package querynode

import (
	"context"
	"errors"
	"testing"

	"github.com/milvus-io/milvus/internal/common"
	"github.com/milvus-io/milvus/internal/proto/querypb"
	"github.com/milvus-io/milvus/internal/util/sessionutil"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"go.etcd.io/etcd/server/v3/etcdserver/api/v3client"
)

func TestShardClusterService(t *testing.T) {
	client := v3client.New(embedetcdServer.Server)
	defer client.Close()
	session := sessionutil.NewSession(context.Background(), "/by-dev/sessions/unittest/querynode/", client)
	clusterService := newShardClusterService(client, session, nil)

	assert.NotPanics(t, func() {
		clusterService.addShardCluster(defaultCollectionID, defaultReplicaID, defaultDMLChannel)
	})

	shardCluster, ok := clusterService.getShardCluster(defaultDMLChannel)
	assert.True(t, ok)
	assert.NotNil(t, shardCluster)

	_, ok = clusterService.getShardCluster("non-exist-channel")
	assert.False(t, ok)

	err := clusterService.releaseShardCluster(defaultDMLChannel)
	assert.NoError(t, err)

	err = clusterService.releaseShardCluster("non-exist-channel")
	assert.Error(t, err)
}

func TestShardClusterService_HandoffSegments(t *testing.T) {
	qn, err := genSimpleQueryNode(context.Background())
	require.NoError(t, err)

	client := v3client.New(embedetcdServer.Server)
	defer client.Close()
	session := sessionutil.NewSession(context.Background(), "/by-dev/sessions/unittest/querynode/", client)
	clusterService := newShardClusterService(client, session, qn)

	clusterService.addShardCluster(defaultCollectionID, defaultReplicaID, defaultDMLChannel)
	//TODO change shardCluster to interface to mock test behavior
	assert.NotPanics(t, func() {
		clusterService.HandoffSegments(defaultCollectionID, &querypb.SegmentChangeInfo{})
	})
}

func TestShardClusterService_SyncReplicaSegments(t *testing.T) {
	qn, err := genSimpleQueryNode(context.Background())
	require.NoError(t, err)

	client := v3client.New(embedetcdServer.Server)
	defer client.Close()
	session := sessionutil.NewSession(context.Background(), "/by-dev/sessions/unittest/querynode/", client)
	clusterService := newShardClusterService(client, session, qn)

	t.Run("sync non-exist shard cluster", func(t *testing.T) {
		err := clusterService.SyncReplicaSegments(defaultDMLChannel, nil)
		assert.Error(t, err)
	})

	t.Run("sync shard cluster", func(t *testing.T) {
		clusterService.addShardCluster(defaultCollectionID, defaultReplicaID, defaultDMLChannel)

		err := clusterService.SyncReplicaSegments(defaultDMLChannel, []*querypb.ReplicaSegmentsInfo{
			{
				NodeId:      1,
				PartitionId: defaultPartitionID,

				SegmentIds: []int64{1},
			},
		})

		assert.NoError(t, err)

		cs, ok := clusterService.getShardCluster(defaultDMLChannel)
		require.True(t, ok)
		segment, ok := cs.getSegment(1)
		assert.True(t, ok)
		assert.Equal(t, common.InvalidNodeID, segment.nodeID)
		assert.Equal(t, defaultPartitionID, segment.partitionID)
		assert.Equal(t, segmentStateLoaded, segment.state)
	})
}

func TestShardClusterService_HandoffVChannelSegments(t *testing.T) {
	qn, err := genSimpleQueryNode(context.Background())
	require.NoError(t, err)

	client := v3client.New(embedetcdServer.Server)
	defer client.Close()
	session := sessionutil.NewSession(context.Background(), "/by-dev/sessions/unittest/querynode/", client)
	clusterService := newShardClusterService(client, session, qn)

	err = clusterService.HandoffVChannelSegments(defaultDMLChannel, &querypb.SegmentChangeInfo{})
	assert.NoError(t, err)

	clusterService.addShardCluster(defaultCollectionID, defaultReplicaID, defaultDMLChannel)

	//TODO change shardCluster to interface to mock test behavior
	t.Run("normal case", func(t *testing.T) {
		assert.NotPanics(t, func() {
			err = clusterService.HandoffVChannelSegments(defaultDMLChannel, &querypb.SegmentChangeInfo{})
			assert.NoError(t, err)
		})

	})

	t.Run("error case", func(t *testing.T) {
		mqn := &mockShardQueryNode{}
		nodeEvents := []nodeEvent{
			{
				nodeID:   3,
				nodeAddr: "addr_3",
			},
		}

		sc := NewShardCluster(defaultCollectionID, defaultReplicaID, defaultDMLChannel,
			&mockNodeDetector{initNodes: nodeEvents}, &mockSegmentDetector{}, func(nodeID int64, addr string) shardQueryNode {
				return mqn
			})
		defer sc.Close()

		mqn.releaseSegmentsErr = errors.New("mocked error")

		// set mocked shard cluster
		clusterService.clusters.Store(defaultDMLChannel, sc)
		assert.NotPanics(t, func() {
			err = clusterService.HandoffVChannelSegments(defaultDMLChannel, &querypb.SegmentChangeInfo{
				OfflineSegments: []*querypb.SegmentInfo{
					{SegmentID: 1, NodeID: 3, CollectionID: defaultCollectionID, DmChannel: defaultDMLChannel, NodeIds: []UniqueID{3}},
				},
			})
			assert.Error(t, err)
		})
	})

}