/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2020 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 6 End-User License
   Agreement and JUCE Privacy Policy (both effective as of the 16th June 2020).

   End User License Agreement: www.juce.com/juce-6-licence
   Privacy Policy: www.juce.com/juce-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

//==============================================================================
class CodeEditorComponent::CodeEditorAccessibilityHandler  : public AccessibilityHandler
{
public:
    explicit CodeEditorAccessibilityHandler (CodeEditorComponent& codeEditorComponentToWrap)
        : AccessibilityHandler (codeEditorComponentToWrap,
                                codeEditorComponentToWrap.isReadOnly() ? AccessibilityRole::staticText
                                                                       : AccessibilityRole::editableText,
                                {},
                                { std::make_unique<CodeEditorComponentTextInterface> (codeEditorComponentToWrap) })
    {
    }

private:
    class CodeEditorComponentTextInterface  : public AccessibilityTextInterface
    {
    public:
        explicit CodeEditorComponentTextInterface (CodeEditorComponent& codeEditorComponentToWrap)
            : codeEditorComponent (codeEditorComponentToWrap)
        {
        }

        bool isDisplayingProtectedText() const override
        {
            return false;
        }

        bool isReadOnly() const override
        {
            return codeEditorComponent.isReadOnly();
        }

        int getTotalNumCharacters() const override
        {
            return codeEditorComponent.document.getAllContent().length();
        }

        Range<int> getSelection() const override
        {
            return { codeEditorComponent.selectionStart.getPosition(),
                     codeEditorComponent.selectionEnd.getPosition() };
        }

        void setSelection (Range<int> r) override
        {
            if (r.isEmpty())
            {
                codeEditorComponent.caretPos.setPosition (r.getStart());
                return;
            }

            auto& doc = codeEditorComponent.document;

            codeEditorComponent.selectRegion (CodeDocument::Position (doc, r.getStart()),
                                              CodeDocument::Position (doc, r.getEnd()));
        }

        String getText (Range<int> r) const override
        {
            auto& doc = codeEditorComponent.document;

            return doc.getTextBetween (CodeDocument::Position (doc, r.getStart()),
                                       CodeDocument::Position (doc, r.getEnd()));
        }

        void setText (const String& newText) override
        {
            codeEditorComponent.document.replaceAllContent (newText);
        }

        int getTextInsertionOffset() const override
        {
            return codeEditorComponent.caretPos.getPosition();
        }

        RectangleList<int> getTextBounds (Range<int> textRange) const override
        {
            auto& doc = codeEditorComponent.document;

            RectangleList<int> localRects;

            CodeDocument::Position startPosition (doc, textRange.getStart());
            CodeDocument::Position endPosition   (doc, textRange.getEnd());

            for (int line = startPosition.getLineNumber(); line <= endPosition.getLineNumber(); ++line)
            {
                CodeDocument::Position lineStart (doc, line, 0);
                CodeDocument::Position lineEnd   (doc, line, doc.getLine (line).length());

                if (line == startPosition.getLineNumber())
                    lineStart = lineStart.movedBy (startPosition.getIndexInLine());

                if (line == endPosition.getLineNumber())
                    lineEnd = { doc, line, endPosition.getIndexInLine() };

                auto startPos = codeEditorComponent.getCharacterBounds (lineStart).getTopLeft();
                auto endPos = codeEditorComponent.getCharacterBounds (lineEnd).getTopLeft();

                localRects.add (startPos.x,
                                startPos.y,
                                endPos.x - startPos.x,
                                codeEditorComponent.getLineHeight());
            }

            RectangleList<int> globalRects;

            for (auto r : localRects)
                globalRects.add (codeEditorComponent.localAreaToGlobal (r));

            return globalRects;
        }

        int getOffsetAtPoint (Point<int> point) const override
        {
            return codeEditorComponent.getPositionAt (point.x, point.y).getPosition();
        }

    private:
        CodeEditorComponent& codeEditorComponent;
    };

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (CodeEditorAccessibilityHandler)
};

//==============================================================================
class CodeEditorComponent::CodeEditorLine
{
public:
    CodeEditorLine() noexcept {}

    bool update (CodeDocument& codeDoc, int lineNum,
                 CodeDocument::Iterator& source,
                 CodeTokeniser* tokeniser, const int tabSpaces,
                 const CodeDocument::Position& selStart,
                 const CodeDocument::Position& selEnd)
    {
        Array<SyntaxToken> newTokens;
        newTokens.ensureStorageAllocated (8);

        if (tokeniser == nullptr)
        {
            auto line = codeDoc.getLine (lineNum);
            addToken (newTokens, line, line.length(), -1);
        }
        else if (lineNum < codeDoc.getNumLines())
        {
            const CodeDocument::Position pos (codeDoc, lineNum, 0);
            createTokens (pos.getPosition(), pos.getLineText(),
                          source, *tokeniser, newTokens);
        }

        replaceTabsWithSpaces (newTokens, tabSpaces);

        int newHighlightStart = 0;
        int newHighlightEnd = 0;

        if (selStart.getLineNumber() <= lineNum && selEnd.getLineNumber() >= lineNum)
        {
            auto line = codeDoc.getLine (lineNum);

            CodeDocument::Position lineStart (codeDoc, lineNum, 0), lineEnd (codeDoc, lineNum + 1, 0);
            newHighlightStart = indexToColumn (jmax (0, selStart.getPosition() - lineStart.getPosition()),
                                               line, tabSpaces);
            newHighlightEnd = indexToColumn (jmin (lineEnd.getPosition() - lineStart.getPosition(), selEnd.getPosition() - lineStart.getPosition()),
                                             line, tabSpaces);
        }

        if (newHighlightStart != highlightColumnStart || newHighlightEnd != highlightColumnEnd)
        {
            highlightColumnStart = newHighlightStart;
            highlightColumnEnd = newHighlightEnd;
        }
        else if (tokens == newTokens)
        {
            return false;
        }

        tokens.swapWith (newTokens);
        return true;
    }

    void getHighlightArea (RectangleList<float>& area, float x, int y, int lineH, float characterWidth) const
    {
        if (highlightColumnStart < highlightColumnEnd)
            area.add (Rectangle<float> (x + (float) highlightColumnStart * characterWidth - 1.0f, (float) y - 0.5f,
                                        (float) (highlightColumnEnd - highlightColumnStart) * characterWidth + 1.5f, (float) lineH + 1.0f));
    }

    void draw (CodeEditorComponent& owner, Graphics& g, const Font& fontToUse,
               const float rightClip, const float x, const int y,
               const int lineH, const float characterWidth) const
    {
        AttributedString as;
        as.setJustification (Justification::centredLeft);

        int column = 0;

        for (auto& token : tokens)
        {
            const float tokenX = x + (float) column * characterWidth;
            if (tokenX > rightClip)
                break;

            as.append (token.text.initialSectionNotContaining ("\r\n"), fontToUse, owner.getColourForTokenType (token.tokenType));
            column += token.length;
        }

        as.draw (g, { x, (float) y, (float) column * characterWidth + 10.0f, (float) lineH });
    }

private:
    struct SyntaxToken
    {
        SyntaxToken (const String& t, const int len, const int type) noexcept
            : text (t), length (len), tokenType (type)
        {}

        bool operator== (const SyntaxToken& other) const noexcept
        {
            return tokenType == other.tokenType
                    && length == other.length
                    && text == other.text;
        }

