package metrics

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

	"github.com/prometheus/client_golang/prometheus/testutil"

	. "github.com/onsi/ginkgo/v2"
	. "github.com/onsi/gomega"
)

func TestMetrics(t *testing.T) {
	RegisterFailHandler(Fail)
	RunSpecs(t, "Metrics Suite")
}

var _ = Describe("Metrics", func() {
	BeforeEach(func() {
		resetMetricsForTest()
	})

	Describe("Handler", func() {
		It("serves metrics with the correct content type", func() {
			req := httptest.NewRequest(http.MethodGet, "/metrics", nil)
			resp := httptest.NewRecorder()

			Handler().ServeHTTP(resp, req)

			Expect(resp.Code).To(Equal(http.StatusOK))
			Expect(resp.Header().Get("Content-Type")).To(ContainSubstring("text/plain"))
		})
	})

	Describe("labelValue helper", func() {
		It("normalizes empty and uppercase values", func() {
			Expect(labelValue("   ")).To(Equal("unknown"))
			Expect(labelValue("SOME_VALUE")).To(Equal("some_value"))
		})
	})

	Describe("record helpers", func() {
		It("record counters and histograms for message processing", func() {
			RecordProcessed("PARSED", "ARR", 150*time.Millisecond)
			RecordFailure("parser")
			RecordMessageHandled("stream1", "consumer1", ResultOK, 80*time.Millisecond)
			RecordRetry("stream1", "consumer1", RetryReasonProcessorError)
			RecordDLQMessage("stream1", "consumer1")
			RecordDLQPublishFailure("stream1", "consumer1")
			RecordPublishFailure("flightPlan")
			RecordDBQuery("insert_one", DBResultOK, 10*time.Millisecond)
			RecordJSAPICall("publish")

			Expect(testutil.ToFloat64(processedCounter.WithLabelValues("parsed", "arr"))).To(BeNumerically("==", 1))
			Expect(testutil.CollectAndCount(parseLatency, MetricParseLatencySeconds)).To(Equal(1))

			Expect(testutil.ToFloat64(failureCounter.WithLabelValues("parser"))).To(BeNumerically("==", 1))

			Expect(testutil.ToFloat64(messagesTotal.WithLabelValues("stream1", "consumer1", ResultOK))).To(BeNumerically("==", 1))
			Expect(testutil.CollectAndCount(handleLatency, MetricHandleLatencySeconds)).To(Equal(1))

			Expect(testutil.ToFloat64(retriesTotal.WithLabelValues("stream1", "consumer1", RetryReasonProcessorError))).To(BeNumerically("==", 1))

			Expect(testutil.ToFloat64(dlqMessagesTotal.WithLabelValues("stream1", "consumer1"))).To(BeNumerically("==", 1))
			Expect(testutil.ToFloat64(dlqPublishFailures.WithLabelValues("stream1", "consumer1"))).To(BeNumerically("==", 1))

			Expect(testutil.ToFloat64(publishFailuresTotal.WithLabelValues("flightplan"))).To(BeNumerically("==", 1))

			Expect(testutil.ToFloat64(dbQueriesTotal.WithLabelValues("insert_one", DBResultOK))).To(BeNumerically("==", 1))
			Expect(testutil.CollectAndCount(dbQueryLatency, MetricDBQueryLatencySeconds)).To(Equal(1))

			Expect(testutil.ToFloat64(jsAPICallsTotal.WithLabelValues("publish"))).To(BeNumerically("==", 1))
		})

		It("records gauge values for pending messages", func() {
			RecordNATSConsumerPending("STREAM_A", "consumerA", 42)
			Expect(testutil.ToFloat64(natsConsumerPending.WithLabelValues("stream_a", "consumera"))).To(BeNumerically("==", 42))

			RecordNATSConsumerPending("STREAM_A", "consumerA", 5)
			Expect(testutil.ToFloat64(natsConsumerPending.WithLabelValues("stream_a", "consumera"))).To(BeNumerically("==", 5))
		})
	})
})

func resetMetricsForTest() {
	once = sync.Once{}
	registry = nil
	processedCounter = nil
	failureCounter = nil
	parseLatency = nil
	messagesTotal = nil
	handleLatency = nil
	retriesTotal = nil
	jsAPICallsTotal = nil
	dlqMessagesTotal = nil
	dlqPublishFailures = nil
	publishFailuresTotal = nil
	dbQueriesTotal = nil
	dbQueryLatency = nil
	natsConsumerPending = nil
}