# Intune Reverse Engineering Migration Guide

**Version**: 1.0.0  
**Last Updated**: 2025-12-09  
**PowerShell Reference**: Commit `2eaf3257` (2025-12-09)  
**Status**: Active

## Table of Contents

1. [Overview](#overview)
2. [PowerShell Reference Location](#powershell-reference-location)
3. [Step-by-Step Implementation Process](#step-by-step-implementation-process)
4. [Data Points to Extract](#data-points-to-extract)
5. [PowerShell to TypeScript Pattern Mapping](#powershell-to-typescript-pattern-mapping)
6. [Concrete Examples](#concrete-examples)
   - [Windows Update Rings](#example-1-windows-update-rings)
   - [Settings Catalog with $expand](#example-2-settings-catalog-with-expand)
   - [Invoke-MSGraphRequest Translation](#example-3-invoke-msgraphrequest-translation)
   - [Property Cleanup Patterns](#example-4-property-cleanup-patterns)
7. [Troubleshooting API Discrepancies](#troubleshooting-api-discrepancies)
8. [Understanding Existing Implementation Patterns](#understanding-existing-implementation-patterns)
9. [Common Questions (FAQ)](#common-questions-faq)
10. [Edge Cases & Advanced Topics](#edge-cases--advanced-topics)
    - [Versioning Strategy](#versioning-strategy)
    - [Fallback Process for Missing PowerShell Reference](#fallback-process-for-missing-powershell-reference)
    - [Handling PowerShell Updates](#handling-powershell-updates)
    - [Deprecated Features](#deprecated-features)
    - [PowerShell Quirks vs Intentional Patterns](#powershell-quirks-vs-intentional-patterns)
11. [Complete End-to-End Example](#complete-end-to-end-example)
12. [Reference Implementations](#reference-implementations)

---

## Overview

This guide documents the **reverse engineering strategy** for implementing Intune sync functionality in TenantPilot. Instead of relying solely on Microsoft Graph API documentation (which is often incomplete or outdated), we analyze the proven PowerShell implementation from [IntuneManagement](https://github.com/Micke-K/IntuneManagement) by Mikael Karlsson to discover the actual API patterns, undocumented parameters, and data transformation logic.

### Why This Approach?

Microsoft Graph API documentation frequently:
- Omits required query parameters (`$expand`, `$filter`, `$select`)
- Incorrectly documents API versions (beta vs v1.0)
- Lacks examples of property cleanup/transformation
- Doesn't specify pagination patterns
- Misses edge cases in error handling

The IntuneManagement PowerShell tool has been battle-tested in production environments and contains the **actual working implementation** of Intune API interactions.

### When to Use This Guide

- **Before implementing any new Intune sync job**: Follow the step-by-step process
- **When troubleshooting API discrepancies**: Compare TypeScript vs PowerShell
- **When onboarding new team members**: Understand rationale for existing patterns
- **When PowerShell reference is updated**: Review for breaking changes

### Scope

This guide focuses on the **process** of reverse engineering PowerShell → TypeScript. It does NOT modify existing sync job implementations. Use this guide for **new implementations** and **troubleshooting existing ones**.

---

## PowerShell Reference Location

**Repository Path**: `reference/IntuneManagement-master/`

### Key Directories

- **`Modules/`**: Core PowerShell modules organized by resource type
  - `ConfigurationPolicies.psm1` - Device configuration policies
  - `Applications.psm1` - App management
  - `DeviceCompliance.psm1` - Compliance policies
  - `WindowsUpdateRings.psm1` - Windows Update for Business
  - `SettingsCatalog.psm1` - Settings Catalog policies
  
- **`Extensions/`**: Utility modules for authentication, API calls, documentation
  - `MSALAuthentication.psm1` - Authentication patterns
  - `IntuneTools.psm1` - Common API utilities
  - `EndpointManagerInfo.psm1` - Endpoint metadata

- **`Core.psm1`**: Base functionality for Graph API calls

### Version Tracking

Current version: **Commit `2eaf3257`** (2025-12-09)  
See `docs/architecture/intune-reference-version.md` for version history and update process.

### Finding the Right Module

1. Identify the Intune resource type you need to implement (e.g., "Compliance Policies")
2. Search `Modules/` directory for related `.psm1` file (e.g., `DeviceCompliance.psm1`)
3. If not obvious, search by Graph API endpoint (e.g., `grep -r "deviceManagement/deviceCompliancePolicies" reference/IntuneManagement-master/`)

---

## Step-by-Step Implementation Process

Follow this process **before writing any TypeScript code** for a new Intune sync job.

