from rest_framework import generics, status
from rest_framework.permissions import AllowAny, IsAuthenticated
from rest_framework.response import Response
from rest_framework.views import APIView
from rest_framework_simplejwt.views import TokenObtainPairView
from rest_framework_simplejwt.serializers import TokenObtainPairSerializer
from django.contrib.auth import get_user_model
from django.core.mail import send_mail
from django.conf import settings
from .models import VerificationCode
from .serializers import RegisterSerializer, UserSerializer, AdminUserSerializer, SendCodeSerializer, CodeLoginSerializer, PasswordLoginSerializer, ResetPasswordSerializer, ConfirmResetPasswordSerializer
from .permissions import IsSuperAdmin

User = get_user_model()


class SendCodeView(APIView):
    """发送邮箱验证码（用于登入或密码重置）"""
    permission_classes = [AllowAny]

    def post(self, request):
        serializer = SendCodeSerializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        email = serializer.validated_data['email']

        # 清除旧验证码
        VerificationCode.objects.filter(email=email).delete()

        # 生成新验证码
        code = VerificationCode.generate_code()
        vc = VerificationCode.objects.create(email=email, code=code)

        # 发送邮件
        try:
            send_mail(
                subject='【集团招聘平台】验证码',
                message=f'您的验证码是：{code}\n\n验证码有效期为10分钟，请勿泄露给他人。',
                from_email=getattr(settings, 'DEFAULT_FROM_EMAIL', 'noreply@offer.com'),
                recipient_list=[email],
                fail_silently=False,
            )
        except Exception as e:
            vc.delete()
            return Response(
                {'error': '邮件发送失败，请稍后重试'},
                status=status.HTTP_500_INTERNAL_SERVER_ERROR
            )

        return Response({'message': '验证码已发送到您的邮箱'})


class RequestResetPasswordView(APIView):
    """请求密码重置（发送验证码）"""
    permission_classes = [AllowAny]

    def post(self, request):
        serializer = ResetPasswordSerializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        email = serializer.validated_data['email']

        # 使用 SendCodeView 的逻辑发送验证码
        VerificationCode.objects.filter(email=email).delete()
        code = VerificationCode.generate_code()
        vc = VerificationCode.objects.create(email=email, code=code)

        try:
            send_mail(
                subject='【集团招聘平台】密码重置验证码',
                message=f'您的验证码是：{code}\n\n验证码有效期为10分钟，请勿泄露给他人。',
                from_email=getattr(settings, 'DEFAULT_FROM_EMAIL', 'noreply@offer.com'),
                recipient_list=[email],
                fail_silently=False,
            )
        except Exception as e:
            vc.delete()
            return Response(
                {'error': '邮件发送失败，请稍后重试'},
                status=status.HTTP_500_INTERNAL_SERVER_ERROR
            )

        return Response({'message': '验证码已发送到您的邮箱'})


class ConfirmResetPasswordView(APIView):
    """确认密码重置"""
    permission_classes = [AllowAny]

    def post(self, request):
        serializer = ConfirmResetPasswordSerializer(data=request.data)
        serializer.is_valid(raise_exception=True)

        user = serializer.validated_data['user']
        vc = serializer.validated_data['vc']
        new_password = serializer.validated_data['new_password']

        # 设置新密码
        user.set_password(new_password)
        user.save()

        # 标记验证码为已使用
        vc.mark_as_verified()

        return Response({'message': '密码重置成功，请使用新密码登入'})


class CustomTokenObtainPairView(TokenObtainPairView):
    """自定义登入视图，支持三种方式：邮箱验证码、邮箱密码、用户名密码"""

    def post(self, request, *args, **kwargs):
        # 判断登入方式
        has_code = 'code' in request.data
        has_email = 'email' in request.data
        has_username = 'username' in request.data
        has_password = 'password' in request.data

        if has_email and has_code:
            # 邮箱验证码登入
            return self._login_with_code(request)
        elif (has_email or has_username) and has_password:
            # 邮箱或用户名 + 密码登入
            return self._login_with_password(request)
        else:
            return Response(
                {'error': '请提供正确的登入方式'},
                status=status.HTTP_400_BAD_REQUEST
            )

    def _login_with_code(self, request):
        """邮箱验证码登入"""
        serializer = CodeLoginSerializer(data=request.data)
        serializer.is_valid(raise_exception=True)

        user = serializer.validated_data['user']
        vc = serializer.validated_data['vc']

        # 标记验证码为已使用
        vc.mark_as_verified()

        # 生成 JWT token
        from rest_framework_simplejwt.tokens import RefreshToken
        refresh = RefreshToken.for_user(user)
        return Response({
            'refresh': str(refresh),
            'access': str(refresh.access_token),
        }, status=status.HTTP_200_OK)

    def _login_with_password(self, request):
        """邮箱或用户名 + 密码登入"""
        serializer = PasswordLoginSerializer(data=request.data)
        serializer.is_valid(raise_exception=True)

        user = serializer.validated_data['user']

        # 生成 JWT token
        from rest_framework_simplejwt.tokens import RefreshToken
        refresh = RefreshToken.for_user(user)
        return Response({
            'refresh': str(refresh),
            'access': str(refresh.access_token),
        }, status=status.HTTP_200_OK)


class RegisterView(APIView):
    """密码注册"""
    permission_classes = [AllowAny]

    def post(self, request):
        serializer = RegisterSerializer(data=request.data)
        serializer.is_valid(raise_exception=True)

        # 创建用户
        user = serializer.save()

        # 生成 JWT token
        from rest_framework_simplejwt.tokens import RefreshToken
        refresh = RefreshToken.for_user(user)

        return Response({
            'user': {
                'id': user.id,
                'username': user.username,
                'email': user.email,
                'role': user.role,
            },
            'refresh': str(refresh),
            'access': str(refresh.access_token),
        }, status=status.HTTP_201_CREATED)


class MeView(APIView):
    permission_classes = [IsAuthenticated]

    def get(self, request):
        return Response(UserSerializer(request.user).data)

    def patch(self, request):
        serializer = UserSerializer(request.user, data=request.data, partial=True)
        serializer.is_valid(raise_exception=True)
        serializer.save()
        return Response(serializer.data)


class UserManageViewSet(generics.ListCreateAPIView):
    """超管：管理所有用户"""
    serializer_class = AdminUserSerializer
    permission_classes = [IsSuperAdmin]
    queryset = User.objects.all()


class UserDetailView(generics.RetrieveUpdateDestroyAPIView):
    serializer_class = AdminUserSerializer
    permission_classes = [IsSuperAdmin]
    queryset = User.objects.all()