# EV Booking System — Business Domain Reference

Reference doc for business rules and domain vocabulary. Pull this up alongside `tickets.md` while working any ticket — it explains *why* a rule exists, not how to code it (see the architecture plan for implementation shape).

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## 1. Glossary

| Term | Meaning |
|---|---|
| **EV Company** | A vehicle operator/fleet owner. Plain reference data — not a tenant (see §4). |
| **Destination** | A city/town served by routes. Used as both origin and endpoint. |
| **Departure Time Slot** | A shared catalog of times (e.g. "06:00 AM"); attached to routes via a pivot, not owned by one route. |
| **EV Route** | Company + From Destination + To Destination + round-trip flag + one or more Time Slots + pricing per Vehicle Option. |
| **Vehicle Option** | What the customer books: `front_seat`, `back_seat`, or `whole_vehicle`. Not a numbered seat — see §2. |
| **Pickup/Dropoff Address** | Free-text address (+ optional lat/lng) the customer supplies when booking — where the EV meets/drops them. Captured per Booking, not a catalog entity — see §2a. |
| **Booking** | A customer's reservation on one Route + Date + Time Slot, with customer-supplied pickup/dropoff addresses. Covers one or more Vehicle Option selections (e.g. `front_seat` + `back_seat` together), each with its own passenger count — see `booking_vehicle_options` in §2. Once `confirmed`, staff assign a driver/vehicle to it — see §5a. |
| **Payment** | One attempt to pay for a Booking through a gateway (may retry after failure). |
| **Refund** | A reversal against a specific successful Payment (not against the Booking directly). |

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## 2. Vehicle Options & Inventory (the core domain quirk)

Unlike a bus-booking system, **there is no seat map and no capacity tracking in v1**:

- A Booking can select **more than one Vehicle Option** in the same booking (e.g. `front_seat` + `back_seat` for a customer traveling with a companion) — stored as one row per selected option in `booking_vehicle_options` (`booking_id`, `vehicle_option`, `passenger_count`, `unit_price`, `line_total`), not a single column on `bookings`. `bookings.price` is the sum of every line's `line_total`.
- Each Vehicle Option can appear **at most once per booking** (no two separate `front_seat` lines — bump `passenger_count` instead). `whole_vehicle` cannot be combined with any other option in the same booking, since it already covers the entire vehicle.
- Any number of *different bookings* can book the same Route + Date + Time Slot. The system does not check whether a "Whole Vehicle" or "Back Seat" is already taken by someone else.
- The **only inventory rule enforced in code** is: **max Front Seats per booking**, checked against `passenger_count` on the `front_seat` line (`BOOKING_FRONT_SEAT_MAX_PER_BOOKING`, currently `1` — a per-booking constraint, not a per-trip inventory check).
- Back Seat and Whole Vehicle availability are controlled by **blunt config toggles**, not database rows:
  - `BOOKING_BACK_SEAT_ENABLED` — whether Back Seat can be selected at all right now.
  - `BOOKING_WHOLE_VEHICLE_ENABLED` — whether Whole Vehicle can be selected at all right now.
  - `BOOKING_FRONT_SEAT_MAX_PER_BOOKING` — currently `1`, expressed as config in case it ever needs to change.
- This is a **deliberate v1 simplification**, not an oversight. Real per-route/date/time-slot capacity holding (e.g. "only 1 Whole Vehicle booking allowed per trip") is an explicitly deferred future phase — see §7. `booking_vehicle_options` is deliberately shaped so that phase can be built as a new query against it (`sum(passenger_count) group by vehicle_option` for a route/date/time-slot) rather than a schema rework.
- Consequence: double-booking of "Whole Vehicle" is possible by design until that future phase ships. Admins reconcile manually via the Filament Booking list (filterable by route + date + time).

**Do not build seat inventory, seat locking, or availability-checking logic against real capacity in current-phase tickets** unless a ticket explicitly says so — it's out of scope until the "Future Scalability" phase.

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## 2a. Pickup & Dropoff (door-to-door, v1)

The real-world business model is **door-to-door**: the EV drives to wherever the customer requests, not a fixed depot. So, unlike a bus system, `EvRoute` does **not** carry a pickup/dropoff location — those live on `Booking` itself:

- `pickup_address` (free text) + optional `pickup_lat`/`pickup_lng`.
- `dropoff_address` (free text) + optional `dropoff_lat`/`dropoff_lng`.
- Captured at booking time (customer types/pins it), not selected from a catalog.

