# Phase 3.5: Diagram Generation

Generate Mermaid diagrams based on report type and analysis data.

> **Reference**: See [mermaid-utils.md](../../_shared/mermaid-utils.md) for utility functions.

## Execution

### Step 1: Determine Required Diagrams

```javascript
const diagramRequirements = {
  architecture: [
    {type: 'architecture', format: 'graph TD', file: 'architecture.mmd'},
    {type: 'layers', format: 'graph TD', file: 'layers.mmd'},
    {type: 'dependencies', format: 'graph LR', file: 'dependencies.mmd'},
    {type: 'dataflow', format: 'flowchart LR', file: 'dataflow.mmd'}
  ],
  design: [
    {type: 'class', format: 'classDiagram', file: 'class-diagram.mmd'},
    {type: 'components', format: 'graph TD', file: 'components.mmd'},
    {type: 'patterns', format: 'graph TD', file: 'patterns.mmd'},
    {type: 'state', format: 'stateDiagram-v2', file: 'state.mmd'}
  ],
  methods: [
    {type: 'algorithm', format: 'flowchart TD', file: 'algorithm-*.mmd'},
    {type: 'sequence', format: 'sequenceDiagram', file: 'sequence-*.mmd'},
    {type: 'critical_path', format: 'flowchart LR', file: 'critical-path.mmd'},
    {type: 'api', format: 'graph LR', file: 'api.mmd'}
  ],
  comprehensive: [
    {type: 'architecture', format: 'graph TD', file: 'architecture.mmd'},
    {type: 'class', format: 'classDiagram', file: 'class-diagram.mmd'},
    {type: 'sequence', format: 'sequenceDiagram', file: 'sequence-main.mmd'},
    {type: 'dataflow', format: 'flowchart LR', file: 'dataflow.mmd'}
  ]
};

const required = diagramRequirements[config.type];
```

### Step 2: Generate Each Diagram

Use shared utilities from `../_shared/mermaid-utils.md`:

```javascript
// Import utilities
const { sanitizeId, escapeLabel, generateClassDiagram, generateSequenceDiagram, validateMermaidSyntax } = require('../_shared/mermaid-utils.md');

for (const diagram of required) {
  const content = generateDiagram(diagram.type, diagram.format, analysisData);
  Write(`${outputDir}/diagrams/${diagram.file}`, content);
}
```

### Step 3: Validate All Diagrams

```javascript
const validationResults = validateDiagramDirectory(`${outputDir}/diagrams`);
const failedDiagrams = validationResults.filter(r => !r.valid);

if (failedDiagrams.length > 0) {
  // Regenerate failed diagrams
  for (const failed of failedDiagrams) {
    regenerateDiagram(failed.file, failed.issues);
  }
}
```

### Step 4: Create Diagram Manifest

```javascript
Write(`${outputDir}/diagrams/manifest.json`, JSON.stringify({
  generated_at: new Date().toISOString(),
  diagrams: required.map(d => ({
    type: d.type,
    file: d.file,
    format: d.format
  })),
  validation: validationResults
}, null, 2));
```

## Output

Save diagrams to `diagrams/` folder with `manifest.json`.