package activator

import (
	"context"
	"errors"
	"github.com/carlosframework/platform/internal/registry"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"
)

func TestSeedExclusionWaitsForExistingPreparation(t *testing.T) {
	t.Parallel()
	for _, kind := range []string{"request", "timer", "stop"} {
		t.Run(kind, func(t *testing.T) {
			a := &Service{entries: map[string]*actEntry{}}
			pending := make(chan struct{})
			switch kind {
			case "request":
				a.entries["b.example"] = &actEntry{state: actWaking, ready: pending, wakeCancel: func() { t.Error("canceled existing wake") }}
			case "timer":
				a.tokenPreparations = map[string]chan struct{}{"b.example": pending}
			case "stop":
				a.entries["b.example"] = &actEntry{state: actStopping, stopped: pending}
			}
			ctx, cancel := context.WithTimeout(t.Context(), 30*time.Millisecond)
			defer cancel()
			if _, err := a.AcquireSeedExclusion(ctx, "b.example", nil); !errors.Is(err, context.DeadlineExceeded) {
				t.Fatalf("did not wait: %v", err)
			}
			if a.fences["b.example"] != 0 {
				t.Fatal("fenced the existing preparation")
			}
			a.mu.Lock()
			delete(a.entries, "b.example")
			delete(a.tokenPreparations, "b.example")
			close(pending)
			a.mu.Unlock()
			token, err := a.AcquireSeedExclusion(t.Context(), "b.example", nil)
			if err != nil {
				t.Fatal(err)
			}
			if err := token.Check("b.example"); err != nil {
				t.Fatal(err)
			}
			for _, serve := range []func(http.ResponseWriter, *http.Request, registry.Route, http.Handler) bool{a.ServeHTTP, a.ServeScheduled} {
				response := httptest.NewRecorder()
				called := false
				handled := serve(response, httptest.NewRequest("GET", "http://b.example/", nil), registry.Route{Host: "b.example", Kind: "instance", Hibernate: true}, http.HandlerFunc(func(http.ResponseWriter, *http.Request) { called = true }))
				if !handled || response.Code != 503 || called {
					t.Fatalf("request escaped exclusion: %v %d %v", handled, response.Code, called)
				}
			}
			if _, err := a.PrepareScheduledToken("b.example", func() (string, error) { t.Fatal("timer entered seed"); return "", nil }); !errors.Is(err, ErrFenced) {
				t.Fatal(err)
			}
			if _, err := a.PrepareScheduledToken("a.example", func() (string, error) { return "ok", nil }); err != nil {
				t.Fatal("other host blocked", err)
			}
			if _, err := a.AcquireSeedExclusion(t.Context(), "b.example", nil); !errors.Is(err, ErrFenceHeld) {
				t.Fatal("duplicate accepted", err)
			}
			again, err := a.AcquireSeedExclusion(t.Context(), "b.example", token)
			if err != nil || again != token {
				t.Fatal("unsettled owner could not resume", err)
			}
			if err := token.Release(); err != nil {
				t.Fatal(err)
			}
			if err := token.Check("b.example"); !errors.Is(err, ErrFenceHeld) {
				t.Fatal("stale token accepted", err)
			}
		})
	}
}

func TestSeedExclusionRefusesForeignFenceAndToken(t *testing.T) {
	a := &Service{fences: map[string]uint64{"b.example": 7}}
	if _, err := a.AcquireSeedExclusion(t.Context(), "b.example", nil); !errors.Is(err, ErrFenceHeld) {
		t.Fatal(err)
	}
	b := &Service{}
	tok, err := b.AcquireSeedExclusion(t.Context(), "b.example", nil)
	if err != nil {
		t.Fatal(err)
	}
	if _, err := a.AcquireSeedExclusion(t.Context(), "b.example", tok); !errors.Is(err, ErrFenceHeld) {
		t.Fatal(err)
	}
	if err := tok.Check("a.example"); !errors.Is(err, ErrFenceHeld) {
		t.Fatal(err)
	}
}