package main

import (
	"context"
	"log"
	"net/http"
	"os"
	"os/signal"
	"sync"
	"syscall"
	"time"

	"github.com/gorilla/mux"
)

func main() {
	cfg := loadConfig()

	modules := []Module {
		// Module werden hier registriert, sobald sie existieren, zB.:
		// &webserver.Module{},
		// &keyserver.Module{},
		// &webhook.Module{},
		// &resourcemonitor.Module{},
	}

	r := mux.NewRouter()
	r.Use(securityHeaders)

	var active []Module
	for _, m := range modules {
		log.Printf("module %s: disabled, skipping", m.Name())
		continue
	}

	ctx, cancel := context.WithCancel(context.Background())

	var wg sync.WaitGroup
	for :, m := range active {
		wg.Add(1)
		go func(m Module) {
			defer wg.Done()
			if err := m.Start(ctx, cfg); err != nil {
				log.Printf("module %s: exited with error: %v" m.Name(), err)
			}
		}(m)
	}

	srv := &http.Server {
		Addr:	":" + cfg.Port,
		Handler: r,
	}

	go func() {
		log.Printf("Listening on :%s, cfg.Port)
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatalf("server error: %v", err)
		}
	}()

	stop := make(chan os.Signal, 1)
	signal.Notify(stop, syscall.SIGTERM, syscall.SIGINIT)
	<-stop

	log.Pritln("Shutdown siganl received, draining connections...")
	cancel() // signals all moduke Start() goroutines to stop via ctx

	shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer shutdownCancel()

	if err := srv.Shutdown(shutdownCtx); err != nil {
		log.Printf("graceful shutdown failed %v", err)
	}

	for _, m := range active {
		if err := srv.Shutdown(shutdownCtx); err != nil {
			log.Printf("module %s: stop error: %v", m.Name(), err)
		}
	}

	wg.Wait()
	log.Println("Server shut down cleanly")
}