const UP = Symbol("UP"); // TOWARD_POSITIVE_INFINITY
const DOWN = Symbol("DOWN"); // TOWARD_NEGATIVE_INFINITY
const TOWARD_ZERO = Symbol("TOWARD_ZERO");
const HALF_AWAY_FROM_ZERO = Symbol("HALF_AWAY_FROM_ZERO");
const HALF_TO_EVEN = Symbol("HALF_TO_EVEN");

export const RoundingMode = {
  UP,
  DOWN,
  TOWARD_ZERO,
  AWAY_FROM_ZERO: Symbol("AWAY_FROM_ZERO"),
  HALF_UP: Symbol("HALF_UP"),
  HALF_DOWN: Symbol("HALF_DOWN"),
  HALF_TOWARD_ZERO: Symbol("HALF_TOWARD_ZERO"),
  HALF_AWAY_FROM_ZERO,
  HALF_TO_EVEN,

  /** Alias for `UP`. */
  CEILING: UP,

  /** Alias for `DOWN`. */
  FLOOR: DOWN,

  /** Alias for `TOWARD_ZERO`. */
  TRUNCATE: TOWARD_ZERO,

  /** Alias for `HALF_AWAY_FROM_ZERO`. */
  ROUND: HALF_AWAY_FROM_ZERO, // Math.roundとは違うので注意（Math.roundは.5の場合切り捨て）

  /** Alias for `HALF_TO_EVEN`. */
  CONVERGENT: HALF_TO_EVEN,
} as const;

export type RoundingMode = typeof RoundingMode[keyof typeof RoundingMode];