package main

import (
	"context"
	"fmt"
	"log"
	"net/url"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/eclipse/paho.golang/autopaho"
	"github.com/eclipse/paho.golang/paho"
)

func main() {
	if err := run(); err != nil {
		log.Fatal(err)
	}
}

func run() error {
	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()

	user := os.Getenv("TEST_MQTT5_MQTT_USERNAME")
	pass := os.Getenv("TEST_MQTT5_MQTT_PASSWORD")

	if user == "" || pass == "" {
		return fmt.Errorf("TEST_MQTT5_MQTT_USERNAME and TEST_MQTT5_MQTT_PASSWORD environment variables not set")
	}

	broker, err := url.Parse("mqtt://127.0.0.1:18883")
	if err != nil {
		return fmt.Errorf("failed to parse broker url: %w", err)
	}

	cfg := autopaho.ClientConfig{
		ServerUrls:                    []*url.URL{broker},
		KeepAlive:                     20,
		CleanStartOnInitialConnection: true,
		SessionExpiryInterval:         0,
		ConnectUsername:               user,
		ConnectPassword:               []byte(pass),
		OnConnectionUp: func(_ *autopaho.ConnectionManager, ack *paho.Connack) {
			log.Printf("connected: session_present=%t reason=0x%02x", ack.SessionPresent, ack.ReasonCode)
		},
		OnConnectionDown: func() bool {
			log.Print("connection down; AutoPaho will retry")
			return true
		},
		OnConnectError: func(err error) {
			log.Printf("connect attempt failed: %v", err)
		},
		ClientID: "lab-backend",
		OnClientError: func(err error) {
			log.Printf("client error: %v", err)
		},
		OnServerDisconnect: func(packet *paho.Disconnect) {
			log.Printf("server disconnected: reason=0x%02x", packet.ReasonCode)
		},
	}

	manager, err := autopaho.NewConnection(ctx, cfg)
	if err != nil {
		return fmt.Errorf("failed to create connection manager: %w", err)
	}

	defer func() {
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()
		if err := manager.Disconnect(shutdownCtx); err != nil {
			log.Printf("shutdown did not finish within deadline: %v", err)
		}
	}()

	startup, cancel := context.WithTimeout(ctx, 10*time.Second)
	err = manager.AwaitConnection(startup)
	cancel()

	if err != nil {
		return fmt.Errorf("failed to connect to broker: %w", err)
	}

	log.Print("connected to broker; pres Ctrl+C to stop")

	<-ctx.Done()

	return nil
}