"""OKX USDⓈ 期权：张数与权利金计算。"""
from __future__ import annotations

import math
from typing import Any


def ct_mult_from_meta(meta: dict[str, Any] | None) -> float:
    if not meta:
        return 0.01
    try:
        return float(meta.get("ctMult") or 0.01)
    except (TypeError, ValueError):
        return 0.01


def min_sz_from_meta(meta: dict[str, Any] | None) -> int:
    if not meta:
        return 1
    try:
        return max(1, int(float(meta.get("minSz") or 1)))
    except (TypeError, ValueError):
        return 1


def premium_per_sheet(quote_per_unit: float, ct_mult: float = 0.01) -> float:
    """报价为每 1 ETH/BTC；每张权利金 = 报价 × ctMult。"""
    return float(quote_per_unit) * float(ct_mult)


def total_premium(quote_per_unit: float, eth_amount: float, ct_mult: float = 0.01) -> float:
    return float(quote_per_unit) * float(eth_amount)


def sheets_from_eth_amount(eth_amount: float, ct_mult: float = 0.01) -> int:
    if eth_amount <= 0 or ct_mult <= 0:
        return 0
    return int(math.floor(eth_amount / ct_mult + 1e-12))


def eth_amount_from_sheets(sheets: int, ct_mult: float = 0.01) -> float:
    return round(int(sheets) * float(ct_mult), 8)


def calc_order_size(
    *,
    quote_per_unit: float,
    ct_mult: float,
    min_sz: int,
    budget_usdc: float | None = None,
    budget_buffer: float = 0.95,
    eth_amount: float | None = None,
    sheets: int | None = None,
    budget_cap: float | None = None,
) -> dict[str, Any]:
    """
    返回 sheets, eth_amount, total_premium。
    mode: budget_full / eth_amount / sheets。
    """
    if quote_per_unit <= 0:
        return {"ok": False, "msg": "卖一价无效", "sheets": 0, "eth_amount": 0.0, "total_premium": 0.0}

    if sheets is not None and int(sheets) > 0:
        sheets = int(sheets)
    elif eth_amount is not None and eth_amount > 0:
        sheets = sheets_from_eth_amount(eth_amount, ct_mult)
    elif budget_usdc is not None and budget_usdc > 0:
        eff = float(budget_usdc) * float(budget_buffer)
        per_sheet = premium_per_sheet(quote_per_unit, ct_mult)
        if per_sheet <= 0:
            return {"ok": False, "msg": "无法计算单张权利金", "sheets": 0, "eth_amount": 0.0, "total_premium": 0.0}
        sheets = int(math.floor(eff / per_sheet))
    else:
        return {"ok": False, "msg": "请指定预算、币数量或张数", "sheets": 0, "eth_amount": 0.0, "total_premium": 0.0}

    if sheets < min_sz:
        per = premium_per_sheet(quote_per_unit, ct_mult)
        return {
            "ok": False,
            "msg": f"预算不足，无法买入 {min_sz} 张（单张约 {per:.4f} USDC）",
            "sheets": sheets,
            "eth_amount": eth_amount_from_sheets(sheets, ct_mult),
            "total_premium": total_premium(quote_per_unit, eth_amount_from_sheets(sheets, ct_mult)),
        }

    eth = eth_amount_from_sheets(sheets, ct_mult)
    prem = total_premium(quote_per_unit, eth)
    if budget_cap is not None and prem > float(budget_cap) + 1e-9:
        return {
            "ok": False,
            "msg": f"权利金 {prem:.4f} 超过单笔上限 {budget_cap} USDC",
            "sheets": sheets,
            "eth_amount": eth,
            "total_premium": prem,
        }
    return {"ok": True, "msg": "", "sheets": sheets, "eth_amount": eth, "total_premium": prem}


def is_shallow_itm(
    *,
    opt_type: str,
    strike: float,
    index_px: float,
    max_dist_usd: float,
) -> bool:
    o = (opt_type or "").upper()
    if o == "C":
        if strike >= index_px:
            return False
        return (index_px - strike) <= max_dist_usd
    if o == "P":
        if strike <= index_px:
            return False
        return (strike - index_px) <= max_dist_usd
    return False


def option_moneyness(*, opt_type: str, strike: float, index_px: float) -> str:
    """返回 itm / otm / atm。"""
    o = (opt_type or "").upper()
    if strike is None or index_px is None or index_px <= 0:
        return "unknown"
    atm_band = max(index_px * 0.002, 2.0)
    if abs(strike - index_px) <= atm_band:
        return "atm"
    if o == "C":
        return "itm" if strike < index_px else "otm"
    if o == "P":
        return "itm" if strike > index_px else "otm"
    return "unknown"


def option_moneyness_label(moneyness: str) -> str:
    return {"itm": "实值", "otm": "虚值", "atm": "平值"}.get((moneyness or "").lower(), "")