### Phase 1: Locate PowerShell Reference

1. **Identify the resource type** from the feature request (e.g., "App Protection Policies")
2. **Search for the PowerShell module**:
   ```bash
   find reference/IntuneManagement-master/Modules -name "*Protection*.psm1"
   # or search by keyword
   grep -r "AppProtection" reference/IntuneManagement-master/Modules/
   ```
3. **Open the corresponding `.psm1` file** in your editor

### Phase 2: Extract API Endpoint Pattern

1. **Find the Graph API call** - Look for `Invoke-MSGraphRequest` or `Invoke-GraphRequest`:
   ```powershell
   $policies = Invoke-MSGraphRequest -Url "/beta/deviceAppManagement/managedAppPolicies"
   ```

2. **Document the endpoint**:
   - Full path: `/beta/deviceAppManagement/managedAppPolicies`
   - API version: `beta` (not `v1.0`)
   - Base segment: `deviceAppManagement`

3. **Check for query parameters**:
   ```powershell
   $policies = Invoke-MSGraphRequest -Url "/beta/deviceManagement/windowsUpdateForBusinessConfigurations?`$expand=assignments"
   ```
   - Note the `$expand=assignments` parameter

### Phase 3: Identify Data Transformation Logic

1. **Look for property deletions**:
   ```powershell
   $policy.PSObject.Properties.Remove('createdDateTime')
   $policy.PSObject.Properties.Remove('lastModifiedDateTime')
   ```
   → These properties must be deleted before saving (read-only)

2. **Look for type conversions**:
   ```powershell
   $policy.scheduledInstallDay = [int]$policy.scheduledInstallDay
   ```
   → Type must be coerced

3. **Look for nested object flattening**:
   ```powershell
   if($policy.assignments) {
       $policy | Add-Member -NotePropertyName assignmentIds -NotePropertyValue ($policy.assignments.id)
   }
   ```
   → Extract IDs from nested structure

### Phase 4: Document Undocumented Behaviors

1. **Check for beta API requirements**:
   ```powershell
   # Uses /beta because v1.0 doesn't support this resource yet
   ```

2. **Note pagination patterns**:
   ```powershell
   do {
       $response = Invoke-MSGraphRequest -Url $url
       $policies += $response.value
       $url = $response.'@odata.nextLink'
   } while($url)
   ```

3. **Document error handling quirks**:
   ```powershell
   # 404 is expected when no policies exist - don't treat as error
   if($response.StatusCode -eq 404) { return @() }
   ```

### Phase 5: Map to TypeScript Implementation

1. **Create the sync job file**: `worker/jobs/sync<ResourceType>.ts`
2. **Translate the endpoint**: PowerShell URL → TypeScript Graph client call
3. **Implement data transformation**: Match PowerShell cleanup logic
4. **Add pagination**: Match PowerShell pagination pattern
5. **Handle errors**: Replicate PowerShell error handling

### Phase 6: Validate

1. **Compare API calls**: Use Graph Explorer to verify endpoint and parameters match
2. **Compare data shape**: Ensure TypeScript returns same structure as PowerShell
3. **Test edge cases**: Empty result sets, large result sets, missing properties
4. **Document deviations**: If TypeScript differs from PowerShell, document why

---

## Data Points to Extract

When analyzing PowerShell reference code, extract these critical data points:

### ✅ Required Extractions

- [ ] **Graph API Endpoint**
  - Full URL path (e.g., `/beta/deviceManagement/configurationPolicies`)
  - API version (`beta` or `v1.0`)
  
- [ ] **Query Parameters**
  - `$filter` - Filtering criteria (e.g., `$filter=isof('microsoft.graph.windows10GeneralConfiguration')`)
  - `$expand` - Related entities to include (e.g., `$expand=assignments,settings`)
  - `$select` - Specific properties to return (e.g., `$select=id,displayName,createdDateTime`)
  - `$top` - Page size limit (e.g., `$top=999`)
  - `$orderby` - Sorting (e.g., `$orderby=displayName`)

- [ ] **Property Cleanup Logic**
  - Read-only properties to delete (e.g., `createdDateTime`, `lastModifiedDateTime`, `@odata.type`)
  - Computed properties to remove (e.g., `version`, `supportsScopeTags`)

