#include "lrcodeeditor.h"

#include "lrglobal.h"
#include "lrscripthighlighter.h"

#include <QAbstractItemView>
#include <QCompleter>
#include <QDebug>
#include <QKeyEvent>
#include <QPainter>
#include <QScrollBar>
#include <QTextBlock>
#include <QWidget>

namespace LimeReport {

CodeEditor::CodeEditor(QWidget* parent): QPlainTextEdit(parent), m_completer(0)
{
    lineNumberArea = new LineNumberArea(this);

    connect(this, SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int)));
    connect(this, SIGNAL(updateRequest(QRect, int)), this, SLOT(updateLineNumberArea(QRect, int)));
    connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(highlightCurrentLine()));

    updateLineNumberAreaWidth(0);
    highlightCurrentLine();
    new ScriptHighlighter(document());
    connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(matchParentheses()));
}

void CodeEditor::setCompleter(QCompleter* value)
{
    if (value)
        disconnect(value, 0, this, 0);
    m_completer = value;
    if (!m_completer)
        return;
    m_completer->setWidget(this);
    m_completer->setCompletionMode(QCompleter::PopupCompletion);
    m_completer->setCaseSensitivity(Qt::CaseInsensitive);

    connect(m_completer, SIGNAL(activated(QString)), this, SLOT(insertCompletion(QString)));
}

void CodeEditor::lineNumberAreaPaintEvent(QPaintEvent* event)
{
    QPainter painter(lineNumberArea);
    QStyleOption option;
    option.initFrom(this);
    // painter.fillRect(event->rect(), QPalette().window().color());
    QColor bg = option.palette.window().color().darker(150);
    painter.fillRect(event->rect(), bg);

    QTextBlock block = firstVisibleBlock();
    int blockNumber = block.blockNumber();
    int top = (int)blockBoundingGeometry(block).translated(contentOffset()).top();
    int bottom = top + (int)blockBoundingRect(block).height();

    while (block.isValid() && top <= event->rect().bottom()) {
        if (block.isVisible() && bottom >= event->rect().top()) {
            QString number = QString::number(blockNumber + 1);
            painter.setPen(option.palette.text().color());
            painter.drawText(0, top, lineNumberArea->width(), fontMetrics().height(),
                             Qt::AlignCenter, number);
        }

        block = block.next();
        top = bottom;
        bottom = top + (int)blockBoundingRect(block).height();
        ++blockNumber;
    }
}

int CodeEditor::lineNumberAreaWidth()
{
    int digits = 1;
    int max = qMax(1, blockCount());
    while (max >= 10) {
        max /= 10;
        ++digits;
    }

    int space = fontMetrics().boundingRect(QLatin1Char('9')).width() * 2
        + fontMetrics().boundingRect(QLatin1Char('9')).width() * digits;

    return space;
}

void CodeEditor::keyPressEvent(QKeyEvent* e)
{
    if (m_completer && m_completer->popup()->isVisible()) {
        switch (e->key()) {
        case Qt::Key_Enter:
        case Qt::Key_Return:
        case Qt::Key_Escape:
        case Qt::Key_Tab:
        case Qt::Key_Backtab:
        case Qt::Key_Right:
        case Qt::Key_Left:
        case Qt::Key_Up:
        case Qt::Key_Down:
            e->ignore();
            return;
        default:
            break;
        }
    }

    bool isShortcut = ((e->modifiers() & Qt::ControlModifier) && e->key() == Qt::Key_Space);
    if (!m_completer || !isShortcut)
        QPlainTextEdit::keyPressEvent(e);

    const bool ctrlOrShift = e->modifiers() & (Qt::ControlModifier | Qt::ShiftModifier);
    if (!m_completer || (ctrlOrShift && e->text().isEmpty()))
        return;

    bool hasModifier = (e->modifiers() != Qt::NoModifier) && !ctrlOrShift;

