Architecture

Architecture Notes

This is a Next.js App Router application. Most logic lives in client components, with a small set of server routes acting as a backend-for-frontend.

Frontend Layers

• UI/state orchestration:
  • TankifyCalculator is the main container component and owns most state.
  • It separates "draft" inputs (what the user is editing) from "committed" inputs (what results are based on).
• Map/station presentation:
  • MapPicker renders the map, markers, and overlays.
  • Map rendering is done with MapLibre in the browser and an OpenFreeMap style.
  • Stations are fetched by bounds ("search here") and displayed on the map and in a list.
• Reusable UI:
  • LocationField provides address autocomplete with an overlay dropdown and a clear button.
  • SliderNumberField combines a slider with a numeric input.
• i18n:
  • Components are driven by a translation schema (t) instead of hardcoded strings.

Backend-For-Frontend

The app uses internal API routes for:

• Gas station lookup (E-Control) with caching and optional debug payloads.
• OSRM table distances for station sorting/labels.
• IP-based location resolution with provider fallback.
• FX rate and currency name fetching with caching.
• Brand logo proxying/caching and local fallback.
• Runtime configuration used by the client (for example debug UI enablement in production).

External Dependencies (Network)

• E-Control fuel stations API (Austria)
• OSRM public routing endpoints
• Nominatim for geocoding and suggestions
• IP location providers
• OpenFreeMap style/tiles endpoints
• Frankfurter FX API
• Logo sources (logo.dev / favicon service) via /api/logo

Caching Strategy

• /api/stations: in-memory cache keyed by rounded bounds for 15 minutes (lean payload only).
• /api/drive-distances: short in-memory cache (20 seconds).
• /api/fx/*: in-memory cache (currencies 24h, rates 1h; serves stale briefly on failure).
• /api/logo: in-memory cache with ETag support and long TTL.

All caches are process-local (per container instance) and reset on restart.