package httputils

import (
	"crypto/tls"
	"io"
	"net"
	"net/http"
	"time"
)

const DefaultTimeout = 10 * time.Second

func HttpGet(url string, timeout time.Duration, customHeaders map[string]string, cookies []*http.Cookie) ([]byte, int, []*http.Cookie, error) {
	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		return nil, 0, nil, err
	}

	for _, c := range cookies {
		req.AddCookie(c)
	}

	transport, err := CreateTransport(&http.Transport{}, timeout, customHeaders)
	if err != nil {
		return nil, 0, nil, err
	}

	client := http.Client{Transport: transport, Timeout: timeout}

	resp, err := client.Do(req)
	if err != nil {
		return nil, 0, nil, err
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	return body, resp.StatusCode, resp.Cookies(), err
}

type customHeadersRoundTripper struct {
	headers    map[string]string
	originalRT http.RoundTripper
}

func (rt *customHeadersRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
	// note: no need to check for nil or empty map - newCustomHeadersRoundTripper will assure us there will always be at least 1
	for k, v := range rt.headers {
		req.Header.Set(k, v)
	}
	return rt.originalRT.RoundTrip(req)
}

func newCustomHeadersRoundTripper(headers map[string]string, rt http.RoundTripper) http.RoundTripper {
	if len(headers) == 0 {
		// if there are no custom headers then there is no need for a special RoundTripper; therefore just return the original RoundTripper
		return rt
	}
	return &customHeadersRoundTripper{
		headers:    headers,
		originalRT: rt,
	}
}

// Creates a new HTTP Transport with TLS, Timeouts, and optional custom headers.
//
// Please remember that setting long timeouts is not recommended as it can make
// idle connections stay open for as long as 2 * timeout. This should only be
// done in cases where you know the request is very likely going to be reused at
// some point in the near future.
func CreateTransport(transportConfig *http.Transport, timeout time.Duration, customHeaders map[string]string) (http.RoundTripper, error) {
	// Limits the time spent establishing a TCP connection if a new one is
	// needed. If DialContext is not set, Dial is used, we only create a new one
	// if neither is defined.
	if transportConfig.DialContext == nil {
		transportConfig.DialContext = (&net.Dialer{
			Timeout: timeout,
		}).DialContext
	}

	transportConfig.IdleConnTimeout = timeout

	transportConfig.TLSClientConfig = &tls.Config{
		InsecureSkipVerify: true,
	}

	// We might need some custom RoundTrippers to manipulate the requests (for auth and other custom request headers).
	// Chain together the RoundTrippers that we need, retaining the outer-most round tripper so we can return it.
	outerRoundTripper := newCustomHeadersRoundTripper(customHeaders, transportConfig)

	return outerRoundTripper, nil
}