perpl_sdk/state/

exchange.rs

use std::iter;

use fastnum::{D64, D256, UD64, UD128};
use itertools::chain;

use super::*;
use crate::{
    Chain,
    abi::dex::Exchange::ExchangeEvents,
    stream,
    types::{EventContext, OrderType},
};

pub type StateBlockEvents = types::BlockEvents<types::EventContext<Vec<StateEvents>>>;

/// Raw maker fill data, common to the V1 and V2 `MakerOrderFilled*` events.
struct RawMakerFill {
    perp_id: U256,
    account_id: U256,
    order_id: U256,
    price_pns: U256,
    lot_lns: U256,
    fee_cns: U256,
    builder_fee_cns: U256,
    locked_balance_cns: U256,
    balance_cns: U256,
}

/// Raw listing data, common to the V1 and V2 `ContractAdded*` events. The
/// versions differ in how the new contract's fees are reported: V1 carried the
/// resolved base rates, V2 carries the fee schedule key they resolve from.
struct RawContractAdded {
    perp_id: U256,
    status: u8,
    price_decimals: U256,
    lot_decimals: U256,
    base_price_pns: U256,
    init_margin_frac_hdths: U256,
    maint_margin_frac_hdths: U256,
}

/// Raw taker fill data, common to the V1 and V2 `TakerOrderFilled*` events.
struct RawTakerFill {
    collat_price_pns: U256,
    lot_lns: U256,
    fee_cns: U256,
    builder_fee_cns: U256,
    balance_cns: U256,
}

/// Exchange state snapshot.
///
/// [`super::SnapshotBuilder`] can be used to create the snapshot at
/// specified/latest block, which can then be kept up to date by
/// calling [`Self::apply_events`] with events from [`crate::stream::raw`].
#[derive(Clone, derive_more::Debug)]
pub struct Exchange {
    chain: Chain,
    instant: types::StateInstant,
    features: ContractFeatures,
    collateral_converter: num::Converter,
    funding_interval_blocks: u32,
    #[debug("{min_post}")]
    min_post: UD128,
    #[debug("{min_settle}")]
    min_settle: UD128,
    #[debug("{recycle_fee}")]
    recycle_fee: UD128,
    fee_schedules: FeeScheduleRegistry,
    perpetuals: HashMap<types::PerpetualId, Perpetual>,
    accounts: HashMap<types::AccountId, Account>,
    is_halted: bool,
    track_all_accounts: bool,
}

impl Exchange {
    #[allow(clippy::too_many_arguments)]
    pub(crate) fn new(
        chain: Chain,
        instant: types::StateInstant,
        features: ContractFeatures,
        collateral_converter: num::Converter,
        funding_interval_blocks: u32,
        min_post: UD128,
        min_settle: UD128,
        recycle_fee: UD128,
        fee_schedules: FeeScheduleRegistry,
        perpetuals: HashMap<types::PerpetualId, Perpetual>,
        accounts: HashMap<types::AccountId, Account>,
        is_halted: bool,
        track_all_accounts: bool,
    ) -> Self {
        Self {
            chain,
            instant,
            features,
            collateral_converter,
            funding_interval_blocks,
            min_post,
            min_settle,
            recycle_fee,
            fee_schedules,
            perpetuals,
            accounts,
            is_halted,
            track_all_accounts,
        }
    }

    /// Revision of the exchange smart contract the SDK targeted at.
    pub const fn revision() -> &'static str { crate::abi::DEX_REVISION }

    /// Chain the snapshot collected from.
    pub fn chain(&self) -> &Chain { &self.chain }

    /// Instant the snapshot is consistent with or was last updated at.
    pub fn instant(&self) -> types::StateInstant { self.instant }

    /// Feature set of the *deployed* contract, which can lag behind the
    /// revision the SDK targets ([`Self::revision`]). Detected while
    /// building the snapshot and kept up to date by `ContractVersionSet`.
    pub fn features(&self) -> ContractFeatures { self.features }

    /// Version reported by the deployed contract, `None` before v1.1.7.4 which
    /// has no version getter.
    pub fn contract_version(&self) -> Option<ContractVersion> { self.features.version() }

    /// Every fee schedule known to the exchange, which perpetual contracts
    /// resolve their fees from by pointing at one (see
    /// [`Perpetual::fee_schedule`]).
    pub fn fee_schedules(&self) -> &FeeScheduleRegistry { &self.fee_schedules }

    /// Exchange-wide default fee schedule, shared by every perpetual contract
    /// that has not been repointed at another one.
    pub fn default_fee_schedule(&self) -> FeeSchedule { self.fee_schedules.default_schedule() }

    /// Exchange-wide default fee schedule for real-world assets.
    pub fn rwa_fee_schedule(&self) -> FeeSchedule { self.fee_schedules.rwa_default_schedule() }

    /// Fee schedule registered under the given key, `None` for a custom
    /// schedule that has never been observed - one keyed by a perpetual the
    /// snapshot does not track, and not written since.
    pub fn fee_schedule(&self, key: FeeScheduleKey) -> Option<FeeSchedule> {
        self.fee_schedules.get(key)
    }

    /// Converter of fixed-point <-> decimal numbers for collateral token
    /// amounts.
    pub fn collateral_converter(&self) -> num::Converter { self.collateral_converter }

    /// Funding interval in blocks.
    ///
    /// Each perpetual contract has own [Perpetual::funding_start_block]  this
    /// interval applied to.
    pub fn funding_interval_blocks(&self) -> u32 { self.funding_interval_blocks }

    /// Minimal amount in collateral token that can be posted to the book.
    pub fn min_post(&self) -> UD128 { self.min_post }

    /// Minimal amount in collateral token that can be settled.
    pub fn min_settle(&self) -> UD128 { self.min_settle }

    /// Amount in collateral token locked with each posted order to
    /// pay the account that cleans it up:
    /// * When cancelled/changed by the original poster -> the original poster
    /// * When filled -> the original poster
    /// * In all other cases -> the one that performed the recycling
    pub fn recycle_fee(&self) -> UD128 { self.recycle_fee }

    /// Perpetual contracts state tracked within the exchange, according to
    /// initial snapshot building configuration.
    pub fn perpetuals(&self) -> &HashMap<types::PerpetualId, Perpetual> { &self.perpetuals }

    /// Accounts state tracked within the exchange, according to initial
    /// snapshot building configuration.
    pub fn accounts(&self) -> &HashMap<types::AccountId, Account> { &self.accounts }

    /// Indicates if exchange is being halted.
    pub fn is_halted(&self) -> bool { self.is_halted }

    /// Updates state snapshot by applying raw exchange events from the
    /// specific block.
    ///
    /// Blocks expected to arrive strictly in-order, with already applied blocks
    /// being ignored, to enforce state consistency as most raw events
    /// provide only incremental state update information rather than full
    /// piece of state snapshot.
    ///
    /// Exchange emits two categories of events:
    /// * State mutation events
    /// * Order request error responses, for requests issued in batches via
    ///   [`crate::abi::dex::Exchange::ExchangeInstance::execOrders`] with
    ///   `revertOnFail` = false.
    ///
    /// This method applies state mutation events only to tracked perpetual
    /// contracts and accounts provided to [`SnapshotBuilder`] during the
    /// initial snapshot creation, and returns order request failure events
    /// only for requests issues by tracked accounts. Successfull order book
    /// mutations are applied to all orders of tracked perpetual contracts,
    /// so client code can keep up to date order book representation externally
    /// if needed.
    ///
    /// # Returns
    ///
    /// On success, list of state mutation and failure [`StateEvents`] produced
    /// from the original raw events, filtered as described above and with
    /// numeric systems conversion applied.
    ///
    /// [`StateEvents`] are roughly resemble
    /// [`crate::abi::dex::Exchange::ExchangeEvents`] so corresponding smart
    /// contract documentation and raw event data for error responses could be
    /// helpful with debugging, but there is no exact match and more than
    /// one state event can be emitted in response to a single raw event, eg.
    /// processing of single order event produces up to two account events on
    /// top of order events within the same event context.
    ///
    /// On failure, the corresponding [`DexError`], any of which indicates some
    /// inconsistency in event sequence or event handling logic and should
    /// not be ignored as it may lead to state inconsistency.
    pub fn apply_events(
        &mut self,
        events: &stream::RawBlockEvents,
    ) -> Result<Option<StateBlockEvents>, DexError> {
        let next_instant = events.instant();
        if self.instant >= next_instant {
            // Block already applied
            return Ok(None);
        }
        if self.instant.block_number() + 1 < next_instant.block_number() {
            // Block arrived out of order
            return Err(DexError::BlockOutOfOrder(
                self.instant.block_number() + 1,
                next_instant.block_number(),
            ));
        }

        // apply_events runs three passes over the block:
        // Pass 1 — funding: settle the block's scheduled funding on each
        // position's pre-event size (before any decreases).
        // Pass 2 — raw events: apply the block's on-chain events
        // in order (orders, position changes, perpetual-parameter updates);
        // a perpetual-parameter change updates the perpetual here and is set
        // aside for Pass 3.
        // Pass 3 — fan-out: fan the perpetual-parameter changes set aside in
        // Pass 2 (e.g. a maintenance-margin-fraction change) out to
        // every tracked position.
        let mut order_context: Option<OrderContext> = None;
        let mut prev_tx_index: Option<u64> = None;
        let mut state_events = vec![];
        let mut perp_events = vec![];

        // Pass 1 — funding: the contract settles a funding-event block at the new
        // funding sum regardless of same-block decreases, so funding must land
        // on each position's PRE-event size, before the block's size-changing
        // events. This is the only place funding is applied.
        let funding_due: Vec<(types::PerpetualId, D64, D256)> = self
            .perpetuals
            .values_mut()
            .filter_map(|perp| {
                perp.take_funding_payment(next_instant)
                    .map(|(rate, payment)| (perp.id(), rate, payment))
            })
            .collect();
        for (perp_id, rate, payment) in funding_due {
            let mut funding_events = vec![];
            if let Some(perp) = self.perpetuals.get(&perp_id) {
                funding_events.push(StateEvents::perpetual(
                    perp,
                    PerpetualEventType::FundingEvent { rate, payment_per_unit: payment },
                ));
            }
            for acc in self.accounts.values_mut() {
                if let Some(pos) = acc.positions_mut().get_mut(&perp_id)
                    && pos.apply_funding_payment(next_instant, payment)
                {
                    funding_events.push(StateEvents::position(
                        pos,
                        &None,
                        PositionEventType::UnrealizedPnLUpdated {
                            pnl: pos.pnl(),
                            delta_pnl: pos.delta_pnl(),
                            premium_pnl: pos.premium_pnl(),
                        },
                    ));
                }
            }
            if !funding_events.is_empty() {
                state_events.push(EventContext::empty(funding_events));
            }
        }

