# Canvas UX Improvements - Master Plan

**Created:** January 2026
**Status:** Planning
**Branch:** `feature/studio-enhancement`

## Overview

This plan addresses three major UX issues in the Canvas Builder:

1. **Resizable Panels** - Right pane (chat/config) is fixed at 384px, cannot be adjusted
2. **Disabled Palette Items** - Model, Solver, Algorithm, Surrogate are grayed out and not draggable
3. **Solver Type Selection** - Solver node should allow selection of solver type (NX Nastran, Python, etc.)

---

## Phase 7: Resizable Panels

### Current State
- Left sidebar: Fixed 240px (expanded) or 56px (collapsed)
- Right panel (Chat/Config): Fixed 384px
- Canvas: Takes remaining space

### Requirements
- Users should be able to drag panel edges to resize
- Minimum/maximum constraints for usability
- Persist panel sizes in localStorage
- Smooth resize with proper cursor feedback

### Implementation

#### 7.1 Create Resizable Panel Hook
```typescript
// hooks/useResizablePanel.ts
interface ResizablePanelState {
  width: number;
  isDragging: boolean;
  startDrag: (e: React.MouseEvent) => void;
}

function useResizablePanel(
  key: string,
  defaultWidth: number,
  minWidth: number,
  maxWidth: number
): ResizablePanelState
```

#### 7.2 Update CanvasView Layout
- Wrap left sidebar with resizer
- Wrap right panel with resizer  
- Add visual drag handles (thin border that highlights on hover)
- Add cursor: col-resize on hover

#### 7.3 Files to Modify
| File | Changes |
|------|---------|
| `hooks/useResizablePanel.ts` | NEW - Resize hook with localStorage persistence |
| `pages/CanvasView.tsx` | Add resizers to left/right panels |
| `components/canvas/ResizeHandle.tsx` | NEW - Visual resize handle component |

#### 7.4 Constraints
| Panel | Min | Default | Max |
|-------|-----|---------|-----|
| Left (Palette/Files) | 200px | 240px | 400px |
| Right (Chat/Config) | 280px | 384px | 600px |

---

## Phase 8: Enable All Palette Items

### Current State
- Model, Solver, Algorithm, Surrogate are marked `canAdd: false`
- They appear grayed out with "Auto-created" text
- Users cannot drag them to canvas

### Problem Analysis
These nodes were marked as "synthetic" because they're derived from:
- **Model**: From `spec.model.sim.path`
- **Solver**: From model's solution type
- **Algorithm**: From `spec.optimization.algorithm`
- **Surrogate**: From `spec.optimization.surrogate`

However, users need to:
1. Add a Model node when creating a new study from scratch
2. Configure the Solver type
3. Choose an Algorithm
4. Enable/configure Surrogate

### Solution: Make All Items Draggable

#### 8.1 Update NodePalette
```typescript
// All items should be draggable
export const PALETTE_ITEMS: PaletteItem[] = [
  { 
    type: 'model', 
    label: 'Model', 
    canAdd: true,  // Changed from false
    description: 'NX/FEM model file',
  },
  { 
    type: 'solver', 
    label: 'Solver', 
    canAdd: true,  // Changed from false
    description: 'Analysis solver',
  },
  // ... etc
];
```

#### 8.2 Handle "Singleton" Nodes
Some nodes should only exist once on the canvas:
- Model (only one model per study)
- Solver (one solver)
- Algorithm (one algorithm config)
- Surrogate (optional, one)

When user drags a singleton that already exists:
- Option A: Show warning toast "Model already exists"
- Option B: Select the existing node instead of creating new
- **Recommended**: Option B (select existing)

#### 8.3 Update SpecRenderer Drop Handler
```typescript
const onDrop = useCallback(async (event: DragEvent) => {
  const type = event.dataTransfer.getData('application/reactflow');
  
  // Check if singleton already exists
  const SINGLETON_TYPES = ['model', 'solver', 'algorithm', 'surrogate'];
  if (SINGLETON_TYPES.includes(type)) {
    const existingNode = nodes.find(n => n.type === type);
    if (existingNode) {
      selectNode(existingNode.id);
      showNotification(`${type} already exists - selected it`);
      return;
    }
  }
  
  // Create new node...
}, [...]);
```

