# Codebase simplification and design patterns

This doc summarizes recent improvements and suggested next steps for readability, extension, and consistency.

## Done

### 1. Single place for template/reachability (DRY)

- **Added** `lib/graph/templateRefs.ts`: `isReachable`, `resolveExtendsRef`, `getTemplateRefs`.
- **Refactored** `config/renderingLogic.ts` and `useRenderingNodeState.ts` to use these helpers instead of duplicating the same logic.
- **Pattern:** Extract shared pure helpers into a small lib module; keep call sites thin and consistent.

### 2. Naming and comments

- **Renamed** `outputMenuRegistry.tsx` → `outputMenuHandlers.tsx` (no registry, only helpers).
- **Updated** `rendering.ts` and `sourceRenderingLogic.ts`: output menu is described as coming from the node descriptor (`getOutputMenuContent`), not a separate registry.
- **Documented** `NodeMenubar`: extra content can come from props or from the descriptor (`getNodeMenuExtraContent`).
- **Documented** `nodeTypes.ts`: clarifies React Flow types vs node type id (nodeRegistry).

### 3. Central pipeline entry

- **rendering.ts** documents the 3-step pipeline, how to add a source/output type, and points to `templateRefs.ts` for shared helpers.

## Design patterns in use

| Pattern        | Where                                      |
|----------------|--------------------------------------------|
| **Registry**   | nodeRegistry, sourceRenderingLogic         |
| **Builder**    | nodeTypeBuilder (descriptor per node type) |
| **Pipeline**   | Resolve → Render → Display (rendering.ts)   |
| **Strategy**   | Source logic per node type; output menu per descriptor |
| **Shared helpers** | templateRefs, outputMenuHandlers, renderingUtils |

## Suggested next steps

1. **CanvasPage** (~950 lines): Split into smaller units, e.g.:
   - `useCanvasGraph()` or similar for graph state and connection rules.
   - A dedicated component for the context menu (add node, paste, etc.).
   - Keeps CanvasPage as composition + layout.

2. **useRenderingNodeState**: Consider extracting:
   - Signature building (config/edges/variables/functions/data) into a pure function or small module, e.g. `buildSourceSignatures(nodes, edges, id, incomingIds, getConfigContent)`.
   - Makes the hook easier to read and the logic testable in isolation.

3. **Config types**: If you add more output types (e.g. Mermaid), consider a small registry API (`registerConfigType`, `getConfigType`) instead of a single large `CONFIG_TYPES` array, so extensions can register without editing the core list.

4. **Consistent node shape in lib**: `templateRefs` uses `EdgeLike` / `NodeLike`; other graph code uses inline `{ source, target }` or `nodes as ...`. You could standardize on the same minimal types where appropriate to reduce casts.