package main

import (
	"encoding/json"
	"fmt"
	"log"
)

// Event to record
type Event struct {
	ID       string            `json:"id"`
	Priority int               `json:"priority"`
	Type     string            `json:"event_type,omitempty"`
	Tags     []string          `json:"tags,omitempty"`
	Extra    map[string]string `json:"extra,omitempty"`
}

// User of the system
type User struct {
	ID   string `json:"id"`
	Name string `json:"name"`
}

func marshalEvent(e Event) ([]byte, error) {
	bin, err := json.MarshalIndent(&e, "", "    ")

	if err != nil {
		return nil, err
	}

	return bin, nil
}

func marshalAndPrintEvent(e Event) error {
	bin, err := marshalEvent(e)

	if err != nil {
		return err
	}

	fmt.Println("Event data from object:")
	fmt.Println(string(bin))
	fmt.Println("")
	return nil
}
func unmarshalUser(user []byte) (User, error) {
	var u User
	err := json.Unmarshal(user, &u)
	return u, err
}

func unmarshalUserAndPrintName(userJSON string) error {
	var user, err = unmarshalUser([]byte(userJSON))

	if err != nil {
		return err
	}

	fmt.Printf("User name: %s\n", user.Name)
	return nil
}

var example = Event{
	ID:       "shutdown",
	Priority: 4,
	Tags: []string{
		"forced",
		"remote",
	},
	Extra: map[string]string{
		"user": "henrique",
	},
}

var userJSON = `{
	"id": "abcd",
	"name": "Bruna"
}`

func main() {
	if err := marshalAndPrintEvent(example); err != nil {
		log.Fatal(err)
	}

	if err := unmarshalUserAndPrintName(userJSON); err != nil {
		log.Fatal(err)
	}
}