import type { DatabaseAdapter, ConnectionConfig, DatabaseEngine } from '../types/database'
import { createAdapter } from '../adapters'
import { NotConnectedError } from '../utils/errors'
/**
* Connection state information
*/
export interface ConnectionState {
isConnected: boolean
engine: DatabaseEngine | null
database: string | null
server: string | null
}
/**
* Singleton class to manage database connection state
* Only one connection can be active at a time
*/
class ConnectionManager {
private adapter: DatabaseAdapter | null = null
private serverAddress: string | null = null
/**
* Get the current adapter (throws if not connected)
*/
getAdapter(): DatabaseAdapter {
if (!this.adapter || !this.adapter.isConnected) {
throw new NotConnectedError()
}
return this.adapter
}
/**
* Check if currently connected
*/
get isConnected(): boolean {
return this.adapter?.isConnected ?? false
}
/**
* Get current connection state
*/
getConnectionState(): ConnectionState {
if (!this.adapter || !this.adapter.isConnected) {
return {
isConnected: false,
engine: null,
database: null,
server: null
}
}
return {
isConnected: true,
engine: this.adapter.engine,
database: this.adapter.currentDatabase,
server: this.serverAddress
}
}
/**
* Connect to a database
* Disconnects any existing connection first
*/
async connect(config: ConnectionConfig): Promise<void> {
// Disconnect existing connection if any
if (this.adapter?.isConnected) {
await this.disconnect()
}
// Create new adapter and connect
this.adapter = createAdapter(config.engine)
await this.adapter.connect(config)
this.serverAddress = config.server
}
/**
* Disconnect from the database
*/
async disconnect(): Promise<void> {
if (this.adapter) {
try {
await this.adapter.disconnect()
} finally {
this.adapter = null
this.serverAddress = null
}
}
}
/**
* Switch to a different database
*/
async switchDatabase(database: string): Promise<void> {
const adapter = this.getAdapter()
await adapter.switchDatabase(database)
}
/**
* List all databases
*/
async listDatabases(): Promise<string[]> {
const adapter = this.getAdapter()
return adapter.listDatabases()
}
/**
* List all tables in current database
*/
async listTables() {
const adapter = this.getAdapter()
return adapter.listTables()
}
/**
* Describe a table's schema
*/
async describeTable(tableName: string, schema?: string) {
const adapter = this.getAdapter()
return adapter.describeTable(tableName, schema)
}
/**
* Execute a SQL query
*/
async executeQuery(sql: string, limit?: number) {
const adapter = this.getAdapter()
return adapter.executeQuery(sql, limit)
}
}
/**
* Singleton instance of ConnectionManager
*/
export const connectionManager = new ConnectionManager()