- [ ] **Type Transformations**
  - Type coercions (string → int, string → boolean)
  - Date formatting (ISO 8601 strings)
  - Enum value mappings

- [ ] **Pagination Pattern**
  - How to handle `@odata.nextLink`
  - Maximum page size
  - Total count handling

- [ ] **Error Handling**
  - Expected error codes (e.g., 404 for empty results)
  - Retry logic
  - Rate limiting handling

### 🔍 Optional Extractions (If Present)

- [ ] **Nested Object Handling**
  - Assignment structures
  - Setting collections
  - Related entity expansions

- [ ] **Conditional Logic**
  - Resource type-specific branching
  - Feature flag checks
  - Tenant capability checks

- [ ] **Batch Operations**
  - Batch request patterns
  - Transaction boundaries

---

## PowerShell to TypeScript Pattern Mapping

Common PowerShell patterns and their TypeScript equivalents:

### Pattern 1: Basic Graph API Call

**PowerShell**:
```powershell
$policies = Invoke-MSGraphRequest -Url "/beta/deviceManagement/configurationPolicies"
```

**TypeScript**:
```typescript
const response = await graphClient
  .api('/deviceManagement/configurationPolicies')
  .version('beta')
  .get();
const policies = response.value;
```

### Pattern 2: Query Parameters

**PowerShell**:
```powershell
$url = "/beta/deviceManagement/configurationPolicies?`$expand=assignments&`$filter=isof('microsoft.graph.configurationPolicy')"
$policies = Invoke-MSGraphRequest -Url $url
```

**TypeScript**:
```typescript
const response = await graphClient
  .api('/deviceManagement/configurationPolicies')
  .version('beta')
  .expand('assignments')
  .filter("isof('microsoft.graph.configurationPolicy')")
  .get();
```

### Pattern 3: Pagination

**PowerShell**:
```powershell
$allPolicies = @()
$url = "/beta/deviceManagement/configurationPolicies"
do {
    $response = Invoke-MSGraphRequest -Url $url
    $allPolicies += $response.value
    $url = $response.'@odata.nextLink'
} while($url)
```

**TypeScript**:
```typescript
let allPolicies = [];
let url = '/deviceManagement/configurationPolicies';
while (url) {
  const response = await graphClient.api(url).version('beta').get();
  allPolicies.push(...response.value);
  url = response['@odata.nextLink'];
}
```

### Pattern 4: Property Deletion

**PowerShell**:
```powershell
$policy.PSObject.Properties.Remove('createdDateTime')
$policy.PSObject.Properties.Remove('lastModifiedDateTime')
$policy.PSObject.Properties.Remove('@odata.context')
```

**TypeScript**:
```typescript
delete policy.createdDateTime;
delete policy.lastModifiedDateTime;
delete policy['@odata.context'];
```

### Pattern 5: Type Conversion

**PowerShell**:
```powershell
$setting.value = [int]$setting.value
$policy.isAssigned = [bool]$policy.isAssigned
```

**TypeScript**:
```typescript
setting.value = parseInt(setting.value, 10);
policy.isAssigned = Boolean(policy.isAssigned);
```

---

## Concrete Examples

### Example 1: Windows Update Rings

**Feature Request**: Implement sync for Windows Update for Business configurations

**Step 1: Locate PowerShell Module**
```bash
$ find reference/IntuneManagement-master -name "*Update*.psm1"
reference/IntuneManagement-master/Modules/WindowsUpdateRings.psm1
```

**Step 2: Extract API Pattern from PowerShell**
```powershell
# From WindowsUpdateRings.psm1
$rings = Invoke-MSGraphRequest -Url "/beta/deviceManagement/windowsUpdateForBusinessConfigurations"
```

**Extracted Data Points**:
- **Endpoint**: `/beta/deviceManagement/windowsUpdateForBusinessConfigurations`
- **API Version**: `beta` (not available in v1.0)
- **Query Params**: None required for list operation
- **Property Cleanup**: `createdDateTime`, `lastModifiedDateTime` must be removed

