// tera-alarmd is the bounded alarm delivery and retry service.
package main

import (
	"errors"
	"log"
	"net"
	"os"
	"os/signal"
	"path/filepath"
	"strconv"
	"syscall"

	"tera-clone/services/tera-api/internal/alarmdelivery"
	"tera-clone/services/tera-api/internal/alarmdelivery/alarmsocket"
	"tera-clone/services/tera-api/internal/secretstore"
)

func main() {
	secretPath := getenv("TERA_ALARMD_SECRET_STORE", "/var/lib/tera-api/secrets.json")
	_, err := secretstore.Open(secretPath)
	if err != nil {
		log.Fatalf("tera-alarmd secret store setup failed: %v", err)
	}
	secrets := secretstore.FileReader{Path: secretPath}
	dispatcher, err := alarmdelivery.NewDispatcher(map[string]alarmdelivery.Transport{
		alarmdelivery.ChannelWeb:      alarmdelivery.WebTransport{},
		alarmdelivery.ChannelSyslog:   alarmdelivery.SyslogTransport{},
		alarmdelivery.ChannelEmail:    alarmdelivery.EmailTransport{Secrets: secrets},
		alarmdelivery.ChannelSNMPTrap: alarmdelivery.SNMPTrapTransport{Secrets: secrets},
	}, alarmdelivery.DispatcherOptions{
		StatePath: getenv("TERA_ALARMD_STATE", "/var/lib/tera-alarmd/deliveries.json"),
		MaxJobs:   getenvInt("TERA_ALARMD_MAX_JOBS", 256),
	})
	if err != nil {
		log.Fatalf("tera-alarmd dispatcher setup failed: %v", err)
	}
	defer dispatcher.Close()

	socketPath := getenv("TERA_ALARMD_SOCKET", alarmsocket.DefaultSocketPath)
	listener, err := listen(socketPath)
	if err != nil {
		log.Fatalf("tera-alarmd socket setup failed: %v", err)
	}
	defer func() {
		_ = listener.Close()
		_ = os.Remove(socketPath)
	}()

	server := alarmsocket.Server{Controller: dispatcher}
	done := make(chan error, 1)
	go func() { done <- server.Serve(listener) }()
	log.Printf("tera-alarmd serving delivery control on %s", socketPath)

	signals := make(chan os.Signal, 1)
	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM)
	select {
	case signal := <-signals:
		log.Printf("tera-alarmd stopping after %s", signal)
		_ = listener.Close()
		if err := <-done; err != nil {
			log.Printf("tera-alarmd stop error: %v", err)
		}
	case err := <-done:
		if err != nil {
			log.Fatalf("tera-alarmd failed: %v", err)
		}
	}
}

func listen(socketPath string) (net.Listener, error) {
	if socketPath == "" || !filepath.IsAbs(socketPath) {
		return nil, errors.New("TERA_ALARMD_SOCKET must be an absolute path")
	}
	if err := os.MkdirAll(filepath.Dir(socketPath), 0o750); err != nil {
		return nil, err
	}
	if info, err := os.Lstat(socketPath); err == nil {
		if info.Mode()&os.ModeSocket == 0 {
			return nil, errors.New("refusing to replace non-socket alarm delivery path")
		}
		if err := os.Remove(socketPath); err != nil {
			return nil, err
		}
	} else if !os.IsNotExist(err) {
		return nil, err
	}
	listener, err := net.Listen("unix", socketPath)
	if err != nil {
		return nil, err
	}
	if err := os.Chmod(socketPath, 0o660); err != nil {
		_ = listener.Close()
		return nil, err
	}
	return listener, nil
}

func getenv(key, fallback string) string {
	if value := os.Getenv(key); value != "" {
		return value
	}
	return fallback
}

func getenvInt(key string, fallback int) int {
	value, err := strconv.Atoi(os.Getenv(key))
	if err != nil || value <= 0 {
		return fallback
	}
	return value
}