package osimage

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"time"

	"github.com/klauspost/compress/zstd"
)

func OpenDecompressedHTTPStream(ctx context.Context, url string, timeout time.Duration) (io.Reader, func() error, error) {
	if url == "" {
		return nil, nil, fmt.Errorf("url is required")
	}
	if timeout <= 0 {
		timeout = 30 * time.Minute
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		return nil, nil, fmt.Errorf("build request: %w", err)
	}

	client := &http.Client{Timeout: timeout}

	resp, err := client.Do(req)
	if err != nil {
		return nil, nil, fmt.Errorf("http get %q: %w", url, err)
	}

	if resp.StatusCode != http.StatusOK {
		resp.Body.Close()
		return nil, nil, fmt.Errorf("unexpected status: %s", resp.Status)
	}

	dec, err := zstd.NewReader(resp.Body)
	if err != nil {
		resp.Body.Close()
		return nil, nil, fmt.Errorf("create zstd decoder: %w", err)
	}

	closeFn := func() error {
		dec.Close()
		return resp.Body.Close()
	}

	return dec, closeFn, nil
}