package activator

import (
	"context"
	"errors"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/carlosframework/platform/internal/registry"
)

func TestStartupWaitUsesWakeTimeoutResponse(t *testing.T) {
	old := wakeWaitBound
	wakeWaitBound = 20 * time.Millisecond
	t.Cleanup(func() { wakeWaitBound = old })
	a := New(Config{}, &fakeBackend{}, nil)
	a.Startup = make(chan struct{})
	defer a.lifeStop()
	rt := registry.Route{Host: "shop.example.com", Kind: "instance", Hibernate: true}
	w := httptest.NewRecorder()
	a.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "http://shop.example.com/", nil), rt, http.NotFoundHandler())
	if w.Code != http.StatusServiceUnavailable || w.Header().Get("Retry-After") != "5" || w.Body.String() != "instance is waking; retry shortly\n" {
		t.Fatalf("startup timeout: %d, %v, %q", w.Code, w.Header(), w.Body.String())
	}
	if a.Owns(rt.Host) {
		t.Fatal("timed-out request created a wake")
	}
}

func TestStartupBlocksWorkerAndSidecarAdmission(t *testing.T) {
	old := wakeWaitBound
	wakeWaitBound = 20 * time.Millisecond
	t.Cleanup(func() { wakeWaitBound = old })
	a := New(Config{}, &fakeBackend{}, nil)
	a.Startup = make(chan struct{})
	defer a.lifeStop()
	rt := registry.Route{Host: "shop.example.com", Kind: "instance", Hibernate: true}
	if err := a.WakeWorker(rt); !errors.Is(err, errWakeTimeout) {
		t.Fatalf("worker: %v", err)
	}
	if err := a.BeginSidecarRequest(t.Context(), rt); !errors.Is(err, errWakeTimeout) {
		t.Fatalf("sidecar: %v", err)
	}
	ctx, cancel := context.WithCancel(t.Context())
	cancel()
	if _, err := a.begin(ctx, rt, true, nil); !errors.Is(err, context.Canceled) {
		t.Fatalf("cancelled request: %v", err)
	}
	if a.Owns(rt.Host) {
		t.Fatal("startup admission created a wake")
	}
}

func TestStartupShutdownAnswersServiceUnavailable(t *testing.T) {
	for _, ready := range []bool{false, true} {
		t.Run(map[bool]string{false: "held", true: "released"}[ready], func(t *testing.T) {
			a := New(Config{}, &fakeBackend{}, nil)
			started := make(chan struct{})
			a.Startup = started
			if ready {
				close(started)
			}
			a.Shutdown(t.Context())
			rt := registry.Route{Host: "shop.example.com", Kind: "instance", Hibernate: true}
			w := httptest.NewRecorder()
			a.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "http://shop.example.com/", nil), rt, http.NotFoundHandler())
			if w.Code != http.StatusServiceUnavailable {
				t.Fatalf("service shutdown answered %d: %q", w.Code, w.Body.String())
			}
			if a.Owns(rt.Host) {
				t.Fatal("shutdown request created a wake")
			}
		})
	}
}

type startupRoutes map[string]registry.Route

func (s startupRoutes) Get(host string) (*registry.Route, error) {
	rt, ok := s[host]
	if !ok {
		return nil, nil
	}
	return &rt, nil
}

// A request held through startup carries the proxy the edge chose before
// recovery ran. When recovery moved the host's socket, it is answered as a
// wake in progress, so the retry is routed afresh, never sent to the old
// socket.
func TestStartupHeldRequestRefusesStaleUpstream(t *testing.T) {
	t.Parallel()
	for _, moved := range []bool{false, true} {
		a := New(Config{}, &fakeBackend{}, nil)
		ready := make(chan struct{})
		a.Startup = ready
		rt := registry.Route{Host: "shop.example.com", Kind: "instance", Hibernate: true, Socket: "/run/carlos/shop.example.com.sock"}
		fresh := rt
		if moved {
			fresh.Socket = "/run/carlos/instances/shop.example.com/app.sock"
		}
		a.Routes = startupRoutes{rt.Host: fresh}
		proxied := false
		proxy := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { proxied = true })
		w := httptest.NewRecorder()
		done := make(chan struct{})
		go func() {
			defer close(done)
			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
			defer cancel()
			a.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "http://shop.example.com/", nil).WithContext(ctx), rt, proxy)
		}()
		time.Sleep(20 * time.Millisecond)
		close(ready)
		<-done
		a.lifeStop()
		if moved {
			if proxied || w.Code != http.StatusServiceUnavailable || w.Header().Get("Retry-After") != "5" {
				t.Fatalf("moved socket: proxied=%v code=%d", proxied, w.Code)
			}
		} else if w.Code == http.StatusServiceUnavailable && w.Body.String() == "instance is waking; retry shortly\n" {
			t.Fatalf("unchanged socket was refused as stale")
		}
	}
}

// The race the waiting check misses: the edge chose its proxy, recovery
// moved the socket and Startup closed before serve looked. A request near
// startup is still checked; one long after it is not.
func TestStartupClosedNearStartupRefusesStaleUpstream(t *testing.T) {
	for _, late := range []bool{false, true} {
		a := New(Config{}, &fakeBackend{}, nil)
		ready := make(chan struct{})
		close(ready)
		a.Startup = ready
		if late {
			a.startupSeenAt.Store(time.Now().Add(-2 * startupFreshWindow).UnixNano())
		}
		rt := registry.Route{Host: "shop.example.com", Kind: "instance", Hibernate: true, Socket: "/run/carlos/shop.example.com.sock"}
		fresh := rt
		fresh.Socket = "/run/carlos/instances/shop.example.com/app.sock"
		a.Routes = startupRoutes{rt.Host: fresh}
		proxied := false
		proxy := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { proxied = true })
		w := httptest.NewRecorder()
		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
		a.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "http://shop.example.com/", nil).WithContext(ctx), rt, proxy)
		cancel()
		a.lifeStop()
		stale := !proxied && w.Code == http.StatusServiceUnavailable && w.Body.String() == "instance is waking; retry shortly\n"
		if !late && !stale {
			t.Fatalf("near startup: moved socket not refused: proxied=%v code=%d", proxied, w.Code)
		}
		if late && stale {
			t.Fatal("long after startup: the route was re-checked")
		}
	}
}