// Copyright (C) 2019-2020 Zilliz. All rights reserved.
//
// 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 storage

import (
	"bytes"
	"crypto/rand"
	"encoding/binary"
	"testing"

	"github.com/milvus-io/milvus/internal/util/funcutil"
	"github.com/milvus-io/milvus/internal/util/uniquegenerator"

	"github.com/milvus-io/milvus/internal/kv"

	"github.com/stretchr/testify/assert"

	memkv "github.com/milvus-io/milvus/internal/kv/mem"
)

type mockLessHeaderDataKV struct {
}

func (kv *mockLessHeaderDataKV) Load(key string) (string, error) {
	panic("implement me")
}

func (kv *mockLessHeaderDataKV) MultiLoad(keys []string) ([]string, error) {
	panic("implement me")
}

func (kv *mockLessHeaderDataKV) LoadWithPrefix(key string) ([]string, []string, error) {
	panic("implement me")
}

func (kv *mockLessHeaderDataKV) Save(key, value string) error {
	panic("implement me")
}

func (kv *mockLessHeaderDataKV) MultiSave(kvs map[string]string) error {
	panic("implement me")
}

func (kv *mockLessHeaderDataKV) Remove(key string) error {
	panic("implement me")
}

func (kv *mockLessHeaderDataKV) MultiRemove(keys []string) error {
	panic("implement me")
}

func (kv *mockLessHeaderDataKV) RemoveWithPrefix(key string) error {
	panic("implement me")
}

func (kv *mockLessHeaderDataKV) Close() {
}

func (kv *mockLessHeaderDataKV) LoadPartial(key string, start, end int64) ([]byte, error) {
	header := &baseEventHeader{}

	headerSize := binary.Size(header)
	mockSize := headerSize - 1

	ret := make([]byte, mockSize)
	_, _ = rand.Read(ret)
	return ret, nil
}

func newMockLessHeaderDataKV() *mockLessHeaderDataKV {
	return &mockLessHeaderDataKV{}
}

type mockWrongHeaderDataKV struct {
}

func (kv *mockWrongHeaderDataKV) Load(key string) (string, error) {
	panic("implement me")
}

func (kv *mockWrongHeaderDataKV) MultiLoad(keys []string) ([]string, error) {
	panic("implement me")
}

func (kv *mockWrongHeaderDataKV) LoadWithPrefix(key string) ([]string, []string, error) {
	panic("implement me")
}

func (kv *mockWrongHeaderDataKV) Save(key, value string) error {
	panic("implement me")
}

func (kv *mockWrongHeaderDataKV) MultiSave(kvs map[string]string) error {
	panic("implement me")
}

func (kv *mockWrongHeaderDataKV) Remove(key string) error {
	panic("implement me")
}

func (kv *mockWrongHeaderDataKV) MultiRemove(keys []string) error {
	panic("implement me")
}

func (kv *mockWrongHeaderDataKV) RemoveWithPrefix(key string) error {
	panic("implement me")
}

func (kv *mockWrongHeaderDataKV) Close() {
	panic("implement me")
}

func (kv *mockWrongHeaderDataKV) LoadPartial(key string, start, end int64) ([]byte, error) {
	header := &baseEventHeader{}

	header.EventLength = -1
	header.NextPosition = -1

	buffer := bytes.Buffer{}
	_ = binary.Write(&buffer, binary.LittleEndian, header)

	return buffer.Bytes(), nil
}

func newMockWrongHeaderDataKV() kv.DataKV {
	return &mockWrongHeaderDataKV{}
}

func TestEstimateMemorySize(t *testing.T) {
	memoryKV := memkv.NewMemoryKV()
	defer memoryKV.Close()

	key := "TestEstimateMemorySize"

	var size int64
	var err error

	// key not in memoryKV
	size, err = EstimateMemorySize(memoryKV, key)
	assert.NoError(t, err)
	assert.Zero(t, size)

	// normal binlog key, for example, index binlog
	indexBuildID := UniqueID(uniquegenerator.GetUniqueIntGeneratorIns().GetInt())
	version := int64(uniquegenerator.GetUniqueIntGeneratorIns().GetInt())
	collectionID := UniqueID(uniquegenerator.GetUniqueIntGeneratorIns().GetInt())
	partitionID := UniqueID(uniquegenerator.GetUniqueIntGeneratorIns().GetInt())
	segmentID := UniqueID(uniquegenerator.GetUniqueIntGeneratorIns().GetInt())
	fieldID := UniqueID(uniquegenerator.GetUniqueIntGeneratorIns().GetInt())
	indexName := funcutil.GenRandomStr()
	indexID := UniqueID(uniquegenerator.GetUniqueIntGeneratorIns().GetInt())
	indexParams := make(map[string]string)
	indexParams["index_type"] = "IVF_FLAT"
	datas := []*Blob{
		{
			Key:   "ivf1",
			Value: []byte{1, 2, 3},
		},
		{
			Key:   "ivf2",
			Value: []byte{4, 5, 6},
		},
		{
			Key:   "large",
			Value: []byte(funcutil.RandomString(maxLengthPerRowOfIndexFile + 1)),
		},
	}

	codec := NewIndexFileBinlogCodec()
	defer codec.Close()

	serializedBlobs, err := codec.Serialize(indexBuildID, version, collectionID, partitionID, segmentID, fieldID, indexParams, indexName, indexID, datas)
	assert.Nil(t, err)

	for _, blob := range serializedBlobs {
		err = memoryKV.Save(blob.Key, string(blob.Value))
		assert.Nil(t, err)

		size, err = EstimateMemorySize(memoryKV, blob.Key)
		assert.Nil(t, err)
		assert.Equal(t, size+int64(binary.Size(MagicNumber)), int64(len(blob.Value)))
	}
}

// cover case that failed to read event header
func TestEstimateMemorySize_less_header(t *testing.T) {
	mockKV := newMockLessHeaderDataKV()

	key := "TestEstimateMemorySize_less_header"

	_, err := EstimateMemorySize(mockKV, key)
	assert.Error(t, err)
}

// cover case that file not in binlog format
func TestEstimateMemorySize_not_in_binlog_format(t *testing.T) {
	mockKV := newMockWrongHeaderDataKV()

	key := "TestEstimateMemorySize_not_in_binlog_format"

	_, err := EstimateMemorySize(mockKV, key)
	assert.Error(t, err)
}