        String text;
        int length;
        int tokenType;
    };

    Array<SyntaxToken> tokens;
    int highlightColumnStart = 0, highlightColumnEnd = 0;

    static void createTokens (int startPosition, const String& lineText,
                              CodeDocument::Iterator& source,
                              CodeTokeniser& tokeniser,
                              Array<SyntaxToken>& newTokens)
    {
        CodeDocument::Iterator lastIterator (source);
        const int lineLength = lineText.length();

        for (;;)
        {
            int tokenType = tokeniser.readNextToken (source);
            int tokenStart = lastIterator.getPosition();
            int tokenEnd = source.getPosition();

            if (tokenEnd <= tokenStart)
                break;

            tokenEnd -= startPosition;

            if (tokenEnd > 0)
            {
                tokenStart -= startPosition;
                const int start = jmax (0, tokenStart);
                addToken (newTokens, lineText.substring (start, tokenEnd),
                          tokenEnd - start, tokenType);

                if (tokenEnd >= lineLength)
                    break;
            }

            lastIterator = source;
        }

        source = lastIterator;
    }

    static void replaceTabsWithSpaces (Array<SyntaxToken>& tokens, const int spacesPerTab)
    {
        int x = 0;

        for (auto& t : tokens)
        {
            for (;;)
            {
                const int tabPos = t.text.indexOfChar ('\t');
                if (tabPos < 0)
                    break;

                const int spacesNeeded = spacesPerTab - ((tabPos + x) % spacesPerTab);
                t.text = t.text.replaceSection (tabPos, 1, String::repeatedString (" ", spacesNeeded));
                t.length = t.text.length();
            }

            x += t.length;
        }
    }

    int indexToColumn (int index, const String& line, int tabSpaces) const noexcept
    {
        jassert (index <= line.length());

        auto t = line.getCharPointer();
        int col = 0;

        for (int i = 0; i < index; ++i)
        {
            if (t.getAndAdvance() != '\t')
                ++col;
            else
                col += tabSpaces - (col % tabSpaces);
        }

        return col;
    }

    static void addToken (Array<SyntaxToken>& dest, const String& text, int length, int type)
    {
        if (length > 1000)
        {
            // subdivide very long tokens to avoid unwieldy glyph sequences
            addToken (dest, text.substring (0, length / 2), length / 2, type);
            addToken (dest, text.substring (length / 2), length - length / 2, type);
        }
        else
        {
            dest.add (SyntaxToken (text, length, type));
        }
    }
};

namespace CodeEditorHelpers
{
    static int findFirstNonWhitespaceChar (StringRef line) noexcept
    {
        auto t = line.text;
        int i = 0;

        while (! t.isEmpty())
        {
            if (! t.isWhitespace())
                return i;

            ++t;
            ++i;
        }

        return 0;
    }
}

//==============================================================================
class CodeEditorComponent::Pimpl   : public Timer,
                                     public AsyncUpdater,
                                     public ScrollBar::Listener,
                                     public CodeDocument::Listener
{
public:
    Pimpl (CodeEditorComponent& ed) : owner (ed) {}

private:
    CodeEditorComponent& owner;

    void timerCallback() override        { owner.newTransaction(); }
    void handleAsyncUpdate() override    { owner.rebuildLineTokens(); }

    void scrollBarMoved (ScrollBar* scrollBarThatHasMoved, double newRangeStart) override
    {
        if (scrollBarThatHasMoved->isVertical())
            owner.scrollToLineInternal ((int) newRangeStart);
        else
            owner.scrollToColumnInternal (newRangeStart);
    }

    void codeDocumentTextInserted (const String& newText, int pos) override
    {
        owner.codeDocumentChanged (pos, pos + newText.length());
    }

    void codeDocumentTextDeleted (int start, int end) override
    {
        owner.codeDocumentChanged (start, end);
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Pimpl)
};

//==============================================================================
class CodeEditorComponent::GutterComponent  : public Component
{
public:
    GutterComponent() {}

    void paint (Graphics& g) override
    {
        jassert (dynamic_cast<CodeEditorComponent*> (getParentComponent()) != nullptr);
        auto& editor = *static_cast<CodeEditorComponent*> (getParentComponent());

        g.fillAll (editor.findColour (CodeEditorComponent::backgroundColourId)
                    .overlaidWith (editor.findColour (lineNumberBackgroundId)));

        auto clip = g.getClipBounds();
        const int lineH = editor.lineHeight;
        const float lineHeightFloat = (float) lineH;
        const int firstLineToDraw = jmax (0, clip.getY() / lineH);
        const int lastLineToDraw = jmin (editor.lines.size(), clip.getBottom() / lineH + 1,
                                         lastNumLines - editor.firstLineOnScreen);

        auto lineNumberFont = editor.getFont().withHeight (jmin (13.0f, lineHeightFloat * 0.8f));
        auto w = (float) getWidth() - 2.0f;
        GlyphArrangement ga;

        for (int i = firstLineToDraw; i < lastLineToDraw; ++i)
            ga.addFittedText (lineNumberFont, String (editor.firstLineOnScreen + i + 1),
                              0, (float) (lineH * i), w, lineHeightFloat,
                              Justification::centredRight, 1, 0.2f);

        g.setColour (editor.findColour (lineNumberTextId));
        ga.draw (g);
    }

    void documentChanged (CodeDocument& doc, int newFirstLine)
    {
        auto newNumLines = doc.getNumLines();

        if (newNumLines != lastNumLines || firstLine != newFirstLine)
        {
            firstLine = newFirstLine;
            lastNumLines = newNumLines;
            repaint();
        }
    }

private:
    int firstLine = 0, lastNumLines = 0;
};


//==============================================================================
CodeEditorComponent::CodeEditorComponent (CodeDocument& doc, CodeTokeniser* const tokeniser)
    : document (doc),
      caretPos (doc, 0, 0),
      selectionStart (doc, 0, 0),
      selectionEnd (doc, 0, 0),
      codeTokeniser (tokeniser)
{
    pimpl.reset (new Pimpl (*this));

    caretPos.setPositionMaintained (true);
    selectionStart.setPositionMaintained (true);
    selectionEnd.setPositionMaintained (true);

    setOpaque (true);
    setMouseCursor (MouseCursor::IBeamCursor);
    setWantsKeyboardFocus (true);

    addAndMakeVisible (verticalScrollBar);
    verticalScrollBar.setSingleStepSize (1.0);

    addAndMakeVisible (horizontalScrollBar);
    horizontalScrollBar.setSingleStepSize (1.0);

