# Copyright (c) 2025-2026 马建军. All rights reserved.
# 专有软件 — 未经授权禁止复制、传播、转售。
# 严禁用于：带单/代客理财、向他人推荐期货品种或买卖建议、融资配资等业务。
# 详见 LICENSE.zh-CN.txt 与 docs/软件购买与使用协议.md

"""趋势回调：纯计算（期货整数手）。"""
from __future__ import annotations

import json
import math
from typing import Any, Optional, Tuple

from contract_specs import get_contract_spec


def validate_trend_bounds(direction: str, stop_loss: float, add_upper: float) -> Optional[str]:
    direction = (direction or "long").strip().lower()
    if direction == "long":
        if not (float(stop_loss) < float(add_upper)):
            return "做多：止损须低于补仓上沿"
    else:
        if not (float(stop_loss) > float(add_upper)):
            return "做空：止损须高于补仓下沿"
    return None


def build_grid_prices(direction: str, sl: float, upper: float, n_legs: int) -> list[float]:
    sl, upper = float(sl), float(upper)
    out: list[float] = []
    if n_legs <= 0:
        return out
    direction = (direction or "long").strip().lower()
    if direction == "long":
        if upper <= sl:
            return out
        span = upper - sl
        for i in range(1, n_legs + 1):
            out.append(sl + (i / float(n_legs + 1)) * span)
        out.sort(reverse=True)
    else:
        if sl <= upper:
            return out
        span = sl - upper
        for i in range(1, n_legs + 1):
            out.append(upper + (i / float(n_legs + 1)) * span)
        out.sort()
    return [round(p, 4) for p in out]


def compute_trend_plan_futures(
    *,
    direction: str,
    stop_loss: float,
    add_upper: float,
    take_profit: float,
    risk_percent: float,
    capital: float,
    live_price: float,
    ths_code: str,
    dca_legs: int = 5,
) -> Tuple[Optional[dict[str, Any]], Optional[str]]:
    err = validate_trend_bounds(direction, stop_loss, add_upper)
    if err:
        return None, err
    spec = get_contract_spec(ths_code)
    mult = spec["mult"]
    d = (direction or "long").strip().lower()
    if d == "short":
        worst_per_lot = (float(stop_loss) - float(add_upper)) * mult
    else:
        worst_per_lot = (float(add_upper) - float(stop_loss)) * mult
    if worst_per_lot <= 0:
        return None, "止损与补仓边界无法计算风险"
    budget = float(capital) * float(risk_percent) / 100.0
    total_lots = int(math.floor(budget / worst_per_lot))
    if total_lots < 3:
        return None, f"按 {risk_percent}% 风险，总手数至少需 3 手才能拆分首仓+补仓（当前 {total_lots} 手）"
    first_lots = total_lots // 2
    remainder = total_lots - first_lots
    legs = max(1, min(int(dca_legs), remainder))
    per_leg = remainder // legs
    leg_amounts = [per_leg] * (legs - 1) + [remainder - per_leg * (legs - 1)]
    if any(x < 1 for x in leg_amounts):
        legs = 1
        leg_amounts = [remainder]
    grid = build_grid_prices(d, stop_loss, add_upper, len(leg_amounts))
    margin_rate = spec["margin_rate"]
    plan_margin = float(live_price) * mult * total_lots * margin_rate
    return {
        "direction": d,
        "stop_loss": float(stop_loss),
        "add_upper": float(add_upper),
        "take_profit": float(take_profit),
        "risk_percent": float(risk_percent),
        "capital_snapshot": float(capital),
        "live_price_ref": float(live_price),
        "target_lots": total_lots,
        "first_lots": first_lots,
        "remainder_lots": remainder,
        "dca_legs": len(leg_amounts),
        "leg_amounts": leg_amounts,
        "leg_amounts_json": json.dumps(leg_amounts),
        "grid_prices_json": json.dumps(grid),
        "grid": grid,
        "plan_margin": round(plan_margin, 2),
        "mult": mult,
    }, None


def trend_dca_level_reached(direction: str, mark_price: float, level: float) -> bool:
    d = (direction or "long").strip().lower()
    pf, lv = float(mark_price), float(level)
    return pf <= lv if d == "long" else pf >= lv