package server

import (
	"bufio"
	"context"
	"regexp"
	"testing"

	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"

	"edge-infra.dev/pkg/lib/server/inmemorylistener"
)

// Add prometheus metric using promauto
var metricFooBarBazTotal = promauto.NewGauge(prometheus.GaugeOpts{
	Name: "foo_bar_baz_total",
	Help: "foo_bar_baz_total counts the number of foobarbaz",
})

// Create a metric using promauto and see if the metrics are being served.
func TestMetricsServesScrapeData(t *testing.T) {
	metricFooBarBazTotal.Inc()
	var l = inmemorylistener.New()
	var httpc = l.HTTPClient()
	var s, err = NewMetricsServer(OptionListener(l))
	if err != nil {
		t.Fatal(err)
	}
	go s.Run()                             //nolint:errcheck
	defer s.Shutdown(context.Background()) //nolint:errcheck

	// Wait for ready.
	for {
		resp, err := httpc.Get("http://localhost/metrics")
		if err == nil && resp.StatusCode == 200 {
			t.Logf("server ready")
			break
		}
		t.Logf("server not ready: %v", err)
	}

	resp, err := httpc.Get("http://localhost/metrics")
	if err != nil {
		t.Fatal(err)
	}

	var scanner = bufio.NewScanner(resp.Body)

	var reMatchFooBarBaz = regexp.MustCompile("^foo_bar_baz_total[ \t]*[0-9]+$")
	var found bool
	for scanner.Scan() {
		txt := scanner.Text()
		if reMatchFooBarBaz.MatchString(txt) {
			found = true
			t.Logf("Found metric line: %q", txt)
		}
	}

	if err := scanner.Err(); err != nil {
		t.Fatal(err)
	}

	if !found {
		t.Fatalf("Did not find metric foo_bar_baz_total")
	}
}