package update

import (
	"encoding/json"
	"errors"
	"io/fs"
	"os"
)

const readableFilePermissions = 0o644

func writeFileAtomically(path string, content []byte, permissions os.FileMode) error {
	temporary := path + ".tmp"
	if err := os.WriteFile(temporary, content, permissions); err != nil {
		return err
	}
	if err := os.Rename(temporary, path); err != nil {
		_ = os.Remove(temporary)
		return err
	}
	return nil
}

func writeJSONAtomically(path string, value any, permissions os.FileMode) error {
	content, err := json.Marshal(value)
	if err != nil {
		return err
	}
	return writeFileAtomically(path, content, permissions)
}

func removeFile(path string) (bool, error) {
	err := os.Remove(path)
	if err == nil {
		return true, nil
	}
	if errors.Is(err, fs.ErrNotExist) {
		return false, nil
	}
	return false, err
}

func removeIfPresent(path string) error {
	_, err := removeFile(path)
	return err
}