from __future__ import annotations

from decimal import Decimal
from decimal import ROUND_HALF_EVEN
from typing import Any


CONVICTION_MIN = 0.5
CONVICTION_MAX = 9.0
EXCHANGE_LEV_MIN = 1
EXCHANGE_LEV_MAX = 3
LEVERAGE_MAPPING_RULE = "round_half_even_linear_0.5_to_9.0_to_1_to_exchange_cap"


def _clamp_exchange_bounds(exchange_min: Any, exchange_max: Any) -> tuple[int, int]:
    lower = int(Decimal(str(exchange_min)))
    upper = int(Decimal(str(exchange_max)))
    if lower < 1:
        lower = 1
    if upper < lower:
        upper = lower
    return lower, upper


def normalize_bingx_leverage_value(
    leverage: Any,
    *,
    exchange_min: Any = EXCHANGE_LEV_MIN,
    exchange_max: Any = EXCHANGE_LEV_MAX,
) -> int:
    """
    BingX exchange leverage is integer-only and conservatively capped.
    """
    lower, upper = _clamp_exchange_bounds(exchange_min, exchange_max)
    desired = int(
        Decimal(str(leverage)).quantize(Decimal("1"), rounding=ROUND_HALF_EVEN)
    )
    if desired < lower:
        return lower
    if desired > upper:
        return upper
    return desired


def map_internal_conviction_to_exchange_leverage_target(
    leverage: Any,
    *,
    exchange_min: Any = EXCHANGE_LEV_MIN,
    exchange_max: Any = EXCHANGE_LEV_MAX,
) -> float:
    """
    Map engine conviction/sizing into BingX exchange leverage.

    The engine retains the fractional conviction signal internally. The exchange
    receives a leverage target derived from that signal.
    """
    lower, upper = _clamp_exchange_bounds(exchange_min, exchange_max)
    internal = float(Decimal(str(leverage)))
    internal = max(CONVICTION_MIN, min(CONVICTION_MAX, internal))
    return float(lower + (
        (internal - CONVICTION_MIN) / (CONVICTION_MAX - CONVICTION_MIN)
    ) * (upper - lower))


def map_internal_conviction_to_exchange_leverage(
    leverage: Any,
    *,
    exchange_min: Any = EXCHANGE_LEV_MIN,
    exchange_max: Any = EXCHANGE_LEV_MAX,
) -> int:
    """
    Backwards-compatible integer exchange leverage mapper.
    """
    target = map_internal_conviction_to_exchange_leverage_target(
        leverage,
        exchange_min=exchange_min,
        exchange_max=exchange_max,
    )
    return normalize_bingx_leverage_value(
        target,
        exchange_min=exchange_min,
        exchange_max=exchange_max,
    )