/*
   Copyright The containerd 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 integration

import (
	"context"
	"fmt"
	"testing"
	"time"

	"github.com/containerd/containerd/integration/images"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	runtime "k8s.io/cri-api/pkg/apis/runtime/v1"
)

const (
	drainContainerEventChannelTimeout = 2 * time.Second
	readContainerEventChannelTimeout  = 10 * time.Second
)

func TestContainerEvents(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	t.Cleanup(cancel)

	t.Log("Set up container events streaming client")
	containerEventsStreamingClient, err := runtimeService.GetContainerEvents(ctx, &runtime.GetEventsRequest{})
	assert.NoError(t, err)
	containerEventsChan := make(chan *runtime.ContainerEventResponse)

	go listenToEventChannel(ctx, t, containerEventsChan, containerEventsStreamingClient)
	// drain all events emitted by previous tests.
	drainContainerEventsChan(containerEventsChan)

	t.Logf("Step 1: RunPodSandbox and check for expected events")
	sandboxName := "container_events_sandbox"
	sbConfig := PodSandboxConfig(sandboxName, "container_events")

	sb, err := runtimeService.RunPodSandbox(sbConfig, *runtimeHandler)
	require.NoError(t, err)
	t.Cleanup(func() {
		expectedContainerStates := []runtime.ContainerState{}
		expectedPodSandboxStatus := &runtime.PodSandboxStatus{State: runtime.PodSandboxState_SANDBOX_NOTREADY}
		t.Logf("Step 6: StopPodSandbox and check events")
		assert.NoError(t, runtimeService.StopPodSandbox(sb))
		checkContainerEventResponse(t, containerEventsChan, runtime.ContainerEventType_CONTAINER_STOPPED_EVENT, expectedPodSandboxStatus, expectedContainerStates)
		t.Logf("Step 7: RemovePodSandbox and check events")
		assert.NoError(t, runtimeService.RemovePodSandbox(sb))
		checkContainerEventResponse(t, containerEventsChan, runtime.ContainerEventType_CONTAINER_DELETED_EVENT, nil, expectedContainerStates)
	})

	// PodSandbox ready, container state list empty
	expectedPodSandboxStatus := &runtime.PodSandboxStatus{State: runtime.PodSandboxState_SANDBOX_READY}
	expectedContainerStates := []runtime.ContainerState{}
	// PodSandbox created. Check for start event for podsandbox container. Should be zero containers in the podsandbox
	checkContainerEventResponse(t, containerEventsChan, runtime.ContainerEventType_CONTAINER_CREATED_EVENT, expectedPodSandboxStatus, expectedContainerStates)
	// PodSandbox started. Check for start event for podsandbox container. Should be zero containers in the podsandbox
	checkContainerEventResponse(t, containerEventsChan, runtime.ContainerEventType_CONTAINER_STARTED_EVENT, expectedPodSandboxStatus, expectedContainerStates)

	t.Logf("Step 2: CreateContainer and check events")
	pauseImage := images.Get(images.Pause)
	EnsureImageExists(t, pauseImage)
	containerConfig := ContainerConfig(
		"container1",
		pauseImage,
		WithTestLabels(),
		WithTestAnnotations(),
	)
	cn, err := runtimeService.CreateContainer(sb, containerConfig, sbConfig)
	require.NoError(t, err)
	expectedContainerStates = []runtime.ContainerState{runtime.ContainerState_CONTAINER_CREATED}
	checkContainerEventResponse(t, containerEventsChan, runtime.ContainerEventType_CONTAINER_CREATED_EVENT, expectedPodSandboxStatus, expectedContainerStates)

	t.Cleanup(func() {
		t.Logf("Step 5: RemoveContainer and check events")
		assert.NoError(t, runtimeService.RemoveContainer(cn))
		// No container status after the container is removed
		expectedContainerStates := []runtime.ContainerState{}
		checkContainerEventResponse(t, containerEventsChan, runtime.ContainerEventType_CONTAINER_DELETED_EVENT, expectedPodSandboxStatus, expectedContainerStates)
	})

	t.Logf("Step 3: StartContainer and check events")
	require.NoError(t, runtimeService.StartContainer(cn))
	expectedContainerStates = []runtime.ContainerState{runtime.ContainerState_CONTAINER_RUNNING}
	checkContainerEventResponse(t, containerEventsChan, runtime.ContainerEventType_CONTAINER_STARTED_EVENT, expectedPodSandboxStatus, expectedContainerStates)

	t.Cleanup(func() {
		t.Logf("Step 4: StopContainer and check events")
		assert.NoError(t, runtimeService.StopContainer(cn, 10))
		expectedContainerStates := []runtime.ContainerState{runtime.ContainerState_CONTAINER_EXITED}
		checkContainerEventResponse(t, containerEventsChan, runtime.ContainerEventType_CONTAINER_STOPPED_EVENT, expectedPodSandboxStatus, expectedContainerStates)
	})
}

func listenToEventChannel(ctx context.Context, t *testing.T, containerEventsChan chan *runtime.ContainerEventResponse, containerEventsStreamingClient runtime.RuntimeService_GetContainerEventsClient) {
	t.Helper()
	for {
		resp, err := containerEventsStreamingClient.Recv()
		// Early return if context is canceled, in which case the error will be
		// context canceled
		select {
		case <-ctx.Done():
			return
		default:
		}
		assert.NoError(t, err)
		if resp != nil {
			containerEventsChan <- resp
		}
	}
}

func drainContainerEventsChan(containerEventsChan chan *runtime.ContainerEventResponse) {
	for {
		select {
		case <-containerEventsChan:
		case <-time.After(drainContainerEventChannelTimeout):
			return
		}
	}
}

func checkContainerEventResponse(t *testing.T, containerEventsChan chan *runtime.ContainerEventResponse, expectedType runtime.ContainerEventType, expectedPodSandboxStatus *runtime.PodSandboxStatus, expectedContainerStates []runtime.ContainerState) error {
	t.Helper()
	var resp *runtime.ContainerEventResponse
	select {
	case resp = <-containerEventsChan:
	case <-time.After(readContainerEventChannelTimeout):
		return fmt.Errorf("assertContainerEventResponse: timeout waiting for events from channel")
	}
	t.Logf("Container Event response received: %+v", *resp)
	assert.Equal(t, expectedType, resp.ContainerEventType)

	// Checking only the State field of PodSandboxStatus
	if expectedPodSandboxStatus == nil {
		assert.Nil(t, resp.PodSandboxStatus)
	} else {
		assert.Equal(t, expectedPodSandboxStatus.State, resp.PodSandboxStatus.State)
	}

	// Checking only the State field of ContainersStatus
	for i, cs := range resp.ContainersStatuses {
		assert.Equal(t, expectedContainerStates[i], cs.State)
	}
	return nil
}