package broker

import (
	"io"
	"net"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"git.asio.asia/nixevol/NixMsg/internal/metrics"
	dto "github.com/prometheus/client_model/go"
)

func TestConnectionMetricsIncDec(t *testing.T) {
	reg := metrics.New()
	b, err := New(Options{Authenticator: AllowAuthenticator{}, Metrics: reg})
	if err != nil {
		t.Fatal(err)
	}
	defer func() { _ = b.Close() }()

	if got := gaugeValue(t, reg, "nixmsg_connections", "tcp"); got != 0 {
		t.Fatalf("before connect tcp=%v", got)
	}

	r, w := net.Pipe()
	done := make(chan struct{})
	go func() {
		defer close(done)
		_ = b.AttachTCP(r)
	}()
	connectAndSubscribe(t, w, "ep-metrics", 0)

	deadline := time.Now().Add(3 * time.Second)
	for {
		if _, ok := b.ConnInfoOf("ep-metrics"); ok {
			break
		}
		if time.Now().After(deadline) {
			t.Fatal("session not established")
		}
		time.Sleep(10 * time.Millisecond)
	}
	if got := gaugeValue(t, reg, "nixmsg_connections", "tcp"); got != 1 {
		t.Fatalf("after connect tcp=%v want 1", got)
	}

	_ = w.Close()
	select {
	case <-done:
	case <-time.After(3 * time.Second):
		t.Fatal("attach did not finish")
	}
	deadline = time.Now().Add(3 * time.Second)
	for {
		if got := gaugeValue(t, reg, "nixmsg_connections", "tcp"); got == 0 {
			break
		}
		if time.Now().After(deadline) {
			t.Fatalf("after disconnect tcp=%v want 0", gaugeValue(t, reg, "nixmsg_connections", "tcp"))
		}
		time.Sleep(10 * time.Millisecond)
	}
}

func TestWSConnectionMetrics(t *testing.T) {
	reg := metrics.New()
	b, err := New(Options{Authenticator: AllowAuthenticator{}, Metrics: reg})
	if err != nil {
		t.Fatal(err)
	}
	defer func() { _ = b.Close() }()

	mux := http.NewServeMux()
	mux.Handle("/mqtt", b.WSHandler(nil))
	srv := httptest.NewServer(mux)
	defer srv.Close()

	// 仅验证 handler 暴露指标文本仍含初始标签；建连用 TCP 测即可。
	req := httptest.NewRequest(http.MethodGet, "/metrics", nil)
	rec := httptest.NewRecorder()
	reg.Handler().ServeHTTP(rec, req)
	body, _ := io.ReadAll(rec.Body)
	if !strings.Contains(string(body), `nixmsg_connections{transport="ws"} 0`) {
		t.Fatalf("missing ws series: %s", body)
	}
}

func gaugeValue(t *testing.T, reg *metrics.Registry, name, transport string) float64 {
	t.Helper()
	mfs, err := reg.Gatherer().Gather()
	if err != nil {
		t.Fatal(err)
	}
	for _, mf := range mfs {
		if mf.GetName() != name {
			continue
		}
		for _, m := range mf.GetMetric() {
			if matchLabel(m, "transport", transport) {
				return m.GetGauge().GetValue()
			}
		}
	}
	t.Fatalf("metric %s transport=%s not found", name, transport)
	return 0
}

func matchLabel(m *dto.Metric, key, val string) bool {
	for _, lp := range m.GetLabel() {
		if lp.GetName() == key && lp.GetValue() == val {
			return true
		}
	}
	return false
}