**Step 3: TypeScript Implementation**
```typescript
// worker/jobs/syncWindowsUpdateRings.ts
import { graphClient } from '../utils/graphClient';
import { db } from '@/lib/db';
import { windowsUpdateRings } from '@/lib/db/schema';

export async function syncWindowsUpdateRings(tenantId: string) {
  const response = await graphClient
    .api('/deviceManagement/windowsUpdateForBusinessConfigurations')
    .version('beta') // PowerShell uses beta
    .get();
  
  const rings = response.value;
  
  // Cleanup properties (matches PowerShell)
  for (const ring of rings) {
    delete ring.createdDateTime;
    delete ring.lastModifiedDateTime;
    delete ring['@odata.context'];
  }
  
  // Save to database
  await db.insert(windowsUpdateRings).values(
    rings.map(ring => ({
      tenantId,
      intuneId: ring.id,
      displayName: ring.displayName,
      data: ring,
      lastSyncedAt: new Date()
    }))
  ).onConflictDoUpdate({
    target: [windowsUpdateRings.tenantId, windowsUpdateRings.intuneId],
    set: { data: ring, lastSyncedAt: new Date() }
  });
}
```

---

### Example 2: Settings Catalog with $expand

**Feature Request**: Implement Settings Catalog policy sync

**Step 1: PowerShell Analysis**
```powershell
# From SettingsCatalog.psm1
$url = "/beta/deviceManagement/configurationPolicies?`$expand=settings"
$policies = Invoke-MSGraphRequest -Url $url
```

**Key Discovery**: The `$expand=settings` parameter is **not documented** in Microsoft Graph API docs, but is **required** to get policy settings in a single call. Without it, you'd need a separate API call per policy to fetch settings.

**Step 2: TypeScript Implementation**
```typescript
// worker/jobs/syncSettingsCatalog.ts
export async function syncSettingsCatalog(tenantId: string) {
  const response = await graphClient
    .api('/deviceManagement/configurationPolicies')
    .version('beta')
    .expand('settings') // CRITICAL: Discovered from PowerShell reference
    .get();
  
  const policies = response.value;
  
  // Now policies include nested settings array
  for (const policy of policies) {
    console.log(`Policy ${policy.displayName} has ${policy.settings?.length || 0} settings`);
  }
  
  // Save to database...
}
```

**Without PowerShell Reference**: You would make N+1 API calls (1 for policies list, N for each policy's settings), causing:
- Slower sync performance
- Higher API rate limit consumption
- Unnecessary complexity

---

### Example 3: Invoke-MSGraphRequest Translation

**PowerShell Pattern**:
```powershell
$requestParams = @{
    Url = "/beta/deviceManagement/deviceCompliancePolicies"
    Method = "GET"
    Headers = @{
        "Accept" = "application/json"
    }
}
$policies = Invoke-MSGraphRequest @requestParams
```

**TypeScript Equivalent**:
```typescript
const response = await graphClient
  .api('/deviceManagement/deviceCompliancePolicies')
  .version('beta')
  .header('Accept', 'application/json')
  .get();
const policies = response.value;
```

**Key Mappings**:
- `Url` → `.api(path).version(version)`
- `Method = "GET"` → `.get()`
- `Method = "POST"` → `.post(body)`
- `Method = "PATCH"` → `.patch(body)`
- `Headers` → `.header(name, value)`

---

### Example 4: Property Cleanup Patterns

**PowerShell Pattern**:
```powershell
# From ConfigurationPolicies.psm1
function Remove-ReadOnlyProperties($policy) {
    $policy.PSObject.Properties.Remove('id')
    $policy.PSObject.Properties.Remove('createdDateTime')
    $policy.PSObject.Properties.Remove('lastModifiedDateTime')
    $policy.PSObject.Properties.Remove('settingCount')
    $policy.PSObject.Properties.Remove('creationSource')
    $policy.PSObject.Properties.Remove('roleScopeTagIds')
    
    # Remove OData metadata
    $policy.PSObject.Properties | Where-Object { $_.Name -like '@odata.*' } | ForEach-Object {
        $policy.PSObject.Properties.Remove($_.Name)
    }
}
```

**Why This Matters**: These properties are:
- **Read-only**: Graph API will reject POST/PATCH requests containing them
- **Server-managed**: Values are computed by Intune, not settable by clients
- **Metadata**: OData annotations are for response enrichment only

**TypeScript Implementation**:
```typescript
function removeReadOnlyProperties(policy: any): void {
  // Core read-only fields
  delete policy.id;
  delete policy.createdDateTime;
  delete policy.lastModifiedDateTime;
  delete policy.settingCount;
  delete policy.creationSource;
  delete policy.roleScopeTagIds;
  
  // Remove all OData metadata
  Object.keys(policy).forEach(key => {
    if (key.startsWith('@odata.')) {
      delete policy[key];
    }
  });
}
```

