// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

package update

import (
	"fmt"
	"io"
	"os"
	"path/filepath"
)

func copyFile(src, dst string) error {
	in, err := os.Open(src)
	if err != nil {
		return fmt.Errorf("cannot open %s: %w", src, err)
	}

	defer func() { _ = in.Close() }()

	if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
		return fmt.Errorf("cannot ensure %s: %w", filepath.Dir(dst), err)
	}

	out, err := os.OpenFile(dst, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o755)
	if err != nil {
		return fmt.Errorf("cannot create %s: %w", dst, err)
	}

	if _, err := io.Copy(out, in); err != nil {
		_ = out.Close()
		_ = os.Remove(dst)

		return fmt.Errorf("cannot copy to %s: %w", dst, err)
	}

	if err := out.Sync(); err != nil {
		_ = out.Close()
		_ = os.Remove(dst)

		return fmt.Errorf("cannot fsync %s: %w", dst, err)
	}

	if err := out.Close(); err != nil {
		_ = os.Remove(dst)
		return fmt.Errorf("cannot close %s: %w", dst, err)
	}

	return nil
}