FTM302 · The FTM Domain

Learning materials — teaching, weekly quizzes, weekly tests. Examination paper — timed paper with marking guide.

Credits 4 · Hours 40 · Prereqs FTM301 · Semester 3

Source

No external course exists. The primary sources are the code, the KB articles, and the prod data:

• backend/booking/models.py — Enquiry, EnquiryBand, EnquiryBandMember
• backend/payments/ — invoices, deposits, Wise, payouts
• backend/bands/search*.py — ranking and blending
• backend/geography/ — regions, points, OSM import
• KB: payments, messaging, state machines, venue intelligence

This module exists because engineering without it produces confidently wrong work.

Objectives

• Narrate a booking from first enquiry to band payout, naming the model and guard at every step.
• Apply the money rules: 18% booking fee, no VAT, FTM is agent not principal, the band sees only its band fee, owed = band net fee − band paid amount, Invoice.band_paid_amount is the only ledger.
• Say how a search result is ordered, and why.
• Name what is never shown to a band, and where that is enforced.

Weekly map

Wk	Topic
1–2	enquiry lifecycle; progressive (soft) auth for anonymous clients
3	quotes, client replies, the invoice coupling
4	BOOKED and its guards — every state transition and where it is enforced
5–6	money: fee arithmetic, deposits, Wise recipient accounts, payout batches, admin-only finality
7–8	search: FTS, embeddings, blended scoring, rank tiers, local-first, the single-booking inflation trap
9–10	geography: regions, OSM import, synthetic regions, place IDs, venue vs region classification
11	adjacent domains: forms/questionnaires, venue intelligence, reviews, channels
12	disclosure rules: is_direct, directly_enquired_at, budget fields, raw requirements

FTM labs

• L1 draw the enquiry state machine from the code; list every guard and its enforcement point.
• L2 account for every message in one real prod enquiry thread — sender, channel, which job processed it.
• L3 find a reachable state that violates a stated rule.
• L4 compute owed for five scenarios and reconcile against the ledger.

Project

The domain law tests — fee arithmetic, band-visible field set, payout owed — as executable specifications the team keeps.

Reading list

There is no textbook for FTM’s domain. These three are for the general shape of the problem, not the specifics.

Book	Author, year	Use	Free
Designing Data-Intensive Applications, ch. 2–3	Martin Kleppmann, 2017	Data models and schema evolution; why the enquiry graph looks like this	No
Domain-Driven Design	Eric Evans, 2003	Ubiquitous language, bounded contexts, invariants as first-class — read ch. 1–6 only	No
Implementing Domain-Driven Design	Vaughn Vernon, 2013	Aggregates and consistency boundaries, if the DDD framing lands	No

For the FTM-specific facts, the source of truth is the KB, not a book. Every claim in this module must be verifiable against backend/ or a real message thread.

Assessment

Coursework 45% (L1–L4) · Project 35% · Check-off viva 10% · Exam 10%.

Deferred: induction and invariants (MIT 6.042J) — read after the first money defect, not before.