# Visione Backend Architecture

## Layout
- `controllers/`: Drogon `HttpController` classes.
- `services/`: application/business logic.
- `repositories/`: database helpers and migrations.
- `common/`: reusable HTTP, auth, crypto, email and validation utilities.
- `migrations/`: versioned SQL files.
- `scripts/generate_openapi.py`: minimal OpenAPI route extractor.
- `docs/openapi/`: manual OpenAPI contract documents.
- `scripts/lab/`: local Streamlit frontend for visual endpoint testing.
- `docs/`: product, API, schema and milestone documentation.

## Drogon Usage
Controllers use Drogon route macros and return JSON with
`HttpResponse::newHttpJsonResponse`. Database access uses
`drogon::orm::DbClient` with raw parameterized SQL placeholders.

The codebase does not use Drogon generated models or `Mapper<T>`. Raw SQL stays
in repository/database helpers because the schema is still evolving.

## Local Email
OTP emails are sent to MailHog over SMTP. MailHog keeps messages local and
inspectable through its web UI.

## Password Hashing
User passwords use PBKDF2-HMAC-SHA256 with per-password random salts and 210000
iterations. This is intentionally slower than a plain SHA-256 digest and is
available through OpenSSL, which is already a Drogon dependency in this project.
Legacy `sha256$` password hashes are rejected instead of silently accepted.

## OpenAPI Generation
`scripts/generate_openapi.py` scans Drogon `ADD_METHOD_TO` route macros in
`controllers/*.h` and extracts only paths, HTTP methods, operation ids, tags and
path parameters. It merges those route skeletons with
`docs/openapi/visione.openapi.yaml`, which owns summaries, request bodies,
responses, schemas and examples. The manual file uses JSON-compatible YAML so
the CMake `openapi` target can run without extra Python packages and writes
`build/openapi/visione.openapi.json`.

If the manual YAML contains an operation that no longer exists in the Drogon
route list, generation fails unless that operation is explicitly marked
`x-manual-only: true`.

## Visione Lab
`scripts/lab/` is a Streamlit dev frontend for visual endpoint testing. It is
intentionally separate from the real product frontend and should stay small:
forms, uploads and response rendering only. Run it with uv from `scripts/lab/`.