// Copyright The OpenTelemetry Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package tracetest

import (
	"context"
	"sync"
	"testing"

	"github.com/stretchr/testify/assert"

	sdktrace "go.opentelemetry.io/otel/sdk/trace"
)

type rwSpan struct {
	sdktrace.ReadWriteSpan
}

func TestSpanRecorderOnStartAppends(t *testing.T) {
	s0, s1 := new(rwSpan), new(rwSpan)
	ctx := context.Background()
	sr := new(SpanRecorder)

	assert.Len(t, sr.started, 0)
	sr.OnStart(ctx, s0)
	assert.Len(t, sr.started, 1)
	sr.OnStart(ctx, s1)
	assert.Len(t, sr.started, 2)

	// Ensure order correct.
	started := sr.Started()
	assert.Same(t, s0, started[0])
	assert.Same(t, s1, started[1])
}

type roSpan struct {
	sdktrace.ReadOnlySpan
}

func TestSpanRecorderOnEndAppends(t *testing.T) {
	s0, s1 := new(roSpan), new(roSpan)
	sr := new(SpanRecorder)

	assert.Len(t, sr.ended, 0)
	sr.OnEnd(s0)
	assert.Len(t, sr.ended, 1)
	sr.OnEnd(s1)
	assert.Len(t, sr.ended, 2)

	// Ensure order correct.
	ended := sr.Ended()
	assert.Same(t, s0, ended[0])
	assert.Same(t, s1, ended[1])
}

func TestSpanRecorderShutdownNoError(t *testing.T) {
	ctx := context.Background()
	assert.NoError(t, new(SpanRecorder).Shutdown(ctx))

	var c context.CancelFunc
	ctx, c = context.WithCancel(ctx)
	c()
	assert.NoError(t, new(SpanRecorder).Shutdown(ctx))
}

func TestSpanRecorderForceFlushNoError(t *testing.T) {
	ctx := context.Background()
	assert.NoError(t, new(SpanRecorder).ForceFlush(ctx))

	var c context.CancelFunc
	ctx, c = context.WithCancel(ctx)
	c()
	assert.NoError(t, new(SpanRecorder).ForceFlush(ctx))
}

func runConcurrently(funcs ...func()) {
	var wg sync.WaitGroup

	for _, f := range funcs {
		wg.Add(1)
		go func(f func()) {
			f()
			wg.Done()
		}(f)
	}

	wg.Wait()
}

func TestEndingConcurrentSafe(t *testing.T) {
	sr := NewSpanRecorder()

	runConcurrently(
		func() { sr.OnEnd(new(roSpan)) },
		func() { sr.OnEnd(new(roSpan)) },
		func() { sr.Ended() },
	)

	assert.Len(t, sr.Ended(), 2)
}

func TestStartingConcurrentSafe(t *testing.T) {
	sr := NewSpanRecorder()

	ctx := context.Background()
	runConcurrently(
		func() { sr.OnStart(ctx, new(rwSpan)) },
		func() { sr.OnStart(ctx, new(rwSpan)) },
		func() { sr.Started() },
	)

	assert.Len(t, sr.Started(), 2)
}