> u64 {
        match self {
            Self::V1(fields) => fields.timestamp * 1_000,
            Self::V2(fields) => fields.timestamp * 1_000,
            Self::V3(fields) => fields.timestamp * 1_000,
            Self::V4(fields) => fields.timestamp_millis.u64(),
            Self::V5(fields) => fields.timestamp_millis.u64(),
            Self::V6(fields) => fields.timestamp_millis.u64(),
        }
    }

    pub fn set_timestamp(&mut self, timestamp: u64, timestamp_millis: u64) {
        match self {
            Self::V1(fields) => {
                fields.timestamp = timestamp;
            },
            Self::V2(fields) => {
                fields.timestamp = timestamp;
            },
            Self::V3(fields) => {
                fields.timestamp = timestamp;
            },
            Self::V4(fields) => {
                fields.timestamp = timestamp;
                fields.timestamp_millis = TimestampMillis::from_millis(timestamp_millis);
            },
            Self::V5(fields) => {
                fields.timestamp = timestamp;
                fields.timestamp_millis = TimestampMillis::from_millis(timestamp_millis);
            },
            Self::V6(fields) => {
                fields.timestamp = timestamp;
                fields.timestamp_millis = TimestampMillis::from_millis(timestamp_millis);
            },
        };
    }

    /// The Espresso block header includes a reference to the current head of the L1 chain.
    ///
    /// Rollups can use this to facilitate bridging between the L1 and L2 in a deterministic way.
    /// This field deterministically associates an L2 block with a recent L1 block the instant the
    /// L2 block is sequenced. Rollups can then define the L2 state after this block as the state
    /// obtained by executing all the transactions in this block _plus_ all the L1 deposits up to
    /// the given L1 block number. Since there is no need to wait for the L2 block to be reflected
    /// on the L1, this bridge design retains the low confirmation latency of HotShot.
    ///
    /// This block number indicates the unsafe head of the L1 chain, so it is subject to reorgs. For
    /// this reason, the Espresso header does not include any information that might change in a
    /// reorg, such as the L1 block timestamp or hash. It includes only the L1 block number, which
    /// will always refer to _some_ block after a reorg: if the L1 head at the time this block was
    /// sequenced gets reorged out, the L1 chain will eventually (and probably quickly) grow to the
    /// same height once again, and a different block will exist with the same height. In this way,
    /// Espresso does not have to handle L1 reorgs, and the Espresso blockchain will always be
    /// reflective of the current state of the L1 blockchain. Rollups that use this block number
    /// _do_ have to handle L1 reorgs, but each rollup and each rollup client can decide how many
    /// confirmations they want to wait for on top of this `l1_head` before they consider an L2
    /// block finalized. This offers a tradeoff between low-latency L1-L2 bridges and finality.
    ///
    /// Rollups that want a stronger guarantee of finality, or that want Espresso to attest to data
    /// from the L1 block that might change in reorgs, can instead use the latest L1 _finalized_
    /// block at the time this L2 block was sequenced: [`Self::l1_finalized`].
    pub fn l1_head(&self) -> u64 {
        *field!(self.l1_head)
    }

    pub fn l1_head_mut(&mut self) -> &mut u64 {
        &mut *field_mut!(self.l1_head)
    }

    /// The Espresso block header includes information about the latest finalized L1 block.
    ///
    /// Similar to [`l1_head`](Self::l1_head), rollups can use this information to implement a
    /// bridge between the L1 and L2 while retaining the finality of low-latency block confirmations
    /// from HotShot. Since this information describes the finalized L1 block, a bridge using this
    /// L1 block will have much higher latency than a bridge using [`l1_head`](Self::l1_head). In
    /// exchange, rollups that use the finalized block do not have to worry about L1 reorgs, and can
    /// inject verifiable attestations to the L1 block metadata (such as its timestamp or hash) into
    /// their execution layers, since Espresso replicas will sign this information for the finalized
    /// L1 block.
    ///
    /// This block may be `None` in the rare case where Espresso has started shortly after the
    /// genesis of the L1, and the L1 has yet to finalize a block. In all other cases it will be
    /// `Some`.
    pub fn l1_finalized(&self) -> Option<L1BlockInfo> {
        *field!(self.l1_finalized)
    }

    pub fn l1_finalized_mut(&mut self) -> &mut Option<L1BlockInfo> {
        &mut *field_mut!(self.l1_finalized)
    }

    pub fn payload_commitment(&self) -> VidCommitment {
        *field!(self.payload_commitment)
    }

    pub fn payload_commitment_mut(&mut self) -> &mut VidCommitment {
        &mut *field_mut!(self.payload_commitment)
    }

    pub fn builder_commitment(&self) -> &BuilderCommitment {
        field!(self.builder_commitment)
    }

    pub fn builder_commitment_mut(&mut self) -> &mut BuilderCommitment {
        &mut *field_mut!(self.builder_commitment)
    }

    pub fn ns_table(&self) -> &NsTable {
        field!(self.ns_table)
    }

    pub fn ns_table_mut(&mut self) -> &mut NsTable {
        &mut *field_mut!(self.ns_table)
    }

