// Copyright 2019 getensh.com. All rights reserved.
// Use of this source code is governed by getensh.com.

package elastic

import (
	"context"
	"errors"
	"fmt"
	"strconv"
	"strings"

	"github.com/tidwall/gjson"
	elastic "gopkg.in/olivere/elastic.v5"
)

const (
	// 分割符
	delimiter = ","

	// 分页常量
	slideUp   = 1 // 向上滑动
	slideDown = 2 // 向下滑动
	positive  = 1 // 正序
	reverse   = 2 // 倒序
)

// SplitTopBottomData 分割分页的top/bottom
func SplitTopBottomData(param string) (base, num, extra int64, err error) {
	if param == "" {
		return 0.0, 0, 0.0, nil
	}

	mems := strings.Split(param, delimiter)
	switch {
	case len(mems) == 0:
		return 0.0, 0, 0.0, errors.New("member is not enough")
	case len(mems) == 1:
		base, _ = strconv.ParseInt(mems[0], 10, 64)
	case len(mems) == 2:
		if base, err = strconv.ParseInt(mems[0], 10, 64); err != nil {
			return 0.0, 0, 0.0, err
		} else {
			num, _ = strconv.ParseInt(mems[1], 10, 64)
		}
	case len(mems) >= 3:
		if base, err = strconv.ParseInt(mems[0], 10, 64); err != nil {
			return 0.0, 0, 0.0, err
		} else {
			num, _ = strconv.ParseInt(mems[1], 10, 64)
			extra, _ = strconv.ParseInt(mems[2], 10, 64)
		}
	default:
		return 0.0, 0, 0.0, nil
	}

	return
}

// JoinTopBottomData 组装分页的top/bottom
func JoinTopBottomData(base, num, extra int64) string {
	return fmt.Sprintf("%d%s%d%s%d", base, delimiter, num, delimiter, extra)
}

// ElasticSort 排序参数结构
type ElasticSort struct {
	Field string
	Asc   bool
}

// ElasticPageParam 分页参数
type ElasticPageParam struct {
	Indexs       []string
	Types        []string
	Match        map[string]string
	Query        elastic.Query
	Sorts        []ElasticSort
	GeoSort      *elastic.GeoDistanceSort
	Size         uint32   // 单次拉取条数
	Slide        uint32   // 滑动方向 1: 向上滑动 2:向下滑动
	Top          string   // 页首数据
	Bottom       string   // 页尾数据
	SequenceType uint32   // 1:正序 2:反序
	BaseFilter   string   // 基础过滤域, 默认为"timestamp"
	ExtraFilter  string   // 附加过滤域
	Includes     []string // includes, 要获取的字段名列表
	Excludes     []string // excludes，不获取的字段名列表
}

// ElasticCountParam 计数参数
type ElasticCountParam struct {
	Indexs []string
	Types  []string
	Match  map[string]string
	Query  elastic.Query
}

// ElasticSumParam 取和参数
type ElasticSumParam struct {
	Indexs    []string
	Types     []string
	Match     map[string]string
	Query     elastic.Query
	AggFields map[string]string
}

// ElasticRandomParam 随机取多条数据
type ElasticRandomParam struct {
	Indexs      []string
	Types       []string
	Query       elastic.Query
	GeoSort     *elastic.GeoDistanceSort
	Size        uint32   // 单次拉取条数
	BaseFilter  string   // 基础过滤域, 默认为"timestamp"
	ExtraFilter string   // 附加过滤域
	OtherKeys   []string // 需要的其它key, 如target
}

// ElasticHit 结果参数
type ElasticHit struct {
	Index  string
	Type   string
	ID     string
	Base   int64
	Extra  int64
	Source string
}

// PageResult 分页结果
type PageResult struct {
	Top        string
	Bottom     string
	HasMore    bool
	TotalCount uint64
	Hits       []ElasticHit
}

// RandomResult 随机结果
type RandomResult struct {
	TotalCount uint64
	Hits       []ElasticHit
}

// GetPageFromElastic 从elastic中读单面数据
func GetPageFromElastic(param *ElasticPageParam) (result PageResult, err error) {
	// 参数检查
	if client == nil || param == nil {
		return result, fmt.Errorf("client or param is nil.")
	}
	if len(param.Indexs) <= 0 || len(param.Types) <= 0 {
		return result, fmt.Errorf("Invalid es params. %v", param)
	}

	// 支持多个索引和type查询
	searchServer := client.Search()
	if len(param.Indexs) > 0 {
		searchServer = searchServer.Index(param.Indexs...)
	}
	if len(param.Types) > 0 {
		searchServer = searchServer.Type(param.Types...)
	}