**Deliberate v1 simplification**: there is no fixed "meet-up checkpoint" catalog and no automatic "customer is too far" detection (no geofencing/service-radius check). In reality, dispatch sometimes asks a too-far customer to meet at a fixed checkpoint instead of door-to-door — that checkpoint catalog (`pickup_locations`/`dropoff_locations` tied to `EvRoute`) is **deferred**, see §7. Until then, "meet at a checkpoint" is handled operationally (dispatch calls the customer), not in the schema.

**Do not build a `pickup_locations`/`dropoff_locations` catalog or attach pickup/dropoff FKs to `EvRoute`** in current-phase tickets — `Booking` carries the address directly instead.

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## 3. Pricing

- `RoutePricing` holds one price per (Route, Vehicle Option) pair.
- When a Booking is created, the resolved price is **snapshotted** onto `bookings.price` and never re-read from `RoutePricing` again. If admin edits pricing later, existing bookings keep their original price. This is intentional — historical bookings must never silently reprice.

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## 4. Tenancy

- **Single tenant.** EV Companies are just rows in a table that the one admin team manages — there is no per-company admin login isolation, no data scoping by company for admin users, and no Spatie Permission "teams" feature in v1.
- If multi-tenant admin isolation is ever needed, it layers onto the existing role/permission tables later without migrating the core booking/route schema (see architecture plan §30).

---

## 5. Booking Lifecycle (status machine)

```
pending_payment ──(payment succeeds)──▶ confirmed
pending_payment ──(customer/admin cancels, no payment yet)──▶ cancelled
confirmed ──(refund processed)──▶ cancelled
pending_payment ──(TTL expiry, future phase)──▶ expired
```

- A Booking is created `pending_payment` — it exists before any money moves.
- It only becomes `confirmed` once the linked Payment succeeds (via the KBZ webhook, not client-reported success — see §6).
- Cancelling a `confirmed` (paid) Booking must go through the Refund flow first — never flip status to `cancelled` on a paid booking without a corresponding refund attempt.

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## 5a. Driver & Vehicle Assignment

Once a Booking is `confirmed` (paid), dispatch assigns who's actually doing the trip — a real driver and a real EV, not a catalog lookup:

- `bookings.driver_name`, `driver_phone`, `car_plate_number`, `car_model` — plain nullable columns directly on `Booking`, not a separate `drivers`/`vehicles` catalog. Null until assigned; `car_model` stays nullable even after assignment (optional detail).
- Filled in via `AssignDriverAction`, gated to `confirmed` bookings only — assigning a driver to a `pending_payment`/`cancelled`/`expired` booking is rejected (`DriverAssignmentNotAllowedException`). Staff can re-run it to reassign a different driver/vehicle as long as the booking is still `confirmed`.
- Filament-only for now: the "Assign Driver" action on the admin Booking list/detail page (`manage_bookings` permission), no customer-facing write path. The values are exposed read-only on the booking API response (`GET /api/v1/bookings*`) so a confirmed customer can see who's picking them up.
- **Deliberate v1 simplification**: no `drivers`/`vehicles` catalog, no driver scheduling/availability, no linking a driver to an `EvCompany`. If driver roster management becomes a real need, this is the natural point to introduce a `Driver`/`Vehicle` catalog and swap these free-text columns for FKs — not scoped now.

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## 6. Payment Domain (ported from `bnf_event`, refined)

The existing KBZ Mini App payment code at `/home/marcspecta/company_projects/bnf_event` (`app/Strategies/Payments/KBZMiniApp.php`, `KBZPay.php`, `BasePayment.php`, `app/Services/PaymentService.php`) is the reference implementation being ported and refined — **read it before starting any Payment-module ticket.**

**What's being kept (business logic, still true in the new system):**
- KBZ's signing scheme: flatten the request array (excluding `sign`/`sign_type`) into sorted `key=val` pairs joined by `&`, append `&key={merchant_key}`, SHA-256 hash, uppercase. Every request sets `sign_type = "SHA256"`.
- Three KBZ API operations matter: `kbz.payment.precreate` (start payment), `kbz.payment.queryorder` (poll/verify status), `kbz.payment.refund` (reverse a payment). All are outbound HTTPS calls; refund additionally requires **mTLS** (client cert + key + CA bundle).
- Client-driven confirmation pattern as a fallback/defense-in-depth: after the client reports payment complete, the server **re-verifies by calling `queryorder`** rather than trusting the client payload blindly.
- Refund reason is a required, human-readable string sent to KBZ and stored for audit.

