#include "hexviewerwidget.h"
#include <QHeaderView>
#include <QFontDatabase>
#include <QScrollBar>
#include <QPainter>
#include <QResizeEvent>
#include <QMouseEvent>
#include <QKeyEvent>
#include <QClipboard>
#include <QApplication>

// ============================================================================
// HexView - Virtualized hex viewer with direct painting
// ============================================================================

HexView::HexView(QWidget *parent)
    : QAbstractScrollArea(parent)
{
    // Set up monospace font
    mMonoFont = QFont("Consolas", 10);
    if (!QFontDatabase::hasFamily("Consolas")) {
        mMonoFont = QFontDatabase::systemFont(QFontDatabase::FixedFont);
        mMonoFont.setPointSize(10);
    }

    QFontMetrics fm(mMonoFont);
    mCharWidth = fm.horizontalAdvance('0');
    mLineHeight = fm.height();

    // Default dark theme colors
    mBgColor = QColor("#1e1e1e");
    mTextColor = QColor("#888888");
    mOffsetColor = QColor("#ad0c0c");
    mNullColor = QColor("#505050");
    mHighColor = QColor("#ad0c0c");
    mPrintableColor = QColor("#c0c0c0");
    mControlColor = QColor("#707070");
    mNonPrintableColor = QColor("#909090");
    mBorderColor = QColor("#333333");
    mSelectionColor = QColor("#264f78");  // Blue selection highlight

    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
    setHorizontalScrollBarPolicy(Qt::ScrollBarAsNeeded);
    viewport()->setAutoFillBackground(false);
    viewport()->setMouseTracking(true);
    setFocusPolicy(Qt::StrongFocus);
}

void HexView::setData(const QByteArray &data)
{
    mData = data;
    recalculateBytesPerLine();
    updateScrollBars();
    viewport()->update();
}

void HexView::setTheme(const Theme &theme)
{
    mBgColor = QColor(theme.backgroundColor);
    mTextColor = QColor(theme.textColorMuted);
    mOffsetColor = QColor(theme.accentColor);
    mHighColor = QColor(theme.accentColor);
    mBorderColor = QColor(theme.borderColor);

    // Derived colors based on theme brightness
    int brightness = mBgColor.lightness();
    if (brightness < 128) {
        // Dark theme
        mNullColor = QColor("#505050");
        mPrintableColor = QColor("#c0c0c0");
        mControlColor = QColor("#707070");
        mNonPrintableColor = QColor("#909090");
    } else {
        // Light theme
        mNullColor = QColor("#a0a0a0");
        mPrintableColor = QColor("#303030");
        mControlColor = QColor("#808080");
        mNonPrintableColor = QColor("#606060");
    }

    viewport()->update();
}

void HexView::setBytesPerLine(int bytes)
{
    if (bytes != mBytesPerLine && bytes >= 8) {
        mBytesPerLine = bytes;
        updateScrollBars();
        viewport()->update();
    }
}

void HexView::updateScrollBars()
{
    if (mData.isEmpty()) {
        verticalScrollBar()->setRange(0, 0);
        horizontalScrollBar()->setRange(0, 0);
        return;
    }

    int totalLines = (mData.size() + mBytesPerLine - 1) / mBytesPerLine;
    // Account for header (1 line) + gap (4px ~= 0.25 lines)
    int headerHeight = mLineHeight + 4;
    int availableHeight = viewport()->height() - headerHeight;
    int visibleLines = qMax(1, availableHeight / mLineHeight);

    verticalScrollBar()->setRange(0, qMax(0, totalLines - visibleLines));
    verticalScrollBar()->setPageStep(visibleLines);
    verticalScrollBar()->setSingleStep(1);

    // Horizontal: offset(10) + hex(3*n) + separator(2) + ascii(n)
    int contentWidth = 10 * mCharWidth + mBytesPerLine * 3 * mCharWidth + 2 * mCharWidth + mBytesPerLine * mCharWidth;
    int viewportWidth = viewport()->width();

    horizontalScrollBar()->setRange(0, qMax(0, contentWidth - viewportWidth));
    horizontalScrollBar()->setPageStep(viewportWidth);
}

void HexView::recalculateBytesPerLine()
{
    if (mData.isEmpty()) return;

    int viewportWidth = viewport()->width();
    if (viewportWidth < 100) return;

