#include "ui/DiffTableModel.h"
#include "ui/PanelTableView.h"
#include <QAbstractItemModel>
#include <QEvent>
#include <QHeaderView>
#include <QPainter>
#include <QPalette>
#include <QProxyStyle>
#include <QStyledItemDelegate>
#include <QStyleOptionViewItem>

namespace whittle {
namespace {

constexpr int kCellPadding = 3;
constexpr int kCheckGap    = 2;

class CellSeparatorDelegate : public QStyledItemDelegate {
public:
    using QStyledItemDelegate::QStyledItemDelegate;

    void initStyleOption(QStyleOptionViewItem* opt,
                         const QModelIndex& ix) const override {
        QStyledItemDelegate::initStyleOption(opt, ix);
        if (ix.column() == DiffTableModel::Name) {
            opt->textElideMode = Qt::ElideLeft;
            opt->features &= ~QStyleOptionViewItem::WrapText;