**Usage**:
```typescript
const policy = await graphClient.api(`/deviceManagement/configurationPolicies/${id}`).get();
removeReadOnlyProperties(policy);
await graphClient.api('/deviceManagement/configurationPolicies').post(policy); // Now succeeds
```

---

## Troubleshooting API Discrepancies

When TypeScript implementation returns different data than PowerShell reference, follow this systematic process:

### Troubleshooting Checklist

- [ ] **1. Compare Endpoints**: Verify exact URL path matches PowerShell
- [ ] **2. Check API Version**: Confirm beta vs v1.0 matches
- [ ] **3. Verify Query Parameters**: Ensure `$expand`, `$filter`, `$select` match
- [ ] **4. Inspect Response Data**: Compare raw JSON from both implementations
- [ ] **5. Check Property Cleanup**: Verify same properties are deleted
- [ ] **6. Review Type Conversions**: Confirm same type coercions applied
- [ ] **7. Test Pagination**: Ensure all pages are fetched correctly
- [ ] **8. Validate Error Handling**: Check for missing error case handling

### Example Troubleshooting Session

**Problem**: TypeScript sync returns incomplete assignment data for Configuration Policies

**Step 1: Compare API Calls**
```typescript
// Current TypeScript (WRONG)
const response = await graphClient
  .api('/deviceManagement/configurationPolicies')
  .version('beta')
  .get();
// Result: Policies have no assignments property
```

**Step 2: Check PowerShell Reference**
```powershell
# From PowerShell (CORRECT)
$policies = Invoke-MSGraphRequest -Url "/beta/deviceManagement/configurationPolicies?`$expand=assignments"
# Result: Policies include assignments array
```

**Root Cause**: Missing `$expand=assignments` parameter

**Step 3: Fix TypeScript**
```typescript
// Fixed TypeScript
const response = await graphClient
  .api('/deviceManagement/configurationPolicies')
  .version('beta')
  .expand('assignments') // Added this
  .get();
// Result: Policies now include assignments
```

---

### Example: 400 Bad Request Debugging

**Problem**: Sync job fails with "400 Bad Request" error

**Step 1: Capture Request Details**
```typescript
try {
  await graphClient.api('/deviceManagement/someEndpoint').version('v1.0').get();
} catch (error) {
  console.error('Request URL:', error.requestUrl);
  console.error('Response:', error.body);
}
```

**Step 2: Check PowerShell for API Version**
```powershell
# PowerShell uses /beta, not /v1.0
$data = Invoke-MSGraphRequest -Url "/beta/deviceManagement/someEndpoint"
```

**Root Cause**: Endpoint only exists in beta API

**Step 3: Fix**
```typescript
await graphClient.api('/deviceManagement/someEndpoint').version('beta').get(); // Changed to beta
```

---

## Understanding Existing Implementation Patterns

### Why We Delete Properties

**Pattern You See**:
```typescript
delete policy.createdDateTime;
delete policy.lastModifiedDateTime;
```

**Rationale**: This matches PowerShell cleanup logic. These properties are:
- **Read-only**: Set by Graph API, not modifiable by clients
- **Validation failures**: Including them in POST/PATCH causes 400 errors
- **Intentional**: Not a refactoring opportunity - DO NOT "clean up" by keeping them

**PowerShell Reference**:
```powershell
$policy.PSObject.Properties.Remove('createdDateTime')
$policy.PSObject.Properties.Remove('lastModifiedDateTime')
```

**To New Developers**: If you see property deletions in sync jobs, check the PowerShell reference before "fixing" them. They're intentional.