    // Calculate available space for hex bytes
    // Format: XXXXXXXX  HH HH HH HH HH HH ...  | AAAA...
    // Offset = 10 chars (8 hex + 2 spaces)
    // Each byte = 3 chars hex + 1 char ascii
    // Separator = 2 chars

    int fixedWidth = 10 * mCharWidth + 2 * mCharWidth;  // offset + separator
    int remaining = viewportWidth - fixedWidth;

    // Each byte needs: 3 chars hex + 1 char ascii = 4 chars
    int bytesPerLine = remaining / (4 * mCharWidth);

    // Round down to multiple of 8 for clean display
    bytesPerLine = qMax(8, (bytesPerLine / 8) * 8);
    bytesPerLine = qMin(32, bytesPerLine);

    if (bytesPerLine != mBytesPerLine) {
        mBytesPerLine = bytesPerLine;
        updateScrollBars();
    }
}

void HexView::paintEvent(QPaintEvent *event)
{
    Q_UNUSED(event);

    QPainter painter(viewport());
    painter.setFont(mMonoFont);
    painter.setRenderHint(QPainter::TextAntialiasing);

    // Fill background
    painter.fillRect(viewport()->rect(), mBgColor);

    if (mData.isEmpty()) {
        painter.setPen(mTextColor);
        painter.drawText(viewport()->rect(), Qt::AlignCenter, "No data");
        return;
    }

    int xOffset = -horizontalScrollBar()->value();
    int firstLine = verticalScrollBar()->value();
    int visibleLines = viewport()->height() / mLineHeight + 2;
    int totalLines = (mData.size() + mBytesPerLine - 1) / mBytesPerLine;

    // Calculate column positions (no extra gaps - uniform spacing)
    int offsetX = xOffset;
    int hexX = offsetX + 10 * mCharWidth;
    int asciiX = hexX + mBytesPerLine * 3 * mCharWidth + 2 * mCharWidth;

    // Draw header line
    int y = mLineHeight;
    painter.setPen(mOffsetColor);
    painter.drawText(offsetX, y - 4, "Offset");

    // Draw hex column headers (uniform spacing)
    painter.setPen(mTextColor);
    for (int i = 0; i < mBytesPerLine; i++) {
        int x = hexX + i * 3 * mCharWidth;
        painter.drawText(x, y - 4, QString("%1").arg(i, 2, 16, QChar('0')).toUpper());
    }

    // Draw "Decoded" header
    painter.setPen(mOffsetColor);
    painter.drawText(asciiX, y - 4, "Decoded");

    // Draw separator line
    painter.setPen(mBorderColor);
    painter.drawLine(0, y, viewport()->width(), y);

    y += 4;  // Small gap after header

    // Get selection range (normalized so start <= end)
    int selStart = qMin(mSelectionStart, mSelectionEnd);
    int selEnd = qMax(mSelectionStart, mSelectionEnd);
    bool hasSelection = mSelectionStart >= 0 && mSelectionEnd >= 0;

    // Draw data rows (only visible ones)
    for (int line = 0; line < visibleLines && (firstLine + line) < totalLines; line++) {
        int dataLine = firstLine + line;
        int offset = dataLine * mBytesPerLine;
        int bytesInLine = qMin(mBytesPerLine, mData.size() - offset);

        y += mLineHeight;

        // Draw offset
        painter.setPen(mOffsetColor);
        QString offsetStr = QString("%1").arg(offset, 8, 16, QChar('0')).toUpper();
        painter.drawText(offsetX, y, offsetStr);

        // Draw hex bytes (uniform spacing)
        for (int i = 0; i < mBytesPerLine; i++) {
            int x = hexX + i * 3 * mCharWidth;

            if (i < bytesInLine) {
                int byteIndex = offset + i;
                quint8 byte = static_cast<quint8>(mData[byteIndex]);

