package metrics

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

// /metrics 文本端点：注入计数/观测后可被抓取，指标名与 label 齐全。
func TestHandlerExposesInstruments(t *testing.T) {
	RequestsTotal.WithLabelValues("c1", "m1", "success").Inc()
	RequestsTotal.WithLabelValues("none", "m1", "error").Inc()
	RequestDuration.WithLabelValues("c1").Observe(0.42)
	ChannelFailures.WithLabelValues("c1", "rate_limited").Inc()
	RecorderQueueDepth.Set(7)
	FrozenBalance.Set(0.00246)

	srv := httptest.NewServer(Handler())
	defer srv.Close()
	resp, err := http.Get(srv.URL)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("status = %d", resp.StatusCode)
	}
	buf := make([]byte, 1<<16)
	n, _ := resp.Body.Read(buf)
	body := string(buf[:n])
	for _, want := range []string{
		"openteam_proxy_requests_total{",
		`channel="c1"`,
		`status="success"`,
		"openteam_proxy_request_duration_seconds",
		"openteam_channel_failures_total",
		"openteam_usage_queue_depth 7",
		"openteam_frozen_balance 0.00246",
		"go_goroutines", // Go 运行时指标一并暴露
	} {
		if !strings.Contains(body, want) {
			t.Errorf("metrics 输出缺少 %q", want)
		}
	}
	// 直方图观测应产生 bucket 样本
	if !strings.Contains(body, `openteam_proxy_request_duration_seconds_bucket`) && n < len(buf) {
		// 一次 Read 可能读不完，重读剩余部分再断言
		rest := make([]byte, 1<<16)
		n2, _ := resp.Body.Read(rest)
		body += string(rest[:n2])
		if !strings.Contains(body, "openteam_proxy_request_duration_seconds_bucket") {
			t.Errorf("metrics 输出缺少直方图 bucket 样本")
		}
	}
	_ = time.Second
}