---
applyTo: "Fuchs_DataService/**"
---

# Fuchs_DataService Instructions

## Overview
`Fuchs_DataService` is a .NET 10 Windows Service (via **Topshelf**) that synchronises MFR entity data into the Fuchs SQL database on a configurable schedule.

## Key Classes
| Class | Role |
|-------|------|
| `FdsMainModule` | Entry point — builds `LoggerFactory`, creates `FdsService`, runs Topshelf |
| `FdsService` | Topshelf `ServiceControl` — owns `PeriodicHostedService` lifecycle |
| `PeriodicHostedService` | Runs one or more `PeriodicJobDefinition` jobs independently |
| `FdsMfr : IFdsMfr` | Singleton business logic — registered via DI constructor injection |
| `FdsMfrClient` | Wraps `MFRClient` + SQL write logic; instantiated per-use inside `FdsMfr` |
| `Archive` (FdsZip) | SevenZip wrapper; created per-use, accepts optional `ILogger<Archive>` |
| `FdsConfig` | Static config accessor — reads from `appsettings.json` under `Fds:` key |
| `FdsShared` | Static SQL/stream helpers — use `FdsDebug.DebugLog` for errors in static methods |
| `FdsDebug` | Legacy static logger — **only for use in static helper methods** |
| `FdsLoggerProvider` | Custom `ILoggerProvider`: Debug output + file + prepared DB logging |

## Dependency Injection
`FdsMfr` is the main business singleton. It receives:
- `ILogger<FdsMfr>` — for its own logging
- `ILoggerFactory` — to create loggers for `FdsMfrClient` and `Archive` it instantiates

```csharp
// FdsService constructor
var mfr = new FdsMfr(loggerFactory.CreateLogger<FdsMfr>(), loggerFactory);
```

## Configuration (`appsettings.json`)
```json
{
  "ConnectionStrings": {
    "fuchs_fds_ConnectionString": "...",
    "fuchs_ConnectionString": "..."
  },
  "Fds": {
    "ExecutionFrequency_Minutes": 15,
    "DebugDetails": false,
    "MFR_UserName": "...",
    "MFR_Password": "...",
    "MFR_host": "https://..."
  }
}
```

## Rules
- Do **not** use `System.Configuration.ConfigurationManager` — always use `FdsConfig` / `IConfiguration`.
- Do **not** use `OCMS` or `OCMS_sharp`.
- Use `FdsSqlOptions` for all SQL calls (`getSQLDatatable_async`, `getSQLDataSet_async`, `setSQLValue_async`).
- Classes that run async work must use `async/await` — never `.Wait()` or `.Result` in new code.
- Add new periodic jobs as `PeriodicJobDefinition` entries in `FdsService` — see `periodic_service.instructions.md`.
- Logging: see `logging.instructions.md`.