/
distance.go
62 lines (54 loc) · 2.14 KB
/
distance.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
// Copyright (c) 2020 SAP SE or an SAP affiliate company. All rights reserved. This file is licensed under the Apache Software License, v. 2 except as noted otherwise in the LICENSE file
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package shoot
import (
"strings"
"github.com/texttheater/golang-levenshtein/levenshtein"
)
var orientations = []string{"north", "south", "east", "west", "central"}
// orientation extracts an orientation relative to a base from a region name
func orientation(name string) (normalized string, orientation string) {
for _, o := range orientations {
if i := strings.Index(name, o); i >= 0 {
orientation = o
normalized = name[:i] + ":" + name[i+len(o):]
return
}
}
return name, ""
}
// distance calculates a formal distance between two region names observing
// some usual orientation keywords. It is based on the levenshtein distance
// of the regions base names plus the difference based on the orientation.
// regions with the same base but different orientations are basically nearer
// to each other than two completely unrelated regions.
func distance(seed, shoot string) int {
d, _ := distanceValues(seed, shoot)
return d
}
func distanceValues(seed, shoot string) (int, int) {
seedBase, seedOrient := orientation(seed)
shootBase, shootOrient := orientation(shoot)
dist := levenshtein.DistanceForStrings([]rune(seedBase), []rune(shootBase), levenshtein.DefaultOptionsWithSub)
if seedOrient != "" || shootOrient != "" {
if seedOrient == "" || shootOrient == "" {
return dist*2 + 1, dist
}
if seedOrient == shootOrient {
return dist * 2, dist
}
return dist*2 + 2, dist
}
return dist * 2, dist
}