package proxy

import (
	"io"
	"net/http"
	"net/http/httptest"
	"net/url"
	"sync/atomic"
	"testing"
)

func TestRemoteHostSharesHTTPTransport(t *testing.T) {
	h1, err := NewRemoteHost[struct{}]("10.0.0.1", "8080")
	if err != nil {
		t.Fatal(err)
	}
	h2, err := NewRemoteHost[struct{}]("10.0.0.2", "8080")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() {
		_ = h1.Close()
		_ = h2.Close()
	})

	if h1.client.Transport != h2.client.Transport {
		t.Fatal("expected all RemoteHost instances to share one http.Transport")
	}
}

func TestRemoteHostProxyUsesKeepAlive(t *testing.T) {
	var requests atomic.Int32
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requests.Add(1)
		w.WriteHeader(http.StatusOK)
		_, _ = io.WriteString(w, `{"ok":true}`)
	}))
	t.Cleanup(srv.Close)

	host, port, err := splitHostPort(srv.URL)
	if err != nil {
		t.Fatal(err)
	}

	remote, err := NewRemoteHost[struct{}](host, port)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = remote.Close() })

	for range 3 {
		mw := NewMockResponseWriter()
		req, err := http.NewRequest(http.MethodGet, "/cart/1", nil)
		if err != nil {
			t.Fatal(err)
		}
		ok, err := remote.Proxy(1, mw, req, nil)
		if err != nil || !ok {
			t.Fatalf("Proxy failed: ok=%v err=%v status=%d body=%q", ok, err, mw.StatusCode, mw.Body.String())
		}
	}

	if requests.Load() != 3 {
		t.Fatalf("server requests = %d, want 3", requests.Load())
	}
}

func TestRemoteHostCloseDoesNotBreakSharedTransport(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.WriteHeader(http.StatusOK)
	}))
	t.Cleanup(srv.Close)

	host, port, err := splitHostPort(srv.URL)
	if err != nil {
		t.Fatal(err)
	}

	h1, err := NewRemoteHost[struct{}](host, port)
	if err != nil {
		t.Fatal(err)
	}
	h2, err := NewRemoteHost[struct{}](host, port)
	if err != nil {
		t.Fatal(err)
	}

	if err := h1.Close(); err != nil {
		t.Fatal(err)
	}

	mw := NewMockResponseWriter()
	req, err := http.NewRequest(http.MethodGet, "/health", nil)
	if err != nil {
		t.Fatal(err)
	}
	ok, err := h2.Proxy(0, mw, req, nil)
	if err != nil || !ok || mw.StatusCode != http.StatusOK {
		t.Fatalf("second host proxy after first close failed: ok=%v err=%v status=%d", ok, err, mw.StatusCode)
	}
}

func splitHostPort(rawURL string) (host, port string, err error) {
	u, err := url.Parse(rawURL)
	if err != nil {
		return "", "", err
	}
	return u.Hostname(), u.Port(), nil
}