        // Pass 2 — raw events: apply the block's on-chain events in order, keeping
        // incremental order context across events within a transaction.
        for event in events.events() {
            if prev_tx_index.is_some_and(|idx| idx < event.tx_index()) {
                // Reset order context at the transaction boundary
                order_context.take();
            }
            let result = self.apply_raw_event(next_instant, event, &mut order_context)?;
            if !result.is_empty() {
                // Set aside perpetual-parameter events for the Pass 3 fan-out below.
                let block_perp_events = result
                    .iter()
                    .filter(|e| e.as_perpetual_event().is_some())
                    .cloned()
                    .collect::<Vec<_>>();
                if !block_perp_events.is_empty() {
                    perp_events.push(block_perp_events);
                }
                state_events.push(event.pass(result));
            }
            prev_tx_index = Some(event.tx_index());
        }

        // Commit the instant: advance each perpetual's state instant and expire stale
        // orders.
        self.instant = events.instant();
        for perp in self.perpetuals.values_mut() {
            perp.update_state_instant(self.instant);
        }

        // Pass 3 — fan-out: apply the perpetual-parameter changes set aside in Pass 2
        // (e.g. a maintenance-margin-fraction change) to every tracked
        // position.
        for event in perp_events.iter().flatten() {
            let result = self.apply_state_event(self.instant, event)?;
            if !result.is_empty() {
                state_events.push(EventContext::empty(result));
            }
        }

        Ok(Some(StateBlockEvents::new(self.instant, state_events)))
    }

    pub(crate) fn apply_raw_event(
        &mut self,
        instant: types::StateInstant,
        event: &stream::RawEvent,
        ctx: &mut Option<OrderContext>,
    ) -> Result<Vec<StateEvents>, DexError> {
        let cc = self.collateral_converter;

        let must_ctx = || {
            ctx.as_ref()
                .ok_or(DexError::OrderContextExpected(event.tx_index(), event.log_index()))
        };

