# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

This is a C# .NET 8.0 solution for Epson TM-m30III thermal receipt printer integration. The solution consists of a core SDK library (Inspectron.Epson) and multiple applications for production printing, configuration, testing, and discovery.

## Solution Structure

### Core Projects

- **Inspectron.Epson** - Core SDK library providing printer communication, status monitoring, and ESC/POS commands
- **EpsonPrintService** - Production console application with SignalR-based remote job source and systemd service support
- **ConfigurationPannel** - ASP.NET Razor Pages web application for printer configuration with embedded print server
- **Discovery** - Printer network discovery utilities (SLP, ENPC, mDNS)
- **EpsonTest** - Test project for SDK functionality
- **TestClient** - SDK usage examples and testing
- **SendPrintJob** - Direct print job submission utility

## Common Build Commands

```bash
# Build entire solution
dotnet build Inspectron.Epson.slnx

# Build specific project
dotnet build Inspectron.Epson/Inspectron.Epson.csproj
dotnet build EpsonPrintService/EpsonPrintService.csproj
dotnet build ConfigurationPannel/ConfigurationPannel.csproj

# Run projects
dotnet run --project EpsonPrintService/EpsonPrintService.csproj
dotnet run --project ConfigurationPannel/ConfigurationPannel.csproj

# Run tests
dotnet test EpsonTest/EpsonTest.csproj

# Clean build artifacts
dotnet clean
```

## Architecture

### Three-Layer Architecture

1. **SDK Layer (Inspectron.Epson)**
   - `EpsonPrinter`: Main facade for printer operations (TCP/IP, async/await)
   - `EpsonCommands`: Static ESC/POS command definitions
   - `EpsonImageConverter`: Image processing with Floyd-Steinberg dithering
   - `EpsonPrinterDiscovery`: Network printer discovery (SLP, ENPC)
   - Status classes: PrinterStatus, OfflineStatus, ErrorStatus, PaperSensorStatus, OverallStatus
   - Exception hierarchy: EpsonPrinterException → EpsonConnectionException, EpsonCommandException

2. **Print Server Layer (PrintServer/ namespace in Inspectron.Epson)**
   - `PrintServer`: Manager for printer queues, coordinates multiple printers by IP
   - `PrinterQueue`: Per-printer queue with retry logic (ConcurrentQueue + priority ConcurrentStack)
   - `PrintLoop`: Orchestrator connecting job sources to print server
   - `IPrintJobSource`: Strategy pattern for job sources (SignalRPrintJobSource, SingleJobSource, NoOpPrintJobSource)
   - `IPrintService`: Print workflow orchestration (EpsonPrintService implementation)
   - `IPrinter`: Printer model abstraction (TM-T30III, TM-U220II)
   - `PrinterFactory`: Factory pattern for creating printer instances by model ID

3. **Application Layer**
   - EpsonPrintService: Production deployment with Ninject DI, SignalR remote jobs, systemd service
   - ConfigurationPannel: ASP.NET Core with Microsoft.Extensions.DI, cookie authentication, hosted service pattern

### Dependency Injection Patterns

The codebase uses TWO different DI containers:

**Ninject (EpsonPrintService console app):**
```csharp
StandardKernel kernel = new();
kernel.Bind<IPrintJobSource, SignalRPrintJobSource>().To<SignalRPrintJobSource>().InSingletonScope();
kernel.Bind<IPrintService>().To<EpsonPrintService>();
kernel.Bind<IAssignedPrinterRepository>().ToConstant(config);
kernel.Bind<IPrinterFactory>().To<PrinterFactory>().InSingletonScope();
kernel.Bind<PrintServer>().ToSelf().InSingletonScope();
```

**Microsoft.Extensions.DependencyInjection (ConfigurationPannel ASP.NET):**
```csharp
builder.Services.AddSingleton<UserService>();
builder.Services.AddSingleton<ConfigurationManager>();
builder.Services.AddHostedService<PrintServerHostedService>();
```

When adding new services, match the DI pattern of the project you're working in.

### Key Interfaces and Abstractions

- `IPrintJobSource`: Pluggable job sources (async via Channel<PrintJob>)
- `IPrintService`: Print workflow execution (PrintAsync returns bool for success/failure)
- `IAssignedPrinterRepository`: Maps work area IDs to printer IPs (GetAssignedPrinter)
- `IPrinterConfigurationSource`: Provides printer configuration (address, font size, logo)
- `IPrinter`: Printer model-specific operations (InitAsync, PrintImageAsync, SetFontSizeAsync, PrintTextAsync, Cut)
- `IPrinterFactory`: Creates IPrinter from model ID byte (0x01 = TM-T30III, 0x13 = TM-U220II)

### Print Job Flow

```
PrintLoop.StartAsync()
  → IPrintJobSource.GetNextJobAsync() [blocks until job available]
  → IAssignedPrinterRepository.GetAssignedPrinter(job.AreaId) [returns printer IP]
  → PrintServer.SubmitJob(printerIp, job)
    → PrinterQueue.Enqueue(job) [per-printer queue]
      → ProcessQueueAsync() [background loop]
        → IPrintService.PrintAsync(printerIp, job)
          → Get configuration, connect to printer, detect model
          → IPrinterFactory.CreatePrinterFromId()
          → Initialize printer, print logo (if configured), set font size
          → Print text content, cut paper
          → Return true/false for success
        → On failure: retry up to 3 times via priority queue
```

### Configuration System

**EpsonPrintServiceConfiguration** (config.json):
```json
{
  "GroupId": "67e534f8e86e816689323023",
  "RestaurantId": "63e37295bd6f26dbd36164c0",
  "PrinterConfigurations": {
    "192.168.1.100": {
      "Address": "192.168.1.100:9100",
      "FontSize": 2,
      "LogoFilename": "logo.png",
      "AreaId": "kitchen"
    }
  }
}
```

This class implements BOTH `IPrinterConfigurationSource` and `IAssignedPrinterRepository` for dual roles.