    /// Root Commitment of Block Merkle Tree
    pub fn block_merkle_tree_root(&self) -> BlockMerkleCommitment {
        *field!(self.block_merkle_tree_root)
    }

    pub fn block_merkle_tree_root_mut(&mut self) -> &mut BlockMerkleCommitment {
        &mut *field_mut!(self.block_merkle_tree_root)
    }

    /// Root Commitment of `FeeMerkleTree`
    pub fn fee_merkle_tree_root(&self) -> FeeMerkleCommitment {
        *field!(self.fee_merkle_tree_root)
    }

    pub fn fee_merkle_tree_root_mut(&mut self) -> &mut FeeMerkleCommitment {
        &mut *field_mut!(self.fee_merkle_tree_root)
    }

    /// Fee paid by the block builder
    pub fn fee_info(&self) -> Vec<FeeInfo> {
        match self {
            Self::V1(fields) => vec![fields.fee_info],
            Self::V2(fields) => vec![fields.fee_info],
            Self::V3(fields) => vec![fields.fee_info],
            Self::V4(fields) => vec![fields.fee_info],
            Self::V5(fields) => vec![fields.fee_info],
            Self::V6(fields) => vec![fields.fee_info],
        }
    }

    pub fn reward_merkle_tree_root(
        &self,
    ) -> Either<RewardMerkleCommitmentV1, RewardMerkleCommitmentV2> {
        let empty_reward_merkle_tree = RewardMerkleTreeV1::new(REWARD_MERKLE_TREE_V1_HEIGHT);
        match self {
            Self::V1(_) => Either::Left(empty_reward_merkle_tree.commitment()),
            Self::V2(_) => Either::Left(empty_reward_merkle_tree.commitment()),
            Self::V3(fields) => Either::Left(fields.reward_merkle_tree_root),
            Self::V4(fields) => Either::Right(fields.reward_merkle_tree_root),
            Self::V5(fields) => Either::Right(fields.reward_merkle_tree_root),
            Self::V6(fields) => Either::Right(fields.reward_merkle_tree_root),
        }
    }

    /// Account (etheruem address) of builder
    ///
    /// This signature is not considered formally part of the header; it is just evidence proving
    /// that other parts of the header ([`fee_info`](Self::fee_info)) are correct. It exists in the
    /// header so that it is available to all nodes to be used during validation. But since it is
    /// checked during consensus, any downstream client who has a proof of consensus finality of a
    /// header can trust that [`fee_info`](Self::fee_info) is correct without relying on the
    /// signature. Thus, this signature is not included in the header commitment.
    pub fn builder_signature(&self) -> Vec<BuilderSignature> {
        match self {
            // Previously we used `Option<BuilderSignature>` to
            // represent presence/absence of signature.  The simplest
            // way to represent the same now that we have a `Vec` is
            // empty/non-empty
            Self::V1(fields) => fields.builder_signature.as_slice().to_vec(),
            Self::V2(fields) => fields.builder_signature.as_slice().to_vec(),
            Self::V3(fields) => fields.builder_signature.as_slice().to_vec(),
            Self::V4(fields) => fields.builder_signature.as_slice().to_vec(),
            Self::V5(fields) => fields.builder_signature.as_slice().to_vec(),
            Self::V6(fields) => fields.builder_signature.as_slice().to_vec(),
        }
    }

    pub fn total_reward_distributed(&self) -> Option<RewardAmount> {
        match self {
            Self::V1(_) | Self::V2(_) | Self::V3(_) => None,
            Self::V4(fields) => Some(fields.total_reward_distributed),
            Self::V5(fields) => Some(fields.total_reward_distributed),
            Self::V6(fields) => Some(fields.total_reward_distributed),
        }
    }
}

#[derive(Debug, Error)]
#[error("Invalid Block Header {msg}")]
pub struct InvalidBlockHeader {
    msg: String,
}
impl InvalidBlockHeader {
    fn new(msg: String) -> Self {
        Self { msg }
    }
}

impl From<anyhow::Error> for InvalidBlockHeader {
    fn from(err: anyhow::Error) -> Self {
        Self::new(format!("{err:#}"))
    }
}

impl BlockHeader<SeqTypes> for Header {
    type Error = InvalidBlockHeader;

    #[tracing::instrument(
        skip_all,
        fields(
            node_id = instance_state.node_id,
            view = ?parent_leaf.view_number(),
            height = parent_leaf.block_header().height(),
        ),
    )]
    #[tracing::instrument(
        skip_all,
        fields(
            height = parent_leaf.block_header().block_number() + 1,
            parent_view = ?parent_leaf.view_number(),
            payload_commitment,
            version,
        )
    )]
    async fn new(
        parent_state: &ValidatedState,
        instance_state: &NodeState,
        parent_leaf: &Leaf2,
        payload_commitment: VidCommitment,
        builder_commitment: BuilderCommitment,
        metadata: <<SeqTypes as NodeType>::BlockPayload as BlockPayload<SeqTypes>>::Metadata,
        builder_fee: BuilderFee<SeqTypes>,
        version: Version,
        view_number: u64,
    ) -> Result<Self, Self::Error> {
        tracing::info!("preparing to propose header");

        let height = parent_leaf.height();
        let view = parent_leaf.view_number();

        let mut validated_state = parent_state.clone();

        let chain_config = if version > instance_state.current_version {
            match instance_state.upgrades.get(&version) {
                Some(upgrade) => match upgrade.upgrade_type {
                    UpgradeType::Fee { chain_config } => chain_config,
                    UpgradeType::Epoch { chain_config } => chain_config,
                    UpgradeType::DrbAndHeader { chain_config } => chain_config,
                    UpgradeType::Da { chain_config } => chain_config,
                    UpgradeType::EpochReward { chain_config } => chain_config,
                },
                None => Header::get_chain_config(&validated_state, instance_state).await?,
            }
        } else {
            Header::get_chain_config(&validated_state, instance_state).await?
        };

        validated_state.chain_config = chain_config.into();