        Ok(match event.event() {
            ExchangeEvents::AccountCreated(e) => {
                if self.track_all_accounts {
                    self.accounts
                        .insert(e.id.to(), Account::created(instant, e.id.to(), e.account));
                    vec![StateEvents::Account(AccountEvent {
                        account_id: e.id.to(),
                        request_id: None,
                        r#type: AccountEventType::Created(e.id.to()),
                    })]
                } else {
                    vec![]
                }
            },
            ExchangeEvents::AccountFeeTierSet(e) => self
                .account(e.accountId)
                .map(|acc| {
                    let tier = e.tier.to();
                    acc.update_fee_tier(instant, tier);
                    StateEvents::account(acc, ctx, AccountEventType::FeeTierUpdated(tier))
                })
                .into_iter()
                .collect(),
            ExchangeEvents::AccountFreeze(e) => self
                .account(e.accountId)
                .map(|acc| {
                    acc.update_frozen(instant, e.status > 0);
                    StateEvents::account(acc, ctx, AccountEventType::Frozen(acc.frozen()))
                })
                .into_iter()
                .collect(),
            ExchangeEvents::AccountFrozen(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::AccountFrozen))
                .into_iter()
                .collect(),
            ExchangeEvents::AccountLiquidationCredit(e) => self
                .account(e.accountId)
                .map(|acc| {
                    acc.update_balance(instant, cc.from_unsigned(e.endBalanceCNS));
                    StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
                })
                .into_iter()
                .collect(),
            ExchangeEvents::AdminChanged(_) => vec![],
            ExchangeEvents::AdministratorUpdated(_) => vec![],
            ExchangeEvents::AmountExceedsAvailableBalance(e) => self
                .err_ctx(ctx, event)?
                .map(|ctx| {
                    StateEvents::order_error(
                        ctx,
                        OrderErrorType::AmountExceedsAvailableBalance(
                            cc.from_unsigned(e.amountCNS),
                            cc.from_unsigned(e.availableBalanceCNS),
                        ),
                    )
                })
                .into_iter()
                .collect(),
            ExchangeEvents::BankruptcyPricePreventsDeleverage(_) => vec![],
            ExchangeEvents::BeaconUpgraded(_) => vec![],
            ExchangeEvents::BlockStatusChanged(_) => vec![],
            ExchangeEvents::BorrowMarginNotMetAfterDecCollateral(_) => vec![],
            ExchangeEvents::BuyToLiquidateSettled(_) => vec![],
            ExchangeEvents::BuyToLiquidateSlippageExceeded(_) => vec![],
            ExchangeEvents::BuyToLiquidateStarted(_) => vec![],
            ExchangeEvents::BuyToLiquidateBuyerRestricted(_) => vec![],
            ExchangeEvents::BuyToLiquidateParamsUpdated(_) => vec![],
            ExchangeEvents::BuyToLiquidateThresholdUpdated(_) => vec![],
            ExchangeEvents::BuyToLiquidateRestrictionUpdated(_) => vec![],
            ExchangeEvents::CancelExistingInvalidCloseOrders(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| {
                    StateEvents::order_error(ctx, OrderErrorType::CancelExistingInvalidCloseOrders)
                })
                .into_iter()
                .collect(),
            ExchangeEvents::CannotAdjustEntryPriceToDecCollateral(_) => vec![],
            ExchangeEvents::CantBuyToLiquidate(_) => vec![],
            ExchangeEvents::CantChangeCloseOrder(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::CantChangeCloseOrder))
                .into_iter()
                .collect(),
            ExchangeEvents::CantDeleverageAgainstOpposingPositions(_) => vec![],
            ExchangeEvents::CantLiquidatePosAboveMMR(_) => vec![],
            ExchangeEvents::ChangeExpiredOrderNeedsNewExpiry(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| {
                    StateEvents::order_error(ctx, OrderErrorType::ChangeExpiredOrderNeedsNewExpiry)
                })
                .into_iter()
                .collect(),
            ExchangeEvents::ClearingExpiredOrder(e) => chain!(
                if let Some(perp) = self.perpetual(e.perpId) {
                    let order_id = std::num::NonZeroU16::new(e.orderId.to::<u16>())
                        .expect("orderId in event cannot be 0");
                    let order = perp.remove_order(order_id)?;
                    Some(StateEvents::order(perp, &order, ctx, OrderEventType::Removed))
                } else {
                    None
                },
                self.account(e.accountId).map(|acc| {
                    acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                    StateEvents::account(
                        acc,
                        ctx,
                        AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                    )
                }),
                if !e.recyclerAmountCNS.is_zero() {
                    self.account(e.recyclerAccountId).map(|acc| {
                        acc.update_balance(instant, cc.from_unsigned(e.recyclerBalanceCNS));
                        StateEvents::account(
                            acc,
                            ctx,
                            AccountEventType::BalanceUpdated(acc.balance()),
                        )
                    })
                } else {
                    None
                },
            )
            .collect(),
            ExchangeEvents::ClearingFrozenAccountOrder(e) => chain!(
                if let Some(perp) = self.perpetual(e.perpId) {
                    let order_id = std::num::NonZeroU16::new(e.orderId.to::<u16>())
                        .expect("orderId in event cannot be 0");
                    let order = perp.remove_order(order_id)?;
                    Some(StateEvents::order(perp, &order, ctx, OrderEventType::Removed))
                } else {
                    None
                },
                self.account(e.accountId).map(|acc| {
                    acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                    StateEvents::account(
                        acc,
                        ctx,
                        AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                    )
                }),
                if !e.recyclerAmountCNS.is_zero() {
                    self.account(e.recyclerAccountId).map(|acc| {
                        acc.update_balance(instant, cc.from_unsigned(e.recyclerBalanceCNS));
                        StateEvents::account(
                            acc,
                            ctx,
                            AccountEventType::BalanceUpdated(acc.balance()),
                        )
                    })
                } else {
                    None
                },
            )
            .collect(),
            ExchangeEvents::ClearingInvalidCloseOrder(e) => chain!(
                if let Some(perp) = self.perpetual(e.perpId) {
                    let order_id = std::num::NonZeroU16::new(e.orderId.to::<u16>())
                        .expect("orderId in event cannot be 0");
                    let order = perp.remove_order(order_id)?;
                    Some(StateEvents::order(perp, &order, ctx, OrderEventType::Removed))
                } else {
                    None
                },
                self.account(e.accountId).map(|acc| {
                    acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                    StateEvents::account(
                        acc,
                        ctx,
                        AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                    )
                }),
                if !e.recyclerAmountCNS.is_zero() {
                    self.account(e.recyclerAccountId).map(|acc| {
                        acc.update_balance(instant, cc.from_unsigned(e.recyclerBalanceCNS));
                        StateEvents::account(
                            acc,
                            ctx,
                            AccountEventType::BalanceUpdated(acc.balance()),
                        )
                    })
                } else {
                    None
                },
            )
            .collect(),
            ExchangeEvents::ClearingRemainingOrderLockBeyondBalance(e) => {
                if let Some(ctx) = ctx {
                    ctx.clearing_remaining_order = true;
                }
                chain!(if !e.recyclerAmountCNS.is_zero() {
                    self.account(e.recyclerAccountId).map(|acc| {
                        acc.update_balance(instant, cc.from_unsigned(e.recyclerBalanceCNS));
                        StateEvents::account(
                            acc,
                            ctx,
                            AccountEventType::BalanceUpdated(acc.balance()),
                        )
                    })
                } else {
                    None
                },)
                .collect()
            },
            ExchangeEvents::ClearingSelfMatchingOrder(e) => chain!(
                if let Some(perp) = self.perpetual(e.perpId) {
                    let order_id = std::num::NonZeroU16::new(e.orderId.to::<u16>())
                        .expect("orderId in event cannot be 0");
                    let order = perp.remove_order(order_id)?;
                    Some(StateEvents::order(perp, &order, ctx, OrderEventType::Removed))
                } else {
                    None
                },
                self.account(e.accountId).map(|acc| {
                    acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                    StateEvents::account(
                        acc,
                        ctx,
                        AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                    )
                }),
                if !e.recyclerAmountCNS.is_zero() {
                    self.account(e.recyclerAccountId).map(|acc| {
                        acc.update_balance(instant, cc.from_unsigned(e.recyclerBalanceCNS));
                        StateEvents::account(
                            acc,
                            ctx,
                            AccountEventType::BalanceUpdated(acc.balance()),
                        )
                    })
                } else {
                    None
                },
            )
            .collect(),
            ExchangeEvents::CloseOrderExceedsPosition(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::CloseOrderExceedsPosition))
                .into_iter()
                .collect(),
            ExchangeEvents::CloseOrderPositionMismatch(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| {
                    StateEvents::order_error(ctx, OrderErrorType::CloseOrderPositionMismatch)
                })
                .into_iter()
                .collect(),
            ExchangeEvents::CollateralDecreaseDeclined(_) => vec![],
            ExchangeEvents::CollateralDecreaseRequestCancelled(_) => vec![],
            ExchangeEvents::CollateralDecreaseRequested(_) => vec![],
            ExchangeEvents::CollateralDecreaseRequestExpired(_) => vec![],
            ExchangeEvents::CollateralDeposit(e) => self
                .account(e.accountId)
                .map(|acc| {
                    acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                    StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
                })
                .into_iter()
                .collect(),
            ExchangeEvents::CollateralWithdrawal(e) => self
                .account(e.accountId)
                .map(|acc| {
                    acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                    StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
                })
                .into_iter()
                .collect(),
            // Superseded by `ContractAddedV2` in v1.1.7.4, replayed from earlier
            // history only, where the listing carried resolved base fees rather
            // than a fee schedule key
            ExchangeEvents::ContractAdded(e) => {
                // Per100K unconditionally: this event was retired in v1.1.7.4, so it
                // can only be replayed from history that predates the redenomination.
                let fee_converter = num::fee_converter();
                vec![self.add_perpetual(
                    instant,
                    &e.name,
                    &e.symbol,
                    RawContractAdded {
                        perp_id: e.perpId,
                        status: e.status,
                        price_decimals: e.priceDecimals,
                        lot_decimals: e.lotDecimals,
                        base_price_pns: e.basePricePNS,
                        init_margin_frac_hdths: e.initMarginFracHdths,
                        maint_margin_frac_hdths: e.maintMarginFracHdths,
                    },
                    FeeSchedule::flat(
                        FeeScheduleKey::Default,
                        fee_converter.from_unsigned(e.takerFeePer100K),
                        fee_converter.from_unsigned(e.makerFeePer100K),
                    ),
                )]
            },
            ExchangeEvents::ContractAddedV2(e) => {
                // The listing reports the contract's fee schedule KEY, the rates
                // being resolvable from it - a new contract is placed on the
                // exchange-wide default schedule, and no `PerpFeeSchedIdSet`
                // accompanies the listing to report the id separately.
                let key = FeeScheduleKey::from_raw(e.perpFeeSchedId);
                let fee_schedule = self.fee_schedule(key).ok_or(
                    // A custom schedule of a contract that does not exist yet has
                    // no rates to resolve; the contract documents that a listing
                    // is always placed on a shared schedule, so this is
                    // unreachable in practice
                    DexError::FeeScheduleNotFound(key),
                )?;
                vec![self.add_perpetual(
                    instant,
                    &e.name,
                    &e.symbol,
                    RawContractAdded {
                        perp_id: e.perpId,
                        status: e.status,
                        price_decimals: e.priceDecimals,
                        lot_decimals: e.lotDecimals,
                        base_price_pns: e.basePricePNS,
                        init_margin_frac_hdths: e.initMarginFracHdths,
                        maint_margin_frac_hdths: e.maintMarginFracHdths,
                    },
                    fee_schedule,
                )]
            },
            ExchangeEvents::ContractNotOperational(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::ContractNotOperational))
                .into_iter()
                .collect(),
            ExchangeEvents::ContractLinkFeedUpdated(e) => self
                .perpetual(e.perpId)
                .map(|perp| {
                    perp.update_oracle_feed_id(instant, e.feedId);
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::OracleConfigurationUpdated {
                            is_used: perp.is_oracle_used(),
                            feed_id: perp.oracle_feed_id(),
                        },
                    )
                })
                .into_iter()
                .collect(),
            ExchangeEvents::ContractPaused(e) => {
                // Bound before the `&mut self` borrow below; a first unpause
                // anchors the contract's funding schedule to this grid.
                let funding_interval = self.funding_interval_blocks as u64;
                self.perpetual(e.perpId)
                    .map(|perp| {
                        perp.update_paused(instant, e.paused, funding_interval);
                        StateEvents::perpetual(perp, PerpetualEventType::Paused(perp.is_paused()))
                    })
                    .into_iter()
                    .collect()
            },
            ExchangeEvents::ContractRemoved(e) => {
                let funding_interval = self.funding_interval_blocks as u64;
                self.perpetual(e.perpId)
                    .map(|perp| {
                        perp.update_paused(instant, true, funding_interval);
                        StateEvents::perpetual(perp, PerpetualEventType::Paused(perp.is_paused()))
                    })
                    .into_iter()
                    .collect()
            },
            ExchangeEvents::ContractVersionSet(e) => {
                let version = ContractVersion::new(e.major.to(), e.minor.to(), e.patch.to());
                self.features.observe_version(version);
                vec![StateEvents::Exchange(ExchangeEvent::ContractVersionUpdated(version))]
            },
            ExchangeEvents::CrossesBook(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::CrossesBook))
                .into_iter()
                .collect(),
            ExchangeEvents::DcpBorrowThreshUpdated(_) => vec![],
            ExchangeEvents::DecreaseCollateralBeyondMarkPrice(_) => vec![],
            // The unit these rates arrive in follows the deployed version, and the
            // contract publishes `ContractVersionSet` BEFORE any schedule event in the
            // upgrade transaction itself -- so reading `self.features` as the event is
            // handled already reflects the cutover.
            ExchangeEvents::DefaultPerpFeeScheduleSet(e) => self.update_fee_schedule(
                instant,
                FeeSchedule::new(
                    FeeScheduleKey::Default,
                    e.takerFeesPer100K,
                    e.makerFeesPer100K,
                    self.features.fee_rate_converter(),
                ),
            ),
            ExchangeEvents::DefaultRwaFeeScheduleSet(e) => self.update_fee_schedule(
                instant,
                FeeSchedule::new(
                    FeeScheduleKey::RwaDefault,
                    e.takerFeesPer100K,
                    e.makerFeesPer100K,
                    self.features.fee_rate_converter(),
                ),
            ),
            ExchangeEvents::DeleveragePositionListEmpty(_) => vec![],
            ExchangeEvents::ExceedsLastExecutionBlock(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::ExceedsLastExecutionBlock))
                .into_iter()
                .collect(),
            ExchangeEvents::ExchangeHalted(e) => {
                self.is_halted = e.halted;
                vec![StateEvents::Exchange(ExchangeEvent::Halted(self.is_halted))]
            },
            ExchangeEvents::ExchangeInitialized(_) => vec![],
            ExchangeEvents::FeeParamsUpdated(_) => vec![],
            ExchangeEvents::FeeScheduleSet(e) => {
                // `setFeeSchedValues(id, …)` rewrites the rates of the schedule
                // registered under `id`, whichever contracts happen to point at
                // it. It does NOT repoint anything: a custom id names a schedule
                // *keyed by* a perpetual's id, not that perpetual's current
                // schedule - only `PerpFeeSchedIdSet` moves a contract onto it.
                self.update_fee_schedule(
                    instant,
                    FeeSchedule::new(
                        FeeScheduleKey::from_raw(e.feeSchedId),
                        e.takerFeesPer100K,
                        e.makerFeesPer100K,
                        self.features.fee_rate_converter(),
                    ),
                )
            },
            // Witnesses of the v1.1.7.5 fee-unit redenomination, carried for
            // completeness rather than state: `initializeV4` emits the id-appropriate
            // `*FeeScheduleSet` alongside every `FeeScheduleMigrated`, and those arms
            // are what move the registry -- already in the new unit, because
            // `ContractVersionSet` came first in the same transaction.
            ExchangeEvents::FeeScheduleMigrated(_) => vec![],
            ExchangeEvents::FeeUnitRedenominated(_) => vec![],
            ExchangeEvents::FundingClampPctUpdated(_) => vec![],
            ExchangeEvents::FundingEventCompleted(e) => {
                if let Some(perp) = self.perpetual(e.perpId) {
                    perp.update_funding(
                        instant,
                        perp.funding_rate_converter()
                            .from_signed(e.actualRatePct100k),
                        perp.funding_sum_converter()
                            .from_i64(e.fundingPaymentPNS.as_i64()),
                        e.fundingEventBlock.to(),
                    );
                }
                vec![]
            },
            ExchangeEvents::FundingEventSetTooEarly(_) => vec![],
            ExchangeEvents::FundingPriceExceedsTol(_) => vec![],
            ExchangeEvents::FundingSumAlreadySet(_) => vec![],
            ExchangeEvents::FundingSumScalingExpUpdated(e) => self
                .perpetual(e.perpId)
                .map(|perp| {
                    perp.update_funding_sum_scaling_exp(instant, e.newExp.to());
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::FundingSumScalingExpUpdated(e.newExp.to()),
                    )
                })
                .into_iter()
                .collect(),
            ExchangeEvents::IgnoreOracleUpdated(e) => self
                .perpetual(e.perpId)
                .map(|perp| {
                    perp.update_is_oracle_used(instant, !e.ignOracle);
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::OracleConfigurationUpdated {
                            is_used: perp.is_oracle_used(),
                            feed_id: perp.oracle_feed_id(),
                        },
                    )
                })
                .into_iter()
                .collect(),
            ExchangeEvents::ImmediateOrCancelExecuted(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::ImmediateOrCancelExecuted))
                .into_iter()
                .collect(),
            ExchangeEvents::IncreasePositionCollateral(e) => chain!(
                self.position(e.accountId, e.perpId)?.map(|(pos, _)| {
                    pos.update_deposit(instant, cc.from_unsigned(e.positionDepositCNS));
                    StateEvents::position(
                        pos,
                        ctx,
                        PositionEventType::DepositUpdated(pos.deposit()),
                    )
                }),
                self.account(e.accountId).map(|acc| {
                    acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                    StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
