Build a deterministic limit-order state machine that rejects impossible transitions instead of silently repairing them.
The decision this tutorial makes visible
Execution systems must agree on whether an order is pending, live, partially filled, terminal, or replaced. Quantity accounting and legal transitions are one contract.
The precise question is: Given a chronological order-event stream, what legal lifecycle state, cumulative quantity, and leaves quantity follow after every event?
This matters to two readers at once. A practitioner needs to know what the diagnostic does and does not justify. A builder needs a contract that can be reproduced from the same ordered inputs in Python, TypeScript, a visual, and a browser lab. This tutorial supplies both views and keeps the selected single-venue convention visible throughout.
Intuition before notation
The state name and quantity ledger move together. A partial fill changes both status and leaves; terminal events block later mutation.
The diagnostic is not a free-floating signal. Its meaning depends on the declared book or lifecycle scope, the event or snapshot clock, equality handling, the included price window, and the treatment of unavailable state. If any of those change, the result is a different estimand or engine rule even when the final field name looks similar.
Scope and nearby methods
The canonical state machine begins pending-new; accept or reject resolves entry; fills update live orders; cancel, expire, fill, reject, and replace are terminal for the original order.
| Variant | Definition | Best use | Main limitation |
|---|---|---|---|
| Canonical accepted-order state machine | One original order with explicit terminal states | Engine and protocol education | Does not model pending cancel/replace races |
| Full FIX session state | Includes pending cancel, pending replace, rejects, restatements, and corrections | Broker/venue integration | More communication than matching state |
| Public-feed reconstruction | Infer visible lifecycle from ITCH events | Market-data replay | Cannot see private rejects or hidden state |
What is sourced, selected, synthetic, and derived
| Role | Material claim | Evidence | Boundary |
|---|---|---|---|
| Sourced fact | Authoritative sources establish only the protocol vocabulary, venue message, or venue-rule behavior recorded for this topic. | S1, S2, S3 | They do not turn the selected teaching engine into a universal or production-conformant venue model. |
| Implementation choice | The canonical state machine begins pending-new; accept or reject resolves entry; fills update live orders; cancel, expire, fill, reject, and replace are terminal for the original order. | Frozen package definition | Auctions, routing, pegging, hidden priority, self-match controls, and other venue rules remain excluded unless named. |
| Synthetic teaching input | The canonical order and event states are repository-authored teaching data. | datasets/canonical-input.json and datasets/scenario-results.json | They are not private acknowledgements, participant records, or licensed venue observations. |
| Author-derived calculation | The synthetic order accepts, fills 300, then 500, then 200 shares. Cumulative quantity reaches 1,000, leaves reaches zero, status becomes filled, and average price is 100.009. | Selected state rule, canonical fixture, Python/TypeScript parity, and independent arithmetic | Definition fidelity does not certify latency, operational safety, venue conformance, or trading value. |
The authoritative sources define feed capabilities, protocol vocabulary, venue-specific rules, or published empirical context. They do not certify the synthetic numbers in this tutorial. The repository fixture is deliberately invented for auditability, and the displayed output is author-derived from that fixture under the selected implementation choice.
Formula, symbols, and numerical policy
leaves = order_quantity - cumulative_fills; status = transition(previous_status,event)
| Symbol | Meaning | Unit | Policy |
|---|---|---|---|
| Q_0 | accepted original order quantity | shares | strictly positive |
| C_t | cumulative executed quantity after event t | shares | sum of unique accepted fills |
| L_t | leaves quantity after event t | shares | Q_0-C_t until terminal cancellation/rejection policy applies |
| F_t | last-fill quantity at event t | shares | zero for non-fill events |
| S_t | lifecycle status after event t | state | selected legal transition table |
- Process events in strictly increasing declared sequence; wall-clock timestamps do not break sequence ties.
- Quantity conservation uses unrounded shares, and average price is null until at least one fill exists.
