package main

import (
	"context"
	"flag"
	"fmt"
	"io/ioutil"

	"github.com/dgraph-io/dgraph/client"
	"github.com/dgraph-io/dgraph/x"
	"google.golang.org/grpc"
)

var (
	dgraph = flag.String("d", "127.0.0.1:9080", "Dgraph server address")
)

type User struct {
	UID     uint64 `dgraph:"_uid_"`
	Email   string `dgraph:"email"`
	Profile string `dgraph:"profile"`
}

type Res struct {
	Root []User `dgraph:"usr"`
}

func main() {
	conn, err := grpc.Dial(*dgraph, grpc.WithInsecure())
	x.Checkf(err, "While trying to dial gRPC")
	defer conn.Close()

	clientDir, err := ioutil.TempDir("", "client_")

	dgraphClient := client.NewDgraphClient([]*grpc.ClientConn{conn}, client.DefaultOptions, clientDir)

	// SET SCHEMA ----------------------------------------------
	req := client.Req{}
	req.SetQuery(`
		mutation {
		  schema {
			email: string @index(hash) .
		  	profile: string .
		  }
		}
	`)
	resp, err := dgraphClient.Run(context.Background(), &req)

	// CREATE USER1 ----------------------------------------------
	req = client.Req{}
	person1, err := dgraphClient.NodeBlank("person1")

	e := person1.Edge("email")
	err = e.SetValueString("user1@aaa.com")
	req.Set(e)

	e = person1.Edge("profile")
	err = e.SetValueString("admin")
	req.Set(e)

	resp, err = dgraphClient.Run(context.Background(), &req)

	// QUERY USER1 ----------------------------------------------
	req = client.Req{}
	req.SetQuery(`{
		usr(func: eq(email, "user1@aaa.com")) {
			_uid_
			email
			profile
		}
	}`)
	resp, err = dgraphClient.Run(context.Background(), &req)

	var r Res
	err = client.Unmarshal(resp.N, &r)
	fmt.Printf("Query1: %+v\n\n", r.Root)

	// UPDATE USER1 ----------------------------------------------

	usr := r.Root[0]
	usrnode := dgraphClient.NodeUid(usr.UID)

	// request 1: remove only (with mutation)
	req = client.Req{}
	req.SetQuery(fmt.Sprintf(`mutation { delete { <%s> <profile> * . } }`, usrnode))
	resp, err = dgraphClient.Run(context.Background(), &req)

	fmt.Println("error is", err)

	// request 2: insert new value
	req = client.Req{}

	e = usrnode.Edge("profile")
	e.SetValueString("root")
	req.Set(e)

	resp, err = dgraphClient.Run(context.Background(), &req)

	// QUERY USER1 ----------------------------------------------
	req = client.Req{}
	req.SetQuery(`{
			usr(func: eq(email, "user1@aaa.com")) {
				_uid_
				email
				profile
			}
		}`)
	resp, err = dgraphClient.Run(context.Background(), &req)

	err = client.Unmarshal(resp.N, &r)
	fmt.Printf("Query2: %+v\n\n", r.Root)

	// DELETE USER1 ----------------------------------------------
	for _, u := range r.Root {

		fmt.Println(u.UID)

		req = client.Req{}
		req.SetQuery(fmt.Sprintf("mutation { delete { <%d> * * . } }", u.UID))

		resp, err = dgraphClient.Run(context.Background(), &req)
	}

	err = dgraphClient.Close()
	x.Check(err)
}