	// 解析top
	topTime, topSameNum, topExtra, err := SplitTopBottomData(param.Top)
	if err != nil {
		return result, err
	}

	// 解析bottom
	botTime, botSameNum, botExtra, err := SplitTopBottomData(param.Bottom)
	if err != nil {
		return result, err
	}

	// 默认为"timestamp"
	if param.BaseFilter == "" {
		param.BaseFilter = "timestamp"
	}

	if len(param.Includes) > 0 || len(param.Excludes) > 0 {
		fetchSourceContext := elastic.NewFetchSourceContext(true)
		if len(param.Includes) > 0 {
			fetchSourceContext.Include(param.Includes...)
		}
		if len(param.Excludes) > 0 {
			fetchSourceContext.Exclude(param.Excludes...)
		}
		searchServer = searchServer.FetchSourceContext(fetchSourceContext)
	}

	// 组装match条件
	// 注意: Match 与 Query 互斥
	boolQuery := elastic.NewBoolQuery()
	if len(param.Match) == 0 {
		if param.Query != nil {
			boolQuery = boolQuery.Must(param.Query)
		} else {
			boolQuery = boolQuery.Must(elastic.NewMatchAllQuery())
		}
	} else {
		for key, value := range param.Match {
			boolQuery = boolQuery.Must(elastic.NewMatchQuery(key, value))
		}
	}

	// 按具体字段排序
	if len(param.Sorts) > 0 {
		for _, s := range param.Sorts {
			searchServer = searchServer.Sort(s.Field, s.Asc)
		}
	}

	// 位置排序
	if param.GeoSort != nil {
		searchServer = searchServer.SortBy(param.GeoSort)
	}

	topRemove := true
	removeCount := uint32(0)
	count := uint32(0)
	positiveFlag := true
	switch param.Slide {
	case slideDown:
		switch param.SequenceType {
		case positive:
			// 正序向下滑 timestamp >=0
			if topTime == 0 {
				// timestamp >= 0   正序排列
				if param.ExtraFilter != "" {
					searchServer = searchServer.Sort(param.ExtraFilter, true)
					boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.ExtraFilter).Gte(0))
				}
				boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.BaseFilter).Gte(0))
				searchServer = searchServer.Sort(param.BaseFilter, true)
			} else {
				// timestamp <= top 倒序排列
				if param.ExtraFilter != "" {
					searchServer = searchServer.Sort(param.ExtraFilter, false)
					boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.ExtraFilter).Lte(topExtra))
				}
				boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.BaseFilter).Lte(topTime))
				searchServer = searchServer.Sort(param.BaseFilter, false)
				positiveFlag = false
			}
		default:
			// 倒序向下滑
			if topTime == 0 {
				// timestamp >= 0 倒序排列
				if param.ExtraFilter != "" {
					searchServer = searchServer.Sort(param.ExtraFilter, false)
					boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.ExtraFilter).Gte(0))
				}
				boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.BaseFilter).Gte(0))
				searchServer = searchServer.Sort(param.BaseFilter, false)
			} else {
				// timestamp >= top 倒序排列
				if param.ExtraFilter != "" {
					searchServer = searchServer.Sort(param.ExtraFilter, false)
					boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.ExtraFilter).Gte(topExtra))
				}
				boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.BaseFilter).Gte(topTime))
				searchServer = searchServer.Sort(param.BaseFilter, false)
			}
		}

		// 删除的数量
		removeCount = uint32(topSameNum)
		// 需要拉取的条数
		count = removeCount + param.Size
		// 去掉头部相同数据
		topRemove = false

	default:
		switch param.SequenceType {
		case positive:
			// 正序向上滑
			if botTime == 0 {
				// timestamp >= 0 正序排序
				if param.ExtraFilter != "" {
					boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.ExtraFilter).Gte(0))
					searchServer = searchServer.Sort(param.ExtraFilter, true)
				}
				boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.BaseFilter).Gte(0))
				searchServer = searchServer.Sort(param.BaseFilter, true)
			} else {
				// timestamp >= bot 正序排序
				if param.ExtraFilter != "" {
					boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.ExtraFilter).Gte(botExtra))
					searchServer = searchServer.Sort(param.ExtraFilter, true)
				}
				boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.BaseFilter).Gte(botTime))
				searchServer = searchServer.Sort(param.BaseFilter, true)
			}
		default:
			// 倒序向上滑
			if botTime == 0 {
				// timestamp >= 0 倒序排序
				if param.ExtraFilter != "" {
					boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.ExtraFilter).Gte(0))
					searchServer = searchServer.Sort(param.ExtraFilter, false)
				}
				boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.BaseFilter).Gte(0))
				searchServer = searchServer.Sort(param.BaseFilter, false)
			} else {
				// timestamp <= bot 倒序排序
				if param.ExtraFilter != "" {
					boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.ExtraFilter).Lte(botExtra))
					searchServer = searchServer.Sort(param.ExtraFilter, false)
				}
				boolQuery = boolQuery.Filter(elastic.NewRangeQuery(param.BaseFilter).Lte(botTime))
				searchServer = searchServer.Sort(param.BaseFilter, false)
			}
		}

