package webserver

import (
	"context"
	"errors"
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"git.dev.m-and-m.ovh/mderasse/gocommon/commonctx"
)

const defaultTimeout = 90 * time.Second
const defaultShutdownTimeout = 10 * time.Second

type cleanupFunc func() error

// ExecuteServerParams are the parameters expected in the ExecuteServer function.
type ExecuteServerParams struct {
	Cleanup         cleanupFunc
	ShutdownTimeout *time.Duration
}

// ExecuteServer will launche a http.Server and handle the "exit" signals and gracefully stop the server
// and call the cleanup function.
func ExecuteServer(ctx context.Context, srv *http.Server, params *ExecuteServerParams) error {

	log := commonctx.GetLogger(ctx)

	if srv == nil {
		return fmt.Errorf("missing http.server params")
	}

	if srv.ReadTimeout == 0 {
		srv.ReadTimeout = defaultTimeout
	}

	if srv.WriteTimeout == 0 {
		srv.WriteTimeout = defaultTimeout
	}

	log.Infof("launching webserver on %s", srv.Addr)

	go func() {
		if err := srv.ListenAndServe(); !errors.Is(err, http.ErrServerClosed) {
			log.WithError(err).Fatalf("HTTP server error: %v", err)
		}
		log.Info("Stopped serving new connections.")
	}()

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

	shutdownCtx, shutdownRelease := context.WithTimeout(ctx, defaultShutdownTimeout)
	defer shutdownRelease()

	if err := srv.Shutdown(shutdownCtx); err != nil {
		log.WithError(err).Warnf("HTTP shutdown error: %v", err)
	}

	if params.Cleanup != nil {
		if err := params.Cleanup(); err != nil {
			log.WithError(err).Warnf("Impossible to cleanup correctly after shutdown. error : %v", err)
			return nil
		}
	}

	log.Info("Graceful shutdown complete.")

	return nil
}