/*
 * Copyright The OpenTelemetry Authors
 * SPDX-License-Identifier: Apache-2.0
 */

package io.opentelemetry.instrumentation.api.instrumenter.http;

import static io.opentelemetry.sdk.testing.assertj.OpenTelemetryAssertions.assertThat;
import static io.opentelemetry.sdk.testing.assertj.OpenTelemetryAssertions.equalTo;

import io.opentelemetry.api.common.Attributes;
import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.SpanContext;
import io.opentelemetry.api.trace.TraceFlags;
import io.opentelemetry.api.trace.TraceState;
import io.opentelemetry.context.Context;
import io.opentelemetry.instrumentation.api.instrumenter.OperationListener;
import io.opentelemetry.sdk.metrics.SdkMeterProvider;
import io.opentelemetry.sdk.testing.exporter.InMemoryMetricReader;
import io.opentelemetry.semconv.trace.attributes.SemanticAttributes;
import java.util.concurrent.TimeUnit;
import org.junit.jupiter.api.Test;

class HttpServerMetricsTest {

  @Test
  void collectsMetrics() {
    InMemoryMetricReader metricReader = InMemoryMetricReader.create();
    SdkMeterProvider meterProvider =
        SdkMeterProvider.builder().registerMetricReader(metricReader).build();

    OperationListener listener = HttpServerMetrics.get().create(meterProvider.get("test"));

    Attributes requestAttributes =
        Attributes.builder()
            .put("http.method", "GET")
            .put("http.host", "host")
            .put("http.target", "/")
            .put("http.scheme", "https")
            .put("net.host.name", "localhost")
            .put("net.host.port", 1234)
            .build();

    Attributes responseAttributes =
        Attributes.builder()
            .put("http.flavor", "2.0")
            .put("http.server_name", "server")
            .put("http.status_code", 200)
            .build();

    Context parent =
        Context.root()
            .with(
                Span.wrap(
                    SpanContext.create(
                        "ff01020304050600ff0a0b0c0d0e0f00",
                        "090a0b0c0d0e0f00",
                        TraceFlags.getSampled(),
                        TraceState.getDefault())));

    Context context1 = listener.onStart(parent, requestAttributes, nanos(100));

    assertThat(metricReader.collectAllMetrics())
        .satisfiesExactlyInAnyOrder(
            metric ->
                assertThat(metric)
                    .hasName("http.server.active_requests")
                    .hasDescription(
                        "The number of concurrent HTTP requests that are currently in-flight")
                    .hasUnit("requests")
                    .hasLongSumSatisfying(
                        sum ->
                            sum.hasPointsSatisfying(
                                point ->
                                    point
                                        .hasValue(1)
                                        .hasAttributesSatisfying(
                                            equalTo(SemanticAttributes.HTTP_HOST, "host"),
                                            equalTo(SemanticAttributes.HTTP_METHOD, "GET"),
                                            equalTo(SemanticAttributes.HTTP_SCHEME, "https"))
                                        .hasExemplarsSatisfying(
                                            exemplar ->
                                                exemplar
                                                    .hasTraceId("ff01020304050600ff0a0b0c0d0e0f00")
                                                    .hasSpanId("090a0b0c0d0e0f00")))));

    Context context2 = listener.onStart(Context.root(), requestAttributes, nanos(150));

    assertThat(metricReader.collectAllMetrics())
        .satisfiesExactlyInAnyOrder(
            metric ->
                assertThat(metric)
                    .hasName("http.server.active_requests")
                    .hasLongSumSatisfying(
                        sum -> sum.hasPointsSatisfying(point -> point.hasValue(2))));

    listener.onEnd(context1, responseAttributes, nanos(250));

    assertThat(metricReader.collectAllMetrics())
        .satisfiesExactlyInAnyOrder(
            metric ->
                assertThat(metric)
                    .hasName("http.server.active_requests")
                    .hasLongSumSatisfying(
                        sum -> sum.hasPointsSatisfying(point -> point.hasValue(1))),
            metric ->
                assertThat(metric)
                    .hasName("http.server.duration")
                    .hasUnit("ms")
                    .hasHistogramSatisfying(
                        histogram ->
                            histogram.hasPointsSatisfying(
                                point ->
                                    point
                                        .hasSum(150 /* millis */)
                                        .hasAttributesSatisfying(
                                            equalTo(SemanticAttributes.HTTP_SCHEME, "https"),
                                            equalTo(SemanticAttributes.HTTP_HOST, "host"),
                                            equalTo(SemanticAttributes.HTTP_METHOD, "GET"),
                                            equalTo(SemanticAttributes.HTTP_STATUS_CODE, 200),
                                            equalTo(SemanticAttributes.HTTP_FLAVOR, "2.0"))
                                        .hasExemplarsSatisfying(
                                            exemplar ->
                                                exemplar
                                                    .hasTraceId("ff01020304050600ff0a0b0c0d0e0f00")
                                                    .hasSpanId("090a0b0c0d0e0f00")))));

    listener.onEnd(context2, responseAttributes, nanos(300));

    assertThat(metricReader.collectAllMetrics())
        .satisfiesExactlyInAnyOrder(
            metric ->
                assertThat(metric)
                    .hasName("http.server.active_requests")
                    .hasLongSumSatisfying(
                        sum -> sum.hasPointsSatisfying(point -> point.hasValue(0))),
            metric ->
                assertThat(metric)
                    .hasName("http.server.duration")
                    .hasHistogramSatisfying(
                        histogram ->
                            histogram.hasPointsSatisfying(
                                point -> point.hasSum(300 /* millis */))));
  }

  @Test
  void collectsHttpRouteFromEndAttributes() {
    // given
    InMemoryMetricReader metricReader = InMemoryMetricReader.create();
    SdkMeterProvider meterProvider =
        SdkMeterProvider.builder().registerMetricReader(metricReader).build();

    OperationListener listener = HttpServerMetrics.get().create(meterProvider.get("test"));

    Attributes requestAttributes =
        Attributes.builder().put("http.host", "host").put("http.scheme", "https").build();

    Attributes responseAttributes = Attributes.builder().put("http.route", "/test/{id}").build();

    Context parentContext = Context.root();

    // when
    Context context = listener.onStart(parentContext, requestAttributes, nanos(100));
    listener.onEnd(context, responseAttributes, nanos(200));

    // then
    assertThat(metricReader.collectAllMetrics())
        .anySatisfy(
            metric ->
                assertThat(metric)
                    .hasName("http.server.duration")
                    .hasUnit("ms")
                    .hasHistogramSatisfying(
                        histogram ->
                            histogram.hasPointsSatisfying(
                                point ->
                                    point
                                        .hasSum(100 /* millis */)
                                        .hasAttributesSatisfying(
                                            equalTo(SemanticAttributes.HTTP_SCHEME, "https"),
                                            equalTo(SemanticAttributes.HTTP_HOST, "host"),
                                            equalTo(
                                                SemanticAttributes.HTTP_ROUTE, "/test/{id}")))));
  }

  private static long nanos(int millis) {
    return TimeUnit.MILLISECONDS.toNanos(millis);
  }
}