                // Draw selection background for hex
                if (hasSelection && byteIndex >= selStart && byteIndex <= selEnd) {
                    QRect selRect(x - 1, y - mLineHeight + 4, 2 * mCharWidth + 2, mLineHeight);
                    painter.fillRect(selRect, mSelectionColor);
                }

                painter.setPen(getByteColor(byte));
                QString byteStr = QString("%1").arg(byte, 2, 16, QChar('0')).toUpper();
                painter.drawText(x, y, byteStr);
            }
        }

        // Draw vertical separator
        int sepX = asciiX - mCharWidth;
        painter.setPen(mBorderColor);
        painter.drawLine(sepX, y - mLineHeight + 4, sepX, y + 2);

        // Draw ASCII/Decoded - show extended ASCII like HxD
        for (int i = 0; i < mBytesPerLine; i++) {
            int x = asciiX + i * mCharWidth;

            if (i < bytesInLine) {
                int byteIndex = offset + i;
                quint8 byte = static_cast<quint8>(mData[byteIndex]);

                // Draw selection background for decoded
                if (hasSelection && byteIndex >= selStart && byteIndex <= selEnd) {
                    QRect selRect(x, y - mLineHeight + 4, mCharWidth, mLineHeight);
                    painter.fillRect(selRect, mSelectionColor);
                }

                painter.setPen(getAsciiColor(byte));
                // Show actual character for printable ASCII and extended ASCII (Latin-1)
                // Control chars (0x00-0x1F) and DEL (0x7F) show as '.'
                QChar c;
                if (byte < 0x20 || byte == 0x7F) {
                    c = '.';
                } else {
                    c = QChar::fromLatin1(static_cast<char>(byte));
                }
                painter.drawText(x, y, QString(c));
            }
        }
    }
}

void HexView::resizeEvent(QResizeEvent *event)
{
    QAbstractScrollArea::resizeEvent(event);
    recalculateBytesPerLine();
    updateScrollBars();
}

void HexView::scrollContentsBy(int dx, int dy)
{
    Q_UNUSED(dx);
    Q_UNUSED(dy);
    viewport()->update();
}

QColor HexView::getByteColor(quint8 byte) const
{
    if (byte == 0x00) {
        return mNullColor;
    } else if (byte == 0xFF) {
        return mHighColor;
    } else if (byte >= 0x20 && byte < 0x7F) {
        return mPrintableColor;
    } else if (byte < 0x20) {
        return mControlColor;
    } else {
        return mNonPrintableColor;
    }
}

QColor HexView::getAsciiColor(quint8 byte) const
{
    if (byte < 0x20 || byte == 0x7F) {
        return mNullColor;  // Control characters shown as '.'
    } else if (byte >= 0x20 && byte < 0x7F) {
        return mPrintableColor;  // Standard ASCII
    } else {
        return mNonPrintableColor;  // Extended ASCII (0x80-0xFF)
    }
}

void HexView::updateColumnPositions()
{
    mOffsetX = -horizontalScrollBar()->value();
    mHexX = mOffsetX + 10 * mCharWidth;
    mAsciiX = mHexX + mBytesPerLine * 3 * mCharWidth + 2 * mCharWidth;
    mHeaderHeight = mLineHeight + 4;
}

int HexView::byteIndexAtPos(const QPoint &pos, SelectionSource *source) const
{
    // Check if in header area
    if (pos.y() < mHeaderHeight) {
        return -1;
    }

    // Calculate which line
    int lineY = pos.y() - mHeaderHeight;
    int line = lineY / mLineHeight + verticalScrollBar()->value();
    int col = -1;

    // Check if in hex area
    int hexEndX = mHexX + mBytesPerLine * 3 * mCharWidth;
    if (pos.x() >= mHexX && pos.x() < hexEndX) {
        int relX = pos.x() - mHexX;
        col = relX / (3 * mCharWidth);
        if (source) *source = SelectionSource::Hex;
    }
    // Check if in decoded/ASCII area
    else if (pos.x() >= mAsciiX) {
        int relX = pos.x() - mAsciiX;
        col = relX / mCharWidth;
        if (source) *source = SelectionSource::Decoded;
    }

    if (col < 0 || col >= mBytesPerLine) {
        return -1;
    }

    int byteIndex = line * mBytesPerLine + col;
    if (byteIndex < 0 || byteIndex >= mData.size()) {
        return -1;
    }

    return byteIndex;
}

void HexView::clearSelection()
{
    mSelectionStart = -1;
    mSelectionEnd = -1;
    mSelectionSource = SelectionSource::None;
    viewport()->update();
}

bool HexView::hasSelection() const
{
    return mSelectionStart >= 0 && mSelectionEnd >= 0 && mSelectionStart != mSelectionEnd;
}