### Printer Communication

- **Protocol**: ESC/POS over TCP/IP (port 9100 default)
- **Encoding**: UTF-8 (ESC t 255) or CP852 (ESC t 18) with System.Text.Encoding.CodePages
- **Status Queries**: DLE EOT real-time commands (0x10 0x04 + sub-command byte)
- **Image Printing**: Two modes
  - Raster mode (GS ( L): 384px width for TM-T30III
  - Bit-image mode (ESC *): 8-dot or 24-dot with single/double density
- **Error Handling**: All async operations throw EpsonConnectionException or EpsonCommandException on failure

## Adding New Printer Models

1. Get printer ID byte via `EpsonPrinter.GetPrinterIdAsync()` (GS I 1 command)
2. Create new class implementing `IPrinter` in `Inspectron.Epson/PrintServer/Printers/`
3. Implement required methods: InitAsync, PrintImageAsync, SetFontSizeAsync, PrintTextAsync, Cut
4. Add case to `PrinterFactory.CreatePrinterFromId()` with the printer ID byte
5. Test with actual hardware - different models have different image widths and positioning

## Testing Printer Connectivity

```csharp
// Basic connection test
await using var printer = new EpsonPrinter(logger);
await printer.ConnectAsync("192.168.1.100");
var status = await printer.GetOverallStatusAsync();
Console.WriteLine($"Status: {status.StatusText}, Ready: {status.IsReady}");

// Full diagnostics
var diagnostics = new EpsonDiagnostics(logger);
var report = await diagnostics.RunFullDiagnosticsAsync("192.168.1.100");
Console.WriteLine(report);
```

## Deployment

### Systemd Service (Linux)

EpsonPrintService includes systemd service file (`epson.service`):
```bash
# Copy files to deployment directory
cp -r EpsonPrintService/bin/Debug/net8.0/* /home/pi/epson_service/

# Install and start service
sudo cp epson.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable epson.service
sudo systemctl start epson.service

# Check status
sudo systemctl status epson.service
```

### ASP.NET Hosted Service

ConfigurationPannel runs print server as `IHostedService`:
```bash
dotnet run --project ConfigurationPannel/ConfigurationPannel.csproj
```
Access web UI at http://localhost:5000 (default login credentials in users.json).

## Important Implementation Notes

### PrinterQueue Retry Logic

Failed print jobs are automatically retried up to 3 times via priority queue:
- Failed jobs pushed to `ConcurrentStack<PrintJob>` (LIFO)
- Priority stack checked before main queue in `ProcessQueueAsync()`
- RetryCount incremented on each failure
- Jobs with RetryCount >= 3 are discarded

### Image Processing Pipeline

When printing images via `EpsonPrinter.LoadImageAsync()`:
1. Load image with SixLabors.ImageSharp
2. Resize maintaining aspect ratio (max width: printer-specific)
3. Convert to grayscale
4. Apply Floyd-Steinberg dithering for 1-bit black/white conversion
5. Pack pixels to byte-aligned format
6. Generate column format for bit-image mode (ESC * 33)

### SignalR Job Source

`SignalRPrintJobSource` connects to `https://api.gastrojames.ch/hubs/internal`:
- Authentication: Bearer token from configuration
- Group: Joins via GroupId from configuration
- Message: "PrintJob" with { WorkingAreaId, Content }
- Uses Channel<PrintJob> for async producer-consumer pattern

### Font Sizing

Font magnification is 1-8x for both width and height:
- ESC ! command: bits 4-7 control size
- Formula: `(widthMagnifier - 1) << 4 | (heightMagnifier - 1)`
- Example: Size 2 = 0x11 (2x width, 2x height)

## Common Troubleshooting

### "Printer not found" or connection timeout
- Verify IP address with `ping <printer-ip>`
- Check printer is on same network/VLAN
- Ensure port 9100 is not blocked by firewall
- Try printer discovery: run Discovery project

### "Cover open" or "Paper end" errors
- Check `OverallStatus.Recommendations` for specific issues
- Common: Cover not fully closed, paper roll empty/misaligned

### Image not printing or garbled
- Verify image width matches printer specification (384px for TM-T30III)
- Check image file path is accessible
- Ensure printer model supports raster graphics (TM-T30III does, older models may not)

### SignalR connection failures
- Check GroupId and RestaurantId in config.json
- Verify network connectivity to api.gastrojames.ch
- Check bearer token expiration

### ConfigurationPannel login issues
- Default credentials in users.json (BCrypt hashed)
- Cookie expiration: 8 hours with sliding expiration
- Authentication uses CookieAuthenticationDefaults scheme