    Font f (12.0f);
    f.setTypefaceName (Font::getDefaultMonospacedFontName());
    setFont (f);

    if (codeTokeniser != nullptr)
        setColourScheme (codeTokeniser->getDefaultColourScheme());

    setLineNumbersShown (true);

    verticalScrollBar.addListener (pimpl.get());
    horizontalScrollBar.addListener (pimpl.get());
    document.addListener (pimpl.get());

    lookAndFeelChanged();
}

CodeEditorComponent::~CodeEditorComponent()
{
    document.removeListener (pimpl.get());
}

int CodeEditorComponent::getGutterSize() const noexcept
{
    return showLineNumbers ? 35 : 5;
}

void CodeEditorComponent::loadContent (const String& newContent)
{
    clearCachedIterators (0);
    document.replaceAllContent (newContent);
    document.clearUndoHistory();
    document.setSavePoint();
    caretPos.setPosition (0);
    selectionStart.setPosition (0);
    selectionEnd.setPosition (0);
    scrollToLine (0);
}

bool CodeEditorComponent::isTextInputActive() const
{
    return true;
}

void CodeEditorComponent::setTemporaryUnderlining (const Array<Range<int>>&)
{
    jassertfalse; // TODO Windows IME not yet supported for this comp..
}

Rectangle<int> CodeEditorComponent::getCaretRectangle()
{
    if (caret != nullptr)
        return getLocalArea (caret.get(), caret->getLocalBounds());

    return {};
}

void CodeEditorComponent::setLineNumbersShown (const bool shouldBeShown)
{
    if (showLineNumbers != shouldBeShown)
    {
        showLineNumbers = shouldBeShown;
        gutter.reset();

        if (shouldBeShown)
        {
            gutter.reset (new GutterComponent());
            addAndMakeVisible (gutter.get());
        }

        resized();
    }
}

void CodeEditorComponent::setReadOnly (bool b) noexcept
{
    if (readOnly != b)
    {
        readOnly = b;

        if (b)
            removeChildComponent (caret.get());
        else
            addAndMakeVisible (caret.get());

        invalidateAccessibilityHandler();
    }
}

//==============================================================================
void CodeEditorComponent::resized()
{
    auto visibleWidth = getWidth() - scrollbarThickness - getGutterSize();
    linesOnScreen   = jmax (1, (getHeight() - scrollbarThickness) / lineHeight);
    columnsOnScreen = jmax (1, (int) ((float) visibleWidth / charWidth));
    lines.clear();
    rebuildLineTokens();
    updateCaretPosition();

    if (gutter != nullptr)
        gutter->setBounds (0, 0, getGutterSize() - 2, getHeight());

    verticalScrollBar.setBounds (getWidth() - scrollbarThickness, 0,
                                 scrollbarThickness, getHeight() - scrollbarThickness);

    horizontalScrollBar.setBounds (getGutterSize(), getHeight() - scrollbarThickness,
                                   visibleWidth, scrollbarThickness);
    updateScrollBars();
}

void CodeEditorComponent::paint (Graphics& g)
{
    g.fillAll (findColour (CodeEditorComponent::backgroundColourId));

    auto gutterSize = getGutterSize();
    auto bottom = horizontalScrollBar.isVisible() ? horizontalScrollBar.getY() : getHeight();
    auto right  = verticalScrollBar.isVisible()   ? verticalScrollBar.getX()   : getWidth();

    g.reduceClipRegion (gutterSize, 0, right - gutterSize, bottom);

    g.setFont (font);

    auto clip = g.getClipBounds();
    auto firstLineToDraw = jmax (0, clip.getY() / lineHeight);
    auto lastLineToDraw  = jmin (lines.size(), clip.getBottom() / lineHeight + 1);
    auto x = (float) (gutterSize - xOffset * charWidth);
    auto rightClip = (float) clip.getRight();

    {
        RectangleList<float> highlightArea;

        for (int i = firstLineToDraw; i < lastLineToDraw; ++i)
            lines.getUnchecked(i)->getHighlightArea (highlightArea, x, lineHeight * i, lineHeight, charWidth);

        g.setColour (findColour (CodeEditorComponent::highlightColourId));
        g.fillRectList (highlightArea);
    }

    for (int i = firstLineToDraw; i < lastLineToDraw; ++i)
        lines.getUnchecked(i)->draw (*this, g, font, rightClip, x, lineHeight * i, lineHeight, charWidth);
}

void CodeEditorComponent::setScrollbarThickness (const int thickness)
{
    if (scrollbarThickness != thickness)
    {
        scrollbarThickness = thickness;
        resized();
    }
}

void CodeEditorComponent::rebuildLineTokensAsync()
{
    pimpl->triggerAsyncUpdate();
}

void CodeEditorComponent::rebuildLineTokens()
{
    pimpl->cancelPendingUpdate();

    auto numNeeded = linesOnScreen + 1;
    auto minLineToRepaint = numNeeded;
    int maxLineToRepaint = 0;

    if (numNeeded != lines.size())
    {
        lines.clear();

        for (int i = numNeeded; --i >= 0;)
            lines.add (new CodeEditorLine());

        minLineToRepaint = 0;
        maxLineToRepaint = numNeeded;
    }

    jassert (numNeeded == lines.size());

    CodeDocument::Iterator source (document);
    getIteratorForPosition (CodeDocument::Position (document, firstLineOnScreen, 0).getPosition(), source);

    for (int i = 0; i < numNeeded; ++i)
    {
        if (lines.getUnchecked(i)->update (document, firstLineOnScreen + i, source, codeTokeniser,
                                           spacesPerTab, selectionStart, selectionEnd))
        {
            minLineToRepaint = jmin (minLineToRepaint, i);
            maxLineToRepaint = jmax (maxLineToRepaint, i);
        }
    }

    if (minLineToRepaint <= maxLineToRepaint)
        repaint (0, lineHeight * minLineToRepaint - 1,
                 verticalScrollBar.getX(), lineHeight * (1 + maxLineToRepaint - minLineToRepaint) + 2);

    if (gutter != nullptr)
        gutter->documentChanged (document, firstLineOnScreen);
}

void CodeEditorComponent::codeDocumentChanged (const int startIndex, const int endIndex)
{
    const CodeDocument::Position affectedTextStart (document, startIndex);
    const CodeDocument::Position affectedTextEnd (document, endIndex);

    retokenise (startIndex, endIndex);

    updateCaretPosition();
    columnToTryToMaintain = -1;

    if (affectedTextEnd.getPosition() >= selectionStart.getPosition()
         && affectedTextStart.getPosition() <= selectionEnd.getPosition())
        deselectAll();

    if (shouldFollowDocumentChanges)
        if (caretPos.getPosition() > affectedTextEnd.getPosition()
            || caretPos.getPosition() < affectedTextStart.getPosition())
            moveCaretTo (affectedTextStart, false);

    updateScrollBars();
}

void CodeEditorComponent::retokenise (int startIndex, int endIndex)
{
    const CodeDocument::Position affectedTextStart (document, startIndex);
    juce::ignoreUnused (endIndex); // Leave room for more efficient impl in future.

