package proxy

import (
	"log"
	"sort"

	"github.com/zilliztech/milvus-distributed/internal/allocator"
	"github.com/zilliztech/milvus-distributed/internal/errors"
	"github.com/zilliztech/milvus-distributed/internal/msgstream"
	"github.com/zilliztech/milvus-distributed/internal/proto/commonpb"
	"github.com/zilliztech/milvus-distributed/internal/proto/internalpb"
)

func insertRepackFunc(tsMsgs []msgstream.TsMsg,
	hashKeys [][]int32,
	segIDAssigner *allocator.SegIDAssigner,
	together bool) (map[int32]*msgstream.MsgPack, error) {

	result := make(map[int32]*msgstream.MsgPack)

	channelCountMap := make(map[UniqueID]map[int32]uint32) //  reqID --> channelID to count
	reqSchemaMap := make(map[UniqueID][]string)

	for i, request := range tsMsgs {
		if request.Type() != internalpb.MsgType_kInsert {
			return nil, errors.New(string("msg's must be Insert"))
		}
		insertRequest, ok := request.(*msgstream.InsertMsg)
		if !ok {
			return nil, errors.New(string("msg's must be Insert"))
		}

		keys := hashKeys[i]
		timestampLen := len(insertRequest.Timestamps)
		rowIDLen := len(insertRequest.RowIDs)
		rowDataLen := len(insertRequest.RowData)
		keysLen := len(keys)

		if keysLen != timestampLen || keysLen != rowIDLen || keysLen != rowDataLen {
			return nil, errors.New(string("the length of hashValue, timestamps, rowIDs, RowData are not equal"))
		}

		reqID := insertRequest.ReqID
		if _, ok := channelCountMap[reqID]; !ok {
			channelCountMap[reqID] = make(map[int32]uint32)
		}

		if _, ok := reqSchemaMap[reqID]; !ok {
			reqSchemaMap[reqID] = []string{insertRequest.CollectionName, insertRequest.PartitionTag}
		}

		for _, channelID := range keys {
			channelCountMap[reqID][channelID]++
		}

	}

	reqSegCountMap := make(map[UniqueID]map[int32]map[UniqueID]uint32)

	for reqID, countInfo := range channelCountMap {
		if _, ok := reqSegCountMap[reqID]; !ok {
			reqSegCountMap[reqID] = make(map[int32]map[UniqueID]uint32)
		}
		schema := reqSchemaMap[reqID]
		collName, partitionTag := schema[0], schema[1]
		for channelID, count := range countInfo {
			mapInfo, err := segIDAssigner.GetSegmentID(collName, partitionTag, channelID, count)
			if err != nil {
				return nil, err
			}
			reqSegCountMap[reqID][channelID] = make(map[UniqueID]uint32)
			reqSegCountMap[reqID][channelID] = mapInfo
		}
	}

	reqSegAccumulateCountMap := make(map[UniqueID]map[int32][]uint32)
	reqSegIDMap := make(map[UniqueID]map[int32][]UniqueID)
	reqSegAllocateCounter := make(map[UniqueID]map[int32]uint32)

	for reqID, channelInfo := range reqSegCountMap {
		if _, ok := reqSegAccumulateCountMap[reqID]; !ok {
			reqSegAccumulateCountMap[reqID] = make(map[int32][]uint32)
		}
		if _, ok := reqSegIDMap[reqID]; !ok {
			reqSegIDMap[reqID] = make(map[int32][]UniqueID)
		}
		if _, ok := reqSegAllocateCounter[reqID]; !ok {
			reqSegAllocateCounter[reqID] = make(map[int32]uint32)
		}
		for channelID, segInfo := range channelInfo {
			reqSegAllocateCounter[reqID][channelID] = 0
			keys := make([]UniqueID, len(segInfo))
			i := 0
			for key := range segInfo {
				keys[i] = key
				i++
			}
			sort.Slice(keys, func(i, j int) bool { return keys[i] < keys[j] })
			accumulate := uint32(0)
			for _, key := range keys {
				accumulate += segInfo[key]
				if _, ok := reqSegAccumulateCountMap[reqID][channelID]; !ok {
					reqSegAccumulateCountMap[reqID][channelID] = make([]uint32, 0)
				}
				reqSegAccumulateCountMap[reqID][channelID] = append(
					reqSegAccumulateCountMap[reqID][channelID],
					accumulate,
				)
				if _, ok := reqSegIDMap[reqID][channelID]; !ok {
					reqSegIDMap[reqID][channelID] = make([]UniqueID, 0)
				}
				reqSegIDMap[reqID][channelID] = append(
					reqSegIDMap[reqID][channelID],
					key,
				)
			}
		}
	}

	var getSegmentID = func(reqID UniqueID, channelID int32) UniqueID {
		reqSegAllocateCounter[reqID][channelID]++
		cur := reqSegAllocateCounter[reqID][channelID]
		accumulateSlice := reqSegAccumulateCountMap[reqID][channelID]
		segIDSlice := reqSegIDMap[reqID][channelID]
		for index, count := range accumulateSlice {
			if cur <= count {
				return segIDSlice[index]
			}
		}
		log.Panic("Can't Found SegmentID")
		return 0
	}

	for i, request := range tsMsgs {
		insertRequest := request.(*msgstream.InsertMsg)
		keys := hashKeys[i]
		reqID := insertRequest.ReqID
		collectionName := insertRequest.CollectionName
		partitionTag := insertRequest.PartitionTag
		proxyID := insertRequest.ProxyID
		for index, key := range keys {
			ts := insertRequest.Timestamps[index]
			rowID := insertRequest.RowIDs[index]
			row := insertRequest.RowData[index]
			_, ok := result[key]
			if !ok {
				msgPack := msgstream.MsgPack{}
				result[key] = &msgPack
			}
			segmentID := getSegmentID(reqID, key)
			sliceRequest := internalpb.InsertRequest{
				MsgType:        internalpb.MsgType_kInsert,
				ReqID:          reqID,
				CollectionName: collectionName,
				PartitionTag:   partitionTag,
				SegmentID:      segmentID,
				ChannelID:      int64(key),
				ProxyID:        proxyID,
				Timestamps:     []uint64{ts},
				RowIDs:         []int64{rowID},
				RowData:        []*commonpb.Blob{row},
			}
			insertMsg := &msgstream.InsertMsg{
				InsertRequest: sliceRequest,
			}
			if together { // all rows with same hash value are accumulated to only one message
				if len(result[key].Msgs) <= 0 {
					result[key].Msgs = append(result[key].Msgs, insertMsg)
				} else {
					accMsgs, _ := result[key].Msgs[0].(*msgstream.InsertMsg)
					accMsgs.Timestamps = append(accMsgs.Timestamps, ts)
					accMsgs.RowIDs = append(accMsgs.RowIDs, rowID)
					accMsgs.RowData = append(accMsgs.RowData, row)
				}
			} else { // every row is a message
				result[key].Msgs = append(result[key].Msgs, insertMsg)
			}
		}
	}

	return result, nil
}