From 342e2c2bd8c8d1c3de1006870f24f84d51bfb0ee Mon Sep 17 00:00:00 2001
From: Rushil Perera <pererarushil1940@gmail.com>
Date: Mon, 26 Aug 2024 21:55:11 -0400
Subject: [PATCH] fix: use string matching to map to correct title in Aniwatch

---
 .../episodes/getByAniListId/aniwatch.ts       |  26 +++-
 src/libs/findBestMatchingTitle.ts             | 113 ++++++++++++++++++
 2 files changed, 134 insertions(+), 5 deletions(-)
 create mode 100644 src/libs/findBestMatchingTitle.ts

diff --git a/src/controllers/episodes/getByAniListId/aniwatch.ts b/src/controllers/episodes/getByAniListId/aniwatch.ts
index 90cb6b9..7f57227 100644
--- a/src/controllers/episodes/getByAniListId/aniwatch.ts
+++ b/src/controllers/episodes/getByAniListId/aniwatch.ts
@@ -1,3 +1,5 @@
+import { findBestMatchingTitle } from "~/libs/findBestMatchingTitle";
+
 import { Episode, type EpisodesResponse } from "./episode";
 
 export async function getEpisodesFromAniwatch(
@@ -8,9 +10,12 @@ export async function getEpisodesFromAniwatch(
       .then(({ fetchTitleFromAnilist }) =>
         fetchTitleFromAnilist(aniListId, undefined),
       )
-      .then((title) => title?.title?.english ?? title?.title?.userPreferred);
+      .then((title) => ({
+        english: title?.title?.english,
+        userPreferred: title?.title?.userPreferred,
+      }));
 
-    if (!animeTitle) {
+    if (!animeTitle.english && !animeTitle.userPreferred) {
       return null;
     }
 
@@ -55,12 +60,23 @@ export async function getEpisodesFromAniwatch(
   return null;
 }
 
-function getAniwatchId(animeTitle: string): Promise<string | undefined> {
+function getAniwatchId(
+  animeTitle: Partial<{ english: string; userPreferred: string }>,
+): Promise<string | undefined> {
   return fetch(
-    `https://aniwatch.up.railway.app/anime/search?q=${encodeURIComponent(animeTitle)}`,
+    `https://aniwatch.up.railway.app/anime/search?q=${encodeURIComponent(animeTitle.english ?? animeTitle.userPreferred!)}`,
   )
     .then((res) => res.json<AniwatchSearchResponse>())
-    .then(({ animes }) => animes[0]?.id);
+    .then(({ animes }) => {
+      const bestMatchingTitle = findBestMatchingTitle(
+        animeTitle,
+        animes.map((anime) => ({
+          english: anime.name,
+          userPreferred: anime.jname,
+        })),
+      );
+      return animes.find((anime) => anime.name === bestMatchingTitle)?.id;
+    });
 }
 
 export interface AniwatchEpisodesResponse {
diff --git a/src/libs/findBestMatchingTitle.ts b/src/libs/findBestMatchingTitle.ts
new file mode 100644
index 0000000..47f9bca
--- /dev/null
+++ b/src/libs/findBestMatchingTitle.ts
@@ -0,0 +1,113 @@
+function findBestMatch(mainString: string, targets: string[]): string | null {
+  if (targets.length === 0) return null;
+
+  let bestMatch = targets[0];
+  let highestScore = stringMatchingAlgorithm(mainString, bestMatch);
+
+  for (let i = 1; i < targets.length; i++) {
+    const currentScore = stringMatchingAlgorithm(mainString, targets[i]);
+    if (currentScore > highestScore) {
+      highestScore = currentScore;
+      bestMatch = targets[i];
+    }
+  }
+
+  return bestMatch;
+}
+
+type Title = {
+  english: string;
+  userPreferred: string;
+};
+
+export const findBestMatchingTitle = (
+  title: Partial<Title>,
+  titles: Partial<Title>[],
+): string | null => {
+  const { english, userPreferred } = title;
+
+  const userPreferredBestMatch = userPreferred
+    ? findBestMatch(
+        userPreferred,
+        titles
+          .map((title) => title.userPreferred)
+          .filter((title) => title !== undefined),
+      )
+    : null;
+  const englishBestMatch = english
+    ? findBestMatch(
+        english,
+        titles
+          .map((title) => title.english)
+          .filter((title) => title !== undefined),
+      )
+    : null;
+
+  const userPreferredScore = userPreferredBestMatch
+    ? stringMatchingAlgorithm(userPreferred!, userPreferredBestMatch)
+    : 0;
+  const englishScore = englishBestMatch
+    ? stringMatchingAlgorithm(english!, englishBestMatch)
+    : 0;
+
+  console.log(title.english, englishScore);
+  console.log(title.userPreferred, userPreferredScore);
+  if (userPreferredScore >= englishScore) {
+    return userPreferredBestMatch;
+  } else {
+    return englishBestMatch;
+  }
+};
+
+function stringMatchingAlgorithm(s1: string, s2: string): number {
+  // current implementation is the Jaro-Winkler algorithm
+  // copied from https://discord.com/channels/987492554486452315/1273988465222090783/1273988465222090783
+  const m = s1.length;
+  const n = s2.length;
+
+  if (m === 0 && n === 0) return 1.0;
+  if (m === 0 || n === 0) return 0.0;
+
+  const matchDistance = Math.floor(Math.max(m, n) / 2) - 1;
+  const s1Matches = new Array(m).fill(false);
+  const s2Matches = new Array(n).fill(false);
+
+  let matches = 0;
+  let transpositions = 0;
+  for (let i = 0; i < m; i++) {
+    const start = Math.max(0, i - matchDistance);
+    const end = Math.min(n - 1, i + matchDistance);
+
+    for (let j = start; j <= end; j++) {
+      if (s2Matches[j]) continue;
+      if (s1[i] !== s2[j]) continue;
+      s1Matches[i] = true;
+      s2Matches[j] = true;
+      matches++;
+      break;
+    }
+  }
+
+  if (matches === 0) return 0.0;
+
+  let k = 0;
+  for (let i = 0; i < m; i++) {
+    if (!s1Matches[i]) continue;
+    while (!s2Matches[k]) k++;
+    if (s1[i] !== s2[k]) transpositions++;
+    k++;
+  }
+
+  transpositions /= 2;
+
+  const jaro =
+    (matches / m + matches / n + (matches - transpositions) / matches) / 3;
+
+  const prefix = Math.min(
+    4,
+    [...s1].findIndex((ch, i) => s1[i] !== s2[i]),
+  );
+  const p = 0.1;
+
+  return jaro + prefix * p * (1 - jaro);
+}