import type { QueryMode } from '../types/database'
/**
* Application configuration loaded from environment variables
*/
export interface AppConfig {
queryMode: QueryMode
}
/**
* Parse query mode from environment variable
*/
function parseQueryMode(value: string | undefined): QueryMode {
const mode = value?.toLowerCase()
if (mode === 'write' || mode === 'full') {
return mode
}
return 'safe' // default
}
/**
* Load configuration from environment variables
*/
export function loadConfig(): AppConfig {
return {
queryMode: parseQueryMode(process.env.SQL_MCP_MODE)
}
}
/**
* Singleton config instance
*/
let configInstance: AppConfig | null = null
/**
* Get the application configuration (lazy loaded singleton)
*/
export function getConfig(): AppConfig {
if (!configInstance) {
configInstance = loadConfig()
}
return configInstance
}
/**
* Get human-readable description of allowed operations for current mode
*/
export function getModeDescription(mode: QueryMode): string {
switch (mode) {
case 'safe':
return 'Read-only (SELECT, WITH, EXPLAIN)'
case 'write':
return 'Read/Write (SELECT, INSERT, UPDATE, DELETE)'
case 'full':
return 'Full access (all SQL operations including DDL)'
}
}