- Filled, canceled, and rejected are terminal in the selected teaching machine; another event is rejected.
Read the formula in the same order as the algorithm. Validate identity, ordering, units, and supported state first. Apply the selected equality and window rules second. Calculate with unrounded numeric values. Round only at the declared presentation boundary, and preserve null as a diagnostic rather than coercing it to zero.
Build the algorithm
- Initialize pending-new with full leaves
- Accept or reject the entry
- Apply each live-order fill to cumulative and notional
- Resolve cancel, expire, replace, or complete fill
- Emit an audit transition and block post-terminal events
Production-minded operational checklist
- Validate order identity, original quantity, and event sequence.
- Apply exactly one legal transition at a time.
- Reconcile cumulative, leaves, and last quantity after every event.
- Reject duplicate execution identities and events after terminal state.
- Keep FIX vocabulary separate from venue priority and transport behavior.
The checklist is intentionally stricter than a charting demo. A plausible number from stale, incomplete, off-grid, misordered, or unsupported state is more dangerous than an explicit rejection.
Worked synthetic example
The canonical fixture is synthetic teaching data, not an observed venue
snapshot or private order record. Its primary author-derived output,
status, is "filled". The complete input and output
are in datasets/canonical-input.json and datasets/expected-output.json.
The synthetic order accepts, fills 300, then 500, then 200 shares. Cumulative quantity reaches 1,000, leaves reaches zero, status becomes filled, and average price is 100.009.
The structured result retains state and diagnostics in addition to the primary number. That makes the calculation independently reviewable and prevents a partial, null, rejected, or venue-bounded outcome from being mistaken for an unqualified value.
Boundary and counterexample workbook
The playground computes every scenario at 61 deterministic parameter states.
The table shows the midpoint used for prose review; the full state ledger is in
datasets/scenario-results.json.
| Scenario | Purpose | State | Primary output | Diagnostic |
|---|---|---|---|---|
| Canonical path | Move one declared driver through the canonical lifecycle. | partially-filled | 500.0 shares | status partially-filled · leaves 500.0 |
| Live or preserved boundary | Inspect a nonterminal or priority-preserving state. | new | 0.0 shares | status new · leaves 1000.0 |
| Terminal or reset boundary | Inspect a legal terminal or new-priority transition. | rejected | 0.0 shares | status rejected · leaves 0.0 |
| Partial and residual case | Leave quantity live after part of the action completes. | canceled | 350.0 shares | status canceled · leaves 0.0 |
| Comparison path | Compare another valid order type, side, or queue shape. | replaced | 350.0 shares | status replaced · leaves 0.0 |
| Equality and idempotency boundary | Land exactly on a quantity, price, terminal, or priority equality branch. | filled | 1000.0 shares | status filled · leaves 0.0 |
| Adversarial audit path | Use a valid but easily misread state to test conservation and scope guardrails. | canceled | 650.0 shares | status canceled · leaves 0.0 |
These rows are not backtest observations. They are controlled counterexamples that expose how one driver changes the state, output, or reason code while the rest of the contract stays fixed.
Visualize the boundary
Open this SVG at full size, or use the guided playground to compare canonical, equality, null, residual, adversarial, and cross-method scenarios.
The Mermaid flow answers where the selected calculation sits in the processing sequence. The SVG keeps the formula, output, decision boundary, and invariant visible together. The lab lets the reader step through the same structured states without changing the underlying definition.
Implementation walkthrough
The Python and TypeScript references begin with the same validation contract. They reject malformed and unsupported state before calculation, preserve best-to-worse or event-sequence ordering, apply the equality policy in the symbol table, and return a structured diagnostic object rather than one context-free number.
The main implementation branches are:
- Pending-new receives accept — Enter new, because Order becomes live.
- Live order receives a nonfinal fill — Enter partially-filled, because Leaves remain positive.
- Terminal state receives another event — Reject sequence, because Original lifecycle is final.
