#include "clock_widget.h"
#include "config_manager.h"
#include "window_helper.h"
#include <QVBoxLayout>
#include <QDateTime>
#include <QColorDialog>
#include <QFontDialog>
#include <QInputDialog>
#include <QMessageBox>
#include <QApplication>
#include <QScreen>
#include <QTimeZone>
#include <QLineEdit>
#include <QPainter>
#include <QPainterPath>

ClockLabel::ClockLabel(QWidget *parent)
    : QLabel(parent), m_textColor(Qt::white), m_outlineColor(Qt::transparent), m_outlineWidth(0)
{
    setAlignment(Qt::AlignCenter);
}

void ClockLabel::setDisplayColors(const QColor &textColor, const QColor &outlineColor, qreal outlineWidth)
{
    m_textColor = textColor;
    m_outlineColor = outlineColor;
    m_outlineWidth = outlineWidth;
    update();
}

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

    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing);
    painter.setRenderHint(QPainter::TextAntialiasing);

    const QFontMetricsF metrics(font());
    const QStringList lines = text().split('\n');
    const qreal lineHeight = metrics.height();
    const qreal textBlockHeight = lineHeight * lines.size();

    // First baseline so the whole block is vertically centered.
    const qreal firstBaseline = (height() - textBlockHeight) / 2.0 + metrics.ascent();

    for (int i = 0; i < lines.size(); ++i)
    {
        const QString &line = lines.at(i);
        if (line.isEmpty())
        {
            continue;
        }

        const qreal lineWidth = metrics.horizontalAdvance(line);
        QPainterPath linePath;
        linePath.addText(0, 0, font(), line);

        painter.save();
        painter.translate((width() - lineWidth) / 2.0, firstBaseline + i * lineHeight);

        // Outline under the fill so the glyphs stay readable on any backdrop.
        if (m_outlineColor.alpha() > 0 && m_outlineWidth > 0)
        {
            painter.setPen(QPen(m_outlineColor, m_outlineWidth, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
            painter.setBrush(Qt::NoBrush);
            painter.drawPath(linePath);
        }

        painter.setPen(Qt::NoPen);
        painter.setBrush(m_textColor);
        painter.drawPath(linePath);
        painter.restore();
    }
}

ClockWidget::ClockWidget(QWidget *parent)
    : QWidget(parent), m_dragging(false), m_resizing(false), m_resizeBorder(5)
{
    setupUI();
    createMenu();
    loadSettings();

    // Set window properties for cross-platform always-on-top
    Qt::WindowFlags flags = Qt::FramelessWindowHint | Qt::WindowStaysOnTopHint | Qt::Tool;

#ifdef Q_OS_MAC
    // On macOS, we need additional flags for proper always-on-top behavior in fullscreen
    flags |= Qt::WindowDoesNotAcceptFocus;
    setAttribute(Qt::WA_ShowWithoutActivating);
#endif

    setWindowFlags(flags);
    setAttribute(Qt::WA_TranslucentBackground);
    setAttribute(Qt::WA_StyledBackground); // required for widget-level QSS background/border
    setMouseTracking(true); // Enable mouse tracking for resize cursor

    // Set up platform-specific window properties after window creation
    WindowHelper::setupAlwaysOnTopForFullscreen(this);

    // Start timer
    m_timer = new QTimer(this);
    connect(m_timer, &QTimer::timeout, this, &ClockWidget::updateTime);
    m_timer->start(1000);

    updateTime();
}

ClockWidget::~ClockWidget()
{
    // Settings are now saved immediately after changes, no need to save here
}

void ClockWidget::setupUI()
{
    m_primaryTimeLabel = new ClockLabel(this);
    m_primaryLocationLabel = new ClockLabel(this);
    m_secondaryTimeLabel = new ClockLabel(this);
    m_secondaryLocationLabel = new ClockLabel(this);

    QVBoxLayout *layout = new QVBoxLayout(this);
    layout->addWidget(m_primaryTimeLabel);
    layout->addWidget(m_primaryLocationLabel);
    layout->addWidget(m_secondaryTimeLabel);
    layout->addWidget(m_secondaryLocationLabel);
    layout->setContentsMargins(10, 10, 10, 10);
    layout->setSpacing(2);
}

void ClockWidget::createMenu()
{
    m_contextMenu = new QMenu(this);

