package rabbitmq

import (
	"encoding/json"
	"fmt"
	"github.com/streadway/amqp"
	"strings"
	"sync"
	"wdd.io/agent-common/logger"
)

type RabbitMQ interface {
	RabbitSendWriter
	RabbitConnectCloser
	RabbitQueueHandler
}

type RabbitSendWriter interface {
	Send(message []byte)

	Read(autoAck bool) <-chan amqp.Delivery
}

type RabbitConnectCloser interface {
	Connect()

	Close() error
}

type RabbitQueueHandler interface {
	Handle() chan bool
}

type RabbitQueue struct {
	// 连接实体
	RabbitConn *RabbitMQConn
	// 连接属性
	RabbitProp *ConnectProperty
	// 底层连接tcp信息
	RabbitConnectInfo *RabbitTCPConnectInfo
	// 返回消息队列
	ReceiveChan *RabbitReceiveChan
}

// RabbitMQConn is a struct that holds the connection and channel objects
type RabbitMQConn struct {
	Connection *amqp.Connection
	Channel    *amqp.Channel
}

type RabbitReceiveChan struct {
	AgentRChan    chan *OctopusMessage
	ExecutorRChan chan *OctopusMessage
	StatusRChan   chan *OctopusMessage
	InitRChan     chan *OctopusMessage
}

type ConnectProperty struct {
	ExchangeName string
	QueueName    string
	ExchangeType string
	TopicKey     string
}

type RabbitTCPConnectInfo struct {
	UserName    string
	Password    string
	Host        string
	Port        string
	VirtualHost string
}

var log = logger.Log

// 定义全局唯一的 Singleton 实例
var instance *amqp.Connection

// 用 sync.Once 变量确保初始化函数只会被调用一次
var once sync.Once

// 初始化 Singleton 实例的函数
func createInstance(rabbitConnectInfo *RabbitTCPConnectInfo) {
	// 在这里进行 Singleton 的初始化操作

	// 获取RabbitMQ的连接地址
	rabbitMQEndpoint := parseRabbitMQEndpoint(rabbitConnectInfo)

	// 创建全局唯一连接 RabbitMQ连接
	connection, err := amqp.Dial(rabbitMQEndpoint)
	if err != nil {
		log.Error(fmt.Sprintf("failed to connect to RabbitMQ: %v", err))
	}

	instance = connection
}

// GetInstance 获取全局唯一的 Singleton 实例的函数
func GetInstance(rabbitConnectInfo *RabbitTCPConnectInfo) *amqp.Connection {
	// 使用 sync.Once 确保 createInstance 只会被调用一次

	// todo 理解
	once.Do(func() {
		createInstance(rabbitConnectInfo)
	})
	return instance
}

// Connect creates a new RabbitMQ connection object
func (r *RabbitQueue) Connect() {

	// 获取RabbitMQ的连接
	conn := GetInstance(r.RabbitConnectInfo)

	ch, err := conn.Channel()
	if err != nil {
		log.Error(fmt.Sprintf("failed to create RabbitMQ channel: %w", err))
	}

	if err = ch.ExchangeDeclare(
		r.RabbitProp.ExchangeName, // name of the exchange
		r.RabbitProp.ExchangeType, // type of the exchange
		true,                      // durable
		false,                     // delete when complete
		false,                     // internal
		false,                     // noWait
		nil,                       // arguments
	); err != nil {
		log.Error(fmt.Sprintf("failed to declare exchange !: %w", err))
	}

	_, err = ch.QueueDeclare(
		r.RabbitProp.QueueName, // name of the queue
		true,                   // durable
		false,                  // delete when unused
		false,                  // exclusive
		false,                  // noWait
		nil,                    // arguments
	)
	if err != nil {
		log.Error(fmt.Sprintf("failed to declare RabbitMQ queue: %w", err))
	}

	if err = ch.QueueBind(
		r.RabbitProp.QueueName,    // name of the queue
		r.RabbitProp.TopicKey,     // routing key - all topics
		r.RabbitProp.ExchangeName, // name of the exchange
		false,                     // noWait
		nil,                       // arguments
	); err != nil {
		log.Error(fmt.Sprintf("failed to bind RabbitMQ queue: %w", err))
	}