Neither reference silently fetches data, mutates caller-owned inputs outside the declared engine behavior, guesses hidden state, or substitutes a provider default. Shared JSON fixtures make value, null, state, and reason-code drift visible across languages.
Testing and validation
Definition tests compare every canonical field, reject malformed state, and exercise the material boundary. Family validation recomputes every playground state from the reference function. Independent arithmetic is recorded beside the fixture rather than inferred only from implementation output.
The audit must preserve these invariants:
- Cumulative fill never exceeds original quantity.
- While live, cumulative plus leaves equals original quantity.
- A terminal original order accepts no later event.
- The structured output retains
status, lifecycle state, and reason fields needed to replay the branch.
Passing definition and parity checks proves that the implementation matches the selected contract. It does not prove that displayed state remains available, that another venue uses the same rule, or that the diagnostic predicts a later price or fill.
Failure modes and misuse
- Price-time FIFO is the selected teaching model; other venues and products can use pro-rata, size, customer, parity, or hybrid priority.
- Public displayed data cannot reveal all hidden, reserve, routed, or private participant state.
- Definition-correct state processing does not establish latency performance, production safety, or trading value.
Debugging order
When a result looks surprising, inspect the state in this order:
- Confirm instrument, venue, session, order type, and side.
- Confirm price, quantity, tick, clock, and sequence units.
- Confirm the included depth window or lifecycle-event boundary.
- Confirm equality, null, residual, and reset policies.
- Recalculate the invariant and midpoint counterexample before changing code.
Evidence and historical boundary
Historical decision: deferred. A named venue lifecycle case would require synchronized private acknowledgements or a sequence-complete licensed order feed, exact venue and order-type rules, corrections, session state, and redistribution permission. Synthetic events make every transition publicly reproducible.
The primary sources are FIX order-state matrices, Nasdaq TotalView-ITCH 5.0, Nasdaq Equity 4 rules. They support the source roles listed in the research ledger, not a redistributable historical observation, participant-intent claim, venue-conformance certification, profitability claim, or prediction claim.
Summary and next topic
You can now implement and audit a legal order lifecycle. The learning flow is: Market-Depth Heatmap Aggregation → Limit-Order Lifecycle State Machine → Cancel/Replace Priority Rule. Carry the result forward only with its scope, clock, state, and evidence label.
Rendered from the canonical Mermaid sources linked by this article.
Limit-Order Lifecycle State Machine calculation flow
This flow identifies the selected calculation stages and the structured output.
Takeaway: Lifecycle status is inseparable from quantity invariants and terminal-event legality.
ReferencesPrimary sources and evidence notesExpand the source trail, evidence role, and limitations behind the engineering choices.
Expand the source trail, evidence role, and limitations behind the engineering choices.
S1 — Order State Changes
- Organization or authors: FIX Trading Community
- Source type: Official protocol specification guidance
- Publication or effective date: Current online specification accessed 2026-07-30
- Version: Online specification
- URL or DOI: https://www.fixtrading.org/online-specification/order-state-changes/
- Accessed: 2026-07-30
- Jurisdiction: Cross-market protocol semantics
- Supports: Order status, execution type, cumulative quantity, leaves quantity, and state-transition examples.
- Limitations: FIX communication states do not prescribe every venue matching or priority rule.
S2 — Nasdaq TotalView-ITCH 5.0 Specification
- Organization or authors: Nasdaq
- Source type: Official exchange technical specification
- Publication or effective date: Specification current at access
- Version: 5.0
- URL or DOI: https://nasdaqtrader.com/content/technicalsupport/specifications/dataproducts/NQTVITCHSpecification.pdf
- Accessed: 2026-07-30
- Jurisdiction: United States equities; Nasdaq
- Supports: Add, execution, partial cancel, delete, and replace messages, including new reference numbers on replace.
- Limitations: A public market-data feed is not the participant's complete private order-entry acknowledgement stream.