    clearCachedIterators (affectedTextStart.getLineNumber());

    rebuildLineTokensAsync();
}

//==============================================================================
void CodeEditorComponent::updateCaretPosition()
{
    if (caret != nullptr)
    {
        caret->setCaretPosition (getCharacterBounds (getCaretPos()));

        if (auto* handler = getAccessibilityHandler())
            handler->notifyAccessibilityEvent (AccessibilityEvent::textSelectionChanged);
    }
}

void CodeEditorComponent::moveCaretTo (const CodeDocument::Position& newPos, const bool highlighting)
{
    caretPos = newPos;
    columnToTryToMaintain = -1;
    bool selectionWasActive = isHighlightActive();

    if (highlighting)
    {
        if (dragType == notDragging)
        {
            auto oldCaretPos = caretPos.getPosition();
            auto isStart = std::abs (oldCaretPos - selectionStart.getPosition())
                            < std::abs (oldCaretPos - selectionEnd.getPosition());

            dragType = isStart ? draggingSelectionStart : draggingSelectionEnd;
        }

        if (dragType == draggingSelectionStart)
        {
            if (selectionEnd.getPosition() < caretPos.getPosition())
            {
                setSelection (selectionEnd, caretPos);
                dragType = draggingSelectionEnd;
            }
            else
            {
                setSelection (caretPos, selectionEnd);
            }
        }
        else
        {
            if (caretPos.getPosition() < selectionStart.getPosition())
            {
                setSelection (caretPos, selectionStart);
                dragType = draggingSelectionStart;
            }
            else
            {
                setSelection (selectionStart, caretPos);
            }
        }

        rebuildLineTokensAsync();
    }
    else
    {
        deselectAll();
    }

    updateCaretPosition();
    scrollToKeepCaretOnScreen();
    updateScrollBars();
    caretPositionMoved();

    if (auto* handler = getAccessibilityHandler())
        handler->notifyAccessibilityEvent (AccessibilityEvent::textChanged);

    if (appCommandManager != nullptr && selectionWasActive != isHighlightActive())
        appCommandManager->commandStatusChanged();
}

void CodeEditorComponent::deselectAll()
{
    if (isHighlightActive())
        rebuildLineTokensAsync();

    setSelection (caretPos, caretPos);
    dragType = notDragging;
}

void CodeEditorComponent::updateScrollBars()
{
    verticalScrollBar.setRangeLimits (0, jmax (document.getNumLines(), firstLineOnScreen + linesOnScreen));
    verticalScrollBar.setCurrentRange (firstLineOnScreen, linesOnScreen);

    horizontalScrollBar.setRangeLimits (0, jmax ((double) document.getMaximumLineLength(), xOffset + columnsOnScreen));
    horizontalScrollBar.setCurrentRange (xOffset, columnsOnScreen);
}

void CodeEditorComponent::scrollToLineInternal (int newFirstLineOnScreen)
{
    newFirstLineOnScreen = jlimit (0, jmax (0, document.getNumLines() - 1),
                                   newFirstLineOnScreen);

    if (newFirstLineOnScreen != firstLineOnScreen)
    {
        firstLineOnScreen = newFirstLineOnScreen;
        updateCaretPosition();

        updateCachedIterators (firstLineOnScreen);
        rebuildLineTokensAsync();
        pimpl->handleUpdateNowIfNeeded();

        editorViewportPositionChanged();
    }
}

void CodeEditorComponent::scrollToColumnInternal (double column)
{
    const double newOffset = jlimit (0.0, document.getMaximumLineLength() + 3.0, column);

    if (xOffset != newOffset)
    {
        xOffset = newOffset;
        updateCaretPosition();
        repaint();
    }
}

void CodeEditorComponent::scrollToLine (int newFirstLineOnScreen)
{
    scrollToLineInternal (newFirstLineOnScreen);
    updateScrollBars();
}

void CodeEditorComponent::scrollToColumn (int newFirstColumnOnScreen)
{
    scrollToColumnInternal (newFirstColumnOnScreen);
    updateScrollBars();
}

void CodeEditorComponent::scrollBy (int deltaLines)
{
    scrollToLine (firstLineOnScreen + deltaLines);
}

void CodeEditorComponent::scrollToKeepLinesOnScreen (Range<int> rangeToShow)
{
    if (rangeToShow.getStart() < firstLineOnScreen)
        scrollBy (rangeToShow.getStart() - firstLineOnScreen);
    else if (rangeToShow.getEnd() >= firstLineOnScreen + linesOnScreen)
        scrollBy (rangeToShow.getEnd() - (firstLineOnScreen + linesOnScreen - 1));
}

void CodeEditorComponent::scrollToKeepCaretOnScreen()
{
    if (getWidth() > 0 && getHeight() > 0)
    {
        auto caretLine = caretPos.getLineNumber();
        scrollToKeepLinesOnScreen ({ caretLine, caretLine });

        auto column = indexToColumn (caretPos.getLineNumber(), caretPos.getIndexInLine());

        if (column >= xOffset + columnsOnScreen - 1)
            scrollToColumn (column + 1 - columnsOnScreen);
        else if (column < xOffset)
            scrollToColumn (column);
    }
}

Rectangle<int> CodeEditorComponent::getCharacterBounds (const CodeDocument::Position& pos) const
{
    return { roundToInt ((getGutterSize() - xOffset * charWidth) + (float) indexToColumn (pos.getLineNumber(), pos.getIndexInLine()) * charWidth),
             (pos.getLineNumber() - firstLineOnScreen) * lineHeight,
             roundToInt (charWidth),
             lineHeight };
}

CodeDocument::Position CodeEditorComponent::getPositionAt (int x, int y) const
{
    const int line = y / lineHeight + firstLineOnScreen;
    const int column = roundToInt ((x - (getGutterSize() - xOffset * charWidth)) / charWidth);
    const int index = columnToIndex (line, column);

    return CodeDocument::Position (document, line, index);
}

//==============================================================================
void CodeEditorComponent::insertTextAtCaret (const String& newText)
{
    insertText (newText);
}

void CodeEditorComponent::insertText (const String& newText)
{
    if (! readOnly)
    {
        document.deleteSection (selectionStart, selectionEnd);

        if (newText.isNotEmpty())
            document.insertText (caretPos, newText);

        scrollToKeepCaretOnScreen();
        caretPositionMoved();

        if (auto* handler = getAccessibilityHandler())
            handler->notifyAccessibilityEvent (AccessibilityEvent::textChanged);
    }
}

void CodeEditorComponent::insertTabAtCaret()
{
    if (! readOnly)
    {
        if (CharacterFunctions::isWhitespace (caretPos.getCharacter())
             && caretPos.getLineNumber() == caretPos.movedBy (1).getLineNumber())
        {
            moveCaretTo (document.findWordBreakAfter (caretPos), false);
        }

