feat: Improve assemble string after code suggestion

LLMSuggestion.cpp

@@ -9,55 +9,42 @@
 
 namespace QodeAssist {
 
-static QStringList extractTokens(const QString &str)
+static bool isClosingTail(const QString &s, int from)
 {
-    QStringList tokens;
-    QString currentToken;
-    for (const QChar &ch : str) {
-        if (ch.isLetterOrNumber() || ch == '_') {
-            currentToken += ch;
-        } else {
-            if (!currentToken.isEmpty() && currentToken.length() > 1) {
-                tokens.append(currentToken);
-            }
-            currentToken.clear();
-        }
+    static const QString closeChars = QStringLiteral("(){}[];,");
+    for (int i = from; i < s.size(); ++i) {
+        const QChar c = s.at(i);
+        if (!c.isSpace() && !closeChars.contains(c))
+            return false;
     }
-    if (!currentToken.isEmpty() && currentToken.length() > 1) {
-        tokens.append(currentToken);
-    }
-    return tokens;
+    return true;
 }
 
-int LLMSuggestion::calculateReplaceLength(const QString &suggestion, 
-                                         const QString &rightText,
-                                         const QString &entireLine)
+int LLMSuggestion::calculateReplaceLength(const QString &suggestion, const QString &rightText)
 {
-    if (rightText.isEmpty()) {
+    if (rightText.isEmpty())
         return 0;
+
+    const int maxN = qMin(suggestion.size(), rightText.size());
+    int lcp = 0;
+    while (lcp < maxN && suggestion.at(lcp) == rightText.at(lcp))
+        ++lcp;
+
+    if (lcp > 0) {
+        if (isClosingTail(rightText, lcp))
+            return rightText.size();
+        return lcp;
     }
 
-    QString structuralChars = "{}[]()<>;,";
-    bool hasStructuralOverlap = false;
-    for (const QChar &ch : structuralChars) {
-        if (suggestion.contains(ch) && rightText.contains(ch)) {
-            hasStructuralOverlap = true;
-            break;
-        }
-    }
+    if (!isClosingTail(rightText, 0))
+        return 0;
 
-    if (hasStructuralOverlap) {
-        return rightText.length();
-    }
-
-    const QStringList suggestionTokens = extractTokens(suggestion);
-    const QStringList lineTokens = extractTokens(entireLine);
-    
-    for (const auto &token : suggestionTokens) {
-        if (lineTokens.contains(token)) {
-            return rightText.length();
-        }
-    }
+    static const QString closeChars = QStringLiteral("(){}[];,");
+    int i = suggestion.size() - 1;
+    while (i >= 0 && suggestion.at(i).isSpace())
+        --i;
+    if (i >= 0 && closeChars.contains(suggestion.at(i)) && rightText.contains(suggestion.at(i)))
+        return rightText.size();
 
     return 0;
 }
@@ -82,10 +69,9 @@ LLMSuggestion::LLMSuggestion(
     QString rightText = blockText.mid(cursorPositionInBlock);
 
     QString suggestionText = data.text;
-    QString entireLine = blockText;
 
     if (!suggestionText.contains('\n')) {
-        int replaceLength = calculateReplaceLength(suggestionText, rightText, entireLine);
+        int replaceLength = calculateReplaceLength(suggestionText, rightText);
         QString remainingRightText = (replaceLength > 0) ? rightText.mid(replaceLength) : rightText;
 
         QString displayText = leftText + suggestionText + remainingRightText;
@@ -95,7 +81,7 @@ LLMSuggestion::LLMSuggestion(
         QString firstLine = suggestionText.left(firstLineEnd);
         QString restOfCompletion = suggestionText.mid(firstLineEnd);
 
-        int replaceLength = calculateReplaceLength(firstLine, rightText, entireLine);
+        int replaceLength = calculateReplaceLength(firstLine, rightText);
         QString remainingRightText = (replaceLength > 0) ? rightText.mid(replaceLength) : rightText;
 
