# Version Manager

The Version Manager helps manage database migrations and version compatibility across different versions of the software.

## Features

- Track database schema versions
- Handle migrations between versions
- Reset database when necessary (incompatible versions, rollup address change)
- Simple, clean API for version management

## Usage

```typescript
import { version } from '@aztec/foundation';
import { EthAddress } from '@aztec/foundation/eth-address';

// Define your current database version
const DB_VERSION = 3;
const rollupAddress = EthAddress.fromString('0x1234567890123456789012345678901234567890');

// Create version manager for your service
const versionManager = new version.VersionManager(DB_VERSION, rollupAddress, {
  dataDir: '/path/to/data',
  serviceName: 'my-database',
});

// When initializing your database
await versionManager.checkVersionAndHandle(
  // Called when a reset is needed
  async () => {
    // Initialize a fresh database
    await initializeFreshDatabase();
  },
  // Called when an upgrade is needed (optional)
  async (oldVersion, newVersion) => {
    if (oldVersion === 1 && newVersion === 2) {
      // Migrate from version 1 to 2
      await migrateV1ToV2();
    } else if (oldVersion === 2 && newVersion === 3) {
      // Migrate from version 2 to 3
      await migrateV2ToV3();
    } else {
      // Unsupported migration path, will fall back to reset
      throw new Error(`Cannot upgrade from ${oldVersion} to ${newVersion}`);
    }
  },
);

// Get the data directory for your service
const dataDir = versionManager.getDataDirectory();
```

## Automatic Reset Conditions

The database will be reset in the following conditions:

1. No version information exists (first run)
2. Rollup address has changed
3. Version has changed and no upgrade callback is provided
4. Upgrade callback throws an error

When a reset occurs, the data directory is deleted and recreated, and the reset callback is called to initialize a fresh database.