package httpfetcher

import (
	"context"
	"io"
	"net/http"
	"net/http/httptest"
	"testing"

	"github.com/go-chi/chi/v5/middleware"
)

// TestFetchSendsRequestID verifies that a fetch sends the ID of the request
// it serves, which the RequestID middleware stores in the request context,
// to the upstream host as X-Request-Id, so the fetch can be found in that
// host's logs.
func TestFetchSendsRequestID(t *testing.T) {
	t.Parallel()

	const requestID = "test-request-id"

	received := make(chan string, 1)

	srv := httptest.NewServer(http.HandlerFunc(
		func(w http.ResponseWriter, r *http.Request) {
			received <- r.Header.Get("X-Request-Id")

			w.Header().Set("Content-Type", contentTypeJPEG)
			_, _ = io.WriteString(w, imagePayload)
		}))
	t.Cleanup(srv.Close)

	f, _ := newServerFetcher(t, srv, nil)

	ctx := context.WithValue(testContext(t), middleware.RequestIDKey, requestID)

	res, err := f.Fetch(ctx, upstreamURL("/image"))
	if err != nil {
		t.Fatalf("Fetch() error = %v", err)
	}

	_ = res.Content.Close()

	got := <-received
	t.Logf("upstream received X-Request-Id %q", got)

	if got != requestID {
		t.Errorf("upstream X-Request-Id = %q, want %q", got, requestID)
	}
}