                }),
            )
            .collect(),
            ExchangeEvents::Initialized(_) => vec![],
            ExchangeEvents::InitialMarginFractionUpdated(e) => self
                .perpetual(e.perpId)
                .map(|perp| {
                    perp.update_initial_margin(
                        instant,
                        perp.leverage_converter()
                            .from_unsigned(e.initMarginFracHdths),
                    );
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::InitialMarginFractionUpdated(perp.initial_margin()),
                    )
                })
                .into_iter()
                .collect(),
            ExchangeEvents::InsolventPositionCannotBeForcedClose(_) => vec![],
            ExchangeEvents::InsuficientFundsForRecycleFee(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| {
                    StateEvents::order_error(ctx, OrderErrorType::InsuficientFundsForRecycleFee)
                })
                .into_iter()
                .collect(),
            ExchangeEvents::InsufficientFundsToDecCollateral(_) => vec![],
            ExchangeEvents::InsurancePaymentForSettlement(_) => vec![],
            ExchangeEvents::InvalidAccountFrozenOrder(_) => vec![],
            ExchangeEvents::InvalidBankruptcyPrice(_) => vec![],
            ExchangeEvents::InvalidExpiryBlock(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::InvalidExpiryBlock))
                .into_iter()
                .collect(),
            ExchangeEvents::InvalidLinkReportForContract(_) => vec![],
            ExchangeEvents::InvalidLinkReportVersion(_) => vec![],
            ExchangeEvents::InvalidLiquidationPrice(_) => vec![],
            ExchangeEvents::InvalidOrderId(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::InvalidOrderId))
                .into_iter()
                .collect(),
            ExchangeEvents::LastForwardedDescIdReset(_) => vec![],
            ExchangeEvents::LastTriggeredDescIdReset(_) => vec![],
            ExchangeEvents::LinkDatastreamConfigured(_) => vec![],
            ExchangeEvents::LinkDsError_0(_) => vec![],
            ExchangeEvents::LinkDsError_1(_) => vec![],
            ExchangeEvents::LinkDsPanic(_) => vec![],
            ExchangeEvents::LinkPriceUpdated(e) => self
                .perpetual(e.perpId)
                .map(|perp| {
                    perp.update_oracle_price(
                        instant,
                        perp.price_converter().from_unsigned(e.oraclePricePNS),
                    );
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::OraclePriceUpdated(perp.oracle_price()),
                    )
                })
                .into_iter()
                .collect(),
            ExchangeEvents::LiquidationBuyerUpdated(_) => vec![],
            ExchangeEvents::LiquidationParamsUpdated(_) => vec![],
            ExchangeEvents::LotOutOfRange(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::SizeOutOfRange))
                .into_iter()
                .collect(),
            ExchangeEvents::MaintenanceMarginFractionUpdated(e) => self
                .perpetual(e.perpId)
                .map(|perp| {
                    perp.update_maintenance_margin(
                        instant,
                        perp.leverage_converter()
                            .from_unsigned(e.maintMarginFracHdths),
                    );
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::MaintenanceMarginFractionUpdated(
                            perp.maintenance_margin(),
                        ),
                    )
                })
                .into_iter()
                .collect(),
            // Deprecated in v1.1.7.4, replayed from earlier history only
            ExchangeEvents::MakerFeeUpdated(e) => self
                .perpetual(e.perpId)
                .map(|perp| {
                    perp.update_base_maker_fee(
                        instant,
                        perp.fee_converter().from_unsigned(e.makerFeePer100K),
                    );
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::MakerFeeUpdated(perp.maker_fee()),
                    )
                })
                .into_iter()
                .collect(),
            // Superseded by `MakerOrderFilledV2` in v1.1.7.4, replayed from
            // earlier history only, hence no builder fee
            ExchangeEvents::MakerOrderFilled(e) => self.apply_maker_order_filled(
                instant,
                event,
                ctx,
                RawMakerFill {
                    perp_id: e.perpId,
                    account_id: e.accountId,
                    order_id: e.orderId,
                    price_pns: e.pricePNS,
                    lot_lns: e.lotLNS,
                    fee_cns: e.feeCNS,
                    builder_fee_cns: U256::ZERO,
                    locked_balance_cns: e.lockedBalanceCNS,
                    balance_cns: e.balanceCNS,
                },
            )?,
            ExchangeEvents::MakerOrderFilledV2(e) => self.apply_maker_order_filled(
                instant,
                event,
                ctx,
                RawMakerFill {
                    perp_id: e.perpId,
                    account_id: e.accountId,
                    order_id: e.orderId,
                    price_pns: e.pricePNS,
                    lot_lns: e.lotLNS,
                    fee_cns: e.feeCNS,
                    builder_fee_cns: e.builderFeeCNS,
                    locked_balance_cns: e.lockedBalanceCNS,
                    balance_cns: e.balanceCNS,
                },
            )?,
            ExchangeEvents::MakerOrderSettlementFailed(e) => chain!(
                if let Some(perp) = self.perpetual(e.perpId) {
                    let order_id = std::num::NonZeroU16::new(e.orderId.to::<u16>())
                        .expect("orderId in event cannot be 0");
                    let order = perp.remove_order(order_id)?;
                    chain!(
                        Some(StateEvents::order(perp, &order, ctx, OrderEventType::Removed)),
                        self.err_ctx(ctx, event)?
                            .map(|ctx| StateEvents::affected_order_error(
                                ctx,
                                &order,
                                OrderErrorType::MakerOrderSettlementFailed
                            ))
                    )
                    .collect()
                } else {
                    vec![]
                },
                self.account(e.accountId).map(|acc| {
                    acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                    StateEvents::account(
                        acc,
                        ctx,
                        AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                    )
                }),
                if !e.recyclerAmountCNS.is_zero() {
                    self.account(e.recyclerAccountId).map(|acc| {
                        acc.update_balance(instant, cc.from_unsigned(e.recyclerBalanceCNS));
                        StateEvents::account(
                            acc,
                            ctx,
                            AccountEventType::BalanceUpdated(acc.balance()),
                        )
                    })
                } else {
                    None
                },
            )
            .collect(),
            ExchangeEvents::MarginTolUpdated(_) => vec![],
            ExchangeEvents::MarkExceedsTol(_) => vec![],
            ExchangeEvents::MarkPriceAgeExceedsMax(_) => vec![],
            ExchangeEvents::MarkUpdated(e) => {
                let perp_mark = self.perpetual(e.perpId).map(|perp| {
                    perp.update_mark_price(
                        instant,
                        perp.price_converter().from_unsigned(e.pricePNS),
                    );
                    (perp.id(), perp.mark_price())
                });
                if let Some((perp_id, mark_price)) = perp_mark {
                    chain!(
                        Some(StateEvents::Perpetual(PerpetualEvent {
                            perpetual_id: perp_id,
                            r#type: PerpetualEventType::MarkPriceUpdated(mark_price),
                        })),
                        // Applying updated mark to all tracked positions
                        self.accounts.values_mut().filter_map(|acc| {
                            acc.positions_mut().get_mut(&perp_id).map(|pos| {
                                pos.apply_mark_price(instant, mark_price);
                                StateEvents::position(
                                    pos,
                                    &None,
                                    PositionEventType::UnrealizedPnLUpdated {
                                        pnl: pos.pnl(),
                                        delta_pnl: pos.delta_pnl(),
                                        premium_pnl: pos.premium_pnl(),
                                    },
                                )
                            })
                        }),
                    )
                    .collect()
                } else {
                    vec![]
                }
            },
            ExchangeEvents::MaxMatchesReached(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::MaxMatchesReached))
                .into_iter()
                .collect(),
            ExchangeEvents::MaxOpenInterestUpdated(_) => vec![],
            ExchangeEvents::MaximumAccountOrders(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::MaximumAccountOrders))
                .into_iter()
                .collect(),
            ExchangeEvents::MinAccountOpenAmountUpdated(_) => vec![],
            ExchangeEvents::MinPostUpdated(e) => {
                self.min_post = cc.from_unsigned(e.minPostCNS);
                vec![StateEvents::Exchange(ExchangeEvent::MinPostUpdated(self.min_post))]
            },
            ExchangeEvents::MinSettleUpdated(e) => {
                self.min_settle = cc.from_unsigned(e.minSettleCNS);
                vec![StateEvents::Exchange(ExchangeEvent::MinSettleUpdated(self.min_settle))]
            },
            ExchangeEvents::MonitorAdministratorUpdated(_) => vec![],
            ExchangeEvents::MonitorPauseAttempted(_) => vec![],
            ExchangeEvents::OracleAgeExceedsMax(_) => vec![],
            ExchangeEvents::OracleDisabled(_) => vec![],
            ExchangeEvents::OrderBatchCompleted(_) => {
                // Reset context
                ctx.take();
                vec![]
            },
            ExchangeEvents::OrderCancelled(e) => {
                let c = must_ctx()?;
                let order_id = c.order_id.expect("order_id required for OrderCancelled");
                chain!(
                    if let Some(perp) = self.perpetuals.get_mut(&c.perpetual_id) {
                        let order = perp.remove_order(order_id)?;
                        Some(StateEvents::order(perp, &order, ctx, OrderEventType::Removed))
                    } else {
                        None
                    },
                    if let Some(acc) = self.accounts.get_mut(&c.account_id) {
                        acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                        acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                        vec![
                            StateEvents::account(
                                acc,
                                ctx,
                                AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                            ),
                            StateEvents::account(
                                acc,
                                ctx,
                                AccountEventType::BalanceUpdated(acc.balance()),
                            ),
                        ]
                    } else {
                        vec![]
                    },
                )
                .collect()
            },
            ExchangeEvents::OrderCancelledByAdmin(e) => chain!(
                self.order(e.perpId, e.orderId)?.map(|(perp, order)| {
                    perp.remove_order(order.order_id()).expect("order exists");
                    StateEvents::order(perp, &order, ctx, OrderEventType::Removed)
                }),
                self.account(e.accountId).map(|acc| {
                    acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                    StateEvents::account(
                        acc,
                        ctx,
                        AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                    )
                }),
            )
            .collect(),
            ExchangeEvents::OrderCancelledByLiquidator(e) => chain!(
                self.order(e.perpId, e.orderId)?.map(|(perp, order)| {
                    perp.remove_order(order.order_id()).expect("order exists");
                    StateEvents::order(perp, &order, ctx, OrderEventType::Removed)
                }),
                self.account(e.accountId).map(|acc| {
                    acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                    StateEvents::account(
                        acc,
                        ctx,
                        AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                    )
                }),
            )
            .collect(),
            ExchangeEvents::OrderChanged(e) => {
                let c = must_ctx()?;
                let order_id = c.order_id.expect("order_id required for OrderChanged");
                chain!(
                    if let Some(perp) = self.perpetuals.get_mut(&c.perpetual_id) {
                        let order = perp
                            .get_order(order_id)
                            .copied()
                            .ok_or(DexError::OrderNotFound(perp.id(), order_id))?;
                        let new_price = perp.price_converter().from_unsigned(e.pricePNS);
                        let new_size = perp.size_converter().from_unsigned(e.lotLNS);
                        let new_expiry_block = e.expiryBlock.to();
                        let price_update =
                            if order.price() != new_price { Some(new_price) } else { None };
                        let size_update =
                            if order.size() != new_size { Some(new_size) } else { None };
                        let expiry_block_update = if order.expiry_block() != new_expiry_block {
                            Some(new_expiry_block)
                        } else {
                            None
                        };
                        let updated = order.updated(
                            instant,
                            ctx,
                            price_update,
                            size_update,
                            size_update,
                            expiry_block_update,
                        );
                        perp.update_order(updated)?;
                        Some(StateEvents::order(
                            perp,
                            &order,
                            ctx,
                            OrderEventType::Updated {
                                price: price_update,
                                size: size_update,
                                expiry_block: expiry_block_update,
                            },
                        ))
                    } else {
                        None
                    },
                    if let Some(acc) = self.accounts.get_mut(&c.account_id) {
                        acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                        acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                        vec![
                            StateEvents::account(
                                acc,
                                ctx,
                                AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                            ),
                            StateEvents::account(
                                acc,
                                ctx,
                                AccountEventType::BalanceUpdated(acc.balance()),
                            ),
                        ]
                    } else {
                        vec![]
                    },
                )
                .collect()
            },
            ExchangeEvents::OrderDescIdTooLow(_) => vec![],
            ExchangeEvents::OrderDoesNotExist(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::OrderDoesNotExist))
                .into_iter()
                .collect(),
            ExchangeEvents::OrderExtensionRejected(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::OrderExtensionRejected))
                .into_iter()
                .collect(),
            ExchangeEvents::OrderForwardingNotAllowed(_) => vec![],
            ExchangeEvents::OrderForwardingUpdated(_) => vec![],
            ExchangeEvents::OrderPlaced(e) => {
                let c = must_ctx()?;
                let order_id = std::num::NonZeroU16::new(e.orderId.to::<u16>())
                    .expect("orderId in OrderPlaced event cannot be 0");
                chain!(
                    if let Some(perp) = self.perpetuals.get_mut(&c.perpetual_id) {
                        let order = Order::placed(
                            instant,
                            c,
                            order_id,
                            perp.size_converter().from_unsigned(e.lotLNS),
                            perp.price_converter(),
                            perp.leverage_converter(),
                        );
                        let event = OrderEventType::Placed {
                            r#type: order.r#type(),
                            price: order.price(),
                            size: order.size(),
                            expiry_block: order.expiry_block(),
                            leverage: order.leverage(),
                            post_only: order.post_only().unwrap_or_default(),
                            fill_or_kill: order.fill_or_kill().unwrap_or_default(),
                            immediate_or_cancel: order.immediate_or_cancel().unwrap_or_default(),
                        };
                        perp.add_order(order)?;
                        Some(StateEvents::order(perp, &order, ctx, event))
                    } else {
                        None
                    },
                    if let Some(acc) = self.accounts.get_mut(&c.account_id) {
                        acc.update_locked_balance(instant, cc.from_unsigned(e.lockedBalanceCNS));
                        acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                        vec![
                            StateEvents::account(
                                acc,
                                ctx,
                                AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                            ),
                            StateEvents::account(
                                acc,
                                ctx,
                                AccountEventType::BalanceUpdated(acc.balance()),
                            ),
                        ]
                    } else {
                        vec![]
                    },
                )
                .collect()
            },
            ExchangeEvents::OrderPostFailed(e) => self
                .err_ctx(ctx, event)?
                .map(|ctx| {
                    StateEvents::order_error(ctx, OrderErrorType::OrderPostFailed(e.reason.to()))
                })
                .into_iter()
                .collect(),
            // Superseded by `OrderRequestV2` in v1.1.7.4, replayed from earlier
            // history only
            ExchangeEvents::OrderRequest(e) => {
                // Store order request context as it is required to handle
                // future events
                ctx.replace(OrderContext::from(e));
                vec![]
            },
            ExchangeEvents::OrderRequestV2(e) => {
                ctx.replace(OrderContext::from(e));
                vec![]
            },
            ExchangeEvents::OrderSettlementImpliesInsolvent(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| {
                    StateEvents::order_error(ctx, OrderErrorType::OrderSettlementImpliesInsolvent)
                })
                .into_iter()
                .collect(),
            ExchangeEvents::OrderSizeExceedsAvailableSize(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| {
                    StateEvents::order_error(ctx, OrderErrorType::OrderSizeExceedsAvailableSize)
                })
                .into_iter()
                .collect(),
            ExchangeEvents::OverCollatDescentThreshUpdated(_) => vec![],
            ExchangeEvents::OwnershipTransferStarted(_) => vec![],
            ExchangeEvents::OwnershipTransferred(_) => vec![],
            ExchangeEvents::PermissonedCancelParamsUpdated(_) => vec![],
            ExchangeEvents::PerpFeeSchedIdSet(e) => {
                // The only event that repoints a contract at another schedule.
                // Id-only, so the rates come from the registry entry now pointed
                // at.
                //
                // A schedule never observed has no rates to resolve: the id is
                // applied on its own and the `FeeScheduleSet` that eventually
                // writes it reports the rates, rather than surfacing an
                // intermediate schedule pairing the new id with the old rates -
                // a state that never applies to a fill.
                let key = FeeScheduleKey::from_raw(e.feeSchedId);
                let schedule = self.fee_schedules.get(key);
                self.perpetual(e.perpId)
                    .and_then(|perp| match schedule {
                        Some(schedule) => {
                            perp.update_fee_schedule(instant, schedule);
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::FeeScheduleUpdated(perp.fee_schedule()),
                            ))
                        },
                        None => {
                            perp.update_fee_schedule_key(instant, key);
                            None
                        },
                    })
                    .into_iter()
                    .collect()
            },
            ExchangeEvents::PerpPositionBalCreditPositiveSevere(_) => vec![],
            ExchangeEvents::PositionAdministratorUpdated(_) => vec![],
            ExchangeEvents::PositionClosed(e) => {
                if let Some(ctx) = ctx {
                    ctx.position_closed_at_log_index = Some(event.log_index());
                }