---

### When to Use Beta vs V1.0 API

**Pattern You See**:
```typescript
.version('beta')
```

**Decision Process**:
1. **Check PowerShell reference first**: If PowerShell uses `/beta`, you must use beta
2. **Don't "upgrade" to v1.0** without verifying in PowerShell reference
3. **Beta is not always unstable**: Many Intune features are beta-only for years

**Why Beta**:
- Resource type doesn't exist in v1.0 yet (e.g., Settings Catalog)
- Required properties only available in beta
- Microsoft hasn't stabilized the API schema

**PowerShell Example**:
```powershell
# Uses /beta because v1.0 doesn't support this yet
$policies = Invoke-MSGraphRequest -Url "/beta/deviceManagement/configurationPolicies"
```

**TypeScript Equivalent**:
```typescript
// Must use beta to match PowerShell
const response = await graphClient
  .api('/deviceManagement/configurationPolicies')
  .version('beta') // DO NOT change to 'v1.0'
  .get();
```

---

## Common Questions (FAQ)

### Q: Should I always use the PowerShell reference?

**A**: Yes, for Intune-related features. The PowerShell tool has been battle-tested and contains the actual working patterns. Microsoft Graph docs are often incomplete.

### Q: What if the PowerShell reference is outdated?

**A**: Check the version tracking in `docs/architecture/intune-reference-version.md`. If outdated, update the reference and review for breaking changes before implementing new features.

### Q: What if there's no PowerShell equivalent for my feature?

**A**: Use the [Fallback Process](#fallback-process-for-missing-powershell-reference):
1. Use official Graph API docs
2. Test against at least 2 different tenants
3. Validate with 5+ resource instances
4. Document any undocumented behaviors discovered
5. Consider contributing findings back to IntuneManagement project

### Q: Can I skip property cleanup if Graph API doesn't complain?

**A**: No. Match the PowerShell cleanup logic exactly. Graph API behavior can change, and undocumented acceptance of read-only properties shouldn't be relied upon.

### Q: Why not just use the PowerShell tool directly instead of TypeScript?

**A**: Our architecture requires TypeScript for type safety, integration with Next.js, and consistency with the rest of the codebase (see Constitution in `.specify/memory/constitution.md`). We use PowerShell as a **reference**, not as the implementation.

---

## Edge Cases & Advanced Topics

### Versioning Strategy

**Principle**: Document which PowerShell commit was used as reference for each feature implementation.

**Process**:
1. When implementing a new sync job, note the current PowerShell reference commit
2. Add a comment in the TypeScript file:
   ```typescript
   /**
    * Windows Update Rings Sync
    * 
    * PowerShell Reference: commit 2eaf3257 (2025-12-09)
    * Module: WindowsUpdateRings.psm1
    * Last Verified: 2025-12-09
    */
   ```

3. When PowerShell reference is updated, review all sync jobs and update version references

**Why This Matters**: If a sync job breaks after PowerShell update, you can:
- Diff between old and new PowerShell commit
- Identify breaking changes
- Update TypeScript to match new patterns

---

### Fallback Process for Missing PowerShell Reference

**When to Use**: New Intune feature has no corresponding PowerShell module yet.

**Process**:
1. **Check Official Docs**: Start with Microsoft Graph API documentation
2. **Use Graph Explorer**: Test endpoints interactively at https://developer.microsoft.com/en-us/graph/graph-explorer
3. **Extensive Testing**:
   - Test against at least 2 different test tenants
   - Create/read/update/delete at least 5 resource instances
   - Test with different property combinations
   - Test pagination with large result sets
4. **Document Assumptions**:
   ```typescript
   /**
    * [NO POWERSHELL REFERENCE]
    * 
    * Implementation based on Graph API docs (2025-12-09)
    * Assumptions:
    * - Uses beta API (not documented if v1.0 exists)
    * - No $expand parameters documented
    * - Property cleanup based on trial-and-error
    * 
    * TODO: Check IntuneManagement project for updates
    */
   ```
5. **Monitor for PowerShell Update**: Check IntuneManagement repo periodically for new modules

---

### Handling PowerShell Updates

**Scenario**: PowerShell reference is updated with breaking changes.

**Detection**:
1. Monitor IntuneManagement GitHub repository for commits
2. Review release notes in `reference/IntuneManagement-master/ReleaseNotes.md`
3. Check commit messages for "breaking change" or "BREAKING"

**Update Process**:
1. **Pull Latest Changes**:
   ```bash
   cd reference/IntuneManagement-master
   git fetch origin
   git log HEAD..origin/master --oneline # Review changes
   git merge origin/master
   ```

2. **Document New Version**:
   Update `docs/architecture/intune-reference-version.md` with new commit hash

3. **Test Critical Sync Jobs**:
   - Run sync jobs against test tenant
   - Compare output before/after update
   - Verify no data loss or corruption

4. **Update TypeScript Implementations**:
   - Review changed PowerShell modules
   - Update corresponding TypeScript sync jobs
   - Update version comments in code

