package server

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

	"github.com/go-chi/chi/v5"
	log "github.com/sirupsen/logrus"

	"github.com/nais/wonderwall/pkg/config"
)

var (
	defaultTransport *http.Transport
	once             sync.Once
)

func DefaultTransport() *http.Transport {
	once.Do(func() {
		t := http.DefaultTransport.(*http.Transport).Clone()
		t.MaxIdleConns = 200
		t.MaxIdleConnsPerHost = 100
		t.IdleConnTimeout = 5 * time.Second

		defaultTransport = t
	})

	return defaultTransport
}

func Start(cfg *config.Config, r chi.Router) error {
	server := http.Server{
		Addr:    cfg.BindAddress,
		Handler: r,
	}

	serverCtx, serverStopCtx := context.WithCancel(context.Background())

	sig := make(chan os.Signal, 1)
	signal.Notify(sig, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
	go func() {
		<-sig

		shutdownCtx, shutdownStopCtx := context.WithTimeout(serverCtx, 20*time.Second)

		go func() {
			<-shutdownCtx.Done()
			if shutdownCtx.Err() == context.DeadlineExceeded {
				log.Fatal("graceful shutdown timed out.. forcing exit.")
			}
		}()

		err := server.Shutdown(shutdownCtx)
		if err != nil {
			log.Fatal(err)
		}
		shutdownStopCtx()
		serverStopCtx()
	}()

	err := server.ListenAndServe()
	if err != nil && err != http.ErrServerClosed {
		return err
	}

	<-serverCtx.Done()
	return nil
}