// Copyright (c) 2026 Probo Inc <hello@probo.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// 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
}