        // Fetch the latest L1 snapshot.
        let l1_snapshot = instance_state.l1_client.snapshot().await;
        // Fetch the new L1 deposits between parent and current finalized L1 block.
        let l1_deposits = if let (Some(addr), Some(block_info)) =
            (chain_config.fee_contract, l1_snapshot.finalized)
        {
            instance_state
                .l1_client
                .get_finalized_deposits(
                    addr,
                    parent_leaf
                        .block_header()
                        .l1_finalized()
                        .map(|block_info| block_info.number),
                    block_info.number,
                )
                .await
        } else {
            vec![]
        };
        // Find missing fee state entries. We will need to use the builder account which is paying a
        // fee and the recipient account which is receiving it, plus any counts receiving deposits
        // in this block.
        let missing_accounts = parent_state.forgotten_accounts(
            [builder_fee.fee_account, chain_config.fee_recipient]
                .into_iter()
                .chain(l1_deposits.iter().map(|info| info.account())),
        );
        if !missing_accounts.is_empty() {
            tracing::warn!(
                height,
                ?view,
                ?missing_accounts,
                "fetching missing accounts from peers"
            );

            // Fetch missing fee state entries
            let missing_account_proofs = instance_state
                .state_catchup
                .as_ref()
                .fetch_accounts(
                    instance_state,
                    height,
                    view,
                    parent_state.fee_merkle_tree.commitment(),
                    missing_accounts,
                )
                .await?;

            // Insert missing fee state entries
            for proof in missing_account_proofs.iter() {
                proof
                    .remember(&mut validated_state.fee_merkle_tree)
                    .context("remembering fee account")?;
            }
        }

        // Ensure merkle tree has frontier
        if validated_state.need_to_fetch_blocks_mt_frontier() {
            tracing::warn!(height, ?view, "fetching block frontier from peers");
            instance_state
                .state_catchup
                .as_ref()
                .remember_blocks_merkle_tree(
                    instance_state,
                    height,
                    view,
                    &mut validated_state.block_merkle_tree,
                )
                .await
                .context("remembering block proof")?;
        }

        // Handle rewards and calculate leader_counts based on version
        let (leader_counts, total_reward_distributed) = if version >= EPOCH_REWARD_VERSION {
            let epoch_height = instance_state
                .epoch_height
                .context("epoch_height not configured for V6")?;
            // Use the new block's height (parent + 1), not the parent's height
            let new_height = height + 1;
            let leader_index =
                Header::get_leader_index(version, new_height, view_number, instance_state)
                    .await?
                    .context("leader_index must be present for V6")?;

            let leader_counts = Header::calculate_leader_counts(
                parent_leaf.block_header(),
                new_height,
                leader_index,
                epoch_height,
            );

            let (epoch_rewards_applied, _changed_accounts) = Header::handle_epoch_rewards(
                new_height,
                &leader_counts,
                instance_state,
                &mut validated_state,
                None,
            )
            .await?;

            // Note: changed_accounts are not used here during header creation.
            // Delta updates are handled in apply_header during validation.

            let parent_total = parent_leaf
                .block_header()
                .total_reward_distributed()
                .unwrap_or_default();

            (
                Some(leader_counts),
                Some(RewardAmount(parent_total.0 + epoch_rewards_applied.0)),
            )
        } else if version >= EPOCH_VERSION {
            // V3-V4: per-block distribution returns cumulative total
            let total = distribute_block_reward(
                instance_state,
                &mut validated_state,
                parent_leaf,
                ViewNumber::new(view_number),
                version,
            )
            .await?
            .map(|r| r.total_distributed());

            (None, total)
        } else {
            (None, None)
        };

        let mut next_stake_table_hash = None;

        if version >= DRB_AND_HEADER_UPGRADE_VERSION {
            let epoch_height = instance_state
                .epoch_height
                .context("epoch height not in instance state")?;
            if is_ge_epoch_root(height + 1, epoch_height) {
                let coordinator = instance_state.coordinator.clone();
                let first_epoch = {
                    coordinator
                        .membership()
                        .first_epoch()
                        .context("The first epoch was not set.")?
                };

                let epoch = EpochNumber::new(epoch_from_block_number(height + 1, epoch_height));

