# KST4Contest Project Context

Last reviewed: 2026-08-25

This file is the durable technical project context for KST4Contest. It is not a user manual and not a replacement for the changelog. Current code, tests and authoritative external specifications remain the source of truth when this document is stale or ambiguous.

## Purpose

KST4Contest is a Java/JavaFX desktop client for ON4KST chat focused on VHF/UHF/microwave contest workflows. It combines chat handling with contest-oriented station prioritisation, sked/timeline workflows and integrations with logging, aircraft-scatter, rotor and DX-cluster tooling.

## Current Architecture

- Java 21 / JavaFX desktop application built with Maven.
- Main code is under `src/main/java/kst4contest/`.
- Responsibilities are separated across controller, service, logic, model, utility and view areas.
- Network/parser/service/controller/UI boundaries should remain explicit.
- Long-running network/message processing must tolerate malformed or incomplete external input without terminating processing threads.
- JavaFX `ObservableList` state is a UI projection, not the canonical worker-thread domain store.

## Important Invariants

### Chat identity

- Full callsign variants can be distinct chat-member identities.
- Category is part of chat identity.
- Base-call normalization is permitted only for explicitly base-call-wide functions.
- Worked status is shared across suffix variants of the same base call.
- Monitoring a variant such as `DN9APW-2` or `DN9APW-70` intentionally monitors the base call `DN9APW`.
- Suffixes must not be globally interpreted as a band/category/frequency.

### Band and availability semantics

- ON4KST categories 2 and 3 are the main operational categories, but unexpected category values must fail safely.
- `NOT-QRV` overrides positive inferred band-availability hints.
- Unknown/missing frequency, QRB, QTF or similar external data must remain unavailable rather than becoming a fabricated zero/default.
- Features that depend on frequency should use the current/actual QRG according to current implemented rules; do not silently revert to a fixed 144 MHz default.

### JavaFX/threading

Conceptually:

```text
thread-safe canonical domain state
        |
        | projection on JavaFX Application Thread
        v
JavaFX ObservableList / UI state
```

`MessageBusManagementThread` must not directly iterate or mutate UI-bound JavaFX collections. UI-visible changes should cross the controller/UI boundary and run on the JavaFX Application Thread.

## External Interfaces

Treat current implementation/tests and authoritative upstream documentation as source of truth before modifying any interface.

Known integration areas include:

- ON4KST chat;
- AirScout;
- UCXLog / DXLog UDP XML (`contactinfo`, `contactreplace`);
- Win-Test UDP;
- PSTRotator TCP;
- DXCluster;
- local SQLite persistence.

CR/LF framing, XML framing, ports/transports, callsign normalization and frequency formatting are protocol behaviour and must not be changed as incidental cleanup.

## User Workflow / UI Invariants

- Contest operating speed and low-friction interaction are primary goals.
- Incidental code changes must not unexpectedly change selection, focus, sorting, tab state, map zoom or prefilled text.
- Map reset clears the selected target without changing zoom unless explicitly redesigned.
- Station selection preserves the established `/cq callsign` prefill behaviour.
- Sending without an explicitly selected send category preserves the established Main-category fallback unless explicitly changed.

## Autoanswer / Beacon

- Automated-message loops must be prevented.
- Cooldown/minimum-interval rules must be preserved.
- A reply rejected before a complete valid TX item is queued must not consume cooldown.
- Current implementation/tests define the exact message markers and timer details.

## Build / Verification

- Use the repository Maven wrapper (`.\mvnw.cmd` on Windows).
- The project uses Java 21 / JavaFX 21.x at this context snapshot.
- JUnit 5/Mockito, PMD and SpotBugs are part of the verification environment.
- Build/test configuration has historically allowed some test/static-analysis failures not to fail the process exit code. Always read actual summaries/reports.

## Documentation Surfaces

- German and English manuals under `github_docs/`.
- Repository README.
- Eleventy-based project website under `website/`.
- Changelog/release communication.
- This technical project context under `docs/PROJECT_CONTEXT.md`.

After implementation use targeted documentation-impact checks. Do not run a complete manual audit unless explicitly requested, release preparation is broad, or targeted checks indicate systematic drift.

## Website / Deployment Relationship

The repository contains the KST4Contest website under `website/`, published separately from the desktop application build.

Current website/deployment scripts and update-feed behaviour must be inspected before changes; do not rely on historical assumptions.

## Important Decisions and Workarounds

- Preserve full callsign/category identity while applying base-call normalisation only to specifically defined features.
- Keep canonical worker-thread domain state separate from JavaFX UI projections.
- Preserve the established JavaFX WebView/Leaflet workaround that avoids problematic CSS 3D transforms unless the original rendering/flicker issue has been reproduced and the replacement is validated.
- Deliberate test data, comments and Easter eggs are preserved unless explicitly changed.

## Planned Technical Direction

These are planned directions, not necessarily implemented behaviour:

- improve propagation/path modelling using higher-resolution terrain data, including Copernicus GLO-30;
- increase terrain/path sampling through a dedicated service/API;
- support high-precision station locations (e.g. extended Maidenhead locators or direct GPS coordinates) while preserving compatible standard display;
- improve terrain/Fresnel/diffraction/refraction modelling for VHF/UHF/microwave use;
- evaluate/implement richer tropospheric/scatter models;
- continue integration of aircraft-scatter and propagation data into reachability/contest workflows.

Before implementing planned items, re-check current decisions and obtain a fresh concept approval.

## Known Limitations / Maintenance Notes

- Historical project context is useful but may be stale; current code/tests win.
- External service/API behaviour must be verified against current upstream documentation when uncertain.
- Screenshots in manuals/website may need targeted replacement after visible UI changes; never fabricate them.

## Recent Significant Changes

### 2026-08-25 – Durable project context introduced

- Added a persistent technical context layer so future agents/developers can understand architecture, invariants and cross-project dependencies without replaying chat history.
- Documentation maintenance uses targeted impact assessment rather than a full audit after every implementation.

## Related Projects / Integration Points

### KST4Contest website

- Source is maintained inside this repository under `website/`.
- User-facing feature/configuration changes may require a targeted website check.

### hamradioonline.de

- Serves as the broader amateur-radio umbrella site/infrastructure context.
- KST4Contest content/download/manual links and related knowledge content may intersect with the broader site strategy.

### Webserver / hosting infrastructure

- KST4Contest website and other hamradioonline services depend on the hosting environment.
- Operational details should be maintained in a private infrastructure context rather than duplicated into this public project context when sensitive.

### Planned propagation / terrain service

- Intended to provide richer terrain/propagation data (including higher-resolution Copernicus GLO-30-based processing) to KST4Contest and potentially related hamradioonline tooling.
- Interface contracts must be documented on both provider and consumer sides when they become concrete.
