package rabbitmq

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

type RabbitMQ interface {
	RabbitSendWriter
	RabbitConnectCloser
}

type RabbitSendWriter interface {
	Send(message []byte)

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

type RabbitConnectCloser interface {
	Connect()

	Close() error
}

type RabbitQueue struct {
	RabbitConn *RabbitMQConn

	RabbitProp *ConnectProperty
}

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

type ConnectProperty struct {
	ExchangeName string
	QueueName    string
	ExchangeType string
	TopicKey     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() {
	// 在这里进行 Singleton 的初始化操作

	// 获取RabbitMQ的连接地址
	rabbitMQEndpointFromG := parseRabbitMQEndpointFromG()

	// 创建全局唯一连接 RabbitMQ连接
	connection, err := amqp.Dial(rabbitMQEndpointFromG)
	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() *amqp.Connection {
	// 使用 sync.Once 确保 createInstance 只会被调用一次
	once.Do(createInstance)
	return instance
}

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

	// 获取RabbitMQ的连接
	conn := GetInstance()

	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))
	}

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

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
}

// 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) 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
}

// parseRabbitMQEndpoint 根据全局变量agentConfig解析出RabbitMQ的连接地址
func parseRabbitMQEndpointFromG() string {

	agentConfig := g.G.AgentConfig

	var res strings.Builder

	host := agentConfig.GetString("spring.rabbitmq.host")
	port := agentConfig.GetString("spring.rabbitmq.port")
	username := agentConfig.GetString("spring.rabbitmq.username")
	password := agentConfig.GetString("spring.rabbitmq.password")
	virtualHost := agentConfig.GetString("spring.rabbitmq.virtual-host")

	// amqp://{username}:{password}@{hostname}:{port}/{virtual_host}
	res.WriteString("amqp://")
	res.WriteString(username)
	res.WriteString(":")
	res.WriteString(password)
	res.WriteString("@")
	res.WriteString(host)
	res.WriteString(":")
	res.WriteString(port)
	res.WriteString("/")
	res.WriteString(virtualHost)

	s := res.String()

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

	return s
}