5. **Document Breaking Changes**:
   Add to this guide's version history

---

### Deprecated Features

**Scenario**: PowerShell module exists but Microsoft deprecated the Intune feature.

**Identification**:
- PowerShell comments mention "deprecated"
- Graph API returns 404 or "feature not supported"
- Microsoft docs show deprecation notice

**Handling**:
1. **Mark as Reference Only**: Add comment to TypeScript:
   ```typescript
   /**
    * [DEPRECATED FEATURE]
    * 
    * This sync job is based on deprecated PowerShell module.
    * DO NOT use for new implementations.
    * 
    * PowerShell Reference: DeviceCompliance.psm1 (deprecated 2024-06-01)
    * Replacement: Use ComplianceSettings.psm1 instead
    */
   ```

2. **Don't Remove Code**: Keep for reference, but disable in job queue
3. **Document Migration Path**: If replacement exists, document how to migrate

---

### PowerShell Quirks vs Intentional Patterns

**Problem**: How to distinguish between PowerShell bugs and intentional API patterns?

**Decision Framework**:

#### Replicate These (Intentional Patterns)
- Property cleanup logic (read-only field removal)
- Specific `$expand` parameters
- Beta vs v1.0 API version choices
- Pagination patterns
- Error handling for expected errors (404 for empty results)

#### Document But Don't Replicate (PowerShell Quirks)
- PowerShell-specific syntax workarounds
- Windows-specific file path handling
- PowerShell module dependency quirks

**Example of PowerShell Quirk**:
```powershell
# PowerShell-specific: Escape backtick for line continuation
$url = "/beta/deviceManagement/configurationPolicies?``$expand=assignments"
```

**TypeScript Should NOT Replicate**:
```typescript
// DO NOT include backtick - that's PowerShell syntax
const url = '/deviceManagement/configurationPolicies?$expand=assignments';
```

**Marking Quirks**:
```typescript
// [POWERSHELL QUIRK]: PowerShell uses [int] type cast here due to PS type system
// In TypeScript, parseInt() achieves the same result but is more idiomatic
const value = parseInt(setting.value, 10);
```

---

## Complete End-to-End Example

**Feature Request**: Implement sync for Compliance Policies with assignments

### Step 1: Locate PowerShell Module

```bash
$ find reference/IntuneManagement-master -name "*Compliance*.psm1"
reference/IntuneManagement-master/Modules/DeviceCompliance.psm1
```

### Step 2: Analyze PowerShell Implementation

```powershell
# From DeviceCompliance.psm1
function Get-CompliancePolicies {
    $url = "/beta/deviceManagement/deviceCompliancePolicies?`$expand=assignments"
    $policies = Invoke-MSGraphRequest -Url $url
    
    foreach($policy in $policies.value) {
        # Remove read-only properties
        $policy.PSObject.Properties.Remove('createdDateTime')
        $policy.PSObject.Properties.Remove('lastModifiedDateTime')
        $policy.PSObject.Properties.Remove('version')
        
        # Remove OData metadata
        $policy.PSObject.Properties.Remove('@odata.type')
    }
    
    return $policies.value
}
```

**Extracted Data Points**:
- Endpoint: `/beta/deviceManagement/deviceCompliancePolicies`
- API Version: `beta`
- Query Params: `$expand=assignments`
- Property Cleanup: `createdDateTime`, `lastModifiedDateTime`, `version`, `@odata.type`

