# Implementation Plan

## Implementation Plan

### Phase 1: Setup (Week 1-2)
```bash
# Install Vercel SDK
npm install vercel

# Configure credentials
cp .env.example .env.vercel
# Edit with new credentials

# Verify connectivity
node -e "require('vercel').ping()"
```

### Phase 2: Adapter Layer (Week 3-4)
```typescript
// src/adapters/vercel.ts
interface ServiceAdapter {
  create(data: CreateInput): Promise<Resource>;
  read(id: string): Promise<Resource>;
  update(id: string, data: UpdateInput): Promise<Resource>;
  delete(id: string): Promise<void>;
}

class VercelAdapter implements ServiceAdapter {
  async create(data: CreateInput): Promise<Resource> {
    const vercelData = this.transform(data);
    return vercelClient.create(vercelData);
  }

  private transform(data: CreateInput): VercelInput {
    // Map from old format to Vercel format
  }
}
```

### Phase 3: Data Migration (Week 5-6)
```typescript
async function migrateVercelData(): Promise<MigrationResult> {
  const batchSize = 100;
  let processed = 0;
  let errors: MigrationError[] = [];

  for await (const batch of oldSystem.iterateBatches(batchSize)) {
    try {
      const transformed = batch.map(transform);
      await vercelClient.batchCreate(transformed);
      processed += batch.length;
    } catch (error) {
      errors.push({ batch, error });
    }

    // Progress update
    console.log(`Migrated ${processed} records`);
  }

  return { processed, errors };
}
```

### Phase 4: Traffic Shift (Week 7-8)
```typescript
// Feature flag controlled traffic split
function getServiceAdapter(): ServiceAdapter {
  const vercelPercentage = getFeatureFlag('vercel_migration_percentage');

  if (Math.random() * 100 < vercelPercentage) {
    return new VercelAdapter();
  }

  return new LegacyAdapter();
}
```