package grpc

import (
	"context"
	"fmt"
	"log"
	"sync"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	"google.golang.org/grpc/keepalive"

	// 使用生成的 proto 代码（通过 go.mod replace 指向本地目录，不修改 grpc 目录）
	userv1 "grpc/user/userv1"
)

var (
	userClientOnce sync.Once
	userClient     *UserClient
)

type UserClient struct {
	conn   *grpc.ClientConn
	addr   string
	client userv1.UserClient
}

// NewUserClient 创建用户服务 gRPC 客户端
func NewUserClient(addr string) (*UserClient, error) {
	if addr == "" {
		return nil, fmt.Errorf("gRPC server address is empty")
	}

	var err error
	userClientOnce.Do(func() {
		opts := []grpc.DialOption{
			grpc.WithTransportCredentials(insecure.NewCredentials()),
			grpc.WithKeepaliveParams(keepalive.ClientParameters{
				Time:                10 * time.Second,
				Timeout:             3 * time.Second,
				PermitWithoutStream: true,
			}),
		}

		conn, dialErr := grpc.Dial(addr, opts...)
		if dialErr != nil {
			err = fmt.Errorf("failed to connect to gRPC server %s: %w", addr, dialErr)
			return
		}

		client := userv1.NewUserClient(conn)
		userClient = &UserClient{
			conn:   conn,
			addr:   addr,
			client: client,
		}
		log.Printf("gRPC user client connected to %s", addr)
	})

	if err != nil {
		return nil, err
	}

	return userClient, nil
}

// SimpleListAllUser 调用 SimpleListAllUser gRPC 方法
func (c *UserClient) SimpleListAllUser(ctx context.Context, keyword string) (*userv1.SimpleListAllUserResp, error) {
	req := &userv1.SimpleListAllUserReq{
		Keyword: keyword,
	}
	resp, err := c.client.SimpleListAllUser(ctx, req)
	if err != nil {
		return nil, fmt.Errorf("gRPC SimpleListAllUser failed: %w", err)
	}
	return resp, nil
}

// Close 关闭连接
func (c *UserClient) Close() error {
	if c.conn != nil {
		return c.conn.Close()
	}
	return nil
}

// GetConn 获取 gRPC 连接（用于直接调用生成的客户端）
func (c *UserClient) GetConn() *grpc.ClientConn {
	return c.conn
}