"""Exchange amount/price precision helpers for hedge and local trading."""

from __future__ import annotations

from typing import Any, Optional


def _decimals_from_precision_value(value: Any) -> Optional[int]:
    if value in (None, ""):
        return None
    try:
        p = float(value)
    except (TypeError, ValueError):
        return None
    if p >= 1 and abs(p - round(p)) < 1e-9 and p <= 12:
        return int(round(p))
    if 0 < p < 1:
        s = f"{p:.12f}".rstrip("0")
        if "." in s:
            return min(12, len(s.split(".", 1)[1]))
    return None


def _decimals_from_ccxt_str(text: str) -> int:
    s = str(text or "").strip()
    if not s or "." not in s:
        return 0
    frac = s.split(".", 1)[1]
    if not frac:
        return 0
    return min(12, len(frac.rstrip("0") or frac))


def amount_decimals_from_exchange(exchange: Any, exchange_symbol: str) -> int:
    try:
        return _decimals_from_ccxt_str(exchange.amount_to_precision(exchange_symbol, 1.23456789))
    except Exception:
        market = exchange.market(exchange_symbol)
        prec = (market.get("precision") or {}).get("amount")
        d = _decimals_from_precision_value(prec)
        return d if d is not None else 4