# Phase 5: Type-Aware Node System Implementation

## Overview
Successfully implemented Phase 5 of the Type-Aware Node System, creating type-specific node components and a registry for the graph view.

## Files Created

### 1. Node Components

#### `/frontend/apps/web/src/components/graph/nodes/TestNode.tsx`
**Purpose**: Specialized node component for test items with test-specific visualizations.

**Features**:
- Test type badge (unit, integration, e2e, etc.)
- Framework indicator (jest, playwright, vitest)
- Flakiness score with visual warning (0-100%)
- Coverage percentage meter
- Safety level badge (safe, quarantined, disabled)
- Last run status with color-coded indicator
- Quarantine warning banner for flagged tests
- Green accent color (#22c55e)

**Data Structure**:
```typescript
interface TestNodeData {
  testType?: string;
  framework?: string;
  flakinessScore?: number;
  coveragePercent?: number;
  safetyLevel?: "safe" | "quarantined" | "disabled";
  lastRunStatus?: "passed" | "failed" | "skipped" | "error";
}
```

#### `/frontend/apps/web/src/components/graph/nodes/RequirementNode.tsx`
**Purpose**: Specialized node component for requirement items with quality metrics.

**Features**:
- EARS pattern badge (ubiquitous, event_driven, state_driven, optional, unwanted)
- Risk level indicator (low, medium, high, critical)
- WSJF score display (Weighted Shortest Job First)
- Verifiability score with progress gauge (0-100%)
- Verification status badge (not_verified, partially_verified, verified)
- Purple accent color (#9333ea)

**Data Structure**:
```typescript
interface RequirementNodeData {
  earsPatternType?: "ubiquitous" | "event_driven" | "state_driven" | "optional" | "unwanted";
  riskLevel?: "low" | "medium" | "high" | "critical";
  wsjfScore?: number;
  verifiabilityScore?: number;
  verificationStatus?: "not_verified" | "partially_verified" | "verified";
}
```

#### `/frontend/apps/web/src/components/graph/nodes/EpicNode.tsx`
**Purpose**: Specialized node component for epic items with progress tracking.

**Features**:
- Business value badge (low, medium, high, critical)
- Timeline progress bar (0-100%)
- Story completion tracker (completed/total)
- Visual progress indicators
- Completion celebration badge (when 100% complete)
- Blue/Purple accent color (#7c3aed)

**Data Structure**:
```typescript
interface EpicNodeData {
  businessValue?: "low" | "medium" | "high" | "critical";
  timelineProgress?: number;
  storyCount?: number;
  completedStoryCount?: number;
}
```

### 2. Utility Components

#### `/frontend/apps/web/src/components/graph/nodes/index.ts`
**Purpose**: Central export point for all node components.

Exports:
- `TestNode` component and `TestNodeData` type
- `RequirementNode` component and `RequirementNodeData` type
- `EpicNode` component and `EpicNodeData` type

### 3. Data Transformation Layer

#### `/frontend/apps/web/src/components/graph/utils/nodeDataTransformers.ts`
**Purpose**: Convert generic Items to type-specific node data.

**Functions**:
- `itemToNodeData(item, connections)` - Main transformer
- `transformTestItem(item)` - Extract test-specific fields
- `transformRequirementItem(item)` - Extract requirement-specific fields
- `transformEpicItem(item)` - Extract epic-specific fields
- `itemsToNodeData(items, connectionMap)` - Batch transformation

**Type Guards**:
- `isTestItem(item)` - Check if item is a test
- `isRequirementItem(item)` - Check if item is a requirement
- `isEpicItem(item)` - Check if item is an epic

### 4. Node Registry

#### `/frontend/apps/web/src/components/graph/nodeRegistry.ts`
**Purpose**: Registry mapping item types to React Flow node components.

**Exports**:
- `nodeTypes` - React Flow NodeTypes object
- `getNodeType(itemType)` - Get node type string for an item type
- `shouldUseQAEnhancedNode(nodeData)` - Check if QA enhanced node should be used
- `getNodeTypeForItem(itemType, nodeData)` - Recommended function for node type selection

**Registry Contents**:
```typescript
{
  // Legacy nodes
  richPill: RichNodePill,
  qaEnhanced: QAEnhancedNode,

  // Type-specific nodes
  test: TestNode,
  test_case: TestNode,
  test_suite: TestNode,
  requirement: RequirementNode,
  epic: EpicNode,

  // Default fallback
  default: RichNodePill,
}
```

## Design Patterns Used

### 1. Memoization
All node components are wrapped with `memo()` for performance optimization, preventing unnecessary re-renders.