QString HexView::getSelectedHex() const
{
    if (!hasSelection()) return QString();

    int start = qMin(mSelectionStart, mSelectionEnd);
    int end = qMax(mSelectionStart, mSelectionEnd);

    QString result;
    for (int i = start; i <= end && i < mData.size(); i++) {
        result += QString("%1").arg(static_cast<quint8>(mData[i]), 2, 16, QChar('0')).toUpper();
    }
    return result;
}

QString HexView::getSelectedDecoded() const
{
    if (!hasSelection()) return QString();

    int start = qMin(mSelectionStart, mSelectionEnd);
    int end = qMax(mSelectionStart, mSelectionEnd);

    QString result;
    for (int i = start; i <= end && i < mData.size(); i++) {
        quint8 byte = static_cast<quint8>(mData[i]);
        if (byte < 0x20 || byte == 0x7F) {
            result += '.';
        } else {
            result += QChar::fromLatin1(static_cast<char>(byte));
        }
    }
    return result;
}

void HexView::copyToClipboard()
{
    if (!hasSelection()) return;

    QString text;
    if (mSelectionSource == SelectionSource::Hex) {
        text = getSelectedHex();
    } else {
        text = getSelectedDecoded();
    }

    QApplication::clipboard()->setText(text);
}

void HexView::mousePressEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton) {
        updateColumnPositions();
        SelectionSource source = SelectionSource::None;
        int idx = byteIndexAtPos(event->pos(), &source);

        if (idx >= 0) {
            mSelectionStart = idx;
            mSelectionEnd = idx;
            mSelectionSource = source;
            mSelecting = true;
            setFocus();
            viewport()->update();
        } else {
            clearSelection();
        }
    }
    QAbstractScrollArea::mousePressEvent(event);
}

void HexView::mouseMoveEvent(QMouseEvent *event)
{
    if (mSelecting && (event->buttons() & Qt::LeftButton)) {
        updateColumnPositions();
        int idx = byteIndexAtPos(event->pos());

        if (idx >= 0) {
            mSelectionEnd = idx;
            viewport()->update();
        }
    }
    QAbstractScrollArea::mouseMoveEvent(event);
}

void HexView::mouseReleaseEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton) {
        mSelecting = false;
    }
    QAbstractScrollArea::mouseReleaseEvent(event);
}

void HexView::keyPressEvent(QKeyEvent *event)
{
    if (event->matches(QKeySequence::Copy)) {
        copyToClipboard();
        event->accept();
        return;
    }
    // Ctrl+A to select all
    if (event->modifiers() == Qt::ControlModifier && event->key() == Qt::Key_A) {
        if (!mData.isEmpty()) {
            mSelectionStart = 0;
            mSelectionEnd = mData.size() - 1;
            mSelectionSource = SelectionSource::Hex;
            viewport()->update();
        }
        event->accept();
        return;
    }
    QAbstractScrollArea::keyPressEvent(event);
}

// ============================================================================
// HexViewerWidget
// ============================================================================

HexViewerWidget::HexViewerWidget(QWidget *parent)
    : QWidget(parent)
{
    auto *mainLayout = new QVBoxLayout(this);
    mainLayout->setContentsMargins(0, 0, 0, 0);
    mainLayout->setSpacing(0);

    // Splitter for hex view and metadata
    mSplitter = new QSplitter(Qt::Horizontal, this);

    // Left side - hex view container
    auto *hexContainer = new QWidget(mSplitter);
    auto *hexLayout = new QVBoxLayout(hexContainer);
    hexLayout->setContentsMargins(0, 0, 0, 0);
    hexLayout->setSpacing(0);

