package httpclient

import (
	"errors"
	"fmt"
	"io"
	"net/http"
)

// ErrResponseTooLarge means the complete decoded HTTP response exceeded its budget.
var ErrResponseTooLarge = errors.New("httpclient: response body exceeds limit")

// ReadResponseBody reads a complete bounded body, including one extra byte to
// distinguish an exact limit from truncation. Standard Transport gzip decoding
// occurs before this reader, so the limit covers decompressed data as well.
func ReadResponseBody(resp *http.Response, limit int64) ([]byte, error) {
	if limit <= 0 || limit == int64(^uint64(0)>>1) {
		return nil, fmt.Errorf("httpclient: invalid response limit")
	}
	if resp.ContentLength > limit {
		return nil, ErrResponseTooLarge
	}
	body, err := io.ReadAll(io.LimitReader(resp.Body, limit+1))
	if err != nil {
		return nil, err
	}
	if int64(len(body)) > limit {
		return nil, ErrResponseTooLarge
	}
	return body, nil
}