    QAction *alwaysOnTopAction = new QAction("Always on Top", this);
    alwaysOnTopAction->setCheckable(true);
    alwaysOnTopAction->setChecked(true);
    connect(alwaysOnTopAction, &QAction::triggered, this, &ClockWidget::toggleAlwaysOnTop);

    QAction *fontColorAction = new QAction("Set Font Color", this);
    connect(fontColorAction, &QAction::triggered, this, &ClockWidget::changeFontColor);

    QAction *bgColorAction = new QAction("Set Background Color", this);
    connect(bgColorAction, &QAction::triggered, this, &ClockWidget::changeBackgroundColor);

    QAction *fontSizeAction = new QAction("Set Time Font Size", this);
    connect(fontSizeAction, &QAction::triggered, this, &ClockWidget::changeFontSize);

    QAction *locationFontSizeAction = new QAction("Set Location Font Size", this);
    connect(locationFontSizeAction, &QAction::triggered, this, &ClockWidget::changeLocationFontSize);

    QAction *borderColorAction = new QAction("Set Border Color", this);
    connect(borderColorAction, &QAction::triggered, this, &ClockWidget::changeBorderColor);

    QAction *primaryTimeZoneAction = new QAction("Set First Time Zone", this);
    connect(primaryTimeZoneAction, &QAction::triggered, this, &ClockWidget::changePrimaryTimeZone);

    QAction *secondaryTimeZoneAction = new QAction("Set Second Time Zone", this);
    connect(secondaryTimeZoneAction, &QAction::triggered, this, &ClockWidget::changeSecondaryTimeZone);

    QAction *resetAction = new QAction("Reset Settings", this);
    connect(resetAction, &QAction::triggered, this, &ClockWidget::resetSettings);

    QAction *quitAction = new QAction("Quit", this);
    connect(quitAction, &QAction::triggered, this, &ClockWidget::quitApplication);

    m_contextMenu->addAction(alwaysOnTopAction);
    m_contextMenu->addSeparator();
    m_contextMenu->addAction(fontColorAction);
    m_contextMenu->addAction(bgColorAction);
    m_contextMenu->addAction(borderColorAction);
    m_contextMenu->addSeparator();
    m_contextMenu->addAction(fontSizeAction);
    m_contextMenu->addAction(locationFontSizeAction);
    m_contextMenu->addSeparator();
    m_contextMenu->addAction(primaryTimeZoneAction);
    m_contextMenu->addAction(secondaryTimeZoneAction);
    m_contextMenu->addSeparator();
    m_contextMenu->addAction(resetAction);
    m_contextMenu->addAction(quitAction);
}

void ClockWidget::mousePressEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton)
    {
        if (isInResizeArea(event->pos()))
        {
            m_resizing = true;
            m_resizeStartPos = event->globalPosition().toPoint();
            m_resizeStartSize = size();
            event->accept();
        }
        else
        {
            m_dragging = true;
            m_dragPosition = event->globalPosition().toPoint() - frameGeometry().topLeft();
            event->accept();
        }
    }
}

void ClockWidget::mouseMoveEvent(QMouseEvent *event)
{
    if (m_resizing && (event->buttons() & Qt::LeftButton))
    {
        QPoint delta = event->globalPosition().toPoint() - m_resizeStartPos;
        QSize newSize = m_resizeStartSize + QSize(delta.x(), delta.y());

        // Minimum size constraints
        newSize = newSize.expandedTo(QSize(100, 50));

        resize(newSize);
        event->accept();
    }
    else if (m_dragging && (event->buttons() & Qt::LeftButton))
    {
        move(event->globalPosition().toPoint() - m_dragPosition);
        event->accept();
    }
    else
    {
        // Update cursor shape when hovering over resize area
        if (isInResizeArea(event->pos()))
        {
            setCursor(Qt::SizeFDiagCursor);
        }
        else
        {
            setCursor(Qt::ArrowCursor);
        }
    }
}

void ClockWidget::mouseReleaseEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton)
    {
        if (m_resizing)
        {
            m_resizing = false;
            // Save the new size and position to config
            if (m_configManager)
            {
                m_configManager->setWindowPosition(pos());
                m_configManager->setWindowSize(size());
                m_configManager->saveSettings();
            }
            event->accept();
        }
        else if (m_dragging)
        {
            m_dragging = false;
            // Save the new position to config
            if (m_configManager)
            {
                m_configManager->setWindowPosition(pos());
                m_configManager->saveSettings();
            }
            event->accept();
        }
    }
}

void ClockWidget::contextMenuEvent(QContextMenuEvent *event)
{
    Q_UNUSED(event);
    // Menu lives in the tray icon; right-click on the clock does nothing
    // so it never interferes with dragging.
}

