feat: Improve code suggestions (#256)

LLMClientInterface.cpp

@@ -418,12 +418,20 @@ void LLMClientInterface::sendCompletionToClient(
                                   : completion;
     }
 
+    if (processedCompletion.endsWith('\n')) {
+        QString withoutTrailing = processedCompletion.chopped(1);
+        if (!withoutTrailing.contains('\n')) {
+            LOG_MESSAGE(QString("Removed trailing newline from single-line completion"));
+            processedCompletion = withoutTrailing;
+        }
+    }
+
     completionItem[LanguageServerProtocol::textKey] = processedCompletion;
+    
     QJsonObject range;
     range["start"] = position;
-    QJsonObject end = position;
-    end["character"] = position["character"].toInt() + processedCompletion.length();
-    range["end"] = end;
+    range["end"] = position;
+    
     completionItem[LanguageServerProtocol::rangeKey] = range;
     completionItem[LanguageServerProtocol::positionKey] = position;
     completions.append(completionItem);

LLMSuggestion.cpp

@@ -29,34 +29,57 @@
 
 namespace QodeAssist {
 
-QString mergeWithRightText(const QString &suggestion, const QString &rightText)
+static QStringList extractTokens(const QString &str)
 {
-    if (suggestion.isEmpty() || rightText.isEmpty()) {
-        return suggestion;
-    }
-
-    int j = 0;
-    QString processed = rightText;
-    QSet<int> matchedPositions;
-
-    for (int i = 0; i < suggestion.length() && j < processed.length(); ++i) {
-        if (suggestion[i] == processed[j]) {
-            matchedPositions.insert(j);
-            ++j;
+    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();
         }
     }
+    if (!currentToken.isEmpty() && currentToken.length() > 1) {
+        tokens.append(currentToken);
+    }
+    return tokens;
+}
 
-    if (matchedPositions.isEmpty()) {
-        return suggestion + rightText;
+int LLMSuggestion::calculateReplaceLength(const QString &suggestion, 
+                                         const QString &rightText,
+                                         const QString &entireLine)
+{
+    if (rightText.isEmpty()) {
+        return 0;
     }
 
-    QList<int> positions = matchedPositions.values();
-    std::sort(positions.begin(), positions.end(), std::greater<int>());
-    for (int pos : positions) {
-        processed.remove(pos, 1);
+    QString structuralChars = "{}[]()<>;,";
+    bool hasStructuralOverlap = false;
+    for (const QChar &ch : structuralChars) {
+        if (suggestion.contains(ch) && rightText.contains(ch)) {
+            hasStructuralOverlap = true;
+            break;
+        }
+    }
+    
+    if (hasStructuralOverlap) {
+        return rightText.length();
     }
 
-    return suggestion;
+    const QStringList suggestionTokens = extractTokens(suggestion);
+    const QStringList lineTokens = extractTokens(entireLine);
+    
+    for (const auto &token : suggestionTokens) {
+        if (lineTokens.contains(token)) {
+            return rightText.length();
+        }
+    }
+    
+    return 0;
 }
 
 LLMSuggestion::LLMSuggestion(
@@ -66,10 +89,8 @@ LLMSuggestion::LLMSuggestion(
     const auto &data = suggestions[currentCompletion];
 
     int startPos = data.range.begin.toPositionInDocument(sourceDocument);
-    int endPos = data.range.end.toPositionInDocument(sourceDocument);
 
     startPos = qBound(0, startPos, sourceDocument->characterCount());
-    endPos = qBound(startPos, endPos, sourceDocument->characterCount());
 
     QTextCursor cursor(sourceDocument);
     cursor.setPosition(startPos);
@@ -77,17 +98,27 @@ LLMSuggestion::LLMSuggestion(
     QString blockText = block.text();
 
     int cursorPositionInBlock = cursor.positionInBlock();
-
+    QString leftText = blockText.left(cursorPositionInBlock);
     QString rightText = blockText.mid(cursorPositionInBlock);
 