        if (useSpacesForTabs)
        {
            auto caretCol = indexToColumn (caretPos.getLineNumber(), caretPos.getIndexInLine());
            auto spacesNeeded = spacesPerTab - (caretCol % spacesPerTab);
            insertTextAtCaret (String::repeatedString (" ", spacesNeeded));
        }
        else
        {
            insertTextAtCaret ("\t");
        }
    }
}

bool CodeEditorComponent::deleteWhitespaceBackwardsToTabStop()
{
    if (getHighlightedRegion().isEmpty() && ! readOnly)
    {
        for (;;)
        {
            auto currentColumn = indexToColumn (caretPos.getLineNumber(), caretPos.getIndexInLine());

            if (currentColumn <= 0 || (currentColumn % spacesPerTab) == 0)
                break;

            moveCaretLeft (false, true);
        }

        auto selected = getTextInRange (getHighlightedRegion());

        if (selected.isNotEmpty() && selected.trim().isEmpty())
        {
            cut();
            return true;
        }
    }

    return false;
}

void CodeEditorComponent::indentSelection()     { indentSelectedLines ( spacesPerTab); }
void CodeEditorComponent::unindentSelection()   { indentSelectedLines (-spacesPerTab); }

void CodeEditorComponent::indentSelectedLines (const int spacesToAdd)
{
    if (! readOnly)
    {
        newTransaction();

        CodeDocument::Position oldSelectionStart (selectionStart), oldSelectionEnd (selectionEnd), oldCaret (caretPos);
        oldSelectionStart.setPositionMaintained (true);
        oldSelectionEnd.setPositionMaintained (true);
        oldCaret.setPositionMaintained (true);

        const int lineStart = selectionStart.getLineNumber();
        int lineEnd = selectionEnd.getLineNumber();

        if (lineEnd > lineStart && selectionEnd.getIndexInLine() == 0)
            --lineEnd;

        for (int line = lineStart; line <= lineEnd; ++line)
        {
            auto lineText = document.getLine (line);
            auto nonWhitespaceStart = CodeEditorHelpers::findFirstNonWhitespaceChar (lineText);

            if (nonWhitespaceStart > 0 || lineText.trimStart().isNotEmpty())
            {
                const CodeDocument::Position wsStart (document, line, 0);
                const CodeDocument::Position wsEnd   (document, line, nonWhitespaceStart);

                const int numLeadingSpaces = indexToColumn (line, wsEnd.getIndexInLine());
                const int newNumLeadingSpaces = jmax (0, numLeadingSpaces + spacesToAdd);

                if (newNumLeadingSpaces != numLeadingSpaces)
                {
                    document.deleteSection (wsStart, wsEnd);
                    document.insertText (wsStart, getTabString (newNumLeadingSpaces));
                }
            }
        }

        setSelection (oldSelectionStart, oldSelectionEnd);

        if (caretPos != oldCaret)
        {
            caretPos = oldCaret;

            if (auto* handler = getAccessibilityHandler())
                handler->notifyAccessibilityEvent (AccessibilityEvent::textChanged);
        }
    }
}

void CodeEditorComponent::cut()
{
    insertText ({});
}

bool CodeEditorComponent::copyToClipboard()
{
    newTransaction();
    auto selection = document.getTextBetween (selectionStart, selectionEnd);

    if (selection.isNotEmpty())
        SystemClipboard::copyTextToClipboard (selection);

    return true;
}

bool CodeEditorComponent::cutToClipboard()
{
    copyToClipboard();
    cut();
    newTransaction();
    return true;
}

bool CodeEditorComponent::pasteFromClipboard()
{
    newTransaction();
    auto clip = SystemClipboard::getTextFromClipboard();

    if (clip.isNotEmpty())
        insertText (clip);

    newTransaction();
    return true;
}

bool CodeEditorComponent::moveCaretLeft (const bool moveInWholeWordSteps, const bool selecting)
{
    newTransaction();

    if (selecting && dragType == notDragging)
    {
        selectRegion (CodeDocument::Position (selectionEnd), CodeDocument::Position (selectionStart));
        dragType = draggingSelectionStart;
    }

    if (isHighlightActive() && ! (selecting || moveInWholeWordSteps))
    {
        moveCaretTo (selectionStart, false);
        return true;
    }

    if (moveInWholeWordSteps)
        moveCaretTo (document.findWordBreakBefore (caretPos), selecting);
    else
        moveCaretTo (caretPos.movedBy (-1), selecting);

    return true;
}

bool CodeEditorComponent::moveCaretRight (const bool moveInWholeWordSteps, const bool selecting)
{
    newTransaction();

    if (selecting && dragType == notDragging)
    {
        selectRegion (CodeDocument::Position (selectionStart), CodeDocument::Position (selectionEnd));
        dragType = draggingSelectionEnd;
    }

    if (isHighlightActive() && ! (selecting || moveInWholeWordSteps))
    {
        moveCaretTo (selectionEnd, false);
        return true;
    }

    if (moveInWholeWordSteps)
        moveCaretTo (document.findWordBreakAfter (caretPos), selecting);
    else
        moveCaretTo (caretPos.movedBy (1), selecting);

    return true;
}

void CodeEditorComponent::moveLineDelta (const int delta, const bool selecting)
{
    CodeDocument::Position pos (caretPos);
    auto newLineNum = pos.getLineNumber() + delta;

    if (columnToTryToMaintain < 0)
        columnToTryToMaintain = indexToColumn (pos.getLineNumber(), pos.getIndexInLine());

    pos.setLineAndIndex (newLineNum, columnToIndex (newLineNum, columnToTryToMaintain));

    auto colToMaintain = columnToTryToMaintain;
    moveCaretTo (pos, selecting);
    columnToTryToMaintain = colToMaintain;
}

bool CodeEditorComponent::moveCaretDown (const bool selecting)
{
    newTransaction();

    if (caretPos.getLineNumber() == document.getNumLines() - 1)
        moveCaretTo (CodeDocument::Position (document, std::numeric_limits<int>::max(), std::numeric_limits<int>::max()), selecting);
    else
        moveLineDelta (1, selecting);

    return true;
}

bool CodeEditorComponent::moveCaretUp (const bool selecting)
{
    newTransaction();

    if (caretPos.getLineNumber() == 0)
        moveCaretTo (CodeDocument::Position (document, 0, 0), selecting);
    else
        moveLineDelta (-1, selecting);

    return true;
}

bool CodeEditorComponent::pageDown (const bool selecting)
{
    newTransaction();
    scrollBy (jlimit (0, linesOnScreen, 1 + document.getNumLines() - firstLineOnScreen - linesOnScreen));
    moveLineDelta (linesOnScreen, selecting);
    return true;
}

bool CodeEditorComponent::pageUp (const bool selecting)
{
    newTransaction();
    scrollBy (-linesOnScreen);
    moveLineDelta (-linesOnScreen, selecting);
    return true;
}

bool CodeEditorComponent::scrollUp()
{
    newTransaction();
    scrollBy (1);

    if (caretPos.getLineNumber() < firstLineOnScreen)
        moveLineDelta (1, false);

    return true;
}

bool CodeEditorComponent::scrollDown()
{
    newTransaction();
    scrollBy (-1);

