package main

import (
	"encoding/json"
	"github.com/Shopify/sarama"
	"log"
	"time"
)

// 需要发送的消息类型
type Event struct {
	Name   string    `json:"name"`
	Type   string    `json:"type"`
	Source string    `json:"source"`
	Target string    `json:"target"`
	Time   time.Time `json:"time"`
}

type EventEncoder Event

func (e EventEncoder) Encode() ([]byte, error) {
	// 将 Event 类型数据做JSON编码
	j, err := json.Marshal(e)
	if err != nil {
		return nil, err
	}
	return j, nil
}

func (e EventEncoder) Length() int {
	// 编码之后的数据长度
	j, err := json.Marshal(e)
	if err != nil {
		return 0
	}

	return len(j)
}

func main() {
	// 一，获取同步生产者
	brokers := []string{"localhost:9092"}
	producer, err := sarama.NewSyncProducer(brokers, nil)
	if err != nil {
		log.Fatalln(err)
	}
	// 保证关闭生产者
	defer func() {
		if err := producer.Close(); err != nil {
			log.Fatalln(err)
		}
	}()

	// 模拟数据
	evt := Event{
		Name:   "user",
		Type:   "buy",
		Source: "42",
		Target: "10098",
		Time:   time.Now(),
	}

	// 二，设置消息内容
	msg := &sarama.ProducerMessage{
		Topic: "event_topic",
		//Value: sarama.StringEncoder("Mashibing Go Kafka."),
		//Value: sarama.ByteEncoder
		Value: EventEncoder(evt),
	}

	// 三，发送消息
	// 返回：分区索引，偏移量，错误
	partition, offset, err := producer.SendMessage(msg)
	if err != nil {
		log.Printf("Send failed, err: %s\n", err)
	} else {
		log.Printf("Send Success, partition: %d, offset: %d\n", partition, offset)
	}

}