                // first 2 epochs don't have a stake table hash because they are configured.
                if epoch > first_epoch {
                    let epoch_membership = coordinator
                        .stake_table_for_epoch(Some(epoch + 1))
                        .map_err(|e| anyhow::anyhow!("failed to get epoch membership: {e}"))?;
                    next_stake_table_hash = Some(
                        epoch_membership
                            .stake_table_hash()
                            .context("failed to get next stake table hash")?,
                    );
                }
            }
        }

        let now = OffsetDateTime::now_utc();

        let timestamp = now.unix_timestamp() as u64;
        let timestamp_millis = TimestampMillis::from_time(&now).u64();

        Ok(Self::from_info(
            payload_commitment,
            builder_commitment,
            metadata,
            parent_leaf,
            l1_snapshot,
            &l1_deposits,
            vec![builder_fee],
            timestamp,
            timestamp_millis,
            validated_state,
            chain_config,
            version,
            total_reward_distributed,
            next_stake_table_hash,
            leader_counts,
        )?)
    }

    fn genesis(
        instance_state: &NodeState,
        payload: <SeqTypes as NodeType>::BlockPayload,
        metadata: &<<SeqTypes as NodeType>::BlockPayload as BlockPayload<SeqTypes>>::Metadata,
        _: Version,
    ) -> Self {
        let payload_bytes = payload.encode();
        let builder_commitment = payload.builder_commitment(metadata);

        let vid_commitment_version = instance_state.genesis_version;

        let payload_commitment = vid_commitment(
            &payload_bytes,
            &metadata.encode(),
            GENESIS_VID_NUM_STORAGE_NODES,
            vid_commitment_version,
        );

        let ValidatedState {
            fee_merkle_tree,
            block_merkle_tree,
            reward_merkle_tree_v1,
            reward_merkle_tree_v2,
            ..
        } = ValidatedState::genesis(instance_state).0;
        let block_merkle_tree_root = block_merkle_tree.commitment();
        let fee_merkle_tree_root = fee_merkle_tree.commitment();
        let reward_merkle_tree_root = reward_merkle_tree_v2.commitment();

        let time = instance_state.genesis_header.timestamp;

        let timestamp = time.unix_timestamp();
        let timestamp_millis = time.unix_timestamp_millis();

        //  The Header is versioned,
        //  so we create the genesis header for the current version of the sequencer.
        Self::create(
            instance_state.genesis_header.chain_config,
            0,
            timestamp,
            timestamp_millis,
            instance_state
                .l1_genesis
                .map(|block| block.number)
                .unwrap_or_default(),
            instance_state.l1_genesis,
            payload_commitment,
            builder_commitment.clone(),
            metadata.clone(),
            fee_merkle_tree_root,
            block_merkle_tree_root,
            reward_merkle_tree_v1.commitment(),
            reward_merkle_tree_root,
            vec![FeeInfo::genesis()],
            vec![],
            None,
            instance_state.genesis_version,
            None,
            Some([0; 100]),
        )
    }

    fn timestamp(&self) -> u64 {
        self.timestamp_internal()
    }

    fn timestamp_millis(&self) -> u64 {
        self.timestamp_millis_internal()
    }

    fn block_number(&self) -> u64 {
        self.height()
    }

    fn version(&self) -> Version {
        self.version()
    }

    fn payload_commitment(&self) -> VidCommitment {
        self.payload_commitment()
    }

    fn metadata(
        &self,
    ) -> &<<SeqTypes as NodeType>::BlockPayload as BlockPayload<SeqTypes>>::Metadata {
        self.ns_table()
    }

    /// Commit over fee_amount, payload_commitment and metadata
    fn builder_commitment(&self) -> BuilderCommitment {
        self.builder_commitment().clone()
    }

    fn get_light_client_state(&self, view: ViewNumber) -> anyhow::Result<LightClientState> {
        let mut block_comm_root_bytes = vec![];
        self.block_merkle_tree_root()
            .serialize_compressed(&mut block_comm_root_bytes)?;

        Ok(LightClientState {
            view_number: view.u64(),
            block_height: self.height(),
            block_comm_root: hotshot_types::light_client::hash_bytes_to_field(
                &block_comm_root_bytes,
            )?,
        })
    }

    fn auth_root(&self) -> anyhow::Result<B256> {
        match self {
            Header::V1(_) | Header::V2(_) | Header::V3(_) => Ok(B256::ZERO),
            Header::V4(header) => {
                // Temporary placeholder values for future fields
                let placeholder_1 = B256::ZERO;
                let placeholder_2 = B256::ZERO;
                let placeholder_3 = B256::ZERO;
                let placeholder_4 = B256::ZERO;
                let placeholder_5 = B256::ZERO;
                let placeholder_6 = B256::ZERO;
                let placeholder_7 = B256::ZERO;

                let mut hasher = Keccak256::new();

                let digest = header.reward_merkle_tree_root.digest();
                hasher.update(digest.0);
                hasher.update(placeholder_1);
                hasher.update(placeholder_2);
                hasher.update(placeholder_3);
                hasher.update(placeholder_4);
                hasher.update(placeholder_5);
                hasher.update(placeholder_6);
                hasher.update(placeholder_7);