-    if (!data.text.contains('\n')) {
-        QString processedRightText = mergeWithRightText(data.text, rightText);
-        processedRightText = processedRightText.mid(data.text.length());
-        QString displayText = blockText.left(cursorPositionInBlock) + data.text
-                              + processedRightText;
+    QString suggestionText = data.text;
+    QString entireLine = blockText;
+
+    if (!suggestionText.contains('\n')) {
+        int replaceLength = calculateReplaceLength(suggestionText, rightText, entireLine);
+        QString remainingRightText = (replaceLength > 0) ? rightText.mid(replaceLength) : rightText;
+        
+        QString displayText = leftText + suggestionText + remainingRightText;
         replacementDocument()->setPlainText(displayText);
     } else {
-        QString displayText = blockText.left(cursorPositionInBlock) + data.text;
+        int firstLineEnd = suggestionText.indexOf('\n');
+        QString firstLine = suggestionText.left(firstLineEnd);
+        QString restOfCompletion = suggestionText.mid(firstLineEnd);
+        
+        int replaceLength = calculateReplaceLength(firstLine, rightText, entireLine);
+        QString remainingRightText = (replaceLength > 0) ? rightText.mid(replaceLength) : rightText;
+        
+        QString displayText = leftText + firstLine + remainingRightText + restOfCompletion;
         replacementDocument()->setPlainText(displayText);
     }
 }
@@ -104,10 +135,12 @@ bool LLMSuggestion::applyLine(TextEditor::TextEditorWidget *widget)
 
 bool LLMSuggestion::applyPart(Part part, TextEditor::TextEditorWidget *widget)
 {
-    const Utils::Text::Range range = suggestions()[currentSuggestion()].range;
+    const auto &currentSuggestions = suggestions();
+    const auto &currentData = currentSuggestions[currentSuggestion()];
+    const Utils::Text::Range range = currentData.range;
     const QTextCursor cursor = range.begin.toTextCursor(sourceDocument());
     QTextCursor currentCursor = widget->textCursor();
-    const QString text = suggestions()[currentSuggestion()].text;
+    const QString text = currentData.text;
 
     const int startPos = currentCursor.positionInBlock() - cursor.positionInBlock()
                          + (cursor.selectionEnd() - cursor.selectionStart());
@@ -131,6 +164,19 @@ bool LLMSuggestion::applyPart(Part part, TextEditor::TextEditorWidget *widget)
         return false;
     }
 
+    if (startPos == 0) {
+        QTextBlock currentBlock = cursor.block();
+        QString textAfterCursor = currentBlock.text().mid(cursor.positionInBlock());
+        QString entireLine = currentBlock.text();
+        
+        int replaceLength = calculateReplaceLength(text, textAfterCursor, entireLine);
+        
+        if (replaceLength > 0) {
+            currentCursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, replaceLength);
+            currentCursor.removeSelectedText();
+        }
+    }
+
     if (!subText.contains('\n')) {
         currentCursor.insertText(subText);
 
@@ -167,34 +213,47 @@ bool LLMSuggestion::applyPart(Part part, TextEditor::TextEditorWidget *widget)
 
 bool LLMSuggestion::apply()
 {
-    const Utils::Text::Range range = suggestions()[currentSuggestion()].range;
+    const auto &currentSuggestions = suggestions();
+    const auto &currentData = currentSuggestions[currentSuggestion()];
+    const Utils::Text::Range range = currentData.range;
     const QTextCursor cursor = range.begin.toTextCursor(sourceDocument());
-    const QString text = suggestions()[currentSuggestion()].text;
+    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();
 
     int firstLineEnd = text.indexOf('\n');
     if (firstLineEnd != -1) {
         QString firstLine = text.left(firstLineEnd);
         QString restOfText = text.mid(firstLineEnd);
 
-        editCursor.movePosition(QTextCursor::EndOfBlock, QTextCursor::KeepAnchor);
-        editCursor.removeSelectedText();
-
-        QString mergedFirstLine = mergeWithRightText(firstLine, textAfterCursor);
-        editCursor.insertText(mergedFirstLine + restOfText);
+        int replaceLength = calculateReplaceLength(firstLine, textAfterCursor, entireLine);
+        
+        if (replaceLength > 0) {
+            editCursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, replaceLength);
+            editCursor.removeSelectedText();
+        }
+        
+        editCursor.insertText(firstLine + restOfText);
     } else {
-        editCursor.movePosition(QTextCursor::EndOfBlock, QTextCursor::KeepAnchor);
-        editCursor.removeSelectedText();
-
-        QString mergedText = mergeWithRightText(text, textAfterCursor);
-        editCursor.insertText(mergedText);
+        int replaceLength = calculateReplaceLength(text, textAfterCursor, entireLine);
+        
+        if (replaceLength > 0) {
+            editCursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, replaceLength);
+            editCursor.removeSelectedText();
+        }
+        
+        editCursor.insertText(text);
     }
 
