From b5e9480edc56924d652a1a207c7cbf7fa5b5cb92 Mon Sep 17 00:00:00 2001
From: Yannic Link <yl60lepu@studserv.uni-leipzig.de>
Date: Wed, 19 Jan 2022 23:02:36 +0100
Subject: [PATCH] =?UTF-8?q?String-=C3=84hnlichkeit=20durch=20Jaccard-Dista?=
 =?UTF-8?q?nz=20ersetzt?=
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---
 app/build.gradle                              |  1 +
 .../command/commands/PlayCommand.java         | 58 +++++--------------
 2 files changed, 17 insertions(+), 42 deletions(-)

diff --git a/app/build.gradle b/app/build.gradle
index 5b8b1b9..615b995 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -30,6 +30,7 @@ dependencies {
     implementation 'com.sedmelluq:lavaplayer:1.3.73'
 
     implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.0'
+    implementation 'org.apache.commons:commons-text:1.9'
 
     implementation "net.dean.jraw:JRAW:1.1.0"
 
diff --git a/app/src/main/java/de/yannicpunktdee/yoshibot/command/commands/PlayCommand.java b/app/src/main/java/de/yannicpunktdee/yoshibot/command/commands/PlayCommand.java
index e5318a3..3bba353 100644
--- a/app/src/main/java/de/yannicpunktdee/yoshibot/command/commands/PlayCommand.java
+++ b/app/src/main/java/de/yannicpunktdee/yoshibot/command/commands/PlayCommand.java
@@ -5,14 +5,14 @@ import de.yannicpunktdee.yoshibot.command.YoshiCommandContext;
 import de.yannicpunktdee.yoshibot.main.YoshiBot;
 import de.yannicpunktdee.yoshibot.utils.Resources;
 import net.dv8tion.jda.api.EmbedBuilder;
-import net.dv8tion.jda.api.entities.TextChannel;
 import net.dv8tion.jda.api.entities.VoiceChannel;
 
+import org.apache.commons.text.similarity.JaccardDistance;
+
 import java.awt.Color;
 import java.io.File;
 import java.util.Arrays;
 import java.util.List;
-import java.util.Map;
 import java.util.Objects;
 import java.util.stream.Collectors;
 
@@ -44,6 +44,11 @@ public class PlayCommand extends YoshiCommand {
 			sendCustomMessage(eb.build());
 		} else if (context.containsArgument("name")) {
 			String requestedFile = getBestMatch(context.getArgument("name"), getAllFiles());
+			if(requestedFile == null){
+				sendErrorMessage(String.format("Konnte keine Audiodatei namens '%s.opus' finden!",
+						context.getArgument("name")));
+				return false;
+			}
 			File file = new File(Resources.getPathToAudioFile(requestedFile));
 			if (!file.isFile()) {
 				sendErrorMessage(String.format("Konnte keine Audiodatei namens '%s.opus' finden!",
@@ -68,48 +73,17 @@ public class PlayCommand extends YoshiCommand {
 	}
 	
 	private String getBestMatch(String word, List<String> choices) {
-		Map<String, Double> hammingDists =
-				choices.parallelStream()
-						.collect(Collectors.toMap(file -> file,
-												  file -> (double) maximalMatchingChars(file, word) /
-														  Math.max(file.length(),
-																   word.length())));
-		return hammingDists.keySet().stream()
-				.max((file1, file2) -> (int) Math.signum(hammingDists.get(file1) - hammingDists.get(file2)))
-				.orElse(choices.get(0));
-	}
-	
-	private int maximalMatchingChars(String word1, String word2) {
-		int maxMatches = 0;
-		int combinedSize = word1.length() + word2.length() - 1;
-		char[] word1Chars = new char[combinedSize], word2Chars = new char[combinedSize];
-		for (int i = 0; i < combinedSize; i++) {
-			if (i < word2.length()) {
-				word2Chars[i] = word2.charAt(i);
-			} else {
-				word2Chars[i] = '&';
+		double bestScore = 1.0;
+		String bestMatching = null;
+		for(String file : choices){
+			double score = (new JaccardDistance()).apply(word, file);
+			if(score < bestScore){
+				bestScore = score;
+				bestMatching = file;
 			}
 		}
-		for (int i = 0; i < combinedSize; i++) {
-			for (int j = 0; j < combinedSize; j++) {
-				if (i <= j && j < i + word1.length()) {
-					word1Chars[j] = word1.charAt(j - i);
-				} else {
-					word1Chars[j] = '$';
-				}
-			}
-			maxMatches = Math.max(getMatchingChars(word1Chars, word2Chars), maxMatches);
-		}
-		return maxMatches;
-	}
-	
-	private int getMatchingChars(char[] word1, char[] word2) {
-		int dist = 0;
-		assert word1.length == word2.length;
-		for (int i = 0; i < word1.length; i++) {
-			dist += word1[i] == word2[i] ? 1 : 0;
-		}
-		return dist;
+
+		return bestMatching;
 	}
 	
 	private List<String> getAllFiles() {