S3 — Nasdaq Equity 4 — Equity Rules
- Organization or authors: The Nasdaq Stock Market LLC
- Source type: Official exchange rulebook
- Publication or effective date: Current web rulebook accessed 2026-07-30
- Version: Current rule text
- URL or DOI: https://listingcenter.nasdaq.com/rulebook/nasdaq/rules/Nasdaq%20Equity%204
- Accessed: 2026-07-30
- Jurisdiction: United States equities; Nasdaq
- Supports: Time ranking, same-price size-decrease priority preservation, new timestamps for other modifications, decrementation on execution, reserve-size behavior, and price-time processing.
- Limitations: Rules are venue-, order-type-, attribute-, protocol-, session-, and exception-specific and can change.
Evidence boundary
The sources establish feed fields, venue rules, protocol states, or published microstructure definitions. They do not verify the repository-authored synthetic fixture, thresholds, empirical usefulness, execution probability, or profitability. The package-selected choices are labeled as implementation choices wherever they are used.
Full dependency-light reference implementations in both supported languages.
export type JsonObject = Record<string, any>;
function numberValue(name: string, value: unknown, options: {positive?: boolean; nonnegative?: boolean} = {}): number {
if (typeof value !== "number" || !Number.isFinite(value)) throw new TypeError(`${name} must be a finite number`);
if (options.positive && value <= 0) throw new RangeError(`${name} must be positive`);
if (options.nonnegative && value < 0) throw new RangeError(`${name} must be nonnegative`);
return value;
}
function integerValue(name: string, value: unknown, nonnegative = false): number {
const result = numberValue(name, value);
if (!Number.isInteger(result)) throw new RangeError(`${name} must be an integer`);
if (nonnegative && result < 0) throw new RangeError(`${name} must be nonnegative`);
return result;
}
function textValue(name: string, value: unknown): string {
if (typeof value !== "string" || !value.trim()) throw new TypeError(`${name} must be a non-empty string`);
return value;
}
export function limitOrderLifecycle(orderIdRaw: unknown, orderQuantityRaw: unknown, eventsRaw: unknown): JsonObject {
const orderId = textValue("order_id", orderIdRaw), orderQuantity = numberValue("order_quantity", orderQuantityRaw, {positive: true});
if (!Array.isArray(eventsRaw) || eventsRaw.length === 0) throw new RangeError("events must be a non-empty chronological list");
let status = "pending-new", cumulative = 0, leaves = orderQuantity, notional = 0, executionCount = 0;
const terminal = new Set(["filled", "canceled", "rejected", "expired", "replaced"]);
const transitions: JsonObject[] = [];
eventsRaw.forEach((raw, index) => {
if (!raw || typeof raw !== "object") throw new TypeError(`events[${index}] must be an object`);
const event = raw as JsonObject, eventType = textValue(`events[${index}].type`, event.type), before = status;
if (terminal.has(status)) throw new RangeError("terminal order state cannot accept another event");
if (eventType === "accept") {
if (status !== "pending-new") throw new RangeError("accept is valid only from pending-new");
status = "new";
} else if (eventType === "reject") {
if (status !== "pending-new") throw new RangeError("reject is valid only from pending-new");
status = "rejected"; leaves = 0;
} else if (eventType === "fill") {
if (!["new", "partially-filled"].includes(status)) throw new RangeError("fill requires a live accepted order");
const fillQuantity = numberValue(`events[${index}].quantity`, event.quantity, {positive: true});
const fillPrice = numberValue(`events[${index}].price`, event.price, {positive: true});
if (fillQuantity > leaves + 1e-12) throw new RangeError("fill quantity exceeds order leaves quantity");
cumulative += fillQuantity; leaves = Math.max(0, orderQuantity - cumulative); notional += fillQuantity * fillPrice; executionCount += 1;
