package status

import (
	"net/http"
	"net/http/httptest"
	"testing"
	"time"
)

// A box that knows nothing but its own instance id still publishes a
// Metrics block: the id is the join the console's architecture page hangs
// the whole cloud half on, and the attach rule must not drop it for want of
// a memory reading.
func TestCollectBoxPublishesInstanceIDAlone(t *testing.T) {
	box := CollectBox(nil, Probes{InstanceID: "i-0c8e41d9"}, time.Now())
	if box.Metrics == nil {
		t.Fatal("a box that knows its instance id must publish a Metrics block")
	}
	if box.Metrics.InstanceID != "i-0c8e41d9" {
		t.Errorf("InstanceID = %q, want i-0c8e41d9", box.Metrics.InstanceID)
	}
}

// Off-cloud there is no instance id, and absence is the honest answer: it
// is what tells the console this is somebody else's hardware rather than a
// machine it failed to find.
func TestCollectBoxOmitsAnAbsentInstanceID(t *testing.T) {
	box := CollectBox(nil, Probes{}, time.Now())
	if box.Metrics != nil && box.Metrics.InstanceID != "" {
		t.Errorf("InstanceID = %q, want empty", box.Metrics.InstanceID)
	}
}

// InstanceID reads IMDSv2: a PUT for a token, then a GET carrying it. A
// server that refuses the token (IMDSv1-only, or the uid-gate) yields "",
// never a partial or a panic.
func TestInstanceIDReadsIMDSv2(t *testing.T) {
	var sawToken bool
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		switch {
		case r.Method == http.MethodPut && r.URL.Path == "/latest/api/token":
			if r.Header.Get("X-aws-ec2-metadata-token-ttl-seconds") == "" {
				t.Error("token request must carry a TTL header")
			}
			w.Write([]byte("tok123"))
		case r.URL.Path == "/latest/meta-data/instance-id":
			if r.Header.Get("X-aws-ec2-metadata-token") == "tok123" {
				sawToken = true
			}
			w.Write([]byte("i-0abcdef"))
		default:
			http.NotFound(w, r)
		}
	}))
	defer srv.Close()

	if got := instanceIDFrom(srv.URL, time.Second); got != "i-0abcdef" {
		t.Errorf("instanceIDFrom = %q, want i-0abcdef", got)
	}
	if !sawToken {
		t.Error("the metadata GET must present the IMDSv2 token")
	}
}

func TestInstanceIDIsEmptyWhenIMDSIsUnreachable(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "denied", http.StatusForbidden)
	}))
	defer srv.Close()
	if got := instanceIDFrom(srv.URL, time.Second); got != "" {
		t.Errorf("instanceIDFrom = %q, want empty when IMDS refuses", got)
	}
	if got := instanceIDFrom("http://127.0.0.1:1", 200*time.Millisecond); got != "" {
		t.Errorf("instanceIDFrom = %q, want empty when nothing answers", got)
	}
}