// Package mq provides read or write access to message queue services
package mq

import (
	"context"
	"crypto/tls"
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"log"
	"os"
	"time"

	amqp "github.com/rabbitmq/amqp091-go"
	"github.com/youmark/pkcs8"
)

func main() {
	exchangeName := "getting-started-go-exchange"
	queueName := "getting-started-go-queue"
	routingKey := "routing-key"

	deadExchangeName := "getting-started-go-dead-letter-exchange"
	deadQueueName := "getting-started-go-dead-letter-queue"
	deadRoutingKey := "dead-letter-routing-key"

	caCert, err := os.ReadFile("../certs/ca_certificate.pem")
	if err != nil {
		log.Fatal("read ca file failed", err)
	}
	caCertPool := x509.NewCertPool()
	caCertPool.AppendCertsFromPEM(caCert)

	keyData, err := os.ReadFile("../certs/client_key.pem")
	if err != nil {
		log.Fatal("read private key file failed", err)
	}

	block, _ := pem.Decode(keyData)
	password := []byte("ecl3000")
	privateKey, err := pkcs8.ParsePKCS8PrivateKey(block.Bytes, password)
	if err != nil {
		log.Fatal("parse private key failed", err)
	}

	pemBytes, err := x509.MarshalPKCS8PrivateKey(privateKey)
	pemBlock := &pem.Block{Type: "PRIVATE KEY", Bytes: pemBytes}

	certPEM, err := os.ReadFile("../certs/client_certificate.pem")
	clientCert, err := tls.X509KeyPair(certPEM, pem.EncodeToMemory(pemBlock))
	if err != nil {
		log.Fatal("load client cert failed", err)
	}

	tlsConfig := &tls.Config{
		Certificates:       []tls.Certificate{clientCert},
		RootCAs:            caCertPool,
		InsecureSkipVerify: false,
		ServerName:         "douxu-buntu22",
	}

	url := "amqps://192.168.2.104:5671/"

	conn, err := amqp.DialConfig(url, amqp.Config{
		TLSClientConfig: tlsConfig,
		SASL:            []amqp.Authentication{&amqp.ExternalAuth{}},
		Heartbeat:       10 * time.Second,
	})
	if err != nil {
		log.Fatal("Error opening connection: ", err)
	}
	defer conn.Close()

	ch, err := conn.Channel()
	if err != nil {
		log.Fatal("Error opening channel: ", err)
	}
	defer ch.Close()

	go func() {
		closeErr := <-conn.NotifyClose(make(chan *amqp.Error))
		log.Printf("Connection closed: %v", closeErr)
	}()

	err = ch.ExchangeDeclare(deadExchangeName, "topic", true, false, false, false, nil)
	if err != nil {
		log.Fatal("Error declaring dead letter exchange: ", err)
	}

	_, err = ch.QueueDeclare(deadQueueName, true, false, false, false, nil)
	if err != nil {
		log.Fatal("Error declaring dead letter queue: ", err)
	}

	err = ch.QueueBind(deadQueueName, deadRoutingKey, deadExchangeName, false, nil)
	if err != nil {
		log.Fatal("Error binding dead letter: ", err)
	}

	err = ch.ExchangeDeclare(exchangeName, "topic", true, false, false, false, nil)
	if err != nil {
		log.Fatal("Error declaring exchange: ", err)
	}

	args := amqp.Table{
		"x-max-length":              int32(50),
		"x-dead-letter-exchange":    deadExchangeName,
		"x-dead-letter-routing-key": deadRoutingKey,
	}
	_, err = ch.QueueDeclare(queueName, true, false, false, false, args)
	if err != nil {
		log.Fatal("Error declaring queue: ", err)
	}

	err = ch.QueueBind(queueName, routingKey, exchangeName, false, nil)
	if err != nil {
		log.Fatal("Error binding queue: ", err)
	}

	if err := ch.Confirm(false); err != nil {
		log.Fatal("Channel could not be put into confirm mode: ", err)
	}

	confirms := ch.NotifyPublish(make(chan amqp.Confirmation, 1))

	for i := 0; i < 100; i++ {
		msgBody := fmt.Sprintf("Hello, World!%d", i)

		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		err = ch.PublishWithContext(ctx,
			exchangeName, // exchange
			routingKey,   // routing key
			false,        // mandatory
			false,        // immediate
			amqp.Publishing{
				ContentType: "text/plain",
				Body:        []byte(msgBody),
			})
		cancel()

		if err != nil {
			log.Printf("Error publishing message: %v", err)
			time.Sleep(1 * time.Second)
			continue
		}

		select {
		case confirm := <-confirms:
			if confirm.Ack {
				log.Printf("[Publisher] Message %d accepted", i)
			} else {
				log.Printf("[Publisher] Message %d Nack (Rejected by RabbitMQ)", i)
			}
		case <-time.After(5 * time.Second):
			log.Printf("[Publisher] Timeout waiting for confirm for message %d", i)
		}
	}

	log.Println("Producer finished sending messages")
}