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

    // QSS background does not render on macOS with
    // WA_TranslucentBackground, so we paint it manually.
    if (m_backgroundColor.alpha() > 0)
    {
        QPainter painter(this);
        painter.setRenderHint(QPainter::Antialiasing);
        painter.setPen(Qt::NoPen);
        painter.setBrush(m_backgroundColor);
        painter.drawRoundedRect(QRectF(contentsRect()).adjusted(0.5, 0.5, -0.5, -0.5), 10, 10);
    }
}

void ClockWidget::updateTime()
{
    const QTimeZone primaryTimeZone(m_primaryTimeZoneId.toUtf8());
    if (primaryTimeZone.isValid())
    {
        m_primaryTimeLabel->setText(QDateTime::currentDateTimeUtc().toTimeZone(primaryTimeZone).time().toString("HH:mm"));
        m_primaryLocationLabel->setText(locationName(m_primaryTimeZoneId));
    }
    else
    {
        m_primaryTimeLabel->setText("Invalid time zone");
        m_primaryLocationLabel->setText(m_primaryTimeZoneId);
    }

    const QTimeZone secondaryTimeZone(m_secondaryTimeZoneId.toUtf8());
    if (secondaryTimeZone.isValid())
    {
        m_secondaryTimeLabel->setText(QDateTime::currentDateTimeUtc().toTimeZone(secondaryTimeZone).time().toString("HH:mm"));
        m_secondaryLocationLabel->setText(locationName(m_secondaryTimeZoneId));
    }
    else
    {
        m_secondaryTimeLabel->setText("Invalid time zone");
        m_secondaryLocationLabel->setText(m_secondaryTimeZoneId);
    }
}

void ClockWidget::toggleAlwaysOnTop()
{
    m_alwaysOnTop = !m_alwaysOnTop;

    Qt::WindowFlags flags = windowFlags();
    if (m_alwaysOnTop)
    {
        flags |= Qt::WindowStaysOnTopHint;
    }
    else
    {
        flags &= ~Qt::WindowStaysOnTopHint;
    }
    setWindowFlags(flags);
    show();

    // Re-apply platform-specific window properties after changing window flags
    if (m_alwaysOnTop)
    {
        WindowHelper::setupAlwaysOnTopForFullscreen(this);
    }
}

void ClockWidget::changeFontColor()
{
    const std::optional<QColor> color = pickColor("Font Color", m_fontColor, this);
    if (color)
    {
        m_fontColor = *color;
        m_configManager->setFontColor(m_fontColor);
        updateStyleSheet();
        saveSettings();
    }
}

void ClockWidget::changeBackgroundColor()
{
    const std::optional<QColor> color = pickColor("Background Color", m_backgroundColor, this);
    if (color)
    {
        m_backgroundColor = *color;
        m_configManager->setBackgroundColor(m_backgroundColor);
        updateStyleSheet();
        saveSettings();
    }
}

void ClockWidget::changeBorderColor()
{
    const std::optional<QColor> color = pickColor("Border Color", m_borderColor, this);
    if (color)
    {
        m_borderColor = *color;
        m_configManager->setBorderColor(m_borderColor);
        updateStyleSheet();
        saveSettings();
    }
}

void ClockWidget::changeFontSize()
{
    bool ok;
    int size = QInputDialog::getInt(this, "Set Time Font Size", "Font Size:", m_fontSize, 8, 200, 1, &ok);
    if (ok)
    {
        m_fontSize = size;
        m_configManager->setFontSize(m_fontSize);
        updateStyleSheet();
        saveSettings();
    }
}

void ClockWidget::changeLocationFontSize()
{
    bool ok;
    int size = QInputDialog::getInt(this, "Set Location Font Size", "Font Size:", m_locationFontSize, 6, 200, 1, &ok);
    if (ok)
    {
        m_locationFontSize = size;
        m_configManager->setLocationFontSize(m_locationFontSize);
        updateStyleSheet();
        saveSettings();
    }
}