    QString completionPrefix = textUnderCursor();

    if (!isShortcut
        && (hasModifier || e->text().isEmpty() || completionPrefix.length() < 3
            || Const::EOW.contains(e->text().right(1)))) {
        m_completer->popup()->hide();
        return;
    }

    if (completionPrefix != m_completer->completionPrefix()) {
        m_completer->setCompletionPrefix(completionPrefix);
        m_completer->popup()->setCurrentIndex(m_completer->completionModel()->index(0, 0));
    }

    QModelIndex ci = m_completer->completionModel()->index(0, 0);
    if (ci.isValid()
        && m_completer->completionModel()->data(ci).toString().compare(completionPrefix) == 0) {
        m_completer->popup()->hide();
        return;
    }

    QRect cr = cursorRect();
    cr.setWidth(m_completer->popup()->sizeHintForColumn(0)
                + m_completer->popup()->verticalScrollBar()->sizeHint().width());
    m_completer->complete(cr);

    if (!completionPrefix.isEmpty() && completionPrefix.at(completionPrefix.length() - 1) == '.') {
        m_completer->popup();
    }
}

void CodeEditor::focusInEvent(QFocusEvent* e)
{
    if (m_completer)
        m_completer->setWidget(this);
    QPlainTextEdit::focusInEvent(e);
}

void CodeEditor::resizeEvent(QResizeEvent* event)
{
    QPlainTextEdit::resizeEvent(event);
    QRect cr = contentsRect();
    lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height()));
}

QString CodeEditor::textUnderCursor() const
{
    QTextCursor tc = textCursor();
    QString currentText;
    tc.movePosition(QTextCursor::StartOfBlock, QTextCursor::KeepAnchor);
    QString blockText = tc.selectedText();
    for (int i = blockText.length(); i > 0; --i) {
        if (!Const::EOW.contains(blockText.at(i - 1)))
            currentText = blockText.at(i - 1) + currentText;
        else
            break;
    }
    return currentText.trimmed();
}

bool CodeEditor::matchLeftParenthesis(QTextBlock currentBlock, QChar parenthesisType, int i,
                                      int numLeftParentheses)
{
    TextBlockData* data = static_cast<TextBlockData*>(currentBlock.userData());
    if (data) {
        QVector<ParenthesisInfo*> infos = data->parentheses();

        int docPos = currentBlock.position();
        for (; i < infos.size(); ++i) {
            ParenthesisInfo* info = infos.at(i);

            if (info->character == parenthesisType) {
                ++numLeftParentheses;
                continue;
            }

            if (info->character == getParenthesisReverceChar(parenthesisType)) {
                if (numLeftParentheses == 0) {
                    createParenthesisSelection(docPos + info->position);
                    return true;
                } else
                    --numLeftParentheses;
            }
        }
    }

    currentBlock = currentBlock.next();
    if (currentBlock.isValid())
        return matchLeftParenthesis(currentBlock, parenthesisType, 0, numLeftParentheses);

    return false;
}

bool CodeEditor::matchRightParenthesis(QTextBlock currentBlock, QChar parenthesisType, int i,
                                       int numRightParentheses)
{
    TextBlockData* data = static_cast<TextBlockData*>(currentBlock.userData());
    if (data) {
        QVector<ParenthesisInfo*> parentheses = data->parentheses();
        int docPos = currentBlock.position();
        if (i == -2)
            i = parentheses.size() - 1;
        for (; i > -1 && parentheses.size() > 0; --i) {
            ParenthesisInfo* info = parentheses.at(i);
            if (info->character == parenthesisType) {
                ++numRightParentheses;
                continue;
            }
            if (info->character == getParenthesisReverceChar(parenthesisType)) {
                if (numRightParentheses == 0) {
                    createParenthesisSelection(docPos + info->position);
                    return true;
                } else
                    --numRightParentheses;
            }
        }
    }

    currentBlock = currentBlock.previous();
    if (currentBlock.isValid())
        return matchRightParenthesis(currentBlock, parenthesisType, -2, numRightParentheses);

    return false;
}

void CodeEditor::createParenthesisSelection(int pos)
{
    QList<QTextEdit::ExtraSelection> selections = extraSelections();

