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

package processorhelper

import (
	"context"
	"errors"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/sdk/metric/metricdata"

	"go.opentelemetry.io/collector/component"
	"go.opentelemetry.io/collector/component/componenttest"
	"go.opentelemetry.io/collector/consumer"
	"go.opentelemetry.io/collector/consumer/consumertest"
	"go.opentelemetry.io/collector/pdata/ptrace"
	"go.opentelemetry.io/collector/processor/processortest"
)

var testTracesCfg = struct{}{}

func TestNewTracesProcessor(t *testing.T) {
	tp, err := NewTracesProcessor(context.Background(), processortest.NewNopSettings(), &testTracesCfg, consumertest.NewNop(), newTestTProcessor(nil))
	require.NoError(t, err)

	assert.True(t, tp.Capabilities().MutatesData)
	assert.NoError(t, tp.Start(context.Background(), componenttest.NewNopHost()))
	assert.NoError(t, tp.ConsumeTraces(context.Background(), ptrace.NewTraces()))
	assert.NoError(t, tp.Shutdown(context.Background()))
}

func TestNewTracesProcessor_WithOptions(t *testing.T) {
	want := errors.New("my_error")
	tp, err := NewTracesProcessor(context.Background(), processortest.NewNopSettings(), &testTracesCfg, consumertest.NewNop(), newTestTProcessor(nil),
		WithStart(func(context.Context, component.Host) error { return want }),
		WithShutdown(func(context.Context) error { return want }),
		WithCapabilities(consumer.Capabilities{MutatesData: false}))
	assert.NoError(t, err)

	assert.Equal(t, want, tp.Start(context.Background(), componenttest.NewNopHost()))
	assert.Equal(t, want, tp.Shutdown(context.Background()))
	assert.False(t, tp.Capabilities().MutatesData)
}

func TestNewTracesProcessor_NilRequiredFields(t *testing.T) {
	_, err := NewTracesProcessor(context.Background(), processortest.NewNopSettings(), &testTracesCfg, consumertest.NewNop(), nil)
	assert.Error(t, err)
}

func TestNewTracesProcessor_ProcessTraceError(t *testing.T) {
	want := errors.New("my_error")
	tp, err := NewTracesProcessor(context.Background(), processortest.NewNopSettings(), &testTracesCfg, consumertest.NewNop(), newTestTProcessor(want))
	require.NoError(t, err)
	assert.Equal(t, want, tp.ConsumeTraces(context.Background(), ptrace.NewTraces()))
}

func TestNewTracesProcessor_ProcessTracesErrSkipProcessingData(t *testing.T) {
	tp, err := NewTracesProcessor(context.Background(), processortest.NewNopSettings(), &testTracesCfg, consumertest.NewNop(), newTestTProcessor(ErrSkipProcessingData))
	require.NoError(t, err)
	assert.NoError(t, tp.ConsumeTraces(context.Background(), ptrace.NewTraces()))
}

func newTestTProcessor(retError error) ProcessTracesFunc {
	return func(_ context.Context, td ptrace.Traces) (ptrace.Traces, error) {
		return td, retError
	}
}

func TestTracesProcessor_RecordInOut(t *testing.T) {
	// Regardless of how many spans are ingested, emit just one
	mockAggregate := func(_ context.Context, _ ptrace.Traces) (ptrace.Traces, error) {
		td := ptrace.NewTraces()
		td.ResourceSpans().AppendEmpty().ScopeSpans().AppendEmpty().Spans().AppendEmpty()
		return td, nil
	}

	incomingTraces := ptrace.NewTraces()
	incomingSpans := incomingTraces.ResourceSpans().AppendEmpty().ScopeSpans().AppendEmpty().Spans()

	// Add 4 records to the incoming
	incomingSpans.AppendEmpty()
	incomingSpans.AppendEmpty()
	incomingSpans.AppendEmpty()
	incomingSpans.AppendEmpty()

	testTelemetry := setupTestTelemetry()
	tp, err := NewTracesProcessor(context.Background(), testTelemetry.NewSettings(), &testLogsCfg, consumertest.NewNop(), mockAggregate)
	require.NoError(t, err)

	assert.NoError(t, tp.Start(context.Background(), componenttest.NewNopHost()))
	assert.NoError(t, tp.ConsumeTraces(context.Background(), incomingTraces))
	assert.NoError(t, tp.Shutdown(context.Background()))

	testTelemetry.assertMetrics(t, []metricdata.Metrics{
		{
			Name:        "otelcol_processor_incoming_items",
			Description: "Number of items passed to the processor.",
			Unit:        "{items}",
			Data: metricdata.Sum[int64]{
				Temporality: metricdata.CumulativeTemporality,
				IsMonotonic: true,
				DataPoints: []metricdata.DataPoint[int64]{
					{
						Value:      4,
						Attributes: attribute.NewSet(attribute.String("processor", "processorhelper"), attribute.String("otel.signal", "traces")),
					},
				},
			},
		},
		{
			Name:        "otelcol_processor_outgoing_items",
			Description: "Number of items emitted from the processor.",
			Unit:        "{items}",
			Data: metricdata.Sum[int64]{
				Temporality: metricdata.CumulativeTemporality,
				IsMonotonic: true,
				DataPoints: []metricdata.DataPoint[int64]{
					{
						Value:      1,
						Attributes: attribute.NewSet(attribute.String("processor", "processorhelper"), attribute.String("otel.signal", "traces")),
					},
				},
			},
		},
	})
}