# CLAUDE.md

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

## Project Overview

OpenNest is a Windows desktop application for CNC nesting — arranging 2D parts on material plates to minimize waste. It imports DXF drawings, places parts onto plates using rectangle-packing algorithms, and can export nest layouts as DXF or post-process them to G-code for CNC cutting machines.

## Build

This is a .NET 8 solution using SDK-style `.csproj` files targeting `net8.0-windows`. Build with:

```bash
dotnet build OpenNest.sln
```

NuGet dependencies: `ACadSharp` 3.1.32 (DXF/DWG import/export, in OpenNest.IO), `System.Drawing.Common` 8.0.10, `ModelContextProtocol` + `Microsoft.Extensions.Hosting` (in OpenNest.Mcp).

No test projects exist in this solution.

## Architecture

Five projects form a layered architecture:

### OpenNest.Core (class library)
Domain model, geometry, and CNC primitives organized into namespaces:

- **Root** (`namespace OpenNest`): Domain model — `Nest` → `Plate[]` → `Part[]` → `Drawing` → `Program`. A `Nest` is the top-level container. Each `Plate` has a size, material, quadrant, spacing, and contains placed `Part` instances. Each `Part` references a `Drawing` (the template) and has its own location/rotation. A `Drawing` wraps a CNC `Program`. Also contains utilities: `Helper`, `Align`, `Sequence`, `Timing`.
- **CNC** (`CNC/`, `namespace OpenNest.CNC`): `Program` holds a list of `ICode` instructions (G-code-like: `RapidMove`, `LinearMove`, `ArcMove`, `SubProgramCall`). Programs support absolute/incremental mode conversion, rotation, offset, bounding box calculation, and cloning.
- **Geometry** (`Geometry/`, `namespace OpenNest.Geometry`): Spatial primitives (`Vector`, `Box`, `Size`, `Spacing`, `BoundingBox`, `IBoundable`) and higher-level shapes (`Line`, `Arc`, `Circle`, `Polygon`, `Shape`) used for intersection detection, area calculation, and DXF conversion.
- **Converters** (`Converters/`, `namespace OpenNest.Converters`): Bridges between CNC and Geometry — `ConvertProgram` (CNC→Geometry), `ConvertGeometry` (Geometry→CNC), `ConvertMode` (absolute↔incremental).
- **Math** (`Math/`, `namespace OpenNest.Math`): `Angle` (radian/degree conversion), `Tolerance` (floating-point comparison), `Trigonometry`, `Generic` (swap utility), `EvenOdd`. Note: `OpenNest.Math` shadows `System.Math` — use `System.Math` fully qualified where both are needed.
- **Collections** (`Collections/`, `namespace OpenNest.Collections`): `ObservableList<T>`, `DrawingCollection`.
- **Quadrant system**: Plates use quadrants 1-4 (like Cartesian quadrants) to determine coordinate origin placement. This affects bounding box calculation, rotation, and part positioning.

### OpenNest.Engine (class library, depends on Core)
Nesting algorithms. `NestEngine` orchestrates filling plates with parts.

- **RectanglePacking/**: `FillBestFit` (single-item fill, tries horizontal and vertical orientations), `PackBottomLeft` (multi-item bin packing, sorts by area descending). Both operate on `Bin`/`Item` abstractions.
- **CirclePacking/**: Alternative packing for circular parts.
- `NestItem`: Input to the engine — wraps a `Drawing` with quantity, priority, and rotation constraints.
- `BestCombination`: Finds optimal mix of normal/rotated columns for grid fills.

### OpenNest.IO (class library, depends on Core)
File I/O and format conversion. Uses ACadSharp for DXF/DWG support.

- `DxfImporter`/`DxfExporter` — DXF file import/export via ACadSharp.
- `NestReader`/`NestWriter` — custom ZIP-based nest format (XML metadata + G-code programs).
- `ProgramReader` — G-code text parser.
- `Extensions` — conversion helpers between ACadSharp and OpenNest geometry types.

### OpenNest.Mcp (console app, depends on Core + Engine + IO)
MCP server for Claude Code integration. Exposes nesting operations as MCP tools over stdio transport. Published to `~/.claude/mcp/OpenNest.Mcp/`.

- **Tools/InputTools**: `load_nest`, `import_dxf`, `create_drawing` (built-in shapes or G-code).
- **Tools/SetupTools**: `create_plate`, `clear_plate`.
- **Tools/NestingTools**: `fill_plate`, `fill_area`, `fill_remnants`, `pack_plate`.
- **Tools/InspectionTools**: `get_plate_info`, `get_parts`, `check_overlaps`.
- `NestSession` — in-memory state across tool calls (current Nest, standalone plates/drawings).

### OpenNest (WinForms WinExe, depends on Core + Engine + IO)
The UI application with MDI interface.

- **Forms/**: `MainForm` (MDI parent), `EditNestForm` (MDI child per nest), plus dialogs for plate editing, auto-nesting, DXF conversion, cut parameters, etc.
- **Controls/**: `PlateView` (2D plate renderer with zoom/pan), `DrawingListBox`, `DrawControl`, `QuadrantSelect`.
- **Actions/**: User interaction modes — `ActionSelect`, `ActionAddPart`, `ActionClone`, `ActionFillArea`, `ActionZoomWindow`, `ActionSetSequence`.
- **Post-processing**: `IPostProcessor` plugin interface loaded from DLLs in a `Posts/` directory at runtime.

## File Format

Nest files (`.zip`) contain:
- `info` — XML with nest metadata and plate defaults
- `drawing-info` — XML with drawing metadata (name, material, quantities, colors)
- `plate-info` — XML with plate metadata (size, material, spacing)
- `program-NNN` — G-code text for each drawing's cut program
- `plate-NNN` — G-code text encoding part placements (G00 for position, G65 for sub-program call with rotation)

## Tool Preferences

Always use Roslyn Bridge MCP tools (`mcp__RoslynBridge__*`) as the primary method for exploring and analyzing this codebase. It is faster and more efficient than file-based searches. Use it for finding symbols, references, diagnostics, type hierarchies, and code navigation. Only fall back to Glob/Grep when Roslyn Bridge cannot fulfill the query.

## Code Style

- Always use `var` instead of explicit types (e.g., `var parts = new List<Part>();` not `List<Part> parts = new List<Part>();`).

## Key Patterns

- OpenNest.Core uses multiple namespaces: `OpenNest` (root domain), `OpenNest.CNC`, `OpenNest.Geometry`, `OpenNest.Converters`, `OpenNest.Math`, `OpenNest.Collections`.
- `ObservableList<T>` provides ItemAdded/ItemRemoved/ItemChanged events used for automatic quantity tracking between plates and drawings.
- Angles throughout the codebase are in **radians** (use `Angle.ToRadians()`/`Angle.ToDegrees()` for conversion).
- `Tolerance.Epsilon` is used for floating-point comparisons across geometry operations.