# Component Migration Template

## Overview
This template provides step-by-step instructions for migrating Vue components from legacy patterns to PlatformServiceMixin.

## Before Migration Checklist

- [ ] Component uses `import * as databaseUtil`
- [ ] Component uses `import { logConsoleAndDb }`  
- [ ] Component has direct `PlatformServiceFactory.getInstance()` calls
- [ ] Component has manual error handling for database operations
- [ ] Component has verbose SQL result processing

## Step-by-Step Migration

### Step 1: Update Imports

```typescript
// ❌ BEFORE - Legacy imports
import * as databaseUtil from "../db/databaseUtil";
import { logConsoleAndDb } from "../db/databaseUtil";
import { PlatformServiceFactory } from "../services/PlatformServiceFactory";

// ✅ AFTER - Clean imports
import { PlatformServiceMixin } from "@/utils/PlatformServiceMixin";
import { Contact } from "@/db/tables/contacts";
import { Settings } from "@/db/tables/settings";
```

### Step 2: Add Mixin to Component

```typescript
// ❌ BEFORE - No mixin
@Component({
  components: { /* ... */ }
})
export default class MyComponent extends Vue {
  // ...
}

// ✅ AFTER - With mixin
@Component({
  components: { /* ... */ }
})
export default class MyComponent extends Vue {
  mixins: [PlatformServiceMixin],
  // ...
}
```

### Step 3: Replace Database Operations

```typescript
// ❌ BEFORE - Legacy database access
async loadContacts() {
  try {
    const platformService = PlatformServiceFactory.getInstance();
    const result = await platformService.dbQuery("SELECT * FROM contacts");
    const contacts = databaseUtil.mapQueryResultToValues(result);
    await logConsoleAndDb("Contacts loaded successfully");
    return contacts;
  } catch (error) {
    await logConsoleAndDb("Error loading contacts: " + error, true);
    throw error;
  }
}

// ✅ AFTER - Mixin methods
async loadContacts() {
  try {
    const contacts = await this.$getAllContacts();
    await this.$log("Contacts loaded successfully");
    return contacts;
  } catch (error) {
    await this.$logError(`[${this.$options.name}] Error loading contacts: ${error}`);
    throw error;
  }
}
```

### Step 4: Replace Settings Operations

```typescript
// ❌ BEFORE - Legacy settings access
async loadSettings() {
  const settingsRow = await databaseUtil.retrieveSettingsForActiveAccount();
  const settings = settingsRow || {};
  return settings;
}

async saveSettings(changes: Partial<Settings>) {
  await databaseUtil.updateDefaultSettings(changes);
  await logConsoleAndDb("Settings saved");
}

// ✅ AFTER - Mixin methods
async loadSettings() {
  return await this.$settings();
}

async saveSettings(changes: Partial<Settings>) {
  await this.$saveSettings(changes);
  await this.$log("Settings saved");
}
```

### Step 5: Replace Logging Operations

```typescript
// ❌ BEFORE - Legacy logging
try {
  // operation
} catch (error) {
  console.error("Error occurred:", error);
  await logConsoleAndDb("Error: " + error, true);
}

// ✅ AFTER - Mixin logging
try {
  // operation
} catch (error) {
  await this.$logError(`[${this.$options.name}] Error: ${error}`);
}
```

## Common Migration Patterns

### Pattern 1: Database Query + Result Processing

```typescript
// ❌ BEFORE
const platformService = PlatformServiceFactory.getInstance();
const result = await platformService.dbQuery(sql, params);
const processed = databaseUtil.mapQueryResultToValues(result);

// ✅ AFTER
const processed = await this.$query(sql, params);
```

### Pattern 2: Settings Retrieval

```typescript
// ❌ BEFORE
const settingsRow = await databaseUtil.retrieveSettingsForActiveAccount();
const value = settingsRow?.[field] || defaultValue;

// ✅ AFTER
const settings = await this.$settings();
const value = settings[field] || defaultValue;
```

### Pattern 3: Contact Operations

```typescript
// ❌ BEFORE
const platformService = PlatformServiceFactory.getInstance();
const contacts = await platformService.dbQuery("SELECT * FROM contacts");
const mappedContacts = databaseUtil.mapQueryResultToValues(contacts);

// ✅ AFTER
const contacts = await this.$getAllContacts();
```

### Pattern 4: Error Handling

```typescript
// ❌ BEFORE
try {
  // operation
} catch (error) {
  console.error("[MyComponent] Error:", error);
  await databaseUtil.logToDb("Error: " + error, "error");
}

// ✅ AFTER
try {
  // operation
} catch (error) {
  await this.$logError(`[${this.$options.name}] Error: ${error}`);
}
```

