package main

import (
	"context"
	"crypto/tls"
	"crypto/x509"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"time"

	"github.com/Azure/go-amqp"
)

func main() {
	flag.Parse()

	tlsConfig, err := NewTLSConfig("client.cer.pem",
		"client.key.pem",
		"server.cer.pem")
	if err != nil {
		log.Fatal(err)
	}
	

	client, err := amqp.Dial("amqps://server.fr:5671", amqp.ConnTLSConfig(tlsConfig), amqp.ConnSASLAnonymous())
	if err != nil {
		log.Fatal("Dialing AMQP server:", err)
	}
	defer client.Close()

	// Open a session
	session, err := client.NewSession()
	if err != nil {
		log.Fatal("Creating AMQP session:", err)
	}

	ctx := context.Background()

	// Send a message
	{
		// Create a sender
		sender, err := session.NewSender(
			amqp.LinkTargetAddress("/queue-name"),
		)
		if err != nil {
			log.Fatal("Creating sender link:", err)
		}

		ctx, cancel := context.WithTimeout(ctx, 5*time.Second)

		// Send message
		err = sender.Send(ctx, amqp.NewMessage([]byte("Hello!")))
		if err != nil {
			log.Fatal("Sending message:", err)
		}

		sender.Close(ctx)
		cancel()
	}

	// Continuously read messages
	{
		// Create a receiver
		receiver, err := session.NewReceiver(
			amqp.LinkSourceAddress("/queue-name"),
			amqp.LinkCredit(10),
		)
		if err != nil {
			log.Fatal("Creating receiver link:", err)
		}
		defer func() {
			ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
			receiver.Close(ctx)
			cancel()
		}()

		for {
			// Receive next message
			msg, err := receiver.Receive(ctx)
			if err != nil {
				log.Fatal("Reading message from AMQP:", err)
			}

			// Accept message
			receiver.AcceptMessage(context.Background(), msg)
			fmt.Printf("Message received: %s\n", msg.GetData())
		}
	}
}

func NewTLSConfig(clientCertFile, clientKeyFile, caCertFile string) (*tls.Config, error) {
	tlsConfig := tls.Config{}

	// Load client cert
	cert, err := tls.LoadX509KeyPair(clientCertFile, clientKeyFile)
	if err != nil {
		return &tlsConfig, err
	}
	tlsConfig.Certificates = []tls.Certificate{cert}

	// Load CA cert
	caCert, err := ioutil.ReadFile(caCertFile)
	if err != nil {
		return &tlsConfig, err
	}
	caCertPool := x509.NewCertPool()
	caCertPool.AppendCertsFromPEM(caCert)
	tlsConfig.RootCAs = caCertPool

	return &tlsConfig, err
}