### Step 3: Create TypeScript Implementation

```typescript
// worker/jobs/syncCompliancePolicies.ts

/**
 * Compliance Policies Sync
 * 
 * PowerShell Reference: commit 2eaf3257 (2025-12-09)
 * Module: DeviceCompliance.psm1
 * Last Verified: 2025-12-09
 */

import { graphClient } from '../utils/graphClient';
import { db } from '@/lib/db';
import { compliancePolicies } from '@/lib/db/schema';
import { eq, and } from 'drizzle-orm';

interface CompliancePolicy {
  id: string;
  displayName: string;
  description?: string;
  createdDateTime?: string; // Will be deleted
  lastModifiedDateTime?: string; // Will be deleted
  version?: number; // Will be deleted
  assignments?: Array<{
    id: string;
    target: any;
  }>;
  '@odata.type'?: string; // Will be deleted
  [key: string]: any;
}

export async function syncCompliancePolicies(tenantId: string): Promise<void> {
  console.log(`[${tenantId}] Starting compliance policies sync`);
  
  try {
    // Step 1: Fetch policies from Graph API (matches PowerShell)
    const response = await graphClient
      .api('/deviceManagement/deviceCompliancePolicies')
      .version('beta') // PowerShell uses beta
      .expand('assignments') // PowerShell uses $expand=assignments
      .get();
    
    const policies: CompliancePolicy[] = response.value;
    console.log(`[${tenantId}] Fetched ${policies.length} policies`);
    
    // Step 2: Clean up properties (matches PowerShell)
    for (const policy of policies) {
      delete policy.createdDateTime;
      delete policy.lastModifiedDateTime;
      delete policy.version;
      delete policy['@odata.type'];
    }
    
    // Step 3: Save to database
    for (const policy of policies) {
      await db
        .insert(compliancePolicies)
        .values({
          tenantId,
          intuneId: policy.id,
          displayName: policy.displayName,
          description: policy.description,
          data: policy, // Full policy JSON
          lastSyncedAt: new Date(),
        })
        .onConflictDoUpdate({
          target: [compliancePolicies.tenantId, compliancePolicies.intuneId],
          set: {
            displayName: policy.displayName,
            description: policy.description,
            data: policy,
            lastSyncedAt: new Date(),
          },
        });
    }
    
    console.log(`[${tenantId}] Compliance policies sync completed`);
  } catch (error) {
    console.error(`[${tenantId}] Compliance policies sync failed:`, error);
    throw error;
  }
}
```

### Step 4: Register Job in Queue

```typescript
// worker/index.ts

import { syncCompliancePolicies } from './jobs/syncCompliancePolicies';

// Register job processor
syncQueue.process('sync-compliance-policies', async (job) => {
  const { tenantId } = job.data;
  await syncCompliancePolicies(tenantId);
});
```

### Step 5: Test Implementation

```typescript
// scripts/test-compliance-sync.ts

import { syncCompliancePolicies } from '../worker/jobs/syncCompliancePolicies';

async function test() {
  const testTenantId = 'test-tenant-123';
  await syncCompliancePolicies(testTenantId);
  console.log('✓ Sync completed successfully');
}

test().catch(console.error);
```

### Step 6: Validate Against PowerShell

1. Run PowerShell sync:
   ```powershell
   Import-Module ./reference/IntuneManagement-master/DeviceCompliance.psm1
   $policies = Get-CompliancePolicies
   $policies | ConvertTo-Json -Depth 10 > powershell-output.json
   ```

2. Run TypeScript sync and export results:
   ```typescript
   const policies = await syncCompliancePolicies('test-tenant');
   fs.writeFileSync('typescript-output.json', JSON.stringify(policies, null, 2));
   ```

3. Compare outputs:
   ```bash
   diff powershell-output.json typescript-output.json
   # Should show minimal differences (only timestamps, etc.)
   ```

---

## Reference Implementations

See these existing sync jobs for real-world examples:

- **Configuration Policies**: `worker/jobs/syncConfigurationPolicies.ts`
  - Demonstrates `$expand=assignments,settings`
  - Complex property cleanup
  - Nested object handling

- **Applications**: `worker/jobs/syncApplications.ts`
  - Demonstrates type-specific filtering
  - Binary data handling (app icons)
  - Conditional property cleanup

- **Device Enrollment**: `worker/jobs/syncEnrollmentProfiles.ts`
  - Demonstrates beta-only endpoint
  - Multiple $expand parameters
  - Assignment group resolution

Each implementation includes:
- PowerShell reference version comment
- Module source reference
- Last verified date
- Inline explanations of undocumented behaviors

---

## Updates & Maintenance

**This Guide Is a Living Document**

- **Add new examples** when implementing new sync jobs
- **Update patterns** when PowerShell reference changes
- **Document discoveries** of undocumented API behaviors
- **Track PowerShell version** in header when examples are updated

**To Propose Changes**:
1. Create a feature branch
2. Update this guide with new findings
3. Submit PR with rationale for changes
4. Link to PowerShell reference commit showing the pattern

---

**Guide Version**: 1.0.0  
**Last Reviewed**: 2025-12-09  
**PowerShell Reference**: [2eaf3257](https://github.com/Micke-K/IntuneManagement/commit/2eaf3257)  
**Maintainers**: See `docs/architecture/intune-reference-version.md` for update process