1// Copyright 2012-2015 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
7import "errors"
8
9// CompletionSuggester is a fast suggester for e.g. type-ahead completion.
10// See http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-suggesters-completion.html
11// for more details.
12type CompletionSuggester struct {
13	Suggester
14	name           string
15	text           string
16	field          string
17	analyzer       string
18	size           *int
19	shardSize      *int
20	contextQueries []SuggesterContextQuery
21}
22
23// Creates a new completion suggester.
24func NewCompletionSuggester(name string) *CompletionSuggester {
25	return &CompletionSuggester{
26		name:           name,
27		contextQueries: make([]SuggesterContextQuery, 0),
28	}
29}
30
31func (q *CompletionSuggester) Name() string {
32	return q.name
33}
34
35func (q *CompletionSuggester) Text(text string) *CompletionSuggester {
36	q.text = text
37	return q
38}
39
40func (q *CompletionSuggester) Field(field string) *CompletionSuggester {
41	q.field = field
42	return q
43}
44
45func (q *CompletionSuggester) Analyzer(analyzer string) *CompletionSuggester {
46	q.analyzer = analyzer
47	return q
48}
49
50func (q *CompletionSuggester) Size(size int) *CompletionSuggester {
51	q.size = &size
52	return q
53}
54
55func (q *CompletionSuggester) ShardSize(shardSize int) *CompletionSuggester {
56	q.shardSize = &shardSize
57	return q
58}
59
60func (q *CompletionSuggester) ContextQuery(query SuggesterContextQuery) *CompletionSuggester {
61	q.contextQueries = append(q.contextQueries, query)
62	return q
63}
64
65func (q *CompletionSuggester) ContextQueries(queries ...SuggesterContextQuery) *CompletionSuggester {
66	q.contextQueries = append(q.contextQueries, queries...)
67	return q
68}
69
70// completionSuggesterRequest is necessary because the order in which
71// the JSON elements are routed to Elasticsearch is relevant.
72// We got into trouble when using plain maps because the text element
73// needs to go before the completion element.
74type completionSuggesterRequest struct {
75	Text       string      `json:"text"`
76	Completion interface{} `json:"completion"`
77}
78
79// Source creates the JSON structure for the completion suggester.
80func (q *CompletionSuggester) Source(includeName bool) (interface{}, error) {
81	cs := &completionSuggesterRequest{}
82
83	if q.text != "" {
84		cs.Text = q.text
85	}
86
87	suggester := make(map[string]interface{})
88	cs.Completion = suggester
89
90	if q.analyzer != "" {
91		suggester["analyzer"] = q.analyzer
92	}
93	if q.field != "" {
94		suggester["field"] = q.field
95	}
96	if q.size != nil {
97		suggester["size"] = *q.size
98	}
99	if q.shardSize != nil {
100		suggester["shard_size"] = *q.shardSize
101	}
102	switch len(q.contextQueries) {
103	case 0:
104	case 1:
105		src, err := q.contextQueries[0].Source()
106		if err != nil {
107			return nil, err
108		}
109		suggester["context"] = src
110	default:
111		ctxq := make(map[string]interface{})
112		for _, query := range q.contextQueries {
113			src, err := query.Source()
114			if err != nil {
115				return nil, err
116			}
117			// Merge the dictionary into ctxq
118			m, ok := src.(map[string]interface{})
119			if !ok {
120				return nil, errors.New("elastic: context query is not a map")
121			}
122			for k, v := range m {
123				ctxq[k] = v
124			}
125		}
126		suggester["context"] = ctxq
127	}
128
129	// TODO(oe) Add completion-suggester specific parameters here
130
131	if !includeName {
132		return cs, nil
133	}
134
135	source := make(map[string]interface{})
136	source[q.name] = cs
137	return source, nil
138}
139