1package kv
2
3import (
4	"path"
5	"reflect"
6
7	"github.com/kvtools/valkeyrie/store"
8	"github.com/traefik/paerser/parser"
9)
10
11// Decode decodes the given KV pairs into the given element.
12// The operation goes through three stages roughly summarized as:
13// KV pairs -> tree of untyped nodes
14// untyped nodes -> nodes augmented with metadata such as kind (inferred from element)
15// "typed" nodes -> typed element.
16func Decode(pairs []*store.KVPair, element interface{}, rootName string) error {
17	if element == nil {
18		return nil
19	}
20
21	filters := getRootFieldNames(rootName, element)
22
23	node, err := DecodeToNode(pairs, rootName, filters...)
24	if err != nil {
25		return err
26	}
27
28	metaOpts := parser.MetadataOpts{TagName: parser.TagLabel, AllowSliceAsStruct: false}
29	err = parser.AddMetadata(element, node, metaOpts)
30	if err != nil {
31		return err
32	}
33
34	return parser.Fill(element, node, parser.FillerOpts{AllowSliceAsStruct: false})
35}
36
37func getRootFieldNames(rootName string, element interface{}) []string {
38	if element == nil {
39		return nil
40	}
41
42	rootType := reflect.TypeOf(element)
43
44	return getFieldNames(rootName, rootType)
45}
46
47func getFieldNames(rootName string, rootType reflect.Type) []string {
48	var names []string
49
50	if rootType.Kind() == reflect.Ptr {
51		rootType = rootType.Elem()
52	}
53
54	if rootType.Kind() != reflect.Struct {
55		return nil
56	}
57
58	for i := 0; i < rootType.NumField(); i++ {
59		field := rootType.Field(i)
60
61		if !parser.IsExported(field) {
62			continue
63		}
64
65		if field.Anonymous &&
66			(field.Type.Kind() == reflect.Ptr && field.Type.Elem().Kind() == reflect.Struct || field.Type.Kind() == reflect.Struct) {
67			names = append(names, getFieldNames(rootName, field.Type)...)
68			continue
69		}
70
71		names = append(names, path.Join(rootName, field.Name))
72	}
73
74	return names
75}
76