    if (caretPos.getLineNumber() >= firstLineOnScreen + linesOnScreen)
        moveLineDelta (-1, false);

    return true;
}

bool CodeEditorComponent::moveCaretToTop (const bool selecting)
{
    newTransaction();
    moveCaretTo (CodeDocument::Position (document, 0, 0), selecting);
    return true;
}

bool CodeEditorComponent::moveCaretToStartOfLine (const bool selecting)
{
    newTransaction();

    int index = CodeEditorHelpers::findFirstNonWhitespaceChar (caretPos.getLineText());

    if (index >= caretPos.getIndexInLine() && caretPos.getIndexInLine() > 0)
        index = 0;

    moveCaretTo (CodeDocument::Position (document, caretPos.getLineNumber(), index), selecting);
    return true;
}

bool CodeEditorComponent::moveCaretToEnd (const bool selecting)
{
    newTransaction();
    moveCaretTo (CodeDocument::Position (document, std::numeric_limits<int>::max(),
                                         std::numeric_limits<int>::max()), selecting);
    return true;
}

bool CodeEditorComponent::moveCaretToEndOfLine (const bool selecting)
{
    newTransaction();
    moveCaretTo (CodeDocument::Position (document, caretPos.getLineNumber(),
                                         std::numeric_limits<int>::max()), selecting);
    return true;
}

bool CodeEditorComponent::deleteBackwards (const bool moveInWholeWordSteps)
{
    if (moveInWholeWordSteps)
    {
        cut(); // in case something is already highlighted
        moveCaretTo (document.findWordBreakBefore (caretPos), true);
    }
    else if (selectionStart == selectionEnd && ! skipBackwardsToPreviousTab())
    {
        selectionStart.moveBy (-1);
    }

    cut();
    return true;
}

bool CodeEditorComponent::skipBackwardsToPreviousTab()
{
    auto currentLineText = caretPos.getLineText().removeCharacters ("\r\n");
    auto currentIndex = caretPos.getIndexInLine();

    if (currentLineText.isNotEmpty() && currentLineText.length() == currentIndex)
    {
        const int currentLine = caretPos.getLineNumber();
        const int currentColumn = indexToColumn (currentLine, currentIndex);
        const int previousTabColumn = (currentColumn - 1) - ((currentColumn - 1) % spacesPerTab);
        const int previousTabIndex = columnToIndex (currentLine, previousTabColumn);

        if (currentLineText.substring (previousTabIndex, currentIndex).trim().isEmpty())
        {
            selectionStart.moveBy (previousTabIndex - currentIndex);
            return true;
        }
    }

    return false;
}

bool CodeEditorComponent::deleteForwards (const bool moveInWholeWordSteps)
{
    if (moveInWholeWordSteps)
    {
        cut(); // in case something is already highlighted
        moveCaretTo (document.findWordBreakAfter (caretPos), true);
    }
    else
    {
        if (selectionStart == selectionEnd)
            selectionEnd.moveBy (1);
        else
            newTransaction();
    }

    cut();
    return true;
}

bool CodeEditorComponent::selectAll()
{
    newTransaction();
    selectRegion (CodeDocument::Position (document, std::numeric_limits<int>::max(),
                                          std::numeric_limits<int>::max()),
                  CodeDocument::Position (document, 0, 0));
    return true;
}

void CodeEditorComponent::selectRegion (const CodeDocument::Position& start,
                                        const CodeDocument::Position& end)
{
    moveCaretTo (start, false);
    moveCaretTo (end, true);
}

//==============================================================================
bool CodeEditorComponent::undo()
{
    if (readOnly)
        return false;

    ScopedValueSetter<bool> svs (shouldFollowDocumentChanges, true, false);
    document.undo();
    scrollToKeepCaretOnScreen();
    return true;
}

bool CodeEditorComponent::redo()
{
    if (readOnly)
        return false;

    ScopedValueSetter<bool> svs (shouldFollowDocumentChanges, true, false);
    document.redo();
    scrollToKeepCaretOnScreen();
    return true;
}

void CodeEditorComponent::newTransaction()
{
    document.newTransaction();
    pimpl->startTimer (600);
}

void CodeEditorComponent::setCommandManager (ApplicationCommandManager* newManager) noexcept
{
    appCommandManager = newManager;
}

//==============================================================================
Range<int> CodeEditorComponent::getHighlightedRegion() const
{
    return { selectionStart.getPosition(),
             selectionEnd.getPosition() };
}

bool CodeEditorComponent::isHighlightActive() const noexcept
{
    return selectionStart != selectionEnd;
}

void CodeEditorComponent::setHighlightedRegion (const Range<int>& newRange)
{
    selectRegion (CodeDocument::Position (document, newRange.getStart()),
                  CodeDocument::Position (document, newRange.getEnd()));
}

String CodeEditorComponent::getTextInRange (const Range<int>& range) const
{
    return document.getTextBetween (CodeDocument::Position (document, range.getStart()),
                                    CodeDocument::Position (document, range.getEnd()));
}

//==============================================================================
bool CodeEditorComponent::keyPressed (const KeyPress& key)
{
    if (! TextEditorKeyMapper<CodeEditorComponent>::invokeKeyFunction (*this, key))
    {
        if (readOnly)
            return false;

        if (key == KeyPress::tabKey || key.getTextCharacter() == '\t')      handleTabKey();
        else if (key == KeyPress::returnKey)                                handleReturnKey();
        else if (key == KeyPress::escapeKey)                                handleEscapeKey();
        else if (key == KeyPress ('[', ModifierKeys::commandModifier, 0))   unindentSelection();
        else if (key == KeyPress (']', ModifierKeys::commandModifier, 0))   indentSelection();
        else if (key.getTextCharacter() >= ' ')                             insertTextAtCaret (String::charToString (key.getTextCharacter()));
        else                                                                return false;
    }

    pimpl->handleUpdateNowIfNeeded();
    return true;
}

void CodeEditorComponent::handleReturnKey()
{
    insertTextAtCaret (document.getNewLineCharacters());
}

void CodeEditorComponent::handleTabKey()
{
    insertTabAtCaret();
}

void CodeEditorComponent::handleEscapeKey()
{
    newTransaction();
}

void CodeEditorComponent::editorViewportPositionChanged()
{
}

void CodeEditorComponent::caretPositionMoved()
{
}

//==============================================================================
ApplicationCommandTarget* CodeEditorComponent::getNextCommandTarget()
{
    return findFirstTargetParentComponent();
}

void CodeEditorComponent::getAllCommands (Array<CommandID>& commands)
{
    const CommandID ids[] = { StandardApplicationCommandIDs::cut,
                              StandardApplicationCommandIDs::copy,
                              StandardApplicationCommandIDs::paste,
                              StandardApplicationCommandIDs::del,
                              StandardApplicationCommandIDs::selectAll,
                              StandardApplicationCommandIDs::undo,
                              StandardApplicationCommandIDs::redo };