    // Info label
    mInfoLabel = new QLabel(hexContainer);
    hexLayout->addWidget(mInfoLabel);

    // Hex view
    mHexView = new HexView(hexContainer);
    hexLayout->addWidget(mHexView, 1);

    mSplitter->addWidget(hexContainer);

    // Metadata tree
    mMetadataTree = new QTreeWidget(mSplitter);
    mMetadataTree->setHeaderLabels({"Property", "Value"});
    mMetadataTree->header()->setSectionResizeMode(0, QHeaderView::ResizeToContents);
    mMetadataTree->header()->setSectionResizeMode(1, QHeaderView::Stretch);
    mMetadataTree->setAlternatingRowColors(true);
    mSplitter->addWidget(mMetadataTree);

    mSplitter->setSizes({700, 250});
    mainLayout->addWidget(mSplitter);

    // Connect to theme changes
    connect(&Settings::instance(), &Settings::themeChanged, this, &HexViewerWidget::applyTheme);

    // Apply current theme
    applyTheme(Settings::instance().theme());
}

void HexViewerWidget::applyTheme(const Theme &theme)
{
    mCurrentTheme = theme;

    // Update info label
    mInfoLabel->setStyleSheet(QString(
        "QLabel { background-color: %1; color: %2; padding: 4px 8px; font-size: 11px; }"
    ).arg(theme.panelColor, theme.textColorMuted));

    // Update hex view
    mHexView->setTheme(theme);

    // Update metadata tree
    mMetadataTree->setStyleSheet(QString(
        "QTreeWidget { background-color: %1; color: %2; border: none; }"
        "QTreeWidget::item:selected { background-color: %3; color: white; }"
        "QTreeWidget::item:alternate { background-color: %4; }"
        "QHeaderView::section { background-color: %4; color: %5; padding: 4px; border: none; }"
    ).arg(theme.backgroundColor, theme.textColor, theme.accentColor, theme.panelColor, theme.textColorMuted));
}

void HexViewerWidget::setData(const QByteArray &data, const QString &filename)
{
    mData = data;
    mFilename = filename;

    // Update info label
    QString info = QString("%1 | %2 bytes").arg(filename).arg(data.size());
    if (data.size() >= 4) {
        QString magic;
        for (int i = 0; i < qMin(4, data.size()); i++) {
            char c = data[i];
            magic += (c >= 32 && c < 127) ? c : '.';
        }
        info += QString(" | Magic: %1").arg(magic);
    }
    mInfoLabel->setText(info);

    // Update hex view
    mHexView->setData(data);

    // Update metadata tree
    mMetadataTree->clear();

    auto *sizeItem = new QTreeWidgetItem(mMetadataTree);
    sizeItem->setText(0, "File Size");
    sizeItem->setText(1, QString("%1 bytes").arg(data.size()));

    auto *filenameItem = new QTreeWidgetItem(mMetadataTree);
    filenameItem->setText(0, "Filename");
    filenameItem->setText(1, filename);

    if (data.size() >= 4) {
        auto *magicItem = new QTreeWidgetItem(mMetadataTree);
        magicItem->setText(0, "Magic Bytes");
        QString hexMagic;
        for (int i = 0; i < qMin(16, data.size()); i++) {
            hexMagic += QString("%1 ").arg(static_cast<quint8>(data[i]), 2, 16, QChar('0')).toUpper();
        }
        magicItem->setText(1, hexMagic.trimmed());
    }
}

void HexViewerWidget::setMetadata(const QVariantMap &metadata)
{
    // Add metadata from parsed fields (caller provides only visible fields)
    for (auto it = metadata.begin(); it != metadata.end(); ++it) {
        auto *item = new QTreeWidgetItem(mMetadataTree);
        item->setText(0, it.key());

        QVariant val = it.value();
        if (val.typeId() == QMetaType::QByteArray) {
            QByteArray ba = val.toByteArray();
            item->setText(1, QString("<%1 bytes>").arg(ba.size()));
        } else {
            item->setText(1, val.toString());
        }
    }
}