"""支付宝渠道：App 支付下单参数（本地 RSA2 签名）+ 回调 RSA2 验签。

密钥未配置（开发环境）时：下单返回 dev_mock 占位参数便于 App 联调，回调一律验签失败拒绝入账。
生产接入：配置 ALIPAY_APP_ID / ALIPAY_PRIVATE_KEY（应用私钥）/ ALIPAY_PUBLIC_KEY（支付宝公钥）
及 ALIPAY_NOTIFY_URL 后自动启用真实签名与验签。
"""
import json
from datetime import datetime
from urllib.parse import urlencode

from app.config import settings
from app.payment.base import build_sign_content, load_public_key, rsa2_sign, rsa2_verify

METHOD_APP_PAY = "alipay.trade.app.pay"
PRODUCT_CODE = "QUICK_MSECURITY_PAY"
DEFAULT_SUBJECT = "积分充值"
ORDER_EXPIRE = "30m"  # 与订单有效期保持一致


def is_configured() -> bool:
    return bool(settings.alipay_app_id and settings.alipay_private_key and settings.alipay_public_key)


def create_app_pay_params(order_no: str, amount_fen: int) -> dict:
    """生成 App SDK 调起参数 order_string（未配置密钥时返回 dev 占位）"""
    if not is_configured():
        return {"dev_mock": True, "order_string": f"mock://alipay/{order_no}"}

    biz_content = json.dumps({
        "out_trade_no": order_no,
        "total_amount": f"{amount_fen / 100:.2f}",
        "subject": DEFAULT_SUBJECT,
        "product_code": PRODUCT_CODE,
        "timeout_express": ORDER_EXPIRE,
    }, ensure_ascii=False, separators=(",", ":"))

    params = {
        "app_id": settings.alipay_app_id,
        "method": METHOD_APP_PAY,
        "format": "JSON",
        "charset": "utf-8",
        "sign_type": "RSA2",
        "timestamp": datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
        "version": "1.0",
        "biz_content": biz_content,
    }
    if settings.alipay_notify_url:
        params["notify_url"] = settings.alipay_notify_url
    if settings.alipay_return_url:
        params["return_url"] = settings.alipay_return_url

    # 签名串不含 sign_type/sign，按 key 字典序拼接
    params["sign"] = rsa2_sign(build_sign_content(params), settings.alipay_private_key)
    # order_string 为全参数（含 sign）按 key 字典序 URL 编码后的查询串
    return {"order_string": urlencode(sorted(params.items()))}


def verify_callback(form: dict) -> bool:
    """RSA2 验签：用支付宝公钥校验回调 sign（未配置/格式错误一律拒绝）"""
    sign = form.get("sign", "")
    if not sign or not settings.alipay_public_key:
        return False
    try:
        load_public_key(settings.alipay_public_key)
    except Exception:  # noqa: BLE001
        return False
    return rsa2_verify(build_sign_content(form), sign, settings.alipay_public_key)