    QTextEdit::ExtraSelection selection;
    QTextCharFormat format = selection.format;
    format.setBackground(QColor("#619934"));
    format.setForeground(QColor("#ffffff"));
    selection.format = format;

    QTextCursor cursor = textCursor();
    cursor.setPosition(pos);
    cursor.movePosition(QTextCursor::NextCharacter, QTextCursor::KeepAnchor);
    selection.cursor = cursor;

    selections.append(selection);

    setExtraSelections(selections);
}

bool CodeEditor::charIsParenthesis(QChar character, ParenthesisType type)
{
    for (int i = 0; i < PARENHEIS_COUNT; ++i) {
        if (character == parenthesisCharacters[type][i])
            return true;
    }
    return false;
}

QChar CodeEditor::getParenthesisReverceChar(QChar parenthesisChar)
{
    for (int i = 0; i < PARENHEIS_COUNT; ++i) {
        if (parenthesisCharacters[RightParenthesis][i] == parenthesisChar)
            return parenthesisCharacters[LeftParenthesis][i];
        if (parenthesisCharacters[LeftParenthesis][i] == parenthesisChar)
            return parenthesisCharacters[RightParenthesis][i];
    }
    return ' ';
}

void CodeEditor::insertCompletion(const QString& completion)
{
    if (m_completer->widget() != this)
        return;
    QTextCursor tc = textCursor();
    //    QString prefix = m_completer->completionPrefix();
    //    int extra = completion.length() - prefix.length();
    for (int i = 0; i < m_completer->completionPrefix().length(); ++i) {
        tc.deletePreviousChar();
    }
    tc.insertText(completion);
    //    tc.insertText(completion.right(extra));
    setTextCursor(tc);
}

void CodeEditor::updateLineNumberAreaWidth(int /*newBlockCount*/)
{
    setViewportMargins(lineNumberAreaWidth(), 0, 0, 0);
}

void CodeEditor::highlightCurrentLine()
{
    QList<QTextEdit::ExtraSelection> extraSelections;

    if (!isReadOnly()) {
        QTextEdit::ExtraSelection selection;

        QColor lineColor = QColor(QPalette().window().color()).darker(100);

        selection.format.setBackground(lineColor);
        selection.format.setProperty(QTextFormat::FullWidthSelection, true);
        selection.cursor = textCursor();
        selection.cursor.clearSelection();
        extraSelections.append(selection);
    }

    setExtraSelections(extraSelections);
}

void CodeEditor::updateLineNumberArea(const QRect& rect, int dy)
{
    if (dy)
        lineNumberArea->scroll(0, dy);
    else
        lineNumberArea->update(0, rect.y(), lineNumberArea->width(), rect.height());

    if (rect.contains(viewport()->rect()))
        updateLineNumberAreaWidth(0);
}

void CodeEditor::matchParentheses()
{
    QList<QTextEdit::ExtraSelection> selections;
    setExtraSelections(selections);

    TextBlockData* data = static_cast<TextBlockData*>(textCursor().block().userData());

    if (data) {
        QVector<ParenthesisInfo*> infos = data->parentheses();

        int pos = textCursor().block().position();
        for (int i = 0; i < infos.size(); ++i) {
            ParenthesisInfo* info = infos.at(i);

            int curPos = textCursor().position() - textCursor().block().position();

            if ((info->position == (curPos - 1))
                && charIsParenthesis(info->character, LeftParenthesis)) {
                if (matchLeftParenthesis(textCursor().block(), info->character, i + 1, 0))
                    createParenthesisSelection(pos + info->position);
            } else if ((info->position == (curPos - 1))
                       && charIsParenthesis(info->character, RightParenthesis)) {
                if (matchRightParenthesis(textCursor().block(), info->character, i - 1, 0))
                    createParenthesisSelection(pos + info->position);
            }
        }
    }
}

} // namespace LimeReport