"""Shared formatting helpers for consistent text output."""
from typing import Any, Optional
import math
from .constants import (
DISPLAY_MAX_DECIMALS,
PRECISION_ABS_TOL,
PRECISION_MAX_DECIMALS,
PRECISION_MAX_LOSS_PCT,
PRECISION_REL_TOL,
)
def _adaptive_decimals(num: float, max_decimals: int = PRECISION_MAX_DECIMALS) -> int:
scale = max(1.0, abs(num))
tol = max(PRECISION_ABS_TOL, PRECISION_REL_TOL * scale, abs(num) * PRECISION_MAX_LOSS_PCT)
for d in range(0, max_decimals + 1):
factor = 10.0 ** d
rv = round(num * factor) / factor
if abs(rv - num) <= tol:
return d
return max_decimals
def format_number(value: Any, decimals: Optional[int] = None) -> str:
"""Render scalars with consistent numeric/boolean/null representation."""
if value is None:
return "null"
if isinstance(value, bool):
return "true" if value else "false"
try:
num = float(value)
except (TypeError, ValueError):
return str(value)
if not math.isfinite(num):
return str(value)
if decimals is None:
decimals = _adaptive_decimals(num)
text = f"{num:.{int(decimals)}f}".rstrip('0').rstrip('.')
if text in ("", "-0"):
text = "0"
return text