                if let Some((acc, perp)) = self.account_perpetual(e.accountId, e.perpId) {
                    let pos = acc
                        .positions_mut()
                        .remove(&perp.id())
                        .ok_or(DexError::PositionNotFound(acc.id(), perp.id()))?;

                    chain!(
                        Some(StateEvents::position(
                            &pos,
                            ctx,
                            PositionEventType::Closed {
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                exit_price: perp.price_converter().from_unsigned(e.pricePNS),
                                size: pos.size(),
                                delta_pnl: cc.from_signed(e.deltaPnlCNS),
                                premium_pnl: cc.from_signed(e.fundingCNS),
                            }
                        )),
                        if PositionType::from(e.positionType) == PositionType::Long {
                            perp.update_open_interest(instant, pos.size(), UD64::ZERO);
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionCollateralDecreased(e) => {
                if let Some((pos, perp)) = self.position(e.accountId, e.perpId)? {
                    let prev_entry_price = pos.entry_price();
                    pos.update_entry_price(instant, e.endEntryPricePNS, 0, perp.price_converter());
                    pos.update_deposit(instant, cc.from_unsigned(e.endDepositCNS));
                    pos.apply_mark_price(instant, perp.mark_price());
                    pos.apply_maintenance_margin(instant, perp.maintenance_margin());
                    vec![StateEvents::position(
                        pos,
                        ctx,
                        PositionEventType::CollateralDecreased {
                            prev_entry_price,
                            new_entry_price: pos.entry_price(),
                            deposit: pos.deposit(),
                        },
                    )]
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionDecreased(e) => {
                if let Some((pos, perp)) = self.position(e.accountId, e.perpId)? {
                    let prev_size = pos.size();
                    pos.update_size(instant, perp.size_converter().from_unsigned(e.endLotLNS));
                    pos.update_deposit(instant, cc.from_unsigned(e.endDepositCNS));
                    pos.apply_mark_price(instant, perp.mark_price());
                    pos.update_premium_pnl(
                        instant,
                        pos.premium_pnl().sub(cc.from_signed(e.fundingCNS)),
                    );
                    pos.apply_maintenance_margin(instant, perp.maintenance_margin());
                    chain!(
                        Some(StateEvents::position(
                            pos,
                            ctx,
                            PositionEventType::Decreased {
                                prev_size,
                                new_size: pos.size(),
                                deposit: pos.deposit(),
                                delta_pnl: pos.delta_pnl(),
                                premium_pnl: pos.premium_pnl(),
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, prev_size, pos.size());
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionDeleveraged(e) => chain!(
                if let Some((pos, perp)) = self.position(e.accountId, e.perpId)? {
                    let prev_size = pos.size();
                    pos.update_size(instant, perp.size_converter().from_unsigned(e.endLotLNS));
                    pos.update_deposit(instant, cc.from_unsigned(e.endDepositCNS));
                    pos.apply_mark_price(instant, perp.mark_price());
                    pos.update_premium_pnl(
                        instant,
                        pos.premium_pnl().sub(cc.from_signed(e.fundingCNS)),
                    );
                    pos.apply_maintenance_margin(instant, perp.maintenance_margin());
                    chain!(
                        Some(StateEvents::position(
                            pos,
                            ctx,
                            PositionEventType::Deleveraged {
                                force_close: e.forceClose,
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                exit_price: perp
                                    .price_converter()
                                    .from_unsigned(e.deleveragePricePNS),
                                prev_size,
                                new_size: pos.size(),
                                deposit: pos.deposit(),
                                delta_pnl: pos.delta_pnl(),
                                premium_pnl: pos.premium_pnl(),
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, prev_size, pos.size());
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                },
                self.account(e.accountId).map(|acc| {
                    if e.endLotLNS == U256::ZERO {
                        acc.positions_mut()
                            .remove(&e.perpId.to::<types::PerpetualId>());
                    }
                    acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                    StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
                }),
            )
            .collect(),
            ExchangeEvents::PositionDeleveragedV2(e) => chain!(
                if let Some((pos, perp)) = self.position(e.accountId, e.perpId)? {
                    let prev_size = pos.size();
                    pos.update_size(instant, perp.size_converter().from_unsigned(e.endLotLNS));
                    pos.update_deposit(instant, cc.from_unsigned(e.endDepositCNS));
                    pos.apply_mark_price(instant, perp.mark_price());
                    pos.update_premium_pnl(
                        instant,
                        pos.premium_pnl().sub(cc.from_signed(e.fundingCNS)),
                    );
                    pos.apply_maintenance_margin(instant, perp.maintenance_margin());
                    chain!(
                        Some(StateEvents::position(
                            pos,
                            ctx,
                            PositionEventType::Deleveraged {
                                force_close: e.forceClose,
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                exit_price: perp
                                    .price_converter()
                                    .from_unsigned(e.deleveragePricePNS),
                                prev_size,
                                new_size: pos.size(),
                                deposit: pos.deposit(),
                                delta_pnl: pos.delta_pnl(),
                                premium_pnl: pos.premium_pnl(),
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, prev_size, pos.size());
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                },
                self.account(e.accountId).map(|acc| {
                    if e.endLotLNS == U256::ZERO {
                        acc.positions_mut()
                            .remove(&e.perpId.to::<types::PerpetualId>());
                    }
                    acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                    StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
                }),
            )
            .collect(),
            ExchangeEvents::PositionDoesNotExist(_) => vec![],
            ExchangeEvents::PositionIncreased(e) => {
                if let Some((pos, perp)) = self.position(e.accountId, e.perpId)? {
                    let prev_size = pos.size();
                    pos.update_entry_price(instant, e.pricePNS, 0, perp.price_converter());
                    pos.update_size(instant, perp.size_converter().from_unsigned(e.endLotLNS));
                    pos.update_deposit(instant, cc.from_unsigned(e.endDepositCNS));
                    pos.apply_mark_price(instant, perp.mark_price());
                    pos.update_premium_pnl(instant, D256::ZERO);
                    pos.apply_maintenance_margin(instant, perp.maintenance_margin());