                Ok(hasher.finalize())
            },
            Header::V5(header) | Header::V6(header) => {
                // Temporary placeholder values for future fields
                let placeholder_1 = B256::ZERO;
                let placeholder_2 = B256::ZERO;
                let placeholder_3 = B256::ZERO;
                let placeholder_4 = B256::ZERO;
                let placeholder_5 = B256::ZERO;
                let placeholder_6 = B256::ZERO;
                let placeholder_7 = B256::ZERO;

                let mut hasher = Keccak256::new();

                // Start with the reward Merkle tree root digest as the base input
                let digest = header.reward_merkle_tree_root.digest();
                hasher.update(digest.0);
                hasher.update(placeholder_1);
                hasher.update(placeholder_2);
                hasher.update(placeholder_3);
                hasher.update(placeholder_4);
                hasher.update(placeholder_5);
                hasher.update(placeholder_6);
                hasher.update(placeholder_7);

                Ok(hasher.finalize())
            },
        }
    }
}

impl HeightIndexed for Header {
    fn height(&self) -> u64 {
        self.height()
    }
}

impl QueryableHeader<SeqTypes> for Header {
    type NamespaceId = NamespaceId;
    type NamespaceIndex = NsIndex;

    fn namespace_id(&self, i: &NsIndex) -> Option<NamespaceId> {
        self.ns_table().read_ns_id(i)
    }

    fn namespace_size(&self, i: &NsIndex, payload_size: usize) -> u64 {
        self.ns_table()
            .ns_range(i, &PayloadByteLen(payload_size))
            .byte_len()
            .0 as u64
    }

    fn ns_table(&self) -> String {
        BASE64_STANDARD.encode(&self.ns_table().bytes)
    }
}

impl ExplorerHeader<SeqTypes> for Header {
    type BalanceAmount = FeeAmount;
    type WalletAddress = Vec<FeeAccount>;
    type ProposerId = Vec<FeeAccount>;

    // TODO what are these expected values w/ multiple Fees
    fn proposer_id(&self) -> Self::ProposerId {
        self.fee_info().accounts()
    }

    fn fee_info_account(&self) -> Self::WalletAddress {
        self.fee_info().accounts()
    }

    fn fee_info_balance(&self) -> Self::BalanceAmount {
        // TODO this will panic if some amount or total does not fit in a u64
        self.fee_info().amount().unwrap()
    }

    /// reward_balance at the moment is only implemented as a stub, as block
    /// rewards have not yet been implemented.
    ///
    /// TODO: update implementation when rewards have been created / supported.
    ///       Issue: https://github.com/EspressoSystems/espresso-network/issues/1453
    fn reward_balance(&self) -> Self::BalanceAmount {
        FeeAmount::from(0)
    }

    fn namespace_ids(&self) -> Vec<NamespaceId> {
        self.ns_table()
            .iter()
            .map(|i| self.ns_table().read_ns_id_unchecked(&i))
            .collect()
    }
}

#[cfg(test)]
mod test_headers {
    use std::sync::Arc;

    use alloy::{
        node_bindings::Anvil,
        primitives::{Address, U256},
    };
    use hotshot_query_service::testing::mocks::MOCK_UPGRADE;
    use hotshot_types::traits::signature_key::BuilderSignatureKey;
    use v0_1::{BlockMerkleTree, FeeMerkleTree, L1Client};
    use vbs::{BinarySerializer, bincode_serializer::BincodeSerializer, version::StaticVersion};
    use versions::version;

    use super::*;
    use crate::{
        Leaf,
        eth_signature_key::EthKeyPair,
        mock::MockStateCatchup,
        v0_3::{REWARD_MERKLE_TREE_V1_HEIGHT, RewardAccountV1, RewardAmount},
        v0_4::{REWARD_MERKLE_TREE_V2_HEIGHT, RewardAccountV2, RewardMerkleTreeV2},
    };

    #[derive(Debug, Default)]
    #[must_use]
    struct TestCase {
        // Parent header info.
        parent_timestamp: u64,
        parent_timestamp_millis: u64,
        parent_l1_head: u64,
        parent_l1_finalized: Option<L1BlockInfo>,

        // Environment at the time the new header is created.
        l1_head: u64,
        l1_finalized: Option<L1BlockInfo>,
        timestamp: u64,
        timestamp_millis: u64,
        l1_deposits: Vec<FeeInfo>,

        // Expected new header info.
        expected_timestamp: u64,
        expected_timestamp_millis: u64,
        expected_l1_head: u64,
        expected_l1_finalized: Option<L1BlockInfo>,
    }

    impl TestCase {
        async fn run(self) {
            // Check test case validity.
            assert!(self.expected_timestamp >= self.parent_timestamp);
            assert!(self.expected_timestamp_millis >= self.parent_timestamp_millis);
            assert!(self.expected_l1_head >= self.parent_l1_head);
            assert!(self.expected_l1_finalized >= self.parent_l1_finalized);

            let genesis = GenesisForTest::default().await;
            let mut parent = genesis.header.clone();
            parent.set_timestamp(self.parent_timestamp, self.parent_timestamp_millis);
            *parent.l1_head_mut() = self.parent_l1_head;
            *parent.l1_finalized_mut() = self.parent_l1_finalized;

            let mut parent_leaf = genesis.leaf.clone();
            *parent_leaf.block_header_mut() = parent.clone();

