"""防重复提交：Flask session 短窗口去重（下单 / 关键位等）。"""
from __future__ import annotations

import time
from typing import Any, Optional


DEFAULT_SUBMIT_GUARD_TTL = 90.0


def _prune_locks(locks: dict, now: float) -> dict:
    return {k: float(v) for k, v in (locks or {}).items() if float(v) > now}


def check_duplicate_submit(
    session: Any,
    scope: str,
    *,
    ttl: float = DEFAULT_SUBMIT_GUARD_TTL,
) -> Optional[str]:
    """
    同一 scope 在 ttl 秒内仅允许通过一次。
    返回提示文案表示应拒绝；返回 None 表示可继续处理。
    """
    scope = (scope or "").strip()
    if not scope:
        return None
    now = time.time()
    locks = _prune_locks(session.get("_form_submit_guard") or {}, now)
    if scope in locks:
        return "请求正在处理或刚提交过，请勿重复点击（请等待页面刷新后再试）"
    locks[scope] = now + float(ttl)
    session["_form_submit_guard"] = locks
    try:
        session.modified = True
    except Exception:
        pass
    return None


def submit_scope_add_order(symbol: str, direction: str) -> str:
    sym = (symbol or "").strip().upper()
    d = (direction or "").strip().lower()
    return f"add_order:{sym}:{d}"


def submit_scope_add_key(symbol: str, monitor_type: str, direction: str) -> str:
    sym = (symbol or "").strip().upper()
    mt = (monitor_type or "").strip()
    d = (direction or "").strip().lower() or "watch"
    return f"add_key:{sym}:{mt}:{d}"