                    chain!(
                        Some(StateEvents::position(
                            pos,
                            ctx,
                            PositionEventType::Increased {
                                entry_price: pos.entry_price(),
                                prev_size,
                                new_size: pos.size(),
                                deposit: pos.deposit(),
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, prev_size, pos.size());
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionIncreasedV2(e) => {
                if let Some((pos, perp)) = self.position(e.accountId, e.perpId)? {
                    let prev_size = pos.size();
                    pos.update_entry_price(
                        instant,
                        e.pricePNS,
                        e.priceResiduePNSQ16.to(),
                        perp.price_converter(),
                    );
                    pos.update_size(instant, perp.size_converter().from_unsigned(e.endLotLNS));
                    pos.update_deposit(instant, cc.from_unsigned(e.endDepositCNS));
                    pos.apply_mark_price(instant, perp.mark_price());
                    pos.update_premium_pnl(instant, D256::ZERO);
                    pos.apply_maintenance_margin(instant, perp.maintenance_margin());

                    chain!(
                        Some(StateEvents::position(
                            pos,
                            ctx,
                            PositionEventType::Increased {
                                entry_price: pos.entry_price(),
                                prev_size,
                                new_size: pos.size(),
                                deposit: pos.deposit(),
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, prev_size, pos.size());
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionInverted(e) => {
                if let Some((pos, perp)) = self.position(e.accountId, e.perpId)? {
                    let prev_type = pos.r#type();
                    let prev_entry_price = pos.entry_price();
                    let prev_size = pos.size();
                    pos.update_type(instant, PositionType::from(e.positionType));
                    pos.update_entry_price(instant, e.pricePNS, 0, perp.price_converter());
                    pos.update_size(instant, perp.size_converter().from_unsigned(e.endLotLNS));
                    pos.update_deposit(instant, cc.from_unsigned(e.endDepositCNS));
                    pos.apply_mark_price(instant, perp.mark_price());
                    pos.update_premium_pnl(instant, D256::ZERO);
                    pos.apply_maintenance_margin(instant, perp.maintenance_margin());
                    if pos.r#type() == PositionType::Long {
                        perp.update_open_interest(instant, UD64::ZERO, pos.size());
                    } else {
                        perp.update_open_interest(instant, prev_size, UD64::ZERO);
                    }
                    vec![
                        StateEvents::position(
                            pos,
                            ctx,
                            PositionEventType::Closed {
                                r#type: prev_type,
                                entry_price: prev_entry_price,
                                exit_price: pos.entry_price(),
                                size: prev_size,
                                delta_pnl: cc.from_signed(e.deltaPnlCNS),
                                premium_pnl: cc.from_signed(e.fundingCNS),
                            },
                        ),
                        StateEvents::position(
                            pos,
                            ctx,
                            PositionEventType::Inverted {
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                prev_size,
                                new_size: pos.size(),
                                deposit: pos.deposit(),
                                delta_pnl: pos.delta_pnl(),
                                premium_pnl: pos.premium_pnl(),
                            },
                        ),
                        StateEvents::perpetual(
                            perp,
                            PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                        ),
                    ]
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionLiquidated(e) => chain!(
                if let Some((pos, perp)) = self.position(e.posAccountId, e.perpId)? {
                    let prev_size = pos.size();
                    pos.update_size(instant, perp.size_converter().from_unsigned(e.posLotLNS));
                    pos.update_deposit(instant, cc.from_unsigned(e.posDepositCNS));
                    pos.apply_mark_price(instant, perp.mark_price());
                    pos.update_premium_pnl(
                        instant,
                        pos.premium_pnl().sub(cc.from_signed(e.fundingCNS)),
                    );
                    pos.apply_maintenance_margin(instant, perp.maintenance_margin());
                    chain!(
                        Some(StateEvents::position(
                            pos,
                            ctx,
                            PositionEventType::Liquidated {
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                exit_price: perp.price_converter().from_unsigned(e.liqPricePNS),
                                prev_size,
                                liquidated_size: perp.size_converter().from_unsigned(e.liqLotLNS),
                                new_size: pos.size(),
                                deposit: pos.deposit(),
                                delta_pnl: pos.delta_pnl(),
                                premium_pnl: pos.premium_pnl(),
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, prev_size, pos.size());
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                },
                self.account(e.posAccountId).map(|acc| {
                    if e.posLotLNS == U256::ZERO {
                        acc.positions_mut()
                            .remove(&e.perpId.to::<types::PerpetualId>());
                    }
                    acc.update_balance(instant, cc.from_unsigned(e.accBalanceCNS));
                    StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
                }),
            )
            .collect(),
            ExchangeEvents::PositionLiquidationCredit(e) => self
                .position(e.accountId, e.perpId)?
                .map(|(pos, _)| {
                    pos.update_deposit(instant, cc.from_unsigned(e.endDepositCNS));
                    StateEvents::position(
                        pos,
                        ctx,
                        PositionEventType::DepositUpdated(pos.deposit()),
                    )
                })
                .into_iter()
                .collect(),
            ExchangeEvents::PositionOpened(e) => {
                if let Some((acc, perp)) = self.account_perpetual(e.accountId, e.perpId) {
                    let pos = Position::opened(
                        instant,
                        perp.id(),
                        acc.id(),
                        PositionType::from(e.positionType),
                        e.pricePNS,
                        0,
                        perp.price_converter(),
                        perp.size_converter().from_unsigned(e.lotLNS),
                        cc.from_unsigned(e.depositCNS),
                        perp.maintenance_margin(),
                    );
                    let events = chain!(
                        Some(StateEvents::position(
                            &pos,
                            ctx,
                            PositionEventType::Opened {
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                size: pos.size(),
                                deposit: pos.deposit(),
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, UD64::ZERO, pos.size());
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect();
                    acc.positions_mut().insert(perp.id(), pos);
                    events
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionOpenedV2(e) => {
                if let Some((acc, perp)) = self.account_perpetual(e.accountId, e.perpId) {
                    let pos = Position::opened(
                        instant,
                        perp.id(),
                        acc.id(),
                        PositionType::from(e.positionType),
                        e.pricePNS,
                        e.priceResiduePNSQ16.to(),
                        perp.price_converter(),
                        perp.size_converter().from_unsigned(e.lotLNS),
                        cc.from_unsigned(e.depositCNS),
                        perp.maintenance_margin(),
                    );
                    let events = chain!(
                        Some(StateEvents::position(
                            &pos,
                            ctx,
                            PositionEventType::Opened {
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                size: pos.size(),
                                deposit: pos.deposit(),
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, UD64::ZERO, pos.size());
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect();
                    acc.positions_mut().insert(perp.id(), pos);
                    events
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionUnwound(e) => {
                if let Some((acc, perp)) = self.account_perpetual(e.accountId, e.perpId) {
                    let pos = acc
                        .positions_mut()
                        .remove(&perp.id())
                        .ok_or(DexError::PositionNotFound(acc.id(), perp.id()))?;
                    acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                    chain!(
                        Some(StateEvents::position(
                            &pos,
                            ctx,
                            PositionEventType::Unwound {
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                exit_price: perp.price_converter().from_unsigned(e.pricePNS),
                                size: pos.size(),
                                fair_market_value: cc.from_signed(e.positionFmvCNS),
                                payment: cc.from_unsigned(e.paymentCNS),
                            }
                        )),
                        Some(StateEvents::account(
                            acc,
                            ctx,
                            AccountEventType::BalanceUpdated(acc.balance())
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, pos.size(), UD64::ZERO);
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionUnwoundV2(e) => {
                // Position is being removed; residue field is informational only.
                if let Some((acc, perp)) = self.account_perpetual(e.accountId, e.perpId) {
                    let pos = acc
                        .positions_mut()
                        .remove(&perp.id())
                        .ok_or(DexError::PositionNotFound(acc.id(), perp.id()))?;
                    acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                    chain!(
                        Some(StateEvents::position(
                            &pos,
                            ctx,
                            PositionEventType::Unwound {
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                exit_price: perp.price_converter().from_unsigned(e.pricePNS),
                                size: pos.size(),
                                fair_market_value: cc.from_signed(e.positionFmvCNS),
                                payment: cc.from_unsigned(e.paymentCNS),
                            }
                        )),
                        Some(StateEvents::account(
                            acc,
                            ctx,
                            AccountEventType::BalanceUpdated(acc.balance())
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, pos.size(), UD64::ZERO);
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionUnwoundWithoutPayment(e) => {
                if let Some((acc, perp)) = self.account_perpetual(e.accountId, e.perpId) {
                    let pos = acc
                        .positions_mut()
                        .remove(&perp.id())
                        .ok_or(DexError::PositionNotFound(acc.id(), perp.id()))?;
                    chain!(
                        Some(StateEvents::position(
                            &pos,
                            ctx,
                            PositionEventType::Unwound {
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                exit_price: perp.price_converter().from_unsigned(e.pricePNS),
                                size: pos.size(),
                                fair_market_value: cc.from_signed(e.positionFmvCNS),
                                payment: UD128::ZERO,
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, pos.size(), UD64::ZERO);
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PositionUnwoundWithoutPaymentV2(e) => {
                // Position is being removed; residue field is informational only.
                if let Some((acc, perp)) = self.account_perpetual(e.accountId, e.perpId) {
                    let pos = acc
                        .positions_mut()
                        .remove(&perp.id())
                        .ok_or(DexError::PositionNotFound(acc.id(), perp.id()))?;
                    chain!(
                        Some(StateEvents::position(
                            &pos,
                            ctx,
                            PositionEventType::Unwound {
                                r#type: pos.r#type(),
                                entry_price: pos.entry_price(),
                                exit_price: perp.price_converter().from_unsigned(e.pricePNS),
                                size: pos.size(),
                                fair_market_value: cc.from_signed(e.positionFmvCNS),
                                payment: UD128::ZERO,
                            }
                        )),
                        if pos.r#type() == PositionType::Long {
                            perp.update_open_interest(instant, pos.size(), UD64::ZERO);
                            Some(StateEvents::perpetual(
                                perp,
                                PerpetualEventType::OpenInterestUpdated(perp.open_interest()),
                            ))
                        } else {
                            None
                        },
                    )
                    .collect()
                } else {
                    vec![]
                }
            },
            ExchangeEvents::PostOrderUnderMinimum(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::PostOrderUnderMinimum))
                .into_iter()
                .collect(),
            ExchangeEvents::PriceAdministratorUpdated(_) => vec![],
            ExchangeEvents::PriceMaxAgeUpdated(e) => {
                if let Some(perp) = self.perpetual(e.perpId) {
                    perp.update_price_max_age_sec(instant, e.maxAgeSec.to());
                }
                vec![]
            },
            ExchangeEvents::PriceOutOfRange(_) => self
                .err_ctx(ctx, event)
                .ok() // Used both for orders and mark/oracle prices
                .flatten()
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::PriceOutOfRange))
                .into_iter()
                .collect(),
            ExchangeEvents::PriceSetDuringTriggerExec(_) => vec![],
            ExchangeEvents::PriceTolUpdated(_) => vec![],
            ExchangeEvents::ProtocolBalanceDeposit(_) => vec![],
            ExchangeEvents::ProtocolBalanceWithdraw(_) => vec![],
            ExchangeEvents::RecycleBalanceInsufficientSevere(_) => vec![],
            ExchangeEvents::RecycleFeeToAccount(_) => vec![],
            ExchangeEvents::RecycleFeeToProtocol(_) => vec![],
            ExchangeEvents::RecycleFeeUpdated(e) => {
                self.recycle_fee = cc.from_unsigned(e.recycleFeeCNS);
                vec![StateEvents::Exchange(ExchangeEvent::RecycleFeeUpdated(self.recycle_fee()))]
            },
            ExchangeEvents::ReportAgeExceedsLastUpdate(_) => vec![],
            ExchangeEvents::ReportExpiresTooSoon(_) => vec![],
            ExchangeEvents::ReportFromFuture(_) => vec![],
            ExchangeEvents::ReportPriceIsNegative(_) => vec![],
            ExchangeEvents::ResidueBalanceInsufficient(_) => vec![],
            ExchangeEvents::ResidueTransferred(_) => vec![],
            // Deprecated in v1.1.7.4, replayed from earlier history only
            ExchangeEvents::TakerFeeUpdated(e) => self
                .perpetual(e.perpId)
                .map(|perp| {
                    perp.update_base_taker_fee(
                        instant,
                        perp.fee_converter().from_unsigned(e.takerFeePer100K),
                    );
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::TakerFeeUpdated(perp.taker_fee()),
                    )
                })
                .into_iter()
                .collect(),
            // Superseded by `TakerOrderFilledV2` in v1.1.7.4, replayed from
            // earlier history only, hence no builder fee
            ExchangeEvents::TakerOrderFilled(e) => self.apply_taker_order_filled(
                instant,
                event,
                ctx,
                RawTakerFill {
                    collat_price_pns: e.collatPricePNS,
                    lot_lns: e.lotLNS,
                    fee_cns: e.feeCNS,
                    builder_fee_cns: U256::ZERO,
                    balance_cns: e.balanceCNS,
                },
            )?,
            ExchangeEvents::TakerOrderFilledV2(e) => self.apply_taker_order_filled(
                instant,
                event,
                ctx,
                RawTakerFill {
                    collat_price_pns: e.collatPricePNS,
                    lot_lns: e.lotLNS,
                    fee_cns: e.feeCNS,
                    builder_fee_cns: e.builderFeeCNS,
                    balance_cns: e.balanceCNS,
                },
            )?,
            ExchangeEvents::ToleranceAdministratorUpdated(_) => vec![],
            ExchangeEvents::TransferAccountToProtocol(e) => self
                .account(e.accountId)
                .map(|acc| {
                    acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                    StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
                })
                .into_iter()
                .collect(),
            ExchangeEvents::TransferPerpInsToProtocol(_) => vec![],
            ExchangeEvents::TransferPerpPosToProtocol(_) => vec![],
            ExchangeEvents::TransferProtocolToAccount(e) => self
                .account(e.accountId)
                .map(|acc| {
                    acc.update_balance(instant, cc.from_unsigned(e.balanceCNS));
                    StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
                })
                .into_iter()
                .collect(),
            ExchangeEvents::TransferProtocolToPerp(_) => vec![],
            ExchangeEvents::TransferProtocolToRecycleBal(_) => vec![],
            ExchangeEvents::TriggerDescIdTooLow(_) => vec![],
            ExchangeEvents::TriggerOrderExecution(_) => vec![],
            ExchangeEvents::TriggerOrderRequest(_) => vec![],
            ExchangeEvents::UnableToCancelOrder(_) => vec![],
            ExchangeEvents::UnityDescentThreshUpdated(_) => vec![],
            ExchangeEvents::UnspecifiedCollateral(_) => vec![],
            ExchangeEvents::UnwindCompleted(_) => vec![],
            ExchangeEvents::UnwindContractTrigger(_) => vec![],
            ExchangeEvents::UnwindInitializationCleared(_) => vec![],
            ExchangeEvents::UnwindInitialized(_) => vec![],
            ExchangeEvents::UnwindInsufficientBalance(_) => vec![],
            ExchangeEvents::UnwindIterationCompleted(_) => vec![],
            ExchangeEvents::UnwindPrepared(_) => vec![],
            ExchangeEvents::UnwindPreparationCleared(_) => vec![],
            ExchangeEvents::UnwindProcessInProgress(_) => vec![],
            ExchangeEvents::UpdateOracleFailed(_) => vec![],
            ExchangeEvents::Upgraded(_) => vec![],
            ExchangeEvents::ValueExceedsMaximum(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::ValueExceedsMaximum))
                .into_iter()
                .collect(),
            ExchangeEvents::WhitelistAddress(_) => vec![],
            ExchangeEvents::WhitelistingEnabledChanged(_) => vec![],
            ExchangeEvents::WithdrawRateLimitBypassSet(_) => vec![],
            ExchangeEvents::WithdrawRateLimitForceReset(_) => vec![],
            ExchangeEvents::WRLSMinWithdrawLimitUpdated(_) => vec![],
            ExchangeEvents::WRLSThousandthsTvlUpdated(_) => vec![],
            ExchangeEvents::WithdrawRateLimitReset(_) => vec![],
            ExchangeEvents::WrongAccountForOrder(_) => self
                .err_ctx(ctx, event)?
                .map(|ctx| StateEvents::order_error(ctx, OrderErrorType::WrongAccountForOrder))
                .into_iter()
                .collect(),
        })
    }

