package nsq

import (
	"fmt"
	"github.com/fox/fox/log"
	"github.com/nsqio/go-nsq"
	"time"
)

const (
	chanLen = 20 // 消息队列容量
)

type chanState int

const (
	idle chanState = 0
	busy chanState = 1
)

func (ch chanState) String() string {
	switch ch {
	case idle:
		return "idle"
	case busy:
		return "busy"
	default:
		return "unknown"
	}
}

type Consumer struct {
	name     string
	addr     string
	topic    string
	channel  string
	msgChan  chan *nsq.Message
	consumer *nsq.Consumer
	state    chanState
}

func newConsumer(nsqAddr, topic, channel string) (*Consumer, error) {
	var err error
	config := nsq.NewConfig()
	// 心跳设置
	config.HeartbeatInterval = 30 * time.Second
	// 关键配置项
	// config.DialTimeout = 10 * time.Second  // TCP 连接超时（默认系统级）
	// config.ReadTimeout = 60 * time.Second  // 读取数据超时
	// config.WriteTimeout = 60 * time.Second // 写入数据超时
	//
	// // 如果是通过 nsqlookupd 发现服务，调整 HTTP 客户端超时
	// config.LookupdPollInterval = 5 * time.Second // 轮询间隔
	// config.LookupdPollTimeout = 10 * time.Second // 单个 HTTP 请求超时

	c := &Consumer{}
	c.addr = nsqAddr
	c.state = idle
	c.topic = topic
	c.channel = channel
	c.name = fmt.Sprintf("%v-%v", topic, channel)
	c.msgChan = make(chan *nsq.Message, chanLen)
	c.consumer, err = nsq.NewConsumer(topic, channel, config)
	if err != nil {
		return nil, err
	}
	c.consumer.AddHandler(c)

	c.consumer.SetLogger(newNSQLogger(nsq.LogLevelError), nsq.LogLevelError)
	return c, nil
}

// 创建消费者，直连NSQd发现服务
func NewConsumerByNsqD(nsqDAddr, topic, channel string) (*Consumer, error) {
	c, err := newConsumer(nsqDAddr, topic, channel)
	if err != nil {
		return nil, err
	}
	// 连接方式选择：直连NSQd
	if err = c.consumer.ConnectToNSQD(nsqDAddr); err != nil {
		return nil, err
	}
	log.DebugF("consumer %v-%v 注册成功", topic, channel)
	return c, err
}

// 创建消费者，连接NSQLookupD发现服务
func NewConsumer(lookupAddr, topic, channel string) (*Consumer, error) {
	c, err := newConsumer(lookupAddr, topic, channel)
	if err != nil {
		return nil, err
	}
	// 连接NSQLookupD发现服务
	err = c.consumer.ConnectToNSQLookupd(c.addr)
	if err != nil {
		return nil, err
	}
	log.DebugF("consumer %v-%v 注册成功", topic, channel)
	return c, err
}

func (c *Consumer) HandleMessage(msg *nsq.Message) error {
	num := len(c.msgChan)
	if num > chanLen/2 && c.state == idle {
		c.state = busy
		log.WarnF("%v-%v 通道已从闲时转为繁忙状态。当前积压消息数:%v", c.topic, c.channel, len(c.msgChan))
	} else if c.state == busy && num < chanLen/4 {
		c.state = idle
		log.WarnF("%v-%v 通道已从繁忙转为闲时状态。当前积压消息数:%v", c.topic, c.channel, len(c.msgChan))
	}
	c.msgChan <- msg
	msg.Finish()
	return nil
}

func (c *Consumer) Name() string {
	return c.name
}

func (c *Consumer) Read() <-chan *nsq.Message {
	return c.msgChan
}

func (c *Consumer) Close() {
	if c.consumer != nil {
		c.consumer.Stop()
	}
}