	// build for receive chan
	rabbitRCha := &RabbitReceiveChan{}
	if strings.HasPrefix(r.RabbitProp.QueueName, "Init") {
		// init queue
		rabbitRCha.InitRChan = make(chan *OctopusMessage)
	} else {
		// business queue
		rabbitRCha.AgentRChan = make(chan *OctopusMessage, 5)
		rabbitRCha.ExecutorRChan = make(chan *OctopusMessage, 5)
		rabbitRCha.StatusRChan = make(chan *OctopusMessage, 5)
	}

	// connection
	r.RabbitConn = &RabbitMQConn{
		Connection: conn,
		Channel:    ch,
	}

	// receive chan
	r.ReceiveChan = rabbitRCha
}

func (r *RabbitQueue) Close() error {
	var err error

	if r.RabbitConn.Channel != nil {
		if err = r.RabbitConn.Channel.Close(); err != nil {
			log.Error(fmt.Sprintf("Failed to close RabbitMQ channel: %v", err))
		}
	}
	return err
}

func (r *RabbitQueue) Handle() chan bool {

	deliveries := r.Read(true)
	foreverHandle := make(chan bool)
	// 死循环，处理Octopus Message
	P.Submit(func() {
		for delivery := range deliveries {

			var om *OctopusMessage
			err := json.Unmarshal(delivery.Body, &om)
			if err != nil {
				log.Error(fmt.Sprintf("octopus message convert to json is wrong! msg is => %s", delivery.Body))
				// 保存到某处
				continue
			}
			// 策略模式 处理消息
			P.Submit(func() {
				om.HandleMsg(r.ReceiveChan)
			})
		}
	})
	return foreverHandle
}

// Send 向RabbitMQ中发送消息
func (r *RabbitQueue) Send(message []byte) {
	// 往哪里发
	channel := r.RabbitConn.Channel

	// 发送
	err := channel.Publish(
		r.RabbitProp.ExchangeName,
		r.RabbitProp.TopicKey,
		false,
		false,
		amqp.Publishing{
			ContentType: "text/plain",
			Body:        message,
		},
	)
	if err != nil {
		log.Error(fmt.Sprintf("Failed to publish a message: %v", err))
	}
}

func (r *RabbitQueue) SendOMsg(oMessage *OctopusMessage) {
	bytes, err := json.Marshal(&oMessage)
	if err != nil {
		log.ErrorF("octopus message Marshal error %v", &oMessage)
	}

	r.Send(bytes)
}

func (r *RabbitQueue) Read(autoAck bool) <-chan amqp.Delivery {

	// 拿到特定的Channel
	channel := r.RabbitConn.Channel

	// 开始读取队列中的全部消息
	msgs, err := channel.Consume(
		r.RabbitProp.QueueName, // 队列名称
		"",                     // 消费者名称
		autoAck,                // auto-ack
		false,                  // exclusive
		false,                  // no-local
		false,                  // no-wait
		nil,                    // arguments
	)
	if err != nil {
		log.Error(fmt.Sprintf("Failed to register a consumer: %v", err))
	}

	return msgs
}

func parseRabbitMQEndpoint(rabbitConnectInfo *RabbitTCPConnectInfo) string {

	var res strings.Builder

	// amqp://{username}:{password}@{hostname}:{port}/{virtual_host}
	res.WriteString("amqp://")
	res.WriteString(rabbitConnectInfo.UserName)
	res.WriteString(":")
	res.WriteString(rabbitConnectInfo.Password)
	res.WriteString("@")
	res.WriteString(rabbitConnectInfo.Host)
	res.WriteString(":")
	res.WriteString(rabbitConnectInfo.Port)
	res.WriteString("/")
	res.WriteString(rabbitConnectInfo.VirtualHost)

	s := res.String()

	log.Debug(fmt.Sprintf("generate RabbitMQ endpoint is %s", s))

	return s
}