package grpcserver

import (
	"context"
	"fmt"
	"net"

	"backend/services/user-svc/internal/domain"
	"backend/services/user-svc/internal/service"
	"backend/shared/pkg/errors"
	"backend/shared/pkg/logger"

	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"

	// 导入生成的 proto 代码
	userpb "backend/services/user-svc/proto"
)

type UserServer struct {
	userpb.UnimplementedUserServiceServer
	service *service.UserService
}

func NewUserServer(service *service.UserService) *UserServer {
	return &UserServer{service: service}
}

// Register 实现用户注册接口
func (s *UserServer) Register(ctx context.Context, req *userpb.RegisterRequest) (*userpb.RegisterResponse, error) {
	// 转换请求参数
	domainReq := &domain.RegisterRequest{
		Account:  req.GetAccount(),
		Password: req.GetPassword(),
	}

	// 调用服务层注册用户
	resp, err := s.service.Register(domainReq)
	if err != nil {
		logger.Error("Register failed: %v", err)

		// 转换错误类型
		switch {
		case errors.IsConflict(err):
			return &userpb.RegisterResponse{
				Response: &userpb.Response{
					Code:    409,
					Message: "账号已存在",
				},
			}, status.Errorf(codes.AlreadyExists, "账号已存在")
		case errors.IsInvalidInput(err):
			return &userpb.RegisterResponse{
				Response: &userpb.Response{
					Code:    400,
					Message: "无效的输入参数",
				},
			}, status.Errorf(codes.InvalidArgument, "无效的输入参数")
		default:
			return &userpb.RegisterResponse{
				Response: &userpb.Response{
					Code:    500,
					Message: "内部服务器错误",
				},
			}, status.Errorf(codes.Internal, "内部服务器错误")
		}
	}

	// 构造响应
	return &userpb.RegisterResponse{
		UserId: resp.UserID.String(),
		Account: resp.Account,
		Response: &userpb.Response{
			Code:    200,
			Message: "注册成功",
		},
	}, nil
}

// GetUserByAccount 实现根据账号获取用户信息接口
func (s *UserServer) GetUserByAccount(ctx context.Context, req *userpb.GetUserByAccountRequest) (*userpb.GetUserByAccountResponse, error) {
	// 调用服务层获取用户信息
	user, account, _, err := s.service.GetUserByAccount(req.GetAccount())
	if err != nil {
		logger.Error("GetUserByAccount failed: %v", err)

		// 转换错误类型
		switch {
		case errors.IsNotFound(err):
			return &userpb.GetUserByAccountResponse{
				Response: &userpb.Response{
					Code:    404,
					Message: "用户不存在",
				},
			}, status.Errorf(codes.NotFound, "用户不存在")
		case errors.IsInvalidInput(err):
			return &userpb.GetUserByAccountResponse{
				Response: &userpb.Response{
					Code:    400,
					Message: "无效的输入参数",
				},
			}, status.Errorf(codes.InvalidArgument, "无效的输入参数")
		default:
			return &userpb.GetUserByAccountResponse{
				Response: &userpb.Response{
					Code:    500,
					Message: "内部服务器错误",
				},
			}, status.Errorf(codes.Internal, "内部服务器错误")
		}
	}

	// 构造响应
	return &userpb.GetUserByAccountResponse{
		UserId: user.ID.String(),
		Account: account.Account,
		Response: &userpb.Response{
			Code:    200,
			Message: "获取成功",
		},
	}, nil
}

// Start 启动 gRPC 服务器
func Start(service *service.UserService, port int) error {
	server := grpc.NewServer()
	userServer := NewUserServer(service)

	userpb.RegisterUserServiceServer(server, userServer)

	addr := fmt.Sprintf(":%d", port)
	listener, err := net.Listen("tcp", addr)
	if err != nil {
		return err
	}

	logger.Info("User service gRPC server starting on %s", addr)
	return server.Serve(listener)
}