status = leaves === 0 ? "filled" : "partially-filled";
} else if (eventType === "cancel" || eventType === "expire") {
if (!["new", "partially-filled"].includes(status)) throw new RangeError(`${eventType} requires a live accepted order`);
status = eventType === "cancel" ? "canceled" : "expired"; leaves = 0;
} else if (eventType === "replace") {
if (!["new", "partially-filled"].includes(status)) throw new RangeError("replace requires a live accepted order");
textValue(`events[${index}].new_order_id`, event.new_order_id); status = "replaced"; leaves = 0;
} else throw new RangeError(`unsupported lifecycle event: ${eventType}`);
transitions.push({event_index: index, event_type: eventType, before_status: before, after_status: status, cumulative_quantity: cumulative, leaves_quantity: leaves});
});
return {model: "accepted-order-lifecycle-state-machine", order_id: orderId, order_quantity: orderQuantity, cumulative_quantity: cumulative, leaves_quantity: leaves, average_fill_price: cumulative ? notional / cumulative : null, execution_count: executionCount, status, terminal: terminal.has(status), transitions, state: status};
}
export function cancelReplacePriority(originalRaw: unknown, replacementRaw: unknown): JsonObject {
if (!originalRaw || typeof originalRaw !== "object" || !replacementRaw || typeof replacementRaw !== "object") throw new TypeError("original and replacement must be objects");
const original = originalRaw as JsonObject, replacement = replacementRaw as JsonObject;
const orderType = textValue("original.order_type", original.order_type);
if (orderType !== "displayed-limit") throw new RangeError("canonical priority rule supports displayed-limit orders only");
const originalId = textValue("original.order_id", original.order_id), replacementId = textValue("replacement.order_id", replacement.order_id);
const originalPrice = numberValue("original.price", original.price, {positive: true}), replacementPrice = numberValue("replacement.price", replacement.price, {positive: true});
const originalQuantity = numberValue("original.remaining_quantity", original.remaining_quantity, {positive: true}), replacementQuantity = numberValue("replacement.remaining_quantity", replacement.remaining_quantity, {positive: true});
const originalSequence = integerValue("original.priority_sequence", original.priority_sequence, true), replaceSequence = integerValue("replacement.replace_sequence", replacement.replace_sequence, true);
if (replaceSequence <= originalSequence) throw new RangeError("replace_sequence must be after original priority_sequence");
const samePrice = Math.abs(originalPrice - replacementPrice) <= 1e-12, decreaseOnly = replacementQuantity <= originalQuantity, preserved = samePrice && decreaseOnly;
const reason = preserved ? "same-price quantity decrease preserves canonical displayed-order priority" : !samePrice ? "price modification creates a new priority timestamp" : "quantity increase creates a new priority timestamp";
return {model: "nasdaq-style-displayed-limit-priority-rule", original_order_id: originalId, replacement_order_id: replacementId, original_price: originalPrice, replacement_price: replacementPrice, original_remaining_quantity: originalQuantity, replacement_remaining_quantity: replacementQuantity, same_price: samePrice, decrease_only: decreaseOnly, priority_preserved: preserved, original_priority_sequence: originalSequence, effective_priority_sequence: preserved ? originalSequence : replaceSequence, reason, state: preserved ? "priority-preserved" : "new-priority"};
}
export function partialFillResidual(orderQuantityRaw: unknown, fillsRaw: unknown): JsonObject {
const orderQuantity = numberValue("order_quantity", orderQuantityRaw, {positive: true});
if (!Array.isArray(fillsRaw)) throw new TypeError("fills must be a list");
let cumulative = 0, notional = 0;
const seen = new Set<string>(), states: JsonObject[] = [];
fillsRaw.forEach((raw, index) => {
