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// ConstantScoreQuery is a query that wraps a filter and simply returns
8// a constant score equal to the query boost for every document in the filter.
9//
10// For more details, see:
11// https://www.elastic.co/guide/en/elasticsearch/reference/5.2/query-dsl-constant-score-query.html
12type ConstantScoreQuery struct {
13	filter Query
14	boost  *float64
15}
16
17// ConstantScoreQuery creates and initializes a new constant score query.
18func NewConstantScoreQuery(filter Query) *ConstantScoreQuery {
19	return &ConstantScoreQuery{
20		filter: filter,
21	}
22}
23
24// Boost sets the boost for this query. Documents matching this query
25// will (in addition to the normal weightings) have their score multiplied
26// by the boost provided.
27func (q *ConstantScoreQuery) Boost(boost float64) *ConstantScoreQuery {
28	q.boost = &boost
29	return q
30}
31
32// Source returns the query source.
33func (q *ConstantScoreQuery) Source() (interface{}, error) {
34	// "constant_score" : {
35	//     "filter" : {
36	//         ....
37	//     },
38	//     "boost" : 1.5
39	// }
40
41	query := make(map[string]interface{})
42
43	params := make(map[string]interface{})
44	query["constant_score"] = params
45
46	// filter
47	src, err := q.filter.Source()
48	if err != nil {
49		return nil, err
50	}
51	params["filter"] = src
52
53	// boost
54	if q.boost != nil {
55		params["boost"] = *q.boost
56	}
57
58	return query, nil
59}
60