package safefile

import (
	"errors"
	"io"
	"os"
	"path/filepath"
	"testing"
)

func TestPlan14DurableWriteInterruptedSync(t *testing.T) {
	for _, point := range []string{"file-sync", "parent-sync"} {
		t.Run(point, func(t *testing.T) {
			dir := t.TempDir()
			path := filepath.Join(dir, "floor")
			if err := os.WriteFile(path, []byte("old"), 0600); err != nil {
				t.Fatal(err)
			}
			fd, err := OpenDir(dir)
			if err != nil {
				t.Fatal(err)
			}
			defer fd.Close()
			interrupted := errors.New("sync interrupted")
			err = writeAtSteps(int(fd.Fd()), "floor", 0600, func(w io.Writer) error { _, e := w.Write([]byte("new")); return e }, func(stage string, op func() error) error {
				if e := op(); e != nil {
					return e
				}
				if stage == point {
					return interrupted
				}
				return nil
			})
			if !errors.Is(err, interrupted) {
				t.Fatal("lost durability failure", err)
			}
			body, err := os.ReadFile(path)
			if err != nil {
				t.Fatal(err)
			}
			want := "old"
			if point == "parent-sync" {
				want = "new"
			}
			if string(body) != want {
				t.Fatal("publication crossed unsynced boundary", string(body))
			}
			if err := WriteAt(int(fd.Fd()), "floor", []byte("new"), 0600); err != nil {
				t.Fatal("retry", err)
			}
		})
	}
}