if (!raw || typeof raw !== "object") throw new TypeError(`fills[${index}] must be an object`);
const fill = raw as JsonObject, executionId = textValue(`fills[${index}].execution_id`, fill.execution_id);
if (seen.has(executionId)) throw new RangeError("execution_id values must be unique"); seen.add(executionId);
const fillQuantity = numberValue(`fills[${index}].quantity`, fill.quantity, {positive: true}), fillPrice = numberValue(`fills[${index}].price`, fill.price, {positive: true});
if (cumulative + fillQuantity > orderQuantity + 1e-12) throw new RangeError("fills exceed original order quantity");
cumulative += fillQuantity; notional += fillQuantity * fillPrice;
const leaves = Math.max(0, orderQuantity - cumulative);
states.push({execution_id: executionId, last_quantity: fillQuantity, last_price: fillPrice, cumulative_quantity: cumulative, leaves_quantity: leaves, status: leaves === 0 ? "filled" : "partially-filled"});
});
const leaves = orderQuantity - cumulative, status = fillsRaw.length === 0 ? "new" : leaves === 0 ? "filled" : "partially-filled";
return {model: "partial-fill-residual-accounting", order_quantity: orderQuantity, cumulative_quantity: cumulative, leaves_quantity: leaves, fill_notional: notional, average_fill_price: cumulative ? notional / cumulative : null, execution_count: fillsRaw.length, fill_states: states, status, state: status};
}
export function queuePositionAheadVolume(ordersRaw: unknown, targetIdRaw: unknown): JsonObject {
if (!Array.isArray(ordersRaw) || ordersRaw.length === 0) throw new RangeError("orders must be a non-empty list");
const targetId = textValue("target_order_id", targetIdRaw), ids = new Set<string>(), sequences = new Set<number>();
const parsed = ordersRaw.map((raw, index) => {
if (!raw || typeof raw !== "object") throw new TypeError(`orders[${index}] must be an object`);
const order = raw as JsonObject, orderId = textValue(`orders[${index}].order_id`, order.order_id);
if (ids.has(orderId)) throw new RangeError("order_id values must be unique"); ids.add(orderId);
const sequence = integerValue(`orders[${index}].arrival_sequence`, order.arrival_sequence, true);
if (sequences.has(sequence)) throw new RangeError("arrival_sequence values must be unique"); sequences.add(sequence);
const side = textValue(`orders[${index}].side`, order.side);
if (!["buy", "sell"].includes(side)) throw new RangeError("order side must be buy or sell");
if (typeof order.displayed !== "boolean") throw new TypeError("displayed must be boolean");
return {order_id: orderId, side, price: numberValue(`orders[${index}].price`, order.price, {positive: true}), remaining_quantity: numberValue(`orders[${index}].remaining_quantity`, order.remaining_quantity, {positive: true}), arrival_sequence: sequence, displayed: order.displayed};
});
const target = parsed.find(order => order.order_id === targetId);
if (!target) throw new RangeError("target order is not present");
if (!target.displayed) throw new RangeError("canonical queue position requires a displayed target");
const samePrice = parsed.filter(order => order.side === target.side && Math.abs(order.price - target.price) <= 1e-12);
const displayed = samePrice.filter(order => order.displayed).sort((a, b) => a.arrival_sequence - b.arrival_sequence);
const ahead = displayed.filter(order => order.arrival_sequence < target.arrival_sequence), behind = displayed.filter(order => order.arrival_sequence > target.arrival_sequence);
const aheadVolume = ahead.reduce((sum, order) => sum + order.remaining_quantity, 0);
return {model: "displayed-price-time-fifo-ahead-volume", target_order_id: targetId, side: target.side, price: target.price, ahead_order_count: ahead.length, ahead_volume: aheadVolume, displayed_queue_rank: ahead.length + 1, behind_order_count: behind.length, behind_volume: behind.reduce((sum, order) => sum + order.remaining_quantity, 0), hidden_same_price_quantity_excluded: samePrice.filter(order => !order.displayed).reduce((sum, order) => sum + order.remaining_quantity, 0), ahead_order_ids: ahead.map(order => order.order_id), state: ahead.length ? "queued-behind-displayed-volume" : "front-of-displayed-queue"};