#### 8.4 Default Data for New Node Types
```typescript
function getDefaultNodeData(type: NodeType, position) {
  switch (type) {
    case 'model':
      return {
        name: 'Model',
        sim: { path: '', solver: 'nastran' },
        canvas_position: position,
      };
    case 'solver':
      return {
        name: 'Solver',
        type: 'nxnastran',  // Default solver
        solution_type: 'SOL101',
        canvas_position: position,
      };
    case 'algorithm':
      return {
        name: 'Algorithm',
        type: 'TPE',
        budget: { max_trials: 100 },
        canvas_position: position,
      };
    case 'surrogate':
      return {
        name: 'Surrogate',
        enabled: false,
        model_type: 'MLP',
        min_trials: 20,
        canvas_position: position,
      };
    // ... existing cases
  }
}
```

#### 8.5 Files to Modify
| File | Changes |
|------|---------|
| `components/canvas/palette/NodePalette.tsx` | Set `canAdd: true` for all items |
| `components/canvas/SpecRenderer.tsx` | Handle singleton logic in onDrop |
| `lib/spec/converter.ts` | Ensure synthetic nodes have proper IDs |
| `hooks/useSpecStore.ts` | Add model/solver/algorithm to addNode support |

---

## Phase 9: Solver Type Selection

### Current State
- Solver node shows auto-detected solution type (SOL101, etc.)
- No ability to change solver engine or configure it

### Requirements
1. Allow selection of solver engine type
2. Configure solution type
3. Support future solver types

### Solver Types to Support

| Solver | Description | Status |
|--------|-------------|--------|
| `nxnastran` | NX Nastran (built-in) | Current |
| `mscnastran` | MSC Nastran (external) | Future |
| `python` | Python-based solver | Future |
| `abaqus` | Abaqus (via Python API) | Future |
| `ansys` | ANSYS (via Python API) | Future |

### Solution Types per Solver

**NX Nastran / MSC Nastran:**
- SOL101 - Linear Static
- SOL103 - Normal Modes
- SOL105 - Buckling
- SOL106 - Nonlinear Static
- SOL111 - Frequency Response
- SOL112 - Transient Response
- SOL200 - Design Optimization

**Python Solver:**
- Custom (user-defined)

### Schema Updates

#### 9.1 Update AtomizerSpec Types
```typescript
// types/atomizer-spec.ts

export type SolverEngine = 
  | 'nxnastran' 
  | 'mscnastran' 
  | 'python'
  | 'abaqus'
  | 'ansys';

export type NastranSolutionType = 
  | 'SOL101' 
  | 'SOL103' 
  | 'SOL105' 
  | 'SOL106' 
  | 'SOL111' 
  | 'SOL112'
  | 'SOL200';

export interface SolverConfig {
  /** Solver engine type */
  engine: SolverEngine;
  
  /** Solution type (for Nastran) */
  solution_type?: NastranSolutionType;
  
  /** Custom solver script path (for Python solver) */
  script_path?: string;
  
  /** Additional solver options */
  options?: Record<string, unknown>;
}

export interface Model {
  sim?: {
    path: string;
    solver: SolverConfig;  // Changed from just 'nastran' string
  };
  // ...
}
```

#### 9.2 Update SolverNode Component
```typescript
// components/canvas/nodes/SolverNode.tsx

function SolverNodeComponent(props: NodeProps<SolverNodeData>) {
  const { data } = props;
  
  return (
    <BaseNode {...props} icon={<Cpu size={16} />} iconColor="text-violet-400">
      <div className="flex flex-col gap-1">
        <span className="text-sm font-medium">{data.engine || 'nxnastran'}</span>
        <span className="text-xs text-dark-400">
          {data.solution_type || 'Auto-detect'}
        </span>
      </div>
    </BaseNode>
  );
}
```

