10 — Interaction Specification (Fees Module)

Platform interaction detail for the Fees screens; extends 00-shared/08. Motion tokens Mo.* = 00-shared/02 §6; F = focus/touch baseline.

1. Phone / touch

Dues list: tap row → invoice detail; tap inline "Collect" icon-button (44 dp, tooltip) → record-payment sheet; RefreshIndicator; infinite scroll with bottom AppProgress.
Invoices list (student): tap card → detail; pull-to-refresh.
Record payment: full-height AppBottomSheet (r-xl, drag handle) with keyboard avoidance (resizeToAvoidBottomInset: true); CTA pinned above keyboard.
Generate invoice: AppDialog (format): student dropdown + discounts editor; button "Generate invoice".
Receipt view: render + Share action (proposed); long-press number to copy.

Amounts: decimal numeric pad; .next field order; Ctrl/Cmd+Enter submit on forms.
Desktop N = new structure (list screen); E = edit (detail) — app-level.
Hover states on cards/rows (00-shared/02 §9); hover scale on badges (proposed).
Right-click row menu for structure rows (Edit / Delete; Duplicate (planned)).

List transitions Mo.m-entrance stagger 40 ms; card fade for deletion Mo.m-base.
Amount changes animate by counting (AnimatedSwitcher/IntrinsicCounter) over Mo.m-base, only when server-confirmed — never optimistic.
Status chip swaps: AnimatedSwitcher Mo.fast, cross-fade only.
Sheet: standard spring up Mo.m-base; dialog Mo.m-base scale+fade.
Reduced-motion: all Mo.m-instant static; no counting animation, no parallax.

Interaction	Trigger	Feedback
Record payment submit	tap `FilledButton`	spinner (icon→spinner), disabled inputs, live-region announce
Generate invoice	dialog submit	spinner; then snackbar "Invoice issued"
Refresh dues	pull	`RefreshIndicator`; success silent
Overpay attempt (amount > due)	edge	inline tertiary banner "Exceeds remaining balance" + preview resulting `paidAmount`
Amount focus	`MoneyField`	select-all, hide grouping suffix until blur
Copy reference	long-press on `transactionReference` rows	snackbar "Copied {ref}"
Back from dirty sheet	system-back	(proposed) "Discard payment?" dialog
409 duplicate-invoice	submit response	inline `AppBanner(info)`, dialog stays
409 paid/cancelled	submit response	close + snackbar(info)

Retry always on AppErrorState; 429 → countdown text, no auto-retry (00-shared/07 §4 api 100/min).
Snackbar error persists ≥ 4 s (00-shared/03 §A); success < 3 s.
Status changes (e.g. invoice → paid) announce via Semantics(liveRegion).

(proposed) deeplinks: studylyon://fees/dues, studylyon://fees/structures/:id, studylyon://fees/invoices/:id, studylyon://payments/receipts/:id.
Notification tap → invoice detail (when invoice.updated/receipt notification lands; (planned)).
Amounts copying: long-press MoneyAmount → copy raw number + currency.

Client interaction	Server semantics (must not diverge)
Sheet "Record payment" success	server 201 + recompute `paidAmount/status` (`fees.service.ts:168-176`)
Sheet retry with same key	replay original doc (`fees.service.ts:148-152`)
Generate invoice success	server 201, `_id` returned; `issuedAt` set server-side (`fees.service.ts:122-130`)
Duplicate generation 409	treated as already-exists navigation (`fees.service.ts:107-115`)
Refund `amount` reduction	server caps refunds ≤ payment (`payments.service.ts:81-86`)
Online payment	`transactionReference` from server (`payments.service.ts:215-217`); local refs never sent
Any amount displayed	source of truth = server field; formatting client-side only (06 §0; OQ-1)