import base64
import os

from django.conf import settings
from django.contrib.auth import authenticate
from django.db.utils import OperationalError, ProgrammingError
from gmssl import sm4
from rest_framework.response import Response
from rest_framework.views import APIView
from rest_framework_simplejwt.tokens import RefreshToken


class UserLoginView(APIView):
    def post(self, request, *args, **kwargs):
        if os.environ.get("DJANGO_LOGIN_BREAKPOINT", "").strip().lower() in {
            "1",
            "true",
            "yes",
            "y",
            "on",
        }:
            breakpoint()
        try:
            username = request.data.get("username")
            encrypted_password = request.data.get("password")
            if not username or not encrypted_password:
                return Response({"code": "1", "error": "用户名或密码不能为空"})

            private_key = getattr(settings, "SM4_PRIVATE_KEY", getattr(settings, "private_key", ""))
            if not private_key:
                return Response({"code": "1", "error": "缺少加密密钥"})

            try:
                password = self.decrypt_password(encrypted_password, private_key)
            except Exception:
                return Response({"code": "1", "error": "密码解密失败"})

            user = authenticate(request, username=username, password=password)

            if user is not None:
                refresh = RefreshToken.for_user(user)
                user_groups = [group.id for group in user.groups.all()]
                return Response(
                    {
                        "access_token": str(refresh.access_token),
                        "refresh_token": str(refresh),
                        "user_id": user.id,
                        "username": user.username,
                        "email": user.email,
                        "groups": user_groups,
                        "is_superuser": user.is_superuser,
                    }
                )

            return Response({"code": "1", "error": "用户名或密码不正确，请检查并重试！"})
        except (OperationalError, ProgrammingError) as e:
            payload = {"code": "1", "error": "数据库未就绪，请先执行 migrate 并检查 DB 配置"}
            if settings.DEBUG:
                payload["details"] = str(e)
            return Response(payload)
        except Exception as e:
            payload = {"code": "1", "error": "登录服务异常"}
            if settings.DEBUG:
                payload["details"] = str(e)
            return Response(payload)

    def decrypt_password(self, encrypted_text, private_key):
        if not private_key or len(private_key) != 16:
            raise ValueError("invalid sm4 key")
        cipher = sm4.CryptSM4()
        cipher.set_key(private_key.encode(), True)

        encrypted_bytes = base64.b64decode(encrypted_text)
        decrypted_bytes = cipher.crypt_ecb(encrypted_bytes)
        return decrypted_bytes.decode()