**What's changing (the agreed refinements — see architecture plan §17–19, §34):**
- Old: 3x duplicated `switch($payment_type)` at each call site to pick a gateway class. New: a `PaymentGatewayFactory` resolves `PaymentGatewayInterface` implementations by `PaymentMethod` enum, registered once.
- Old: raw associative arrays passed through `PaymentInterface` methods. New: typed DTOs (`PaymentRequestData`, `PaymentResultData`, `RefundResultData`).
- Old: KBZ credentials (merchant code, keys, URLs) lived in a DB singleton `payment_setting` table, editable via admin UI. New: `.env` + `config/services.php` (`KBZ_*` vars) — no DB table, no Filament resource for secrets.
- Old: payment/refund state overloaded onto the `orders` table (`payment_status` int, `order_status` string, `payment_remark` text) with no structured history. New: dedicated `payments` + `refunds` tables (`refunds.payment_id` FK to `payments.id`), each with a proper status enum.
- Old: refund amount was effectively hardcoded to full-amount (the `refund_amount` param was commented out in `KBZMiniApp::refund`). New: `RefundBookingAction` explicitly supports **partial refunds**, validated against the remaining refundable balance on the Payment.
- Old: no real inbound webhook — only client-driven confirmation + server-side re-verification. New: add a genuine **signed inbound webhook** (`POST /api/v1/webhooks/kbz`) that verifies KBZ's signature before processing — confirm KBZ's actual inbound-webhook signature spec as part of the Phase 5 webhook ticket (flagged risk, KBZ's spec was never implemented in the old code, only referenced by a `notify_url` config value).
- Old: status transitions applied inline inside `BasePayment::paymentStatusChange()`, tightly coupling the gateway class to booking-status logic. New: gateway strategies only return a `PaymentResultData`/`RefundResultData` — booking-status changes happen in **listeners** reacting to `PaymentCompleted` / `PaymentFailed` / `RefundProcessed` domain events, keeping the gateway strategy ignorant of the Booking module.

**Webhook idempotency**: KBZ may retry the notify webhook. The handler must check the Payment's current status before transitioning it — never assume a webhook call is the first/only delivery.

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## 7. Deferred / Future (do not build yet)

- Fixed pickup/dropoff checkpoint catalog (`pickup_locations`/`dropoff_locations`, FK'd from `EvRoute`) for when a customer is too far for door-to-door — v1 is pure free-text `pickup_address`/`dropoff_address` on `Booking` (see §2a). Revisit if checkpoint meet-ups become common enough to need a curated, reusable list instead of ad-hoc dispatch calls.
- Real per-route/date/time-slot capacity holding + availability checks (see §2).
- DB row locking (`SELECT ... FOR UPDATE`) for booking concurrency — only needed once real inventory exists.
- Multi-tenant admin isolation (Spatie Permission "teams").
- Multiple payment gateways beyond KBZ (the factory is designed to support this later with zero call-site changes).
- Booking auto-expiry TTL job for stale `pending_payment` bookings.
- Customer notifications (booking confirmation, payment status push).

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## 8. External Actors & Access Boundaries

- **Mini App / Mobile App**: customer-facing clients, authenticate via Sanctum token, full customer ability set (create/view/cancel own bookings, initiate payment).
- **FastAPI AI Agent** (external service, owns Gemini/tool-calling — Laravel has zero AI SDK code): authenticates via a Sanctum token scoped to a **restricted ability set** — `route:read`, `booking:create`, `booking:read` only. It must **never** be able to refund, cancel someone else's booking, or write catalog/pricing data. It never touches the database directly, only `/api/v1`.
- **Filament Admin**: session-based, role-gated (`super_admin`, `admin`, `support`), the only place catalog/pricing mutation and refund initiation happen for staff.
