import type { Pool } from 'mysql2/promise';
import { ErrorCode, McpError } from '@modelcontextprotocol/sdk/types.js';
import type { ConnectionConfig, ConnectionArgs } from '../types/index.js';
import { loadConfig } from './config.js';
import { createPool, testConnection, executeQuery, closePool } from './pool.js';
import { handleDatabaseError } from '../utils/errors.js';
import { logger } from '../utils/logger.js';
export class ConnectionManager {
private pool: Pool | null = null;
private config: ConnectionConfig | null = null;
getConfig(): ConnectionConfig | null {
return this.config;
}
getDatabaseName(): string | null {
return this.config?.database ?? null;
}
isConnected(): boolean {
return this.pool !== null && this.config !== null;
}
async connect(args: ConnectionArgs): Promise<{ host: string; database: string; port?: number }> {
this.config = await loadConfig(args);
logger.info('Configuration loaded', {
host: this.config.host,
database: this.config.database,
});
try {
this.pool = createPool(this.config);
await testConnection(this.pool);
logger.info('Successfully connected to database', {
host: this.config.host,
port: this.config.port,
database: this.config.database,
});
return {
host: this.config.host,
database: this.config.database,
port: this.config.port,
};
} catch (error) {
if (this.pool) {
await this.pool.end().catch(() => {});
this.pool = null;
}
this.config = null;
handleDatabaseError(error);
}
}
private ensureConnected(): Pool {
if (!this.config) {
throw new McpError(
ErrorCode.InvalidRequest,
'Not connected to a database. Use connect_db tool first.'
);
}
if (!this.pool) {
throw new McpError(ErrorCode.InternalError, 'Connection pool not initialized');
}
return this.pool;
}
async query<T>(sql: string, params: (string | number | boolean | null)[] = []): Promise<T> {
const pool = this.ensureConnected();
return executeQuery<T>(pool, sql, params);
}
async close(): Promise<void> {
if (this.pool) {
await closePool(this.pool);
this.pool = null;
}
this.config = null;
logger.info('Database connection closed');
}
async reconnect(): Promise<void> {
if (!this.config) {
throw new McpError(ErrorCode.InvalidRequest, 'Cannot reconnect: no previous configuration');
}
const savedConfig = { ...this.config };
await this.close();
this.config = savedConfig;
this.pool = createPool(this.config);
await testConnection(this.pool);
logger.info('Successfully reconnected to database');
}
}
