/**
 * Structured logger — writes newline-delimited JSON to stdout/stderr.
 */

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

interface LogEntry {
  level: LogLevel;
  time: string;
  msg: string;
  [key: string]: unknown;
}

function write(stream: typeof process.stdout | typeof process.stderr, entry: LogEntry): void {
  stream.write(JSON.stringify(entry) + '\n');
}

export const logger = {
  info(msg: string, data?: Record<string, unknown>): void {
    write(process.stdout, { level: 'info', time: new Date().toISOString(), msg, ...data });
  },
  warn(msg: string, data?: Record<string, unknown>): void {
    write(process.stderr, { level: 'warn', time: new Date().toISOString(), msg, ...data });
  },
  error(msg: string, data?: Record<string, unknown>): void {
    write(process.stderr, { level: 'error', time: new Date().toISOString(), msg, ...data });
  },
};