Restore prefix-penalty scoring semantics and remove dead scoring allocation

FuzzySearch.Test/FuzzyTests.cs

@@ -218,6 +218,22 @@ public void Contains_WithScore_CamelCaseMatch_GetsBonus()
 		Assert.IsGreaterThanOrEqualTo(Fuzzy.camelCaseMatchBonus, score, "Score should include camelCase bonus");
 	}
 
+	[TestMethod]
+	public void Contains_WithScore_LatePrefixMatch_ScoresLowerThanStartMatch()
+	{
+		// Arrange
+		string pattern = "foo";
+
+		// Act
+		bool earlyResult = Fuzzy.Contains("foo", pattern, out int earlyScore);
+		bool lateResult = Fuzzy.Contains("xxxxxxxxxxfoo", pattern, out int lateScore);
+
+		// Assert
+		Assert.IsTrue(earlyResult, "Start-position match should return true.");
+		Assert.IsTrue(lateResult, "Late-position match should return true.");
+		Assert.IsGreaterThan(lateScore, earlyScore, "Match at the start should score higher than a late prefix match.");
+	}
+
 	#endregion
 
 	#region Apply Bonuses Tests
@@ -329,7 +345,23 @@ public void PenalizeNonPatternCharacters_FirstPatternChar_AppliesPrefixPenalty()
 		int initialScore = 10;
 		int patternIdx = 0;
 		int strIdx = 3;  // 3 chars before first match
-		int expectedPenalty = Math.Max(strIdx * Fuzzy.unmatchedPrefixLetterPenalty, Fuzzy.maxPrefixPenalty);
+		int expectedPenalty = -3;
+
+		// Act
+		int result = Fuzzy.PenalizeNonPatternCharacters(initialScore, patternIdx, strIdx);
+
+		// Assert
+		Assert.AreEqual(initialScore + expectedPenalty, result);
+	}
+
+	[TestMethod]
+	public void PenalizeNonPatternCharacters_FirstPatternChar_CapsPrefixPenalty()
+	{
+		// Arrange
+		int initialScore = 10;
+		int patternIdx = 0;
+		int strIdx = 10;
+		int expectedPenalty = -5;
 
 		// Act
 		int result = Fuzzy.PenalizeNonPatternCharacters(initialScore, patternIdx, strIdx);

FuzzySearch/Fuzzy.cs

@@ -27,10 +27,10 @@
 	internal const int camelCaseMatchBonus = 10;
 
 	/// <summary>The penalty for each unmatched character at the beginning of the string.</summary>
-	internal const int unmatchedPrefixLetterPenalty = 0;
+	internal const int unmatchedPrefixLetterPenalty = -1;
 
 	/// <summary>The maximum prefix penalty that can be applied.</summary>
-	internal const int maxPrefixPenalty = 0;
+	internal const int maxPrefixPenalty = -5;
 
 	/// <summary>The penalty for each unmatched character in the string.</summary>
 	internal const int unmatchedLetterPenalty = -1;
@@ -96,7 +96,7 @@
 	/// or the pattern is empty and the subject is not; otherwise, <c>false</c>.
 	/// </param>
 	/// <returns>A score representing the quality of the match. Higher scores indicate better matches.</returns>
 	internal static int CalculateScore(ReadOnlySpan<char> subject, ReadOnlySpan<char> pattern, out bool wholePatternIsPresent)
 	{
 		if (pattern.IsEmpty)
 		{
@@ -119,8 +119,6 @@
 		int? bestLetterIdx = null;
 		int bestLetterScore = 0;
 
-		List<int> matchedIndices = [];
-
 		// Loop over characters in subject
 		while (strIdx != strLength)
 		{
@@ -139,7 +137,6 @@
 			if (bestLetterIdx is not null && (advanced || patternRepeat))
 			{
 				score += bestLetterScore;
-				matchedIndices.Add((int)bestLetterIdx);
 				bestLetter = null;
 				bestLower = null;
 				bestLetterIdx = null;
@@ -196,7 +193,6 @@
 		if (bestLetter is not null && bestLetterIdx is not null)
 		{
 			score += bestLetterScore;
-			matchedIndices.Add((int)bestLetterIdx);
 		}
 
 		wholePatternIsPresent = patternIdx == patternLength;