		// 删除的数量
		removeCount = uint32(botSameNum)
		// 需要拉取的条数
		count = removeCount + param.Size
	}

	// 执行搜索
	searchServer = searchServer.From(0).Size(int(count))
	res, err := searchServer.Query(boolQuery).Do(context.Background())
	if err != nil {
		return result, err
	}

	result.Hits = make([]ElasticHit, 0, len(res.Hits.Hits))
	if res != nil && res.Hits != nil && len(res.Hits.Hits) > 0 {
		result.HasMore = res.Hits.TotalHits > int64(count)
		if res.Hits.TotalHits > int64(removeCount) {
			result.TotalCount = uint64(res.Hits.TotalHits - int64(removeCount))
		}
		for _, hit := range res.Hits.Hits {
			if hit.Source != nil {
				result.Hits = append(result.Hits, ElasticHit{
					ID:     hit.Id,
					Index:  hit.Index,
					Type:   hit.Type,
					Base:   gjson.GetBytes(*hit.Source, param.BaseFilter).Int(),
					Extra:  gjson.GetBytes(*hit.Source, param.ExtraFilter).Int(),
					Source: string(*hit.Source),
				})
			}
		}
	}

	// 计算top与bottom
	length := len(result.Hits)
	if length > 0 {
		// 检查 删除数据比查找到的数据要多直接返回空
		if length <= int(removeCount) {
			return PageResult{}, nil
		}

		// 倒序
		if !positiveFlag {
			//需要倒序结果 对其数据进行正序
			for i := 0; i < length/2; i++ {
				result.Hits[i], result.Hits[length-1-i] = result.Hits[length-1-i], result.Hits[i]
			}
		}

		topBase := result.Hits[0].Base
		topExtra := result.Hits[0].Extra
		botBase := result.Hits[length-1].Base
		botExtra := result.Hits[length-1].Extra

		// 去掉上一次访问过的数据
		if topRemove {
			// 去掉头部
			result.Hits = result.Hits[removeCount:]
		} else {
			// 去掉尾部
			result.Hits = result.Hits[:length-int(removeCount)]
		}

		// 对重复数据删除后的处理时需要重新计算length与topbase/botbase等, 否则会可能内存越界
		length = len(result.Hits)
		if length > 0 {
			topBase = result.Hits[0].Base
			topExtra = result.Hits[0].Extra
			botBase = result.Hits[length-1].Base
			botExtra = result.Hits[length-1].Extra
		}
		topNum := int64(0)
		bottomNum := int64(0)

		for _, item := range result.Hits {
			if item.Base == topBase {
				topNum += 1
			} else {
				break
			}
		}

		for i := length - 1; i >= 0; i -= 1 {
			if result.Hits[i].Base == botBase {
				bottomNum += 1
			} else {
				break
			}
		}

		result.Top = JoinTopBottomData(topBase, topNum, topExtra)
		result.Bottom = JoinTopBottomData(botBase, bottomNum, botExtra)
	}

	return result, nil
}

// GetPageFromElasticByIndex 索引取分页，类似于mysql的 from to 分页
func GetPageFromElasticByIndex(param *ElasticPageParam) (result PageResult, err error) {
	// 参数检查
	if client == nil || param == nil {
		return result, fmt.Errorf("client or param is nil.")
	}
	if len(param.Indexs) <= 0 || len(param.Types) <= 0 {
		return result, fmt.Errorf("Invalid es params. %v", param)
	}

	// 支持多个索引和type查询
	searchServer := client.Search()
	if len(param.Indexs) > 0 {
		searchServer = searchServer.Index(param.Indexs...)
	}
	if len(param.Types) > 0 {
		searchServer = searchServer.Type(param.Types...)
	}