            let block_merkle_tree =
                BlockMerkleTree::from_elems(Some(32), Vec::<Commitment<Header>>::new()).unwrap();

            let fee_info = FeeInfo::genesis();
            let fee_merkle_tree = FeeMerkleTree::from_kv_set(
                20,
                Vec::from([(fee_info.account(), fee_info.amount())]),
            )
            .unwrap();

            let reward_account_v1 = RewardAccountV1::default();
            let reward_account = RewardAccountV2::default();
            let reward_amount = RewardAmount::default();
            let reward_merkle_tree_v2 =
                RewardMerkleTreeV2::from_kv_set(20, Vec::from([(reward_account, reward_amount)]))
                    .unwrap();

            let reward_merkle_tree_v1 = RewardMerkleTreeV1::from_kv_set(
                20,
                Vec::from([(reward_account_v1, reward_amount)]),
            )
            .unwrap();

            let mut validated_state = ValidatedState {
                block_merkle_tree: block_merkle_tree.clone(),
                fee_merkle_tree,
                reward_merkle_tree_v2,
                reward_merkle_tree_v1,
                chain_config: genesis.instance_state.chain_config.into(),
            };

            let (fee_account, fee_key) = FeeAccount::generated_from_seed_indexed([0; 32], 0);
            let fee_amount = 0;
            let fee_signature =
                FeeAccount::sign_fee(&fee_key, fee_amount, &genesis.ns_table).unwrap();

            let header = Header::from_info(
                genesis.header.payload_commitment(),
                genesis.header.builder_commitment().clone(),
                genesis.ns_table,
                &parent_leaf,
                L1Snapshot {
                    head: self.l1_head,
                    finalized: self.l1_finalized,
                },
                &self.l1_deposits,
                vec![BuilderFee {
                    fee_account,
                    fee_amount,
                    fee_signature,
                }],
                self.timestamp,
                self.timestamp_millis,
                validated_state.clone(),
                genesis.instance_state.chain_config,
                version(0, 1),
                None, // total_reward_distributed
                None, // next_stake_table_hash
                None, // leader_counts
            )
            .unwrap();
            assert_eq!(header.height(), parent.height() + 1);
            assert_eq!(header.timestamp(), self.expected_timestamp);
            assert_eq!(header.timestamp_millis(), self.expected_timestamp_millis);
            assert_eq!(header.l1_head(), self.expected_l1_head);
            assert_eq!(header.l1_finalized(), self.expected_l1_finalized);

            // Check deposits were inserted before computing the fee merkle tree root.
            for fee_info in self.l1_deposits {
                validated_state.insert_fee_deposit(fee_info).unwrap();
            }
            assert_eq!(
                validated_state.fee_merkle_tree.commitment(),
                header.fee_merkle_tree_root(),
            );

            assert_eq!(
                block_merkle_tree,
                BlockMerkleTree::from_elems(Some(32), Vec::<Commitment<Header>>::new()).unwrap()
            );
        }
    }

    fn l1_block(number: u64) -> L1BlockInfo {
        L1BlockInfo {
            number,
            ..Default::default()
        }
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header() {
        // Simplest case: building on genesis, L1 info and timestamp unchanged.
        TestCase::default().run().await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_advance_timestamp() {
        TestCase {
            timestamp: 1,
            timestamp_millis: 1_000,
            expected_timestamp: 1,
            expected_timestamp_millis: 1_000,
            ..Default::default()
        }
        .run()
        .await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_advance_l1_block() {
        TestCase {
            parent_l1_head: 0,
            parent_l1_finalized: Some(l1_block(0)),

            l1_head: 1,
            l1_finalized: Some(l1_block(1)),

            expected_l1_head: 1,
            expected_l1_finalized: Some(l1_block(1)),

            ..Default::default()
        }
        .run()
        .await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_advance_l1_finalized_from_none() {
        TestCase {
            l1_finalized: Some(l1_block(1)),
            expected_l1_finalized: Some(l1_block(1)),
            ..Default::default()
        }
        .run()
        .await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_timestamp_behind_finalized_l1_block() {
        let l1_finalized = Some(L1BlockInfo {
            number: 1,
            timestamp: U256::from(1),
            ..Default::default()
        });
        TestCase {
            l1_head: 1,
            l1_finalized,
            timestamp: 0,
            timestamp_millis: 0,

            expected_l1_head: 1,
            expected_l1_finalized: l1_finalized,
            expected_timestamp: 1,
            expected_timestamp_millis: 1_000,

            ..Default::default()
        }
        .run()
        .await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_timestamp_behind() {
        TestCase {
            parent_timestamp: 1,
            parent_timestamp_millis: 1_000,
            timestamp: 0,
            timestamp_millis: 0,
            expected_timestamp: 1,
            expected_timestamp_millis: 1_000,

            ..Default::default()
        }
        .run()
        .await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_l1_head_behind() {
        TestCase {
            parent_l1_head: 1,
            l1_head: 0,
            expected_l1_head: 1,

            ..Default::default()
        }
        .run()
        .await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_l1_finalized_behind_some() {
        TestCase {
            parent_l1_finalized: Some(l1_block(1)),
            l1_finalized: Some(l1_block(0)),
            expected_l1_finalized: Some(l1_block(1)),

