"""Shared formatting helpers for consistent text output."""
from typing import Any, List, Optional
import math
from .constants import (
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_float(value: float, decimals: int) -> str:
"""Format a float with fixed decimals and trimmed trailing zeros."""
text = f"{float(value):.{int(decimals)}f}"
if "." in text:
text = text.rstrip("0").rstrip(".")
if text in ("", "-0"):
return "0"
return text
def optimal_decimals(
values: List[float],
rel_tol: float = PRECISION_REL_TOL,
abs_tol: float = PRECISION_ABS_TOL,
max_decimals: int = PRECISION_MAX_DECIMALS,
max_loss_pct: float = PRECISION_MAX_LOSS_PCT,
) -> int:
"""Infer minimal decimals that preserve numeric variation under tolerance."""
if not values:
return 0
nums: List[float] = []
for v in values:
try:
fv = float(v)
except Exception:
continue
if math.isfinite(fv):
nums.append(fv)
if not nums:
return 0
vmin = min(nums)
vmax = max(nums)
value_range = vmax - vmin
if value_range <= 0.0:
scale = max(1.0, max(abs(v) for v in nums))
tol = max(abs_tol, rel_tol * scale)
else:
tol = max(abs_tol, value_range * max_loss_pct)
for d in range(0, int(max_decimals) + 1):
factor = 10.0 ** d
max_diff = 0.0
for v in nums:
rv = round(v * factor) / factor
diff = abs(rv - v)
if diff > max_diff:
max_diff = diff
if max_diff > tol:
break
if max_diff <= tol:
return d
return int(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)
return format_float(num, int(decimals))
