package apt

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
)

// fetchBytes performs a GET request and returns the response body.
func fetchBytes(ctx context.Context, httpClient *http.Client, url string) ([]byte, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		return nil, err
	}
	resp, err := httpClient.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("HTTP %d for %s", resp.StatusCode, url)
	}
	return io.ReadAll(resp.Body)
}

// atomicWrite writes data to path via a temporary file and an atomic rename.
func atomicWrite(path string, data []byte) error {
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		return err
	}
	tmp := path + ".tmp"
	if err := os.WriteFile(tmp, data, 0o644); err != nil {
		return err
	}
	if err := os.Rename(tmp, path); err != nil {
		os.Remove(tmp)
		return err
	}
	return nil
}