    commands.addArray (ids, numElementsInArray (ids));
}

void CodeEditorComponent::getCommandInfo (const CommandID commandID, ApplicationCommandInfo& result)
{
    const bool anythingSelected = isHighlightActive();

    switch (commandID)
    {
        case StandardApplicationCommandIDs::cut:
            result.setInfo (TRANS ("Cut"), TRANS ("Copies the currently selected text to the clipboard and deletes it."), "Editing", 0);
            result.setActive (anythingSelected && ! readOnly);
            result.defaultKeypresses.add (KeyPress ('x', ModifierKeys::commandModifier, 0));
            break;

        case StandardApplicationCommandIDs::copy:
            result.setInfo (TRANS ("Copy"), TRANS ("Copies the currently selected text to the clipboard."), "Editing", 0);
            result.setActive (anythingSelected);
            result.defaultKeypresses.add (KeyPress ('c', ModifierKeys::commandModifier, 0));
            break;

        case StandardApplicationCommandIDs::paste:
            result.setInfo (TRANS ("Paste"), TRANS ("Inserts text from the clipboard."), "Editing", 0);
            result.setActive (! readOnly);
            result.defaultKeypresses.add (KeyPress ('v', ModifierKeys::commandModifier, 0));
            break;

        case StandardApplicationCommandIDs::del:
            result.setInfo (TRANS ("Delete"), TRANS ("Deletes any selected text."), "Editing", 0);
            result.setActive (anythingSelected && ! readOnly);
            break;

        case StandardApplicationCommandIDs::selectAll:
            result.setInfo (TRANS ("Select All"), TRANS ("Selects all the text in the editor."), "Editing", 0);
            result.defaultKeypresses.add (KeyPress ('a', ModifierKeys::commandModifier, 0));
            break;

        case StandardApplicationCommandIDs::undo:
            result.setInfo (TRANS ("Undo"), TRANS ("Undo"), "Editing", 0);
            result.defaultKeypresses.add (KeyPress ('z', ModifierKeys::commandModifier, 0));
            result.setActive (document.getUndoManager().canUndo() && ! readOnly);
            break;

        case StandardApplicationCommandIDs::redo:
            result.setInfo (TRANS ("Redo"), TRANS ("Redo"), "Editing", 0);
            result.defaultKeypresses.add (KeyPress ('z', ModifierKeys::commandModifier | ModifierKeys::shiftModifier, 0));
            result.setActive (document.getUndoManager().canRedo() && ! readOnly);
            break;

        default:
            break;
    }
}

bool CodeEditorComponent::perform (const InvocationInfo& info)
{
    return performCommand (info.commandID);
}

void CodeEditorComponent::lookAndFeelChanged()
{
    caret.reset (getLookAndFeel().createCaretComponent (this));
    addAndMakeVisible (caret.get());
}

bool CodeEditorComponent::performCommand (const CommandID commandID)
{
    switch (commandID)
    {
        case StandardApplicationCommandIDs::cut:        cutToClipboard(); break;
        case StandardApplicationCommandIDs::copy:       copyToClipboard(); break;
        case StandardApplicationCommandIDs::paste:      pasteFromClipboard(); break;
        case StandardApplicationCommandIDs::del:        cut(); break;
        case StandardApplicationCommandIDs::selectAll:  selectAll(); break;
        case StandardApplicationCommandIDs::undo:       undo(); break;
        case StandardApplicationCommandIDs::redo:       redo(); break;
        default:                                        return false;
    }

    return true;
}

void CodeEditorComponent::setSelection (CodeDocument::Position newSelectionStart,
                                        CodeDocument::Position newSelectionEnd)
{
    if (selectionStart != newSelectionStart
        || selectionEnd != newSelectionEnd)
    {
        selectionStart = newSelectionStart;
        selectionEnd = newSelectionEnd;

        if (auto* handler = getAccessibilityHandler())
            handler->notifyAccessibilityEvent (AccessibilityEvent::textSelectionChanged);
    }
}

//==============================================================================
void CodeEditorComponent::addPopupMenuItems (PopupMenu& m, const MouseEvent*)
{
    m.addItem (StandardApplicationCommandIDs::cut,   TRANS ("Cut"), isHighlightActive() && ! readOnly);
    m.addItem (StandardApplicationCommandIDs::copy,  TRANS ("Copy"), ! getHighlightedRegion().isEmpty());
    m.addItem (StandardApplicationCommandIDs::paste, TRANS ("Paste"), ! readOnly);
    m.addItem (StandardApplicationCommandIDs::del,   TRANS ("Delete"), ! readOnly);
    m.addSeparator();
    m.addItem (StandardApplicationCommandIDs::selectAll, TRANS ("Select All"));
    m.addSeparator();
    m.addItem (StandardApplicationCommandIDs::undo,  TRANS ("Undo"), document.getUndoManager().canUndo());
    m.addItem (StandardApplicationCommandIDs::redo,  TRANS ("Redo"), document.getUndoManager().canRedo());
}

void CodeEditorComponent::performPopupMenuAction (const int menuItemID)
{
    performCommand (menuItemID);
}

static void codeEditorMenuCallback (int menuResult, CodeEditorComponent* editor)
{
    if (editor != nullptr && menuResult != 0)
        editor->performPopupMenuAction (menuResult);
}

//==============================================================================
void CodeEditorComponent::mouseDown (const MouseEvent& e)
{
    newTransaction();
    dragType = notDragging;

    if (e.mods.isPopupMenu())
    {
        setMouseCursor (MouseCursor::NormalCursor);

        if (getHighlightedRegion().isEmpty())
        {
            CodeDocument::Position start, end;
            document.findTokenContaining (getPositionAt (e.x, e.y), start, end);

            if (start.getPosition() < end.getPosition())
                selectRegion (start, end);
        }

        PopupMenu m;
        m.setLookAndFeel (&getLookAndFeel());
        addPopupMenuItems (m, &e);

        m.showMenuAsync (PopupMenu::Options(),
                         ModalCallbackFunction::forComponent (codeEditorMenuCallback, this));
    }
    else
    {
        beginDragAutoRepeat (100);
        moveCaretTo (getPositionAt (e.x, e.y), e.mods.isShiftDown());
    }
}

void CodeEditorComponent::mouseDrag (const MouseEvent& e)
{
    if (! e.mods.isPopupMenu())
        moveCaretTo (getPositionAt (e.x, e.y), true);
}

void CodeEditorComponent::mouseUp (const MouseEvent&)
{
    newTransaction();
    beginDragAutoRepeat (0);
    dragType = notDragging;
    setMouseCursor (MouseCursor::IBeamCursor);
}

void CodeEditorComponent::mouseDoubleClick (const MouseEvent& e)
{
    CodeDocument::Position tokenStart (getPositionAt (e.x, e.y));
    CodeDocument::Position tokenEnd (tokenStart);

    if (e.getNumberOfClicks() > 2)
        document.findLineContaining (tokenStart, tokenStart, tokenEnd);
    else
        document.findTokenContaining (tokenStart, tokenStart, tokenEnd);

    selectRegion (tokenStart, tokenEnd);
    dragType = notDragging;
}

void CodeEditorComponent::mouseWheelMove (const MouseEvent& e, const MouseWheelDetails& wheel)
{
    if ((verticalScrollBar.isVisible() && wheel.deltaY != 0.0f)
         || (horizontalScrollBar.isVisible() && wheel.deltaX != 0.0f))
    {
        {
            MouseWheelDetails w (wheel);
            w.deltaX = 0;
            verticalScrollBar.mouseWheelMove (e, w);
        }