+    editCursor.endEditBlock();
     return true;
 }
 
 } // namespace QodeAssist
+

LLMSuggestion.hpp

@@ -41,5 +41,9 @@ public:
     bool applyLine(TextEditor::TextEditorWidget *widget) override;
     bool applyPart(Part part, TextEditor::TextEditorWidget *widget);
     bool apply() override;
+
+    static int calculateReplaceLength(const QString &suggestion, 
+                                     const QString &rightText,
+                                     const QString &entireLine);
 };
 } // namespace QodeAssist

test/CMakeLists.txt

@@ -1,8 +1,10 @@
 add_executable(QodeAssistTest
     ../CodeHandler.cpp
     ../LLMClientInterface.cpp
+    ../LLMSuggestion.cpp
     CodeHandlerTest.cpp
     DocumentContextReaderTest.cpp
+    LLMSuggestionTest.cpp
     # LLMClientInterfaceTests.cpp
     unittest_main.cpp
 )

test/LLMSuggestionTest.cpp

@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2024-2025 Petr Mironychev
+ *
+ * This file is part of QodeAssist.
+ *
+ * QodeAssist is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * QodeAssist is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with QodeAssist. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "LLMSuggestion.hpp"
+#include "TestUtils.hpp"
+
+#include <gtest/gtest.h>
+#include <QObject>
+#include <QString>
+
+using namespace QodeAssist;
+
+class LLMSuggestionTest : public QObject, public testing::Test
+{
+    Q_OBJECT
+};
+
+// Basic tests
+TEST_F(LLMSuggestionTest, testCalculateReplaceLengthEmptyRight)
+{
+    int result = LLMSuggestion::calculateReplaceLength("foo", "", "foo");
+    EXPECT_EQ(result, 0); // No rightText to replace
+}
+
+TEST_F(LLMSuggestionTest, testCalculateReplaceLengthNoOverlap)
+{
+    // No structural or token overlap
+    int result = LLMSuggestion::calculateReplaceLength("foo", "bar", "foobar");
+    EXPECT_EQ(result, 0); // Just insert, don't replace
+}
+
+// Structural overlap tests
+TEST_F(LLMSuggestionTest, testCalculateReplaceLengthStructuralBraces)
+{
+    // suggestion contains {}, rightText contains {}
+    int result = LLMSuggestion::calculateReplaceLength("= {\"red\"}", "{};", "colors{};");
+    EXPECT_EQ(result, 3); // Replace all rightText
+}
+
+TEST_F(LLMSuggestionTest, testCalculateReplaceLengthStructuralSemicolon)
+{
+    // suggestion contains ;, rightText contains ;
+    int result = LLMSuggestion::calculateReplaceLength("x;", ";", "int x;");
+    EXPECT_EQ(result, 1); // Replace the ;
+}
+
+TEST_F(LLMSuggestionTest, testCalculateReplaceLengthStructuralParens)
+{
+    // suggestion contains (), rightText contains )
+    int result = LLMSuggestion::calculateReplaceLength("arg1, arg2)", ")", "foo(arg1, arg2)");
+    EXPECT_EQ(result, 1); // Replace the )
+}
+
+TEST_F(LLMSuggestionTest, testCalculateReplaceLengthStructuralBrackets)
+{
+    // suggestion contains [], rightText contains ]
+    int result = LLMSuggestion::calculateReplaceLength("[0]", "];", "arr[0];");
+    EXPECT_EQ(result, 2); // Replace ];
+}
+
+// Token overlap tests
+TEST_F(LLMSuggestionTest, testCalculateReplaceLengthCommonToken)
+{
+    // 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
+}
+
+TEST_F(LLMSuggestionTest, testCalculateReplaceLengthMultipleCommonTokens)
+{
+    // Multiple tokens in common
+    int result = LLMSuggestion::calculateReplaceLength("engine.load()", "engine.rootContext()", "QmlEngine engine.rootContext()");
+    EXPECT_EQ(result, 20); // Replace all rightText
+}
+
+// Real-world scenarios
+TEST_F(LLMSuggestionTest, testCursorInBraces)
+{
+    // 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
+}
+
+TEST_F(LLMSuggestionTest, testCursorBeforeBraces)
+{
+    // 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
+}
+
+TEST_F(LLMSuggestionTest, testCursorAfterType)
+{
+    // 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
+}
+
+TEST_F(LLMSuggestionTest, testCursorInMiddleNoConflict)
+{
+    // 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
+}
+
+TEST_F(LLMSuggestionTest, testCursorWithEqualsSign)
+{
+    // LLM sends code with = and ;
+    int result = LLMSuggestion::calculateReplaceLength("= 5;", ";", "int x;");
+    EXPECT_EQ(result, 1); // Structural overlap on ;
+}
+
+// Edge cases
+TEST_F(LLMSuggestionTest, testNoStructuralButHasToken)
+{
+    // 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)
+}
+
+TEST_F(LLMSuggestionTest, testOnlyWhitespace)
+{
+    // 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
+}
+
+#include "LLMSuggestionTest.moc"