         QString displayText = leftText + firstLine + remainingRightText + restOfCompletion;
@@ -147,9 +133,8 @@ bool LLMSuggestion::applyPart(Part part, TextEditor::TextEditorWidget *widget)
     if (startPos == 0) {
         QTextBlock currentBlock = cursor.block();
         QString textAfterCursor = currentBlock.text().mid(cursor.positionInBlock());
-        QString entireLine = currentBlock.text();
 
-        int replaceLength = calculateReplaceLength(text, textAfterCursor, entireLine);
+        int replaceLength = calculateReplaceLength(text, textAfterCursor);
 
         if (replaceLength > 0) {
             currentCursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, replaceLength);
@@ -200,9 +185,7 @@ bool LLMSuggestion::apply()
     QString text = currentData.text;
 
     QTextBlock currentBlock = cursor.block();
-    QString textBeforeCursor = currentBlock.text().left(cursor.positionInBlock());
     QString textAfterCursor = currentBlock.text().mid(cursor.positionInBlock());
-    QString entireLine = currentBlock.text();
 
     QTextCursor editCursor = cursor;
     editCursor.beginEditBlock();
@@ -212,7 +195,7 @@ bool LLMSuggestion::apply()
         QString firstLine = text.left(firstLineEnd);
         QString restOfText = text.mid(firstLineEnd);
 
-        int replaceLength = calculateReplaceLength(firstLine, textAfterCursor, entireLine);
+        int replaceLength = calculateReplaceLength(firstLine, textAfterCursor);
 
         if (replaceLength > 0) {
             editCursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, replaceLength);
@@ -221,7 +204,7 @@ bool LLMSuggestion::apply()
 
         editCursor.insertText(firstLine + restOfText);
     } else {
-        int replaceLength = calculateReplaceLength(text, textAfterCursor, entireLine);
+        int replaceLength = calculateReplaceLength(text, textAfterCursor);
 
         if (replaceLength > 0) {
             editCursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, replaceLength);

LLMSuggestion.hpp

@@ -42,8 +42,6 @@ public:
     bool applyPart(Part part, TextEditor::TextEditorWidget *widget);
     bool apply() override;
 
-    static int calculateReplaceLength(const QString &suggestion, 
-                                     const QString &rightText,
-                                     const QString &entireLine);
+    static int calculateReplaceLength(const QString &suggestion, const QString &rightText);
 };
 } // namespace QodeAssist

test/LLMSuggestionTest.cpp

@@ -15,127 +15,97 @@ class LLMSuggestionTest : public QObject, public testing::Test
     Q_OBJECT
 };
 
-// Basic tests
-TEST_F(LLMSuggestionTest, testCalculateReplaceLengthEmptyRight)
+// Degenerate / no-op cases
+TEST_F(LLMSuggestionTest, emptyRight)
 {
-    int result = LLMSuggestion::calculateReplaceLength("foo", "", "foo");
-    EXPECT_EQ(result, 0); // No rightText to replace
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("foo", ""), 0);
 }
 
-TEST_F(LLMSuggestionTest, testCalculateReplaceLengthNoOverlap)
+TEST_F(LLMSuggestionTest, noOverlap)
 {
-    // No structural or token overlap
-    int result = LLMSuggestion::calculateReplaceLength("foo", "bar", "foobar");
-    EXPECT_EQ(result, 0); // Just insert, don't replace
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("foo", "bar"), 0);
 }
 
-// Structural overlap tests
-TEST_F(LLMSuggestionTest, testCalculateReplaceLengthStructuralBraces)
+TEST_F(LLMSuggestionTest, singleCharNoOverlap)
 {
-    // suggestion contains {}, rightText contains {}
-    int result = LLMSuggestion::calculateReplaceLength("= {\"red\"}", "{};", "colors{};");
-    EXPECT_EQ(result, 3); // Replace all rightText
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("a", "b"), 0);
 }
 