    /// Starts tracking a newly listed perpetual contract, shared by the V1 and
    /// V2 listing events.
    fn add_perpetual(
        &mut self,
        instant: types::StateInstant,
        name: &str,
        symbol: &str,
        listing: RawContractAdded,
        fee_schedule: FeeSchedule,
    ) -> StateEvents {
        let perp = Perpetual::added(
            instant,
            listing.perp_id.to(),
            name.to_string(),
            symbol.to_string(),
            listing.status == 0, // PerpStatusEnum::Paused
            listing.price_decimals.to(),
            listing.lot_decimals.to(),
            listing.base_price_pns,
            fee_schedule,
            listing.init_margin_frac_hdths,
            listing.maint_margin_frac_hdths,
        );
        let event = StateEvents::perpetual(&perp, PerpetualEventType::Added);
        self.perpetuals.insert(perp.id(), perp);
        event
    }

    /// Applies a maker fill, shared by the V1 and V2 event variants which
    /// differ only in carrying the builder fee earned on the fill.
    fn apply_maker_order_filled(
        &mut self,
        instant: types::StateInstant,
        event: &stream::RawEvent,
        ctx: &mut Option<OrderContext>,
        fill: RawMakerFill,
    ) -> Result<Vec<StateEvents>, DexError> {
        let cc = self.collateral_converter;
        Ok(chain!(
            if let Some((perp, order)) = self.order(fill.perp_id, fill.order_id)? {
                let fill_price = perp.price_converter().from_unsigned(fill.price_pns);
                let fill_size = perp.size_converter().from_unsigned(fill.lot_lns);
                let fee = cc.from_unsigned(fill.fee_cns);
                let builder_fee = cc.from_unsigned(fill.builder_fee_cns);
                perp.update_last_price(instant, fill_price);
                let clearing_remaining_order = if let Some(ctx) = ctx {
                    ctx.maker_fills.push(types::MakerFill {
                        log_index: event.log_index(),
                        maker_account_id: order.account_id(),
                        maker_order_id: order.order_id(),
                        maker_client_order_id: order.client_order_id(),
                        price: fill_price,
                        size: fill_size,
                        fee,
                        builder: order.builder(),
                        builder_fee,
                    });
                    let position_closed_by_smart_contract = if event.log_index() > 0 {
                        // Smart contract explicitly removes Close* order if position was
                        // closed, between `PositionClosed` and `MakerOrderFilled` events
                        // there can be a `RecycleFeeToAccount` event as well
                        match order.r#type() {
                            OrderType::CloseLong | OrderType::CloseShort => {
                                Some(event.log_index() - 1) == ctx.position_closed_at_log_index
                                    || Some(event.log_index() - 2)
                                        == ctx.position_closed_at_log_index
                            },
                            _ => false,
                        }
                    } else {
                        false
                    };
                    ctx.clearing_remaining_order | position_closed_by_smart_contract
                } else {
                    false
                };
                vec![
                    if order.size() > fill_size && !clearing_remaining_order {
                        let new_size = order.size() - fill_size;
                        perp.update_order(order.updated(
                            instant,
                            ctx,
                            None,
                            Some(new_size),
                            None,
                            None,
                        ))
                        .expect("order exists");
                        StateEvents::order(
                            perp,
                            &order,
                            ctx,
                            OrderEventType::Updated {
                                price: None,
                                size: Some(new_size),
                                expiry_block: None,
                            },
                        )
                    } else {
                        perp.remove_order(order.order_id()).expect("order exists");
                        StateEvents::order(perp, &order, ctx, OrderEventType::Removed)
                    },
                    StateEvents::order(
                        perp,
                        &order,
                        ctx,
                        OrderEventType::Filled {
                            fill_price,
                            fill_size,
                            fee,
                            builder_fee,
                            is_maker: true,
                        },
                    ),
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::LastPriceUpdated(perp.last_price()),
                    ),
                ]
            } else {
                vec![]
            },
            self.account(fill.account_id).map(|acc| {
                acc.update_locked_balance(instant, cc.from_unsigned(fill.locked_balance_cns));
                StateEvents::account(
                    acc,
                    ctx,
                    AccountEventType::LockedBalanceUpdated(acc.locked_balance()),
                )
            }),
            self.account(fill.account_id).map(|acc| {
                acc.update_balance(instant, cc.from_unsigned(fill.balance_cns));
                StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
            }),
        )
        .collect())
    }