void ClockWidget::changePrimaryTimeZone()
{
    changeTimeZone(true);
}

void ClockWidget::changeSecondaryTimeZone()
{
    changeTimeZone(false);
}

void ClockWidget::resetSettings()
{
    int ret = QMessageBox::question(this, "Reset Settings", "Are you sure you want to reset all settings?");
    if (ret == QMessageBox::Yes)
    {
        m_configManager->resetToDefaults();
        loadSettings();
        updateStyleSheet();
        // Reset to default size
        resize(m_configManager->windowSize());
    }
}

void ClockWidget::quitApplication()
{
    qApp->quit();
}

bool ClockWidget::isInResizeArea(const QPoint &pos) const
{
    // Check if mouse is in the bottom-right corner resize area
    QRect resizeArea(rect().bottomRight() - QPoint(m_resizeBorder * 2, m_resizeBorder * 2),
                     QSize(m_resizeBorder * 2, m_resizeBorder * 2));
    return resizeArea.contains(pos);
}

void ClockWidget::positionAtBottomRight()
{
    // Get primary screen geometry
    QScreen *screen = QApplication::primaryScreen();
    if (!screen)
    {
        // Fallback to default position if no screen available
        move(100, 100);
        return;
    }

    QRect screenGeometry = screen->availableGeometry();
    QSize windowSize = m_configManager->windowSize();

    // Calculate position: bottom-right corner with some margin
    int margin = 20; // 20 pixels margin from screen edges
    int x = screenGeometry.right() - windowSize.width() - margin;
    int y = screenGeometry.bottom() - windowSize.height() - margin;

    move(x, y);
}

void ClockWidget::loadSettings()
{
    m_configManager = new ConfigManager(this);

    // Load from XML config file
    if (!m_configManager->loadSettings())
    {
        // If loading fails, config manager already has default values
        qDebug() << "Using default settings";
    }

    // Apply loaded settings
    m_fontColor = m_configManager->fontColor();
    m_backgroundColor = m_configManager->backgroundColor();
    m_borderColor = m_configManager->borderColor();
    m_fontSize = m_configManager->fontSize();
    m_locationFontSize = m_configManager->locationFontSize();
    m_alwaysOnTop = m_configManager->alwaysOnTop();
    m_primaryTimeZoneId = m_configManager->primaryTimeZoneId();
    m_secondaryTimeZoneId = m_configManager->secondaryTimeZoneId();

    // Restore window position and size
    QPoint windowPos = m_configManager->windowPosition();
    if (windowPos.x() == -1 && windowPos.y() == -1)
    {
        // First time: position at bottom-right corner
        positionAtBottomRight();
    }
    else
    {
        move(windowPos);
    }
    resize(m_configManager->windowSize());

    // Update always on top checkbox in menu
    QList<QAction *> actions = m_contextMenu->actions();
    for (QAction *action : actions)
    {
        if (action->text() == QString("Always on Top"))
        {
            action->setChecked(m_alwaysOnTop);
            break;
        }
    }

    updateStyleSheet();
}

void ClockWidget::saveSettings()
{
    if (!m_configManager)
        return;

    // Update config manager with current values
    m_configManager->setFontColor(m_fontColor);
    m_configManager->setBackgroundColor(m_backgroundColor);
    m_configManager->setBorderColor(m_borderColor);
    m_configManager->setFontSize(m_fontSize);
    m_configManager->setLocationFontSize(m_locationFontSize);
    m_configManager->setAlwaysOnTop(m_alwaysOnTop);
    m_configManager->setWindowPosition(pos());
    m_configManager->setWindowSize(size());
    m_configManager->setPrimaryTimeZoneId(m_primaryTimeZoneId);
    m_configManager->setSecondaryTimeZoneId(m_secondaryTimeZoneId);

    // Save to XML file
    if (!m_configManager->saveSettings())
    {
        qDebug() << "Failed to save settings to config.xml";
    }
}

void ClockWidget::updateStyleSheet()
{
    // Fonts via QSS; glyph fill + outline via ClockLabel::paintEvent.
    const auto labelFontStyleSheet = [](int size) {
        return QString("QLabel { font-family: 'SF Pro Rounded'; font-size: %1pt; background: transparent; }")
            .arg(size);
    };

    m_primaryTimeLabel->setStyleSheet(labelFontStyleSheet(m_fontSize));
    m_secondaryTimeLabel->setStyleSheet(labelFontStyleSheet(m_fontSize));
    m_primaryLocationLabel->setStyleSheet(labelFontStyleSheet(m_locationFontSize));
    m_secondaryLocationLabel->setStyleSheet(labelFontStyleSheet(m_locationFontSize));