-TEST_F(LLMSuggestionTest, testCalculateReplaceLengthStructuralSemicolon)
+// LCP: model echoed the existing right side as its own prefix
+TEST_F(LLMSuggestionTest, lcpExtendsRight)
 {
-    // suggestion contains ;, rightText contains ;
-    int result = LLMSuggestion::calculateReplaceLength("x;", ";", "int x;");
-    EXPECT_EQ(result, 1); // Replace the ;
+    // cursor: int |myVariable ; suggestion echoes "myVar" then adds nothing.
+    // LCP=5, remainder "iable" not a closing tail -> replace 5.
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("myVar", "myVariable"), 5);
 }
 
-TEST_F(LLMSuggestionTest, testCalculateReplaceLengthStructuralParens)
+TEST_F(LLMSuggestionTest, lcpPartialEngineCall)
 {
-    // suggestion contains (), rightText contains )
-    int result = LLMSuggestion::calculateReplaceLength("arg1, arg2)", ")", "foo(arg1, arg2)");
-    EXPECT_EQ(result, 1); // Replace the )
+    // cursor: |engine.rootContext() ; suggestion: engine.load()
+    // LCP="engine." (7); remainder "rootContext()" is not closing-only -> keep LCP
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("engine.load()", "engine.rootContext()"), 7);
 }
 
-TEST_F(LLMSuggestionTest, testCalculateReplaceLengthStructuralBrackets)
+// LCP + closing-only tail: extend to full right
+TEST_F(LLMSuggestionTest, lcpThenClosingTailExtendsFull)
 {
-    // suggestion contains [], rightText contains ]
-    int result = LLMSuggestion::calculateReplaceLength("[0]", "];", "arr[0];");
-    EXPECT_EQ(result, 2); // Replace ];
+    // cursor: QStringList |colors{}; ; suggestion: colors << "red"
+    // LCP=6 ("colors"); remainder "{};" is punctuation -> replace all (9)
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("colors << \"red\"", "colors{};"), 9);
 }
 
-// Token overlap tests
-TEST_F(LLMSuggestionTest, testCalculateReplaceLengthCommonToken)
+// LCP=0, right is closing-only, suggestion ends with a matching closer -> replace full right
+TEST_F(LLMSuggestionTest, closingTailReplaceSemicolon)
 {
-    // suggestion contains "colors", entireLine contains "colors"
-    int result = LLMSuggestion::calculateReplaceLength("colors << \"red\"", "colors{};", "QStringList colors{};");
-    EXPECT_EQ(result, 9); // Replace all rightText due to common token
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("x;", ";"), 1);
 }
 
-TEST_F(LLMSuggestionTest, testCalculateReplaceLengthMultipleCommonTokens)
+TEST_F(LLMSuggestionTest, closingTailReplaceParen)
 {
-    // Multiple tokens in common
-    int result = LLMSuggestion::calculateReplaceLength("engine.load()", "engine.rootContext()", "QmlEngine engine.rootContext()");
-    EXPECT_EQ(result, 20); // Replace all rightText
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("arg1, arg2)", ")"), 1);
 }
 
-// Real-world scenarios
-TEST_F(LLMSuggestionTest, testCursorInBraces)
+TEST_F(LLMSuggestionTest, closingTailReplaceBrackets)
 {
-    // Cursor in braces: QStringList colors{<cursor>};
-    // LLM sends: "\"red\", \"green\"", rightText: "};"
-    // No common tokens ("red" and "green" are strings, not identifiers in entireLine)
-    // No structural overlap (suggestion doesn't contain } or ;)
-    int result = LLMSuggestion::calculateReplaceLength("\"red\", \"green\"", "};", "QStringList colors{};");
-    EXPECT_EQ(result, 0); // No overlap, just insert
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("[0]", "];"), 2);
 }
 
