src/utils/logger.ts

/**
 * src/utils/logger.ts
 *
 * Structured application logger built on Winston.
 * In development: coloured, human-readable output.
 * In production: single-line timestamped output for HF Spaces logs.
 */

import winston from 'winston';

const { combine, timestamp, colorize, printf, errors } = winston.format;

const isDev = (process.env.NODE_ENV ?? 'production') === 'development';

const devFormat = combine(
  colorize({ all: true }),
  timestamp({ format: 'HH:mm:ss' }),
  errors({ stack: true }),
  printf(({ timestamp: ts, level, message, stack }) =>
    stack
      ? `[${ts}] ${level}: ${message}\n${stack}`
      : `[${ts}] ${level}: ${message}`
  )
);

const prodFormat = combine(
  timestamp({ format: 'YYYY-MM-DD HH:mm:ss' }),
  errors({ stack: true }),
  printf(({ timestamp: ts, level, message, stack }) =>
    stack
      ? `[${ts}] ${level.toUpperCase()}: ${message}\n${stack}`
      : `[${ts}] ${level.toUpperCase()}: ${message}`
  )
);

export const logger = winston.createLogger({
  level: isDev ? 'debug' : 'info',
  format: isDev ? devFormat : prodFormat,
  transports: [new winston.transports.Console()],
});