1// Copyright 2012-present Oliver Eilhard. All rights reserved.
2// Use of this source code is governed by a MIT-license.
3// See http://olivere.mit-license.org/license.txt for details.
4
5package elastic
6
7// ChildrenAggregation is a special single bucket aggregation that enables
8// aggregating from buckets on parent document types to buckets on child documents.
9// It is available from 1.4.0.Beta1 upwards.
10// See: https://www.elastic.co/guide/en/elasticsearch/reference/6.7/search-aggregations-bucket-children-aggregation.html
11type ChildrenAggregation struct {
12	typ             string
13	subAggregations map[string]Aggregation
14	meta            map[string]interface{}
15}
16
17func NewChildrenAggregation() *ChildrenAggregation {
18	return &ChildrenAggregation{
19		subAggregations: make(map[string]Aggregation),
20	}
21}
22
23func (a *ChildrenAggregation) Type(typ string) *ChildrenAggregation {
24	a.typ = typ
25	return a
26}
27
28func (a *ChildrenAggregation) SubAggregation(name string, subAggregation Aggregation) *ChildrenAggregation {
29	a.subAggregations[name] = subAggregation
30	return a
31}
32
33// Meta sets the meta data to be included in the aggregation response.
34func (a *ChildrenAggregation) Meta(metaData map[string]interface{}) *ChildrenAggregation {
35	a.meta = metaData
36	return a
37}
38
39func (a *ChildrenAggregation) Source() (interface{}, error) {
40	// Example:
41	//	{
42	//    "aggs" : {
43	//      "to-answers" : {
44	//        "children": {
45	//          "type" : "answer"
46	//        }
47	//      }
48	//    }
49	//	}
50	// This method returns only the { "type" : ... } part.
51
52	source := make(map[string]interface{})
53	opts := make(map[string]interface{})
54	source["children"] = opts
55	opts["type"] = a.typ
56
57	// AggregationBuilder (SubAggregations)
58	if len(a.subAggregations) > 0 {
59		aggsMap := make(map[string]interface{})
60		source["aggregations"] = aggsMap
61		for name, aggregate := range a.subAggregations {
62			src, err := aggregate.Source()
63			if err != nil {
64				return nil, err
65			}
66			aggsMap[name] = src
67		}
68	}
69
70	// Add Meta data if available
71	if len(a.meta) > 0 {
72		source["meta"] = a.meta
73	}
74
75	return source, nil
76}
77