        {
            MouseWheelDetails w (wheel);
            w.deltaY = 0;
            horizontalScrollBar.mouseWheelMove (e, w);
        }
    }
    else
    {
        Component::mouseWheelMove (e, wheel);
    }
}

//==============================================================================
void CodeEditorComponent::focusGained (FocusChangeType)     { updateCaretPosition(); }
void CodeEditorComponent::focusLost (FocusChangeType)       { updateCaretPosition(); }

//==============================================================================
void CodeEditorComponent::setTabSize (const int numSpaces, const bool insertSpaces)
{
    useSpacesForTabs = insertSpaces;

    if (spacesPerTab != numSpaces)
    {
        spacesPerTab = numSpaces;
        rebuildLineTokensAsync();
    }
}

String CodeEditorComponent::getTabString (const int numSpaces) const
{
    return String::repeatedString (useSpacesForTabs ? " " : "\t",
                                   useSpacesForTabs ? numSpaces
                                                    : (numSpaces / spacesPerTab));
}

int CodeEditorComponent::indexToColumn (int lineNum, int index) const noexcept
{
    auto line = document.getLine (lineNum);
    auto t = line.getCharPointer();
    int col = 0;

    for (int i = 0; i < index; ++i)
    {
        if (t.isEmpty())
        {
            jassertfalse;
            break;
        }

        if (t.getAndAdvance() != '\t')
            ++col;
        else
            col += getTabSize() - (col % getTabSize());
    }

    return col;
}

int CodeEditorComponent::columnToIndex (int lineNum, int column) const noexcept
{
    auto line = document.getLine (lineNum);
    auto t = line.getCharPointer();
    int i = 0, col = 0;

    while (! t.isEmpty())
    {
        if (t.getAndAdvance() != '\t')
            ++col;
        else
            col += getTabSize() - (col % getTabSize());

        if (col > column)
            break;

        ++i;
    }

    return i;
}

//==============================================================================
void CodeEditorComponent::setFont (const Font& newFont)
{
    font = newFont;
    charWidth = font.getStringWidthFloat ("0");
    lineHeight = roundToInt (font.getHeight());
    resized();
}

void CodeEditorComponent::ColourScheme::set (const String& name, Colour colour)
{
    for (auto& tt : types)
    {
        if (tt.name == name)
        {
            tt.colour = colour;
            return;
        }
    }

    TokenType tt;
    tt.name = name;
    tt.colour = colour;
    types.add (tt);
}

void CodeEditorComponent::setColourScheme (const ColourScheme& scheme)
{
    colourScheme = scheme;
    repaint();
}

Colour CodeEditorComponent::getColourForTokenType (const int tokenType) const
{
    return isPositiveAndBelow (tokenType, colourScheme.types.size())
                ? colourScheme.types.getReference (tokenType).colour
                : findColour (CodeEditorComponent::defaultTextColourId);
}

void CodeEditorComponent::clearCachedIterators (const int firstLineToBeInvalid)
{
    int i;
    for (i = cachedIterators.size(); --i >= 0;)
        if (cachedIterators.getUnchecked (i).getLine() < firstLineToBeInvalid)
            break;

    cachedIterators.removeRange (jmax (0, i - 1), cachedIterators.size());
}

void CodeEditorComponent::updateCachedIterators (int maxLineNum)
{
    const int maxNumCachedPositions = 5000;
    const int linesBetweenCachedSources = jmax (10, document.getNumLines() / maxNumCachedPositions);

    if (cachedIterators.size() == 0)
        cachedIterators.add (CodeDocument::Iterator (document));

    if (codeTokeniser != nullptr)
    {
        for (;;)
        {
            const auto last = cachedIterators.getLast();

            if (last.getLine() >= maxLineNum)
                break;

            cachedIterators.add (CodeDocument::Iterator (last));
            auto& t = cachedIterators.getReference (cachedIterators.size() - 1);
            const int targetLine = jmin (maxLineNum, last.getLine() + linesBetweenCachedSources);

            for (;;)
            {
                codeTokeniser->readNextToken (t);

                if (t.getLine() >= targetLine)
                    break;

                if (t.isEOF())
                    return;
            }
        }
    }
}

void CodeEditorComponent::getIteratorForPosition (int position, CodeDocument::Iterator& source)
{
    if (codeTokeniser != nullptr)
    {
        for (int i = cachedIterators.size(); --i >= 0;)
        {
            auto& t = cachedIterators.getReference (i);

            if (t.getPosition() <= position)
            {
                source = t;
                break;
            }
        }

        while (source.getPosition() < position)
        {
            const CodeDocument::Iterator original (source);
            codeTokeniser->readNextToken (source);

            if (source.getPosition() > position || source.isEOF())
            {
                source = original;
                break;
            }
        }
    }
}

CodeEditorComponent::State::State (const CodeEditorComponent& editor)
    : lastTopLine (editor.getFirstLineOnScreen()),
      lastCaretPos (editor.getCaretPos().getPosition()),
      lastSelectionEnd (lastCaretPos)
{
    auto selection = editor.getHighlightedRegion();

    if (lastCaretPos == selection.getStart())
        lastSelectionEnd = selection.getEnd();
    else
        lastSelectionEnd = selection.getStart();
}

CodeEditorComponent::State::State (const State& other) noexcept
    : lastTopLine (other.lastTopLine),
      lastCaretPos (other.lastCaretPos),
      lastSelectionEnd (other.lastSelectionEnd)
{
}

void CodeEditorComponent::State::restoreState (CodeEditorComponent& editor) const
{
    editor.selectRegion (CodeDocument::Position (editor.getDocument(), lastSelectionEnd),
                         CodeDocument::Position (editor.getDocument(), lastCaretPos));

    if (lastTopLine > 0 && lastTopLine < editor.getDocument().getNumLines())
        editor.scrollToLine (lastTopLine);
}

CodeEditorComponent::State::State (const String& s)
{
    auto tokens = StringArray::fromTokens (s, ":", {});

    lastTopLine      = tokens[0].getIntValue();
    lastCaretPos     = tokens[1].getIntValue();
    lastSelectionEnd = tokens[2].getIntValue();
}

String CodeEditorComponent::State::toString() const
{
    return String (lastTopLine) + ":" + String (lastCaretPos) + ":" + String (lastSelectionEnd);
}

//==============================================================================
std::unique_ptr<AccessibilityHandler> CodeEditorComponent::createAccessibilityHandler()
{
    return std::make_unique<CodeEditorAccessibilityHandler> (*this);
}

} // namespace juce