### 2. Type Guards
TypeScript type guards ensure type-safe transformations and proper component selection.

### 3. Progressive Enhancement
Nodes gracefully handle missing data fields, showing only available information.

### 4. Consistent Styling
- All nodes follow the same 260px width
- Consistent color accent bar at the top
- Uniform spacing and typography
- Shared interaction patterns (click, hover)

### 5. Accessibility
- Tooltips for all metrics and badges
- Proper ARIA labels via component library
- Color-coded indicators with text labels
- React Flow handles for keyboard navigation

## Integration Points

### Using the Node Registry
```typescript
import { nodeTypes, getNodeTypeForItem } from './components/graph/nodeRegistry';

// In React Flow component
<ReactFlow nodeTypes={nodeTypes} ... />

// When creating nodes
const nodeType = getNodeTypeForItem(item.type, nodeData);
const node = {
  id: item.id,
  type: nodeType,
  data: nodeData,
  position: { x: 0, y: 0 },
};
```

### Using the Transformers
```typescript
import { itemToNodeData, itemsToNodeData } from './components/graph/utils/nodeDataTransformers';

// Transform single item
const nodeData = itemToNodeData(item, connections);

// Transform multiple items
const nodesData = itemsToNodeData(items, connectionMap);
```

## Visual Characteristics

### Color Scheme
- **Test Nodes**: Green (#22c55e) - Represents testing/validation
- **Requirement Nodes**: Purple (#9333ea) - Represents specifications
- **Epic Nodes**: Deep Purple (#7c3aed) - Represents high-level business items

### Special Indicators
- **Flaky Tests**: Yellow highlight when flakiness > 50%
- **Quarantined Tests**: Yellow warning banner
- **High Risk Requirements**: Color-coded risk badges
- **Completed Epics**: Green celebration badge

## Next Steps

### Integration Tasks
1. Update `FlowGraphViewInner.tsx` to use the node registry
2. Implement connection counting for accurate metrics
3. Add metadata extraction for type-specific fields
4. Create data migration scripts if needed

### Future Enhancements
1. Add more type-specific nodes (UserStory, Task, Bug)
2. Implement node-specific context menus
3. Add inline editing for certain fields
4. Create node templates for quick creation

## Testing Recommendations

### Unit Tests
- Test each transformer function with various item types
- Verify type guards correctly identify items
- Test node registry mapping logic

### Integration Tests
- Verify nodes render correctly with real data
- Test graceful handling of missing fields
- Verify callback functions work properly

### Visual Tests
- Snapshot tests for each node type
- Verify responsive behavior
- Test color schemes and accessibility

## Performance Considerations

1. **Memoization**: All components are memoized
2. **Lazy Loading**: Import nodes on-demand if needed
3. **Data Transformation**: Cache transformed data when possible
4. **Connection Counting**: Pre-compute connection maps

## Documentation

### Developer Guide
See existing node components (RichNodePill, QAEnhancedNode) for patterns and best practices.

### Type Definitions
All types are exported from component files and available via the index.

### API Reference
```typescript
// Node Registry API
getNodeType(itemType: string): string
getNodeTypeForItem(itemType: string, nodeData: Record<string, unknown>): string
shouldUseQAEnhancedNode(nodeData: Record<string, unknown>): boolean

// Transformer API
itemToNodeData(item: Item, connections?): NodeData
itemsToNodeData(items: Item[], connectionMap?): NodeData[]
transformTestItem(item: TestItem): Partial<TestNodeData>
transformRequirementItem(item: RequirementItem): Partial<RequirementNodeData>
transformEpicItem(item: EpicItem): Partial<EpicNodeData>
```

## Completion Status

✅ Phase 5.1: Node Registry - Complete
✅ Phase 5.2: TestNode Component - Complete
✅ Phase 5.3: RequirementNode Component - Complete
✅ Phase 5.4: EpicNode Component - Complete
✅ Phase 5.5: Node Data Transformers - Complete
✅ Phase 5.6: Type Guards and Utilities - Complete

**Status**: Phase 5 Implementation Complete
**Date**: 2026-01-30
**Files Created**: 6
**Lines of Code**: ~900
