From a7ba55f2b781544cd74927137025f2c00a398f69 Mon Sep 17 00:00:00 2001
From: Kristóf Marussy <kristof@marussy.com>
Date: Sun, 31 Oct 2021 01:53:11 +0200
Subject: fix(web): fix server-side content assist filtering

---
 .../refinery/language/ide/ProblemIdeModule.java    |  8 +++-
 .../language/ide/contentassist/FuzzyMatcher.java   | 44 ++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 language-ide/src/main/java/tools/refinery/language/ide/contentassist/FuzzyMatcher.java

(limited to 'language-ide')

diff --git a/language-ide/src/main/java/tools/refinery/language/ide/ProblemIdeModule.java b/language-ide/src/main/java/tools/refinery/language/ide/ProblemIdeModule.java
index 5327f7b4..3502c29f 100644
--- a/language-ide/src/main/java/tools/refinery/language/ide/ProblemIdeModule.java
+++ b/language-ide/src/main/java/tools/refinery/language/ide/ProblemIdeModule.java
@@ -3,16 +3,22 @@
  */
 package tools.refinery.language.ide;
 
+import org.eclipse.xtext.ide.editor.contentassist.IPrefixMatcher;
 import org.eclipse.xtext.ide.editor.syntaxcoloring.ISemanticHighlightingCalculator;
 
+import tools.refinery.language.ide.contentassist.FuzzyMatcher;
 import tools.refinery.language.ide.syntaxcoloring.ProblemSemanticHighlightingCalculator;
 
 /**
  * Use this class to register ide components.
  */
 public class ProblemIdeModule extends AbstractProblemIdeModule {
-
 	public Class<? extends ISemanticHighlightingCalculator> bindISemanticHighlightingCalculator() {
 		return ProblemSemanticHighlightingCalculator.class;
 	}
+	
+	@Override
+	public Class<? extends IPrefixMatcher> bindIPrefixMatcher() {
+		return FuzzyMatcher.class;
+	}
 }
diff --git a/language-ide/src/main/java/tools/refinery/language/ide/contentassist/FuzzyMatcher.java b/language-ide/src/main/java/tools/refinery/language/ide/contentassist/FuzzyMatcher.java
new file mode 100644
index 00000000..fe722ca1
--- /dev/null
+++ b/language-ide/src/main/java/tools/refinery/language/ide/contentassist/FuzzyMatcher.java
@@ -0,0 +1,44 @@
+package tools.refinery.language.ide.contentassist;
+
+import org.eclipse.xtext.ide.editor.contentassist.IPrefixMatcher;
+
+import com.google.inject.Singleton;
+
+/**
+ * Implements the candidate matching algoritm used by CodeMirror 6.
+ * 
+ * Using this class ensures that the same candidates will be returned when
+ * filtering content assist proposals on the server as on the client.
+ * 
+ * The matching is "fuzzy" (<code>fzf</code>-like), i.e., the prefix characters
+ * may occur anywhere in the name, but must be in the same order as in the
+ * prefix.
+ * 
+ * @author Kristóf Marussy
+ */
+@Singleton
+public class FuzzyMatcher implements IPrefixMatcher {
+	@Override
+	public boolean isCandidateMatchingPrefix(String name, String prefix) {
+		var nameIgnoreCase = name.toLowerCase();
+		var prefixIgnoreCase = prefix.toLowerCase();
+		int prefixLength = prefixIgnoreCase.length();
+		if (prefixLength == 0) {
+			return true;
+		}
+		int nameLength = nameIgnoreCase.length();
+		if (prefixLength > nameLength) {
+			return false;
+		}
+		int prefixIndex = 0;
+		for (int nameIndex = 0; nameIndex < nameLength; nameIndex++) {
+			if (nameIgnoreCase.charAt(nameIndex) == prefixIgnoreCase.charAt(prefixIndex)) {
+				prefixIndex++;
+				if (prefixIndex == prefixLength) {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+}
-- 
cgit v1.2.3-70-g09d2