mcp-outline-postgresql/src/utils/logger.ts

/**
 * MCP Outline PostgreSQL - Logger
 * Optimized for MCP - reduce logs to not exhaust Claude context
 * @author Descomplicar® | @link descomplicar.pt | @copyright 2026
 */

type LogLevel = 'error' | 'warn' | 'info' | 'debug';

interface LogEntry {
  timestamp: string;
  level: LogLevel;
  message: string;
  data?: Record<string, unknown>;
}

const LOG_LEVELS: Record<LogLevel, number> = {
  error: 0,
  warn: 1,
  info: 2,
  debug: 3
};

class Logger {
  private level: LogLevel;

  constructor() {
    this.level = (process.env.LOG_LEVEL as LogLevel) || 'error';
  }

  private shouldLog(level: LogLevel): boolean {
    return LOG_LEVELS[level] <= LOG_LEVELS[this.level];
  }

  private formatLog(level: LogLevel, message: string, data?: Record<string, unknown>): string {
    const entry: LogEntry = {
      timestamp: new Date().toISOString(),
      level,
      message,
      ...(data && { data })
    };
    return JSON.stringify(entry);
  }

  private write(level: LogLevel, message: string, data?: Record<string, unknown>): void {
    if (!this.shouldLog(level)) return;

    const formatted = this.formatLog(level, message, data);

    // For MCP, send logs to stderr
    if (process.env.MCP_MODE !== 'false') {
      process.stderr.write(formatted + '\n');
    } else {
      console.log(formatted);
    }
  }

  error(message: string, data?: Record<string, unknown>): void {
    this.write('error', message, data);
  }

  warn(message: string, data?: Record<string, unknown>): void {
    this.write('warn', message, data);
  }

  info(message: string, data?: Record<string, unknown>): void {
    this.write('info', message, data);
  }

  debug(message: string, data?: Record<string, unknown>): void {
    this.write('debug', message, data);
  }
}

export const logger = new Logger();

// Log queries for auditing (if enabled) - OPTIMIZED
export function logQuery(
  sql: string,
  _params?: any[],
  duration?: number,
  _clientId?: string
): void {
  // DISABLED by default to save Claude context
  if (process.env.ENABLE_AUDIT_LOG === 'true' && process.env.NODE_ENV !== 'production') {
    logger.debug('SQL', {
      sql: sql.substring(0, 50),
      duration
    });
  }
}