-TEST_F(LLMSuggestionTest, testCursorBeforeBraces)
+TEST_F(LLMSuggestionTest, closingTailReplaceBracesAndSemi)
 {
-    // Cursor before braces: QStringList colors<cursor>{};
-    // LLM sends: " = {\"red\"}", rightText: "{};"
-    int result = LLMSuggestion::calculateReplaceLength(" = {\"red\"}", "{};", "QStringList colors{};");
-    EXPECT_EQ(result, 3); // Structural overlap - replace all
+    // cursor: colors|{}; ; suggestion: = {"red"}
+    // LCP=0; right "{};" is closing-only; suggestion ends on "}" which is in right -> replace 3
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("= {\"red\"}", "{};"), 3);
 }
 
-TEST_F(LLMSuggestionTest, testCursorAfterType)
+TEST_F(LLMSuggestionTest, closingTailWithLeadingSpace)
 {
-    // Cursor after type: QStringList <cursor>colors{};
-    // LLM sends: "colors << \"red\"", rightText: "colors{};"
-    int result = LLMSuggestion::calculateReplaceLength("colors << \"red\"", "colors{};", "QStringList colors{};");
-    EXPECT_EQ(result, 9); // Common token - replace all
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength(" = {\"red\"}", "{};"), 3);
 }
 
-TEST_F(LLMSuggestionTest, testCursorInMiddleNoConflict)
+TEST_F(LLMSuggestionTest, closingTailEqualsSemi)
 {
-    // Cursor in middle: int <cursor>myVar = 5;
-    // LLM sends: "myVar", rightText: " = 5;", entireLine: "int myVar = 5;"
-    // "myVar" is a common token -> replace rightText
-    int result = LLMSuggestion::calculateReplaceLength("myVar", " = 5;", "int myVar = 5;");
-    EXPECT_EQ(result, 5); // Common token found, replace all rightText
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("= 5;", ";"), 1);
 }
 
-TEST_F(LLMSuggestionTest, testCursorWithEqualsSign)
+// LCP=0, right is closing-only but suggestion does not end on any of its chars -> leave right alone
+TEST_F(LLMSuggestionTest, closingTailNoMatchingClose)
 {
-    // LLM sends code with = and ;
-    int result = LLMSuggestion::calculateReplaceLength("= 5;", ";", "int x;");
-    EXPECT_EQ(result, 1); // Structural overlap on ;
+    // right "};" closes; suggestion ends on '"' (not in close set) -> 0
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("\"red\", \"green\"", "};"), 0);
 }
 
-// Edge cases
-TEST_F(LLMSuggestionTest, testNoStructuralButHasToken)
+// Right side has real code (not closing-only) and no LCP -> leave it alone
+TEST_F(LLMSuggestionTest, realCodeRightNoLcp)
 {
-    // Token overlap but no structural
-    int result = LLMSuggestion::calculateReplaceLength("myVar", "myVariable", "int myVariable");
-    EXPECT_EQ(result, 0); // No structural overlap, tokens too different (length > 1 check)
+    // cursor: int |myVar = 5; ; suggestion: myVar
+    // LCP=0, right " = 5;" is not closing-only (has '5') -> 0
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("myVar", " = 5;"), 0);
 }
 
-TEST_F(LLMSuggestionTest, testOnlyWhitespace)
+// Trailing whitespace is not treated as a closer, suggestion has no closer -> leave alone
+TEST_F(LLMSuggestionTest, trailingWhitespaceOnlyLeftAlone)
 {
-    // rightText is just whitespace, but "code" is common token
-    int result = LLMSuggestion::calculateReplaceLength("code", "   ", "code   ");
-    EXPECT_EQ(result, 3); // Common token "code", replace rightText
-}
-
-TEST_F(LLMSuggestionTest, testSingleCharTokenIgnored)
-{
-    // Tokens must be > 1 character
-    int result = LLMSuggestion::calculateReplaceLength("a", "b", "ab");
-    EXPECT_EQ(result, 0); // Single char tokens ignored
+    EXPECT_EQ(LLMSuggestion::calculateReplaceLength("code", "   "), 0);
 }
 
 #include "LLMSuggestionTest.moc"