package nginxgateway

import (
	"errors"
	"testing"
)

func TestSwapManagedSiteRestoresPreviousOnFailure(t *testing.T) {
	for _, failAt := range []string{"validate", "reload", "persist"} {
		t.Run(failAt, func(t *testing.T) {
			site := "old"
			validations, reloads := 0, 0
			write := func(content string) error { site = content; return nil }
			validate := func() error {
				validations++
				if failAt == "validate" && site == "new" {
					return errors.New("invalid nginx config")
				}
				return nil
			}
			reload := func() error {
				reloads++
				if failAt == "reload" && site == "new" {
					return errors.New("reload failed")
				}
				return nil
			}
			persist := func() error {
				if failAt == "persist" {
					return errors.New("save failed")
				}
				return nil
			}
			if err := swapManagedSite("old", "new", persist, write, validate, reload); err == nil {
				t.Fatal("expected failure")
			}
			if site != "old" || validations < 2 || reloads < 1 {
				t.Fatalf("old site not restored: site=%s validations=%d reloads=%d", site, validations, reloads)
			}
		})
	}
}