	// 组装match条件
	// 注意: Match 与 Query 互斥
	boolQuery := elastic.NewBoolQuery()
	if len(param.Match) == 0 {
		if param.Query != nil {
			boolQuery = boolQuery.Must(param.Query)
		} else {
			boolQuery = boolQuery.Must(elastic.NewMatchAllQuery())
		}
	} else {
		for key, value := range param.Match {
			boolQuery = boolQuery.Must(elastic.NewMatchQuery(key, value))
		}
	}

	if len(param.Sorts) > 0 {
		for _, s := range param.Sorts {
			searchServer = searchServer.Sort(s.Field, s.Asc)
		}
	}

	if param.GeoSort != nil {
		searchServer = searchServer.SortBy(param.GeoSort)
	}

	// 解析top
	from, _, _, err := SplitTopBottomData(param.Bottom)
	if err != nil {
		return result, err
	}

	searchServer = searchServer.From(int(from)).Size(int(param.Size))
	res, err := searchServer.Query(boolQuery).Do(context.Background())
	if err != nil {
		return result, err
	}

	result.Hits = make([]ElasticHit, 0, len(res.Hits.Hits))
	if res != nil && res.Hits != nil && len(res.Hits.Hits) > 0 {
		result.HasMore = res.Hits.TotalHits > int64(param.Size)
		result.TotalCount = uint64(res.Hits.TotalHits)
		for _, hit := range res.Hits.Hits {
			if hit.Source != nil {
				result.Hits = append(result.Hits, ElasticHit{
					ID:     hit.Id,
					Index:  hit.Index,
					Type:   hit.Type,
					Source: string(*hit.Source),
				})
			}
		}
	}

	// 计算top与bottom
	len := int64(len(result.Hits))
	if len > 0 {
		result.Top = JoinTopBottomData(from, 0, 0)
		result.Bottom = JoinTopBottomData(from+len, 0, 0)
	}

	return result, nil
}

// GetSumFromElastic 取和函数
func GetSumFromElastic(param *ElasticSumParam) (map[string]int64, error) {
	// 参数检查
	if client == nil || param == nil {
		return nil, fmt.Errorf("client or param is nil.")
	}
	if len(param.Indexs) <= 0 || len(param.Types) <= 0 {
		return nil, fmt.Errorf("Invalid es params. %v", param)
	}

	// 支持多个索引和type查询
	searchServer := client.Search()
	if len(param.Indexs) > 0 {
		searchServer = searchServer.Index(param.Indexs...)
	}
	if len(param.Types) > 0 {
		searchServer = searchServer.Type(param.Types...)
	}

	// 组装要汇总的参数字段
	for key, field := range param.AggFields {
		agg := elastic.NewSumAggregation().Field(field)
		searchServer = searchServer.Aggregation(key, agg)
	}

	// 开始查询
	res, err := searchServer.Query(param.Query).Do(context.Background())
	if err != nil {
		return nil, err
	}

	// 取出结果
	result := make(map[string]int64, len(param.AggFields))
	if res != nil && res.Hits != nil && len(res.Hits.Hits) > 0 {
		agg := res.Aggregations
		if agg != nil {
			for k, v := range agg {
				result[k] = gjson.GetBytes(*v, "value").Int()
			}

		}
	}

	return result, nil
}

// GetCountFromElastic 计数函数
func GetCountFromElastic(param *ElasticCountParam) (int64, error) {
	// 参数检查
	if client == nil || param == nil {
		return 0, fmt.Errorf("client or param is nil.")
	}
	if len(param.Indexs) <= 0 || len(param.Types) <= 0 {
		return 0, fmt.Errorf("Invalid es params. %v", param)
	}

	return client.Count(param.Indexs...).Type(param.Types...).Query(param.Query).Do(context.TODO())
}

// GGetRandomFromElastic 随机取多条数据函数
func GetRandomFromElastic(param *ElasticRandomParam) (result RandomResult, err error) {
	// 参数检查
	if client == nil || param == nil {
		return result, fmt.Errorf("client or param is nil.")
	}
	if len(param.Indexs) <= 0 || len(param.Types) <= 0 {
		return result, fmt.Errorf("Invalid es params. %v", param)
	}

	// 支持多个索引和type查询
	searchServer := client.Search()
	if len(param.Indexs) > 0 {
		searchServer = searchServer.Index(param.Indexs...)
	}
	if len(param.Types) > 0 {
		searchServer = searchServer.Type(param.Types...)
	}

	if param.GeoSort != nil {
		searchServer = searchServer.SortBy(param.GeoSort)
	}

	searchServer = searchServer.Size(int(param.Size))
	res, err := searchServer.Query(param.Query).Do(context.Background())
	if err != nil {
		return result, err
	}

	result.Hits = make([]ElasticHit, 0, len(res.Hits.Hits))
	if res != nil && res.Hits != nil && len(res.Hits.Hits) > 0 {
		result.TotalCount = uint64(res.Hits.TotalHits)
		for _, hit := range res.Hits.Hits {
			if hit.Source != nil {
				result.Hits = append(result.Hits, ElasticHit{
					ID:     hit.Id,
					Index:  hit.Index,
					Type:   hit.Type,
					Source: string(*hit.Source),
				})
			}
		}
	}

	return result, nil
}