            ..Default::default()
        }
        .run()
        .await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_l1_finalized_behind_none() {
        TestCase {
            parent_l1_finalized: Some(l1_block(0)),
            l1_finalized: None,
            expected_l1_finalized: Some(l1_block(0)),

            ..Default::default()
        }
        .run()
        .await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_deposits_one() {
        TestCase {
            l1_deposits: vec![FeeInfo::new(Address::default(), 1)],
            ..Default::default()
        }
        .run()
        .await
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_new_header_deposits_many() {
        TestCase {
            l1_deposits: [
                (Address::default(), 1),
                (Address::default(), 2),
                (Address::random(), 3),
            ]
            .iter()
            .map(|(address, amount)| FeeInfo::new(*address, *amount))
            .collect(),
            ..Default::default()
        }
        .run()
        .await
    }

    struct GenesisForTest {
        pub instance_state: NodeState,
        pub validated_state: ValidatedState,
        pub leaf: Leaf2,
        pub header: Header,
        pub ns_table: NsTable,
    }

    impl GenesisForTest {
        async fn default() -> Self {
            let instance_state = NodeState::mock();
            let validated_state = ValidatedState::genesis(&instance_state).0;
            let leaf: Leaf2 = Leaf::genesis(&validated_state, &instance_state, MOCK_UPGRADE.base)
                .await
                .into();
            let header = leaf.block_header().clone();
            let ns_table = leaf.block_payload().unwrap().ns_table().clone();
            Self {
                instance_state,
                validated_state,
                leaf,
                header,
                ns_table,
            }
        }
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_proposal_validation_success() {
        let anvil = Anvil::new().block_time(1u64).spawn();
        let mut genesis_state = NodeState::mock()
            .with_l1(L1Client::new(vec![anvil.endpoint_url()]).expect("Failed to create L1 client"))
            .with_current_version(version(0, 1));

        let genesis = GenesisForTest::default().await;

        let mut parent_state = genesis.validated_state.clone();

        let mut block_merkle_tree = parent_state.block_merkle_tree.clone();
        let fee_merkle_tree = parent_state.fee_merkle_tree.clone();

        // Populate the tree with an initial `push`.
        block_merkle_tree.push(genesis.header.commit()).unwrap();
        let block_merkle_tree_root = block_merkle_tree.commitment();
        let fee_merkle_tree_root = fee_merkle_tree.commitment();
        parent_state.block_merkle_tree = block_merkle_tree.clone();
        parent_state.fee_merkle_tree = fee_merkle_tree.clone();

        let mut parent_header = genesis.header.clone();
        *parent_header.block_merkle_tree_root_mut() = block_merkle_tree_root;
        *parent_header.fee_merkle_tree_root_mut() = fee_merkle_tree_root;

        let mut parent_leaf = genesis.leaf.clone();
        *parent_leaf.block_header_mut() = parent_header.clone();

        // Forget the state to trigger lookups in Header::new
        let forgotten_state = parent_state.forget();
        genesis_state.state_catchup = Arc::new(MockStateCatchup::from_iter([(
            parent_leaf.view_number(),
            Arc::new(parent_state.clone()),
        )]));
        // Get a proposal from a parent

        // TODO this currently fails because after fetching the blocks frontier
        // the element (header commitment) does not match the one in the proof.
        let key_pair = EthKeyPair::for_test();
        let fee_amount = 0u64;
        let payload_commitment = parent_header.payload_commitment();
        let builder_commitment = parent_header.builder_commitment();
        let ns_table = genesis.ns_table;
        let fee_signature = FeeAccount::sign_fee(&key_pair, fee_amount, &ns_table).unwrap();
        let builder_fee = BuilderFee {
            fee_amount,
            fee_account: key_pair.fee_account(),
            fee_signature,
        };
        let proposal = Header::new(
            &forgotten_state,
            &genesis_state,
            &parent_leaf,
            payload_commitment,
            builder_commitment.clone(),
            ns_table,
            builder_fee,
            version(0, 1),
            *parent_leaf.view_number() + 1,
        )
        .await
        .unwrap();

        let mut proposal_state = parent_state.clone();
        for fee_info in genesis_state
            .l1_client
            .get_finalized_deposits(Address::default(), None, 0)
            .await
        {
            proposal_state.insert_fee_deposit(fee_info).unwrap();
        }

        let mut block_merkle_tree = proposal_state.block_merkle_tree.clone();
        block_merkle_tree.push(proposal.commit()).unwrap();

        let _proposal_state = proposal_state
            .apply_header(
                &genesis_state,
                &genesis_state.state_catchup,
                &parent_leaf,
                &proposal,
                version(0, 1),
                parent_leaf.view_number() + 1,
            )
            .await
            .unwrap()
            .0;

        // ValidatedTransition::new(
        //     proposal_state.clone(),
        //     &parent_leaf.block_header(),
        //     Proposal::new(&proposal, ADVZScheme::get_payload_byte_len(&vid_common)),
        // )
        // .validate()
        // .unwrap();

        // assert_eq!(
        //     proposal_state.block_merkle_tree.commitment(),
        //     proposal.block_merkle_tree_root()
        // );
    }