#### 9.3 Solver Configuration Panel
Add to `NodeConfigPanelV2.tsx`:

```typescript
function SolverNodeConfig({ spec }: SpecConfigProps) {
  const { patchSpec } = useSpecStore();
  const solver = spec.model?.sim?.solver || { engine: 'nxnastran' };
  
  const handleEngineChange = (engine: SolverEngine) => {
    patchSpec('model.sim.solver.engine', engine);
  };
  
  const handleSolutionTypeChange = (type: NastranSolutionType) => {
    patchSpec('model.sim.solver.solution_type', type);
  };
  
  return (
    <>
      <div>
        <label className={labelClass}>Solver Engine</label>
        <select 
          value={solver.engine}
          onChange={(e) => handleEngineChange(e.target.value as SolverEngine)}
          className={selectClass}
        >
          <option value="nxnastran">NX Nastran</option>
          <option value="mscnastran">MSC Nastran</option>
          <option value="python">Python Script</option>
        </select>
      </div>
      
      {(solver.engine === 'nxnastran' || solver.engine === 'mscnastran') && (
        <div>
          <label className={labelClass}>Solution Type</label>
          <select
            value={solver.solution_type || ''}
            onChange={(e) => handleSolutionTypeChange(e.target.value as NastranSolutionType)}
            className={selectClass}
          >
            <option value="">Auto-detect from model</option>
            <option value="SOL101">SOL101 - Linear Static</option>
            <option value="SOL103">SOL103 - Normal Modes</option>
            <option value="SOL105">SOL105 - Buckling</option>
            <option value="SOL106">SOL106 - Nonlinear Static</option>
            <option value="SOL111">SOL111 - Frequency Response</option>
            <option value="SOL112">SOL112 - Transient Response</option>
          </select>
        </div>
      )}
      
      {solver.engine === 'python' && (
        <div>
          <label className={labelClass}>Solver Script</label>
          <input
            type="text"
            value={solver.script_path || ''}
            onChange={(e) => patchSpec('model.sim.solver.script_path', e.target.value)}
            placeholder="/path/to/solver.py"
            className={inputClass}
          />
          <p className="text-xs text-dark-500 mt-1">
            Python script that runs the analysis
          </p>
        </div>
      )}
    </>
  );
}
```

#### 9.4 Files to Modify
| File | Changes |
|------|---------|
| `types/atomizer-spec.ts` | Add SolverEngine, SolverConfig types |
| `components/canvas/nodes/SolverNode.tsx` | Show engine and solution type |
| `components/canvas/panels/NodeConfigPanelV2.tsx` | Add SolverNodeConfig |
| `lib/canvas/schema.ts` | Update SolverNodeData |
| Backend: `config/spec_models.py` | Add SolverConfig Pydantic model |

---

## Implementation Order

| Phase | Effort | Priority | Dependencies |
|-------|--------|----------|--------------|
| **7.1** Resizable Panel Hook | 2h | High | None |
| **7.2** CanvasView Resizers | 2h | High | 7.1 |
| **8.1** Enable Palette Items | 1h | High | None |
| **8.2** Singleton Logic | 2h | High | 8.1 |
| **8.3** Default Node Data | 1h | High | 8.2 |
| **9.1** Schema Updates | 2h | Medium | None |
| **9.2** SolverNode UI | 1h | Medium | 9.1 |
| **9.3** Solver Config Panel | 2h | Medium | 9.1, 9.2 |

**Total Estimated Effort:** ~13 hours

---

## Success Criteria

### Phase 7 (Resizable Panels)
- [ ] Left panel can be resized between 200-400px
- [ ] Right panel can be resized between 280-600px
- [ ] Resize handles show cursor feedback
- [ ] Panel sizes persist across page reload
- [ ] Double-click on handle resets to default

### Phase 8 (Enable Palette Items)
- [ ] All 8 node types are draggable from palette
- [ ] Dragging singleton to canvas with existing node selects existing
- [ ] Toast notification explains the behavior
- [ ] New studies can start with empty canvas and add Model first

### Phase 9 (Solver Selection)
- [ ] Solver node shows engine type (nxnastran, python, etc.)
- [ ] Clicking solver node opens config panel
- [ ] Can select solver engine from dropdown
- [ ] Nastran solvers show solution type dropdown
- [ ] Python solver shows script path input
- [ ] Changes persist to atomizer_spec.json

---

## Future Considerations

### Additional Solver Support
- ANSYS integration via pyANSYS
- Abaqus integration via abaqus-python
- OpenFOAM for CFD
- Custom Python solvers with standardized interface

### Multi-Solver Workflows
- Support for chained solvers (thermal → structural)
- Co-simulation workflows
- Parallel solver execution

### Algorithm Node Enhancement
- Similar to Solver, allow algorithm selection
- Show algorithm-specific parameters
- Support custom algorithms

---

## Commit Strategy

```bash
# Phase 7
git commit -m "feat: Add resizable panels to canvas view"

# Phase 8
git commit -m "feat: Enable all palette items with singleton handling"

# Phase 9
git commit -m "feat: Add solver type selection and configuration"
```