Create the database (once):
```
createdb cyberhybridhub
```
Copy and edit environment variables:
```
cp .env.example .env
```
Install dependencies and run (from this server/ directory):
```
dart pub get
dart run bin/server.dart
```

The API listens on http://localhost:3000 by default (PORT in .env).

Endpoints

Method	Path	Auth
`GET`	`/v1/me/profile`	`Authorization: Bearer <Firebase ID token>`
`PUT`	`/v1/me/profile`	same
`POST`	`/v1/me/incoming-question`	same — pushes a question to the client via SignalR
`POST`	`/v1/me/questions/bootstrap`	ensure starter question at login
`GET`	`/v1/me/questions`	list unanswered questions (queue order)
`POST`	`/v1/me/questions/{id}/answer`	submit answer (`{"answer": 0}` default)
`POST`	`/v1/me/questions/{id}/defer`	move question to end of queue

SignalR — incoming questions

Hub URL: http://localhost:3000/hubs/questions

The Flutter app calls POST /v1/me/questions/bootstrap once at login to ensure a starter question exists (random correct answer from -10 to 10) when the user has none. After sign-in it connects to SignalR and listens for ReceiveQuestion. On each new WebSocket connection the API only delivers an existing unanswered question — it does not create new rows.

Client payload (correct answer is not sent):

{
  "id": "uuid",
  "assignedUserId": "firebase-uid",
  "text": "...",
  "sentAt": "...",
  "unansweredCount": 2
}

unansweredCount is the number of unanswered rows for that user (shown in the app when greater than 1).

questions table: id (UUID), assigned_user_id, question_text, user_response (nullable), correct_answer, created_at, modified_at.

Background question pipeline

A background worker runs inside the API process (enabled by default). On each interval it walks registered users, fetches data from public web APIs, and enqueues pipeline questions when the user's queue is not full.

Env var	Default	Purpose
`QUESTION_WORKER_ENABLED`	`true`	Set to `false` to disable the worker
`QUESTION_WORKER_INTERVAL_SECONDS`	`60`	Seconds between maintenance cycles
`QUESTION_PIPELINE_TEST_MODE`	`false`	Use random -10..10 starter-style questions instead of API copy

External APIs used

REST Countries — population and capital facts
Open-Meteo — current temperature by city

Branching flow

Track choice — user swipes toward +10 (weather) or -10 (geography).
Geography — yes/no population threshold, then capital confirmation; wrong population guess triggers a recovery question.
Weather — yes/no warm/cool for a random European city, then a follow-up to continue weather or switch to geography.

When a user submits an answer (POST .../answer), the pipeline evaluates the response and may immediately create the next branched question and push it over SignalR.

Pipeline state is stored in user_pipeline_state; questions may include source_tag, pipeline_key, and pipeline_step columns (migration 003_question_pipeline.sql).

Test from the shell (replace ID_TOKEN):

curl -s -X POST http://localhost:3000/v1/me/incoming-question \
  -H "Authorization: Bearer ID_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"text":"What is your preferred contact method?"}'

Flutter client

Run the app with the API URL (defaults to http://localhost:3000):

flutter run --dart-define=API_BASE_URL=http://localhost:3000