import {
  type LogLevel,
  FormatLogger,
  logLevelPrefix,
  LogContext,
} from '@rocicorp/logger';

function maybeStringifyForLogs(
  unk: unknown,
  allowNewlines: boolean,
): unknown | string {
  if (typeof unk !== 'object') {
    return unk;
  }
  let s = JSON.stringify(unk, null, 1);
  if (!allowNewlines) {
    s = s.replace(/\n/g, '');
  }
  return s;
}

// A LogContext that's appropriate for server-side logging. It:
// - prepends the log level
// - readably stringifies objects
// - optionally removes newlines
//
// TODO once the dust settles on this move it to @rocicorp/logger. It's here
// for faster development for the time being.
export function newLogContext(
  level: LogLevel,
  allowNewlines = true,
): LogContext {
  const fl = new FormatLogger(
    (lvl: LogLevel, ...args: unknown[]): unknown[] => {
      return [
        logLevelPrefix[lvl],
        ...args.map(unk => maybeStringifyForLogs(unk, allowNewlines)),
      ];
    },
  );
  return new LogContext(level, undefined, fl);
}