    #[test_log::test]
    fn verify_builder_signature() {
        // simulate a fixed size hash by padding our message
        let message = ";)";
        let mut commitment = [0u8; 32];
        commitment[..message.len()].copy_from_slice(message.as_bytes());

        let key = FeeAccount::generated_from_seed_indexed([0; 32], 0).1;
        let signature = FeeAccount::sign_builder_message(&key, &commitment).unwrap();
        assert!(
            key.fee_account()
                .validate_builder_signature(&signature, &commitment)
        );
    }

    #[test_log::test(tokio::test(flavor = "multi_thread"))]
    async fn test_versioned_header_serialization() {
        let genesis = GenesisForTest::default().await;
        let header = genesis.header.clone();
        let ns_table = genesis.ns_table;

        let (fee_account, _) = FeeAccount::generated_from_seed_indexed([0; 32], 0);

        let v1_header = Header::create(
            genesis.instance_state.chain_config,
            1,
            2,
            2_000_000_000,
            3,
            Default::default(),
            header.payload_commitment(),
            header.builder_commitment().clone(),
            ns_table.clone(),
            header.fee_merkle_tree_root(),
            header.block_merkle_tree_root(),
            header.reward_merkle_tree_root().left().unwrap_or_else(|| {
                RewardMerkleTreeV1::new(REWARD_MERKLE_TREE_V1_HEIGHT).commitment()
            }),
            header.reward_merkle_tree_root().right().unwrap_or_else(|| {
                RewardMerkleTreeV2::new(REWARD_MERKLE_TREE_V2_HEIGHT).commitment()
            }),
            vec![FeeInfo {
                amount: 0.into(),
                account: fee_account,
            }],
            Default::default(),
            None,
            version(0, 1),
            None,
            None, // leader_counts
        );

        let serialized = serde_json::to_string(&v1_header).unwrap();
        let deserialized: Header = serde_json::from_str(&serialized).unwrap();
        assert_eq!(v1_header, deserialized);

        let v2_header = Header::create(
            genesis.instance_state.chain_config,
            1,
            2,
            2_000_000_000,
            3,
            Default::default(),
            header.payload_commitment(),
            header.builder_commitment().clone(),
            ns_table.clone(),
            header.fee_merkle_tree_root(),
            header.block_merkle_tree_root(),
            header.reward_merkle_tree_root().left().unwrap_or_else(|| {
                RewardMerkleTreeV1::new(REWARD_MERKLE_TREE_V1_HEIGHT).commitment()
            }),
            header.reward_merkle_tree_root().right().unwrap_or_else(|| {
                RewardMerkleTreeV2::new(REWARD_MERKLE_TREE_V2_HEIGHT).commitment()
            }),
            vec![FeeInfo {
                amount: 0.into(),
                account: fee_account,
            }],
            Default::default(),
            None,
            version(0, 2),
            None,
            None, // leader_counts
        );

        let serialized = serde_json::to_string(&v2_header).unwrap();
        let deserialized: Header = serde_json::from_str(&serialized).unwrap();
        assert_eq!(v2_header, deserialized);

        let v3_header = Header::create(
            genesis.instance_state.chain_config,
            1,
            2,
            2_000_000_000,
            3,
            Default::default(),
            header.payload_commitment(),
            header.builder_commitment().clone(),
            ns_table.clone(),
            header.fee_merkle_tree_root(),
            header.block_merkle_tree_root(),
            header.reward_merkle_tree_root().left().unwrap_or_else(|| {
                RewardMerkleTreeV1::new(REWARD_MERKLE_TREE_V1_HEIGHT).commitment()
            }),
            header.reward_merkle_tree_root().right().unwrap_or_else(|| {
                RewardMerkleTreeV2::new(REWARD_MERKLE_TREE_V2_HEIGHT).commitment()
            }),
            vec![FeeInfo {
                amount: 0.into(),
                account: fee_account,
            }],
            Default::default(),
            None,
            version(0, 3),
            None,
            None, // leader_counts
        );

        let serialized = serde_json::to_string(&v3_header).unwrap();
        let deserialized: Header = serde_json::from_str(&serialized).unwrap();
        assert_eq!(v3_header, deserialized);

        let v1_bytes = BincodeSerializer::<StaticVersion<0, 1>>::serialize(&v1_header).unwrap();
        let deserialized: Header =
            BincodeSerializer::<StaticVersion<0, 1>>::deserialize(&v1_bytes).unwrap();
        assert_eq!(v1_header, deserialized);

        let v2_bytes = BincodeSerializer::<StaticVersion<0, 2>>::serialize(&v2_header).unwrap();
        let deserialized: Header =
            BincodeSerializer::<StaticVersion<0, 2>>::deserialize(&v2_bytes).unwrap();
        assert_eq!(v2_header, deserialized);

        let v3_bytes = BincodeSerializer::<StaticVersion<0, 3>>::serialize(&v3_header).unwrap();
        let deserialized: Header =
            BincodeSerializer::<StaticVersion<0, 3>>::deserialize(&v3_bytes).unwrap();
        assert_eq!(v3_header, deserialized);
    }
}