}
export function icebergReplenishment(totalRaw: unknown, initialRaw: unknown, displaySizeRaw: unknown, fillsRaw: unknown, priorityRaw: unknown): JsonObject {
const total = numberValue("total_quantity", totalRaw, {positive: true});
let displayed = numberValue("initial_display_quantity", initialRaw, {positive: true});
const tranche = numberValue("display_size", displaySizeRaw, {positive: true});
let priority = integerValue("starting_priority_sequence", priorityRaw, true);
if (displayed > total) throw new RangeError("initial displayed quantity cannot exceed total quantity");
if (!Array.isArray(fillsRaw)) throw new TypeError("fills must be a list");
let reserve = total - displayed, executed = 0, unfilledRequested = 0, replenishments = 0;
const events: JsonObject[] = [];
const replenish = () => {
if (displayed !== 0 || reserve <= 0) return;
const amount = Math.min(tranche, reserve); reserve -= amount; displayed = amount; priority += 1; replenishments += 1;
events.push({type: "replenish", quantity: amount, new_priority_sequence: priority, displayed_remaining: displayed, reserve_remaining: reserve});
};
fillsRaw.forEach((rawFill, index) => {
let remainingRequest = numberValue(`fills[${index}]`, rawFill, {positive: true});
while (remainingRequest > 1e-12) {
replenish();
if (displayed <= 0) { unfilledRequested += remainingRequest; break; }
const amount = Math.min(displayed, remainingRequest);
displayed -= amount; remainingRequest -= amount; executed += amount;
events.push({type: "fill", fill_request_index: index, quantity: amount, displayed_remaining: displayed, reserve_remaining: reserve, priority_sequence: priority});
}
replenish();
});
const remainingTotal = displayed + reserve;
return {model: "zero-displayed-tranche-replenishment", total_quantity: total, display_size: tranche, executed_quantity: executed, displayed_remaining: displayed, reserve_remaining: reserve, total_remaining: remainingTotal, replenishment_count: replenishments, current_priority_sequence: priority, unfilled_requested_quantity: unfilledRequested, events, state: remainingTotal === 0 ? "filled" : reserve > 0 ? "active-reserve" : "displayed-only"};
}
export function marketableOrderSweep(incomingRaw: unknown, restingRaw: unknown): JsonObject {
if (!incomingRaw || typeof incomingRaw !== "object" || !Array.isArray(restingRaw)) throw new TypeError("incoming_order must be an object and resting_orders a list");
const incoming = incomingRaw as JsonObject, incomingId = textValue("incoming_order.order_id", incoming.order_id), side = textValue("incoming_order.side", incoming.side);
if (!["buy", "sell"].includes(side)) throw new RangeError("incoming side must be buy or sell");
const orderType = textValue("incoming_order.order_type", incoming.order_type);
if (!["market", "limit"].includes(orderType)) throw new RangeError("order_type must be market or limit");
const tif = textValue("incoming_order.time_in_force", incoming.time_in_force);
if (!["GTC", "IOC"].includes(tif)) throw new RangeError("time_in_force must be GTC or IOC");
const quantity = numberValue("incoming_order.quantity", incoming.quantity, {positive: true});
let limit: number | null = null;
if (orderType === "limit") limit = numberValue("incoming_order.limit_price", incoming.limit_price, {positive: true});
else if (incoming.limit_price != null) throw new RangeError("market order must not specify limit_price");
const arrivalSequence = integerValue("incoming_order.arrival_sequence", incoming.arrival_sequence, true), ids = new Set([incomingId]), sequences = new Set<number>();
const parsed = restingRaw.map((raw, index) => {
if (!raw || typeof raw !== "object") throw new TypeError(`resting_orders[${index}] must be an object`);
const order = raw as JsonObject, orderId = textValue(`resting_orders[${index}].order_id`, order.order_id);