    /// Applies a taker fill, shared by the V1 and V2 event variants which
    /// differ only in carrying the builder fee earned on the fill.
    fn apply_taker_order_filled(
        &mut self,
        instant: types::StateInstant,
        event: &stream::RawEvent,
        ctx: &mut Option<OrderContext>,
        fill: RawTakerFill,
    ) -> Result<Vec<StateEvents>, DexError> {
        let cc = self.collateral_converter;
        let c = ctx
            .as_ref()
            .ok_or(DexError::OrderContextExpected(event.tx_index(), event.log_index()))?;
        let taker_fee = cc.from_unsigned(fill.fee_cns);
        let taker_builder_fee = cc.from_unsigned(fill.builder_fee_cns);
        Ok(chain!(
            self.perpetuals
                .get(&c.perpetual_id)
                .map(|perp| StateEvents::Order(OrderEvent {
                    perpetual_id: perp.id(),
                    account_id: c.account_id,
                    request_id: Some(c.request_id),
                    client_order_id: Some(c.request_id),
                    order_id: None,
                    builder: c.builder,
                    r#type: OrderEventType::Filled {
                        fill_price: perp.price_converter().from_unsigned(fill.collat_price_pns),
                        fill_size: perp.size_converter().from_unsigned(fill.lot_lns),
                        fee: taker_fee,
                        builder_fee: taker_builder_fee,
                        is_maker: false,
                    },
                })),
            self.accounts.get_mut(&c.account_id).map(|acc| {
                acc.update_balance(instant, cc.from_unsigned(fill.balance_cns));
                StateEvents::account(acc, ctx, AccountEventType::BalanceUpdated(acc.balance()))
            }),
            iter::once(StateEvents::trade(c, taker_fee, taker_builder_fee)),
        )
        .collect())
    }

    /// Registers a rewrite of a fee schedule, fanning it out to every tracked
    /// contract *currently pointing at it* - a contract keyed by the same id
    /// but resolving its fees elsewhere is left alone, as only
    /// `PerpFeeSchedIdSet` moves a contract between schedules.
    fn update_fee_schedule(
        &mut self,
        instant: types::StateInstant,
        schedule: FeeSchedule,
    ) -> Vec<StateEvents> {
        self.fee_schedules.set(schedule);
        chain!(
            iter::once(StateEvents::Exchange(ExchangeEvent::FeeScheduleUpdated(schedule))),
            self.perpetuals
                .values_mut()
                .filter(|perp| perp.fee_schedule().key() == schedule.key())
                .map(|perp| {
                    perp.update_fee_schedule(instant, schedule);
                    StateEvents::perpetual(
                        perp,
                        PerpetualEventType::FeeScheduleUpdated(perp.fee_schedule()),
                    )
                }),
        )
        .collect()
    }

    fn apply_state_event(
        &mut self,
        instant: types::StateInstant,
        event: &StateEvents,
    ) -> Result<Vec<StateEvents>, DexError> {
        Ok(match event {
            StateEvents::Perpetual(pe) => {
                match pe.r#type {
                    PerpetualEventType::MaintenanceMarginFractionUpdated(maintenance_margin) => {
                        // Applying new maintenance margin to all tracked positions
                        self.accounts
                            .values_mut()
                            .filter_map(|acc| {
                                acc.positions_mut().get_mut(&pe.perpetual_id).map(|pos| {
                                    pos.apply_maintenance_margin(instant, maintenance_margin);
                                    StateEvents::position(
                                        pos,
                                        &None,
                                        PositionEventType::MaintenanceMarginUpdated(
                                            pos.maintenance_margin_requirement(),
                                        ),
                                    )
                                })
                            })
                            .collect()
                    },
                    _ => vec![],
                }
            },
            _ => vec![],
        })
    }

    fn err_ctx<'c>(
        &self,
        ctx: &'c mut Option<OrderContext>,
        event: &stream::RawEvent,
    ) -> Result<Option<&'c OrderContext>, DexError> {
        let c = ctx
            .as_ref()
            .ok_or(DexError::OrderContextExpected(event.tx_index(), event.log_index()))?;
        Ok(self.accounts.contains_key(&c.account_id).then_some(c))
    }

    fn ensure_account(&mut self, id: U256) {
        let id = id.to::<types::AccountId>();
        if self.track_all_accounts && !self.accounts.contains_key(&id) {
            self.accounts
                .insert(id, Account::untracked(types::StateInstant::default(), id));
        }
    }

    fn account(&mut self, id: U256) -> Option<&mut Account> {
        self.ensure_account(id);
        self.accounts.get_mut(&id.to::<types::AccountId>())
    }

    fn order(
        &mut self,
        perp_id: U256,
        ord_id: U256,
    ) -> Result<Option<(&mut Perpetual, Order)>, DexError> {
        let ord_id = std::num::NonZeroU16::new(ord_id.to::<u16>())
            .expect("ord_id in order lookup cannot be 0");
        Ok(if let Some(perp) = self.perpetuals.get_mut(&perp_id.to::<types::PerpetualId>()) {
            let ord = perp
                .get_order(ord_id)
                .copied()
                .ok_or(DexError::OrderNotFound(perp.id(), ord_id))?;
            Some((perp, ord))
        } else {
            None
        })
    }

    fn perpetual(&mut self, id: U256) -> Option<&mut Perpetual> {
        self.perpetuals.get_mut(&id.to::<types::PerpetualId>())
    }

    fn account_perpetual(
        &mut self,
        acc_id: U256,
        perp_id: U256,
    ) -> Option<(&mut Account, &mut Perpetual)> {
        self.ensure_account(acc_id);
        self.accounts
            .get_mut(&acc_id.to::<types::AccountId>())
            .zip(self.perpetuals.get_mut(&perp_id.to::<types::PerpetualId>()))
    }

    fn position(
        &mut self,
        acc_id: U256,
        perp_id: U256,
    ) -> Result<Option<(&mut Position, &mut Perpetual)>, DexError> {
        self.ensure_account(acc_id);
        let acc_id = acc_id.to::<types::AccountId>();
        let perp_id = perp_id.to::<types::PerpetualId>();
        Ok(
            if let Some(acc) = self.accounts.get_mut(&acc_id)
                && let Some(perp) = self.perpetuals.get_mut(&perp_id)
            {
                let pos = acc
                    .positions_mut()
                    .get_mut(&perp_id)
                    .ok_or(DexError::PositionNotFound(acc_id, perp_id))?;
                Some((pos, perp))
            } else {
                None
            },
        )
    }
}

#[cfg(feature = "display")]
impl std::fmt::Display for Exchange {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        use colored::Colorize;
        use tabled::{Table, settings::Style};

        writeln!(
            f,
            "{}",
            format!(
                "{} | {}{} | {} (sdk {}) | chain {}",
                self.instant,
                if self.is_halted { "[HALTED] ".bold().bright_red() } else { Default::default() },
                self.chain.exchange(),
                self.features,
                Self::revision(),
                self.chain.chain_id(),
            )
            .bold()
            .purple(),
        )?;

        let mut params = Table::from_iter(vec![vec![
            format!("Min Post: {}", self.min_post),
            format!("Min Settle: {}", self.min_settle),
            format!("Recycle Fee: {}", self.recycle_fee),
            format!("Funding Interval: {}", self.funding_interval_blocks),
        ]]);
        params.with(Style::modern());
        writeln!(f, "{params}")?;

        // One row per registered schedule, the tier rates stacked taker over
        // maker. Pre-v1.1.7.4 contracts have no schedule registry - fees live on
        // the perpetual contract itself, and are rendered with it.
        //
        // Full renderings only: the whole tier grid is a dozen rarely-changing
        // rates, too much of a header for a live view that redraws every block.
        // Each perpetual still reports the base rates it resolves to.
        if f.alternate() && self.features.keyed_fee_schedules() {
            let mut fees = Table::from_iter(chain!(
                iter::once(
                    chain!(
                        iter::once("Fees (tkr/mkr)".to_string()),
                        (0..FEE_TIERS).map(|tier| format!("Tier {tier}")),
                    )
                    .collect::<Vec<_>>(),
                ),
                self.fee_schedules.schedules().map(|schedule| chain!(
                    iter::once(schedule.key().to_string()),
                    (0..FEE_TIERS as types::FeeTier).map(move |tier| format!(
                        "{}\n{}",
                        schedule.taker_fee(tier),
                        schedule.maker_fee(tier),
                    )),
                )
                .collect::<Vec<_>>()),
            ));
            fees.with(Style::modern());
            writeln!(f, "{fees}")?;
        }
        writeln!(f)?;

        // Render perpetuals and accounts in alternate mode
        if f.alternate() && !self.perpetuals().is_empty() {
            let mut perpetuals: Vec<_> = self.perpetuals().values().collect();
            perpetuals.sort_by_key(|p| p.id());
            for perpetual in perpetuals {
                writeln!(f, "{:#}", perpetual)?;
            }
        }

        if f.alternate() && !self.accounts().is_empty() {
            let mut accounts: Vec<_> = self.accounts().values().collect();
            accounts.sort_by_key(|a| a.id());
            for account in accounts {
                writeln!(f, "{:#}", account)?;
            }
        }

        Ok(())
    }
}