julian
8a8e74561d
Pivot from the hardware/integrity layer to the parking operation. All wiki-only; no code yet. Core principle throughout: business entities are projections over the signed append-only event log, never mutable tables. New concepts: parking-session, tariff (composable/versioned, FX-ready), shift (manned-only Z-report), capacity-occupancy, validation-discounts, reporting-analytics, clock-integrity, ticket-encoding, anti-passback. New entities: permit, opencv-anpr-service, blocklist. Decisions: session-model, vision-service (host-side ANPR + vehicle verification; scoped AGPL exception for the isolated service). Updates: append-only-event-chain (new event types + vision witness), local-jwt-auth (drop 8h expiry -> until logout; code change pending), lpr-camera (host-side recognition supersedes edge-AI), standing-decisions (AGPL exception), open-questions (+FX, +pay-station money corners, backup). Deferred + flagged: intercom/help-call, receipts/refunds/change, FX engine, lane topology (#1).
47 lines
2.1 KiB
Markdown
47 lines
2.1 KiB
Markdown
---
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type: concept
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tags: [parking, domain, business, pricing, revenue]
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sources: []
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updated: 2026-06-15
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status: open
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---
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# Validation & Discounts
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A merchant (shop, hotel, clinic) **validates** a customer's parking so they pay less or nothing —
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a common revenue/retention feature that modifies what a [[parking-session]] owes.
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## Model: a discount is a signed event, applied at fee time
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A validation is **not** an edit to the session or a mutable "discount applied" flag — same reason
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as everything else ([[threat-model]]: an operator/merchant could otherwise fake free parking). It's
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recorded so the fee computation and the audit both see it:
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- A **discount/validation event** references the session: `{ sessionRef, kind, value, issuedBy,
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ts }` — e.g. *2 hours free*, *€5 off*, *flat €1*, *100% off*. Appended + signed
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([[append-only-event-chain]]).
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- The [[tariff]] fee function applies eligible validations when computing what's due at the pay
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station: `due = max(0, tariff_fee − discounts)` (or time-based: subtract validated minutes before
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pricing). Pure + reproducible, like the base fee.
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- The `payment` event then records gross fee, discount total, and net paid — so revenue reporting
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([[reporting-analytics]]) can show **discount leakage** (how much was given away, by whom).
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## How a validation is presented
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- **Merchant terminal / portal** stamps the customer's ticket id (or plate) — issues the validation
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event for that session.
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- Or a **validation code** the customer enters at the pay station.
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- Either way it ties to the session by **ticket id or plate** ([[parking-session]] identity).
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## Anti-abuse
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Because each validation is signed and attributed (`issuedBy`), over-validation by a colluding
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merchant is **visible to [[reconciliation]]** (a merchant validating far more than their footfall is
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an anomaly), rather than invisible free parking.
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## Open
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- Validation types the site needs (free hours / fixed amount / percentage / flat rate).
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- Whether merchants self-serve (portal/terminal) or the operator applies it.
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- Caps (max discount, max per merchant/day).
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