/**
 * Structured logger built on pino.
 *
 * - level: from LOG_LEVEL env var (default "info")
 * - dev: pretty-printed, colorized output
 * - prod: JSON output suitable for ingestion by log shippers
 *
 * Use child loggers (`logger.child({ component: "name" })`) to tag log lines
 * by subsystem so they remain easy to grep in production.
 */
import pino, { type LoggerOptions } from "pino";

const NODE_ENV = process.env.NODE_ENV ?? "development";
const IS_PROD = NODE_ENV === "production";
const LEVEL = process.env.LOG_LEVEL ?? "info";

const baseOptions: LoggerOptions = {
  level: LEVEL,
  base: { env: NODE_ENV },
  timestamp: pino.stdTimeFunctions.isoTime,
};

const transport = IS_PROD
  ? undefined
  : {
      target: "pino-pretty",
      options: {
        colorize: true,
        translateTime: "SYS:HH:MM:ss.l",
        ignore: "pid,hostname,env",
        singleLine: false,
      },
    };

export const logger = pino({
  ...baseOptions,
  ...(transport ? { transport } : {}),
});

export type Logger = typeof logger;

export function childLogger(component: string, extra: Record<string, unknown> = {}) {
  return logger.child({ component, ...extra });
}