    // Shrink/grow the window to fit the text exactly (fonts may have changed).
    adjustSize();

    // Background is painted manually in paintEvent() — QSS does not render
    // it on macOS with WA_TranslucentBackground. Text colors + outline go
    // through ClockLabel (QSS cannot stroke glyphs).
    const qreal outlineWidth = m_borderColor.alpha() > 0 ? 1.0 : 0.0;
    m_primaryTimeLabel->setDisplayColors(m_fontColor, m_borderColor, outlineWidth);
    m_secondaryTimeLabel->setDisplayColors(m_fontColor, m_borderColor, outlineWidth);
    m_primaryLocationLabel->setDisplayColors(m_fontColor, m_borderColor, outlineWidth * 0.75);
    m_secondaryLocationLabel->setDisplayColors(m_fontColor, m_borderColor, outlineWidth * 0.75);
    update();
}

void ClockWidget::changeTimeZone(bool primaryClock)
{
    QStringList timeZoneIds;
    for (const QByteArray &timeZoneId : QTimeZone::availableTimeZoneIds())
    {
        timeZoneIds.append(QString::fromUtf8(timeZoneId));
    }

    const QString currentTimeZoneId = primaryClock ? m_primaryTimeZoneId : m_secondaryTimeZoneId;
    const int currentIndex = timeZoneIds.indexOf(currentTimeZoneId);
    bool accepted = false;
    const QString selectedTimeZoneId = QInputDialog::getItem(
        this,
        primaryClock ? "Set First Time Zone" : "Set Second Time Zone",
        "Time Zone:",
        timeZoneIds,
        currentIndex < 0 ? 0 : currentIndex,
        false,
        &accepted);

    if (!accepted)
    {
        return;
    }

    if (primaryClock)
    {
        m_primaryTimeZoneId = selectedTimeZoneId;
        m_configManager->setPrimaryTimeZoneId(selectedTimeZoneId);
    }
    else
    {
        m_secondaryTimeZoneId = selectedTimeZoneId;
        m_configManager->setSecondaryTimeZoneId(selectedTimeZoneId);
    }

    if (!m_configManager->saveSettings())
    {
        qDebug() << "Failed to save time zone settings to config.xml";
    }
    updateTime();
}

QString ClockWidget::formattedTime(const QString &timeZoneId) const
{
    const QTimeZone timeZone(timeZoneId.toUtf8());
    if (!timeZone.isValid())
    {
        qWarning() << "Invalid time zone configured:" << timeZoneId;
        return QString("Invalid time zone\n%1").arg(timeZoneId);
    }

    const QDateTime timeInZone = QDateTime::currentDateTimeUtc().toTimeZone(timeZone);
    const QString cityName = QString::fromUtf8(timeZone.id()).section('/', -1).replace('_', ' ');
    return QString("%1\n%2")
        .arg(timeInZone.time().toString("HH:mm"), cityName);
}

QString ClockWidget::locationName(const QString &timeZoneId) const
{
    return timeZoneId.section('/', -1).replace('_', ' ');
}

std::optional<QColor> ClockWidget::pickColor(const QString &title, const QColor &current, QWidget *parent)
{
    bool ok = false;
    const QString input = QInputDialog::getText(
        parent, "Set " + title,
        QString("HTML color (#RRGGBB or #AARRGGBB), or type 'transparent':"),
        QLineEdit::Normal,
        current.alpha() == 0 ? QStringLiteral("transparent") : current.name(QColor::HexArgb),
        &ok);

    if (!ok || input.trimmed().isEmpty())
    {
        return std::nullopt; // cancelled — keep current color
    }

    const QString normalized = input.trimmed().toLower();
    if (normalized == "transparent")
    {
        return QColor(Qt::transparent);
    }

    const QColor parsed(normalized);
    if (parsed.isValid())
    {
        return parsed;
    }

    // Not valid HTML text — fall back to the visual color dialog.
    return QColorDialog::getColor(current, parent, "Choose " + title);
}