## After Migration Checklist

- [ ] All `databaseUtil` imports removed
- [ ] All `logConsoleAndDb` imports removed
- [ ] All direct `PlatformServiceFactory.getInstance()` calls removed
- [ ] Component includes `PlatformServiceMixin` in mixins array
- [ ] Database operations use mixin methods (`$db`, `$query`, `$getAllContacts`, etc.)
- [ ] Settings operations use mixin methods (`$settings`, `$saveSettings`)
- [ ] Logging uses mixin methods (`$log`, `$logError`, `$logAndConsole`)
- [ ] Error handling includes component name context
- [ ] Component compiles without TypeScript errors
- [ ] Component functionality works as expected

## Testing Migration

1. **Compile Check**: `npm run build` should complete without errors
2. **Runtime Check**: Component should load and function normally
3. **Logging Check**: Verify logs appear in console and database
4. **Error Handling Check**: Verify errors are properly logged and handled

## Troubleshooting

### Common Issues

1. **Missing Mixin Methods**: Ensure component properly extends PlatformServiceMixin
2. **TypeScript Errors**: Check that all types are properly imported
3. **Runtime Errors**: Verify all async operations are properly awaited
4. **Missing Context**: Add component name to error messages for better debugging

### Performance Considerations

- Mixin methods include caching for frequently accessed data
- Database operations are queued and optimized
- Error logging includes proper context and formatting 

## Phase 4: Testing and Validation

### 4.1 Multi-Platform Testing Requirements

**ALL MIGRATIONS MUST BE TESTED ON ALL SUPPORTED PLATFORMS:**

#### Web Platform Testing (Required)
- [ ] Test in Chrome/Chromium (primary browser)
- [ ] Test in Firefox (secondary browser)
- [ ] Test in Safari (if applicable)
- [ ] Verify PWA functionality works correctly
- [ ] Test responsive design on different screen sizes

#### Desktop Platform Testing (Required)
- [ ] Test Electron app functionality
- [ ] Verify desktop-specific features work
- [ ] Test file system access (if applicable)
- [ ] Verify native desktop integrations

#### Mobile Platform Testing (Required)
- [ ] Test iOS app via Capacitor
- [ ] Test Android app via Capacitor  
- [ ] Verify mobile-specific features (camera, contacts, etc.)
- [ ] Test deep linking functionality
- [ ] Verify push notifications work

### 4.2 Functional Testing Per Platform

For each platform, test these core scenarios:

#### Database Operations
- [ ] Create/Read/Update/Delete operations work
- [ ] Data persistence across app restarts
- [ ] Database migration handling (if applicable)

#### Logging and Error Handling
- [ ] Errors are logged correctly to console
- [ ] Errors are stored in database logs
- [ ] Error messages display appropriately to users
- [ ] Network errors are handled gracefully

#### User Interface
- [ ] All buttons and interactions work
- [ ] Loading states display correctly
- [ ] Error states display appropriately
- [ ] Responsive design works on platform

### 4.3 Platform-Specific Testing Notes

#### Web Platform
- Test offline/online scenarios
- Verify IndexedDB storage works
- Test service worker functionality
- Check browser developer tools for errors

#### Desktop Platform  
- Test native menu integrations
- Verify file system permissions
- Test auto-updater functionality
- Check Electron developer tools

#### Mobile Platform
- Test device permissions (camera, storage, etc.)
- Verify app store compliance
- Test background/foreground transitions
- Check native debugging tools

### 4.4 Sign-Off Requirements

**MIGRATION IS NOT COMPLETE UNTIL ALL PLATFORMS ARE TESTED AND SIGNED OFF:**

```markdown
## Testing Sign-Off Checklist

### Web Platform ✅/❌
- [ ] Chrome: Tested by [Name] on [Date]
- [ ] Firefox: Tested by [Name] on [Date]  
- [ ] Safari: Tested by [Name] on [Date]
- [ ] Notes: [Any platform-specific issues or observations]

### Desktop Platform ✅/❌
- [ ] Windows: Tested by [Name] on [Date]
- [ ] macOS: Tested by [Name] on [Date]
- [ ] Linux: Tested by [Name] on [Date]
- [ ] Notes: [Any platform-specific issues or observations]

### Mobile Platform ✅/❌
- [ ] iOS: Tested by [Name] on [Date]
- [ ] Android: Tested by [Name] on [Date]
- [ ] Notes: [Any platform-specific issues or observations]

### Final Sign-Off
- [ ] All platforms tested and working
- [ ] No regressions identified
- [ ] Performance is acceptable
- [ ] Migration completed by: [Name] on [Date]
```