From a7216352dc2eb7c472c8eac965bb5b55bd6c185e Mon Sep 17 00:00:00 2001
From: Niklas Marion <niklas.marion@gmx.de>
Date: Wed, 19 Jun 2024 11:30:24 +0200
Subject: [PATCH] calcualte levenshtein distance for search results

---
 src/athletes/athlete.dto.ts      |  5 +++++
 src/athletes/athletes.service.ts | 12 ++++++++++--
 src/levenshtein-distance.ts      | 19 +++++++++++++++++++
 3 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 src/levenshtein-distance.ts

diff --git a/src/athletes/athlete.dto.ts b/src/athletes/athlete.dto.ts
index 1127456..592fbcc 100644
--- a/src/athletes/athlete.dto.ts
+++ b/src/athletes/athlete.dto.ts
@@ -121,4 +121,9 @@ export class AthleteSearchResult {
   sex: 'MALE' | 'FEMALE' | null;
   @ApiProperty({ nullable: true, type: Date })
   birthdate: Date | null;
+  @ApiProperty({
+    type: Number,
+    description: 'Levenshtein distance between search query and athlete name',
+  })
+  levenshteinDistance: number;
 }
diff --git a/src/athletes/athletes.service.ts b/src/athletes/athletes.service.ts
index 6d3e757..96f6a76 100644
--- a/src/athletes/athletes.service.ts
+++ b/src/athletes/athletes.service.ts
@@ -9,6 +9,7 @@ import parseVenue from './venue.utils';
 import mapDisciplineToCode from 'src/discipline.utils';
 import { formatLastname } from 'src/name.utils';
 import { GraphqlService } from 'src/graphql/graphql.service';
+import { levenshteinDistance } from 'src/levenshtein-distance';
 
 @Injectable()
 export class AthletesService {
@@ -27,7 +28,7 @@ export class AthletesService {
           searchCompetitors: z.array(AthleteSearchSchema),
         })
         .parse(data);
-      return response.searchCompetitors.map((item) => {
+      const searchResults = response.searchCompetitors.map((item) => {
         const sex =
           item.gender === 'Men'
             ? 'MALE'
@@ -40,9 +41,16 @@ export class AthletesService {
           firstname: item.givenName,
           lastname: formatLastname(item.familyName),
           birthdate: item.birthDate,
+          levenshteinDistance: levenshteinDistance(
+            name.toLowerCase().trim(),
+            (item.givenName + ' ' + item.familyName).toLowerCase().trim(),
+          ),
           sex,
         };
-      });
+      }) as AthleteSearchResult[];
+      return searchResults.sort(
+        (a, b) => a.levenshteinDistance - b.levenshteinDistance,
+      );
     } catch (error) {
       console.error(error);
       Sentry.captureException(error);
diff --git a/src/levenshtein-distance.ts b/src/levenshtein-distance.ts
new file mode 100644
index 0000000..d0c27cc
--- /dev/null
+++ b/src/levenshtein-distance.ts
@@ -0,0 +1,19 @@
+export const levenshteinDistance = (s, t) => {
+  if (!s.length) return t.length;
+  if (!t.length) return s.length;
+  const arr = [];
+  for (let i = 0; i <= t.length; i++) {
+    arr[i] = [i];
+    for (let j = 1; j <= s.length; j++) {
+      arr[i][j] =
+        i === 0
+          ? j
+          : Math.min(
+              arr[i - 1][j] + 1,
+              arr[i][j - 1] + 1,
+              arr[i - 1][j - 1] + (s[j - 1] === t[i - 1] ? 0 : 1),
+            );
+    }
+  }
+  return arr[t.length][s.length];
+};