if (ids.has(orderId)) throw new RangeError("order_id values must be unique"); ids.add(orderId);
const restingSide = textValue(`resting_orders[${index}].side`, order.side);
if (!["buy", "sell"].includes(restingSide)) throw new RangeError("resting side must be buy or sell");
const sequence = integerValue(`resting_orders[${index}].priority_sequence`, order.priority_sequence, true);
if (sequences.has(sequence)) throw new RangeError("priority_sequence values must be unique"); sequences.add(sequence);
return {order_id: orderId, side: restingSide, price: numberValue(`resting_orders[${index}].price`, order.price, {positive: true}), remaining_quantity: numberValue(`resting_orders[${index}].remaining_quantity`, order.remaining_quantity, {positive: true}), priority_sequence: sequence};
});
const opposite = side === "buy" ? "sell" : "buy";
const candidates = parsed.filter(order => order.side === opposite).sort((a, b) => side === "buy" ? a.price - b.price || a.priority_sequence - b.priority_sequence : b.price - a.price || a.priority_sequence - b.priority_sequence);
let remaining = quantity, notional = 0;
const fills: JsonObject[] = [];
for (const resting of candidates) {
const marketable = limit == null || (side === "buy" ? resting.price <= limit : resting.price >= limit);
if (!marketable) break;
const amount = Math.min(remaining, resting.remaining_quantity);
if (amount <= 0) continue;
resting.remaining_quantity -= amount; remaining -= amount; notional += amount * resting.price;
fills.push({resting_order_id: resting.order_id, price: resting.price, quantity: amount, resting_remaining_quantity: resting.remaining_quantity});
if (remaining <= 1e-12) { remaining = 0; break; }
}
const filled = quantity - remaining;
let residualAction = "none";
if (remaining > 0) {
if (orderType === "limit" && tif === "GTC") {
parsed.push({order_id: incomingId, side, price: limit as number, remaining_quantity: remaining, priority_sequence: arrivalSequence}); residualAction = "posted";
} else residualAction = "canceled";
}
const finalBook = parsed.filter(order => order.remaining_quantity > 0).sort((a, b) => {
if (a.side !== b.side) return a.side === "buy" ? -1 : 1;
return a.side === "buy" ? b.price - a.price || a.priority_sequence - b.priority_sequence : a.price - b.price || a.priority_sequence - b.priority_sequence;
});
const status = remaining === 0 ? "filled" : filled > 0 && residualAction === "posted" ? "partially-filled-and-posted" : filled > 0 ? "partially-filled-and-canceled" : residualAction === "posted" ? "posted" : "unfilled-and-canceled";
return {model: "single-venue-price-time-marketable-sweep", incoming_order_id: incomingId, incoming_side: side, requested_quantity: quantity, filled_quantity: filled, residual_quantity: remaining, fill_notional: notional, average_fill_price: filled ? notional / filled : null, fills, residual_action: residualAction, final_book: finalBook, status, state: status};
}
export function calculate(topicId: string, inputs: JsonObject): JsonObject {
if (!inputs || typeof inputs !== "object" || Array.isArray(inputs)) throw new TypeError("inputs must be an object");
if (topicId === "D12-F04-A01") return limitOrderLifecycle(inputs.order_id, inputs.order_quantity, inputs.events);
if (topicId === "D12-F04-A02") return cancelReplacePriority(inputs.original, inputs.replacement);
if (topicId === "D12-F04-A03") return partialFillResidual(inputs.order_quantity, inputs.fills);
if (topicId === "D12-F04-A04") return queuePositionAheadVolume(inputs.orders, inputs.target_order_id);
if (topicId === "D12-F04-A05") return icebergReplenishment(inputs.total_quantity, inputs.initial_display_quantity, inputs.display_size, inputs.fills, inputs.starting_priority_sequence);
if (topicId === "D12-F04-A06") return marketableOrderSweep(inputs.incoming_order, inputs.resting_orders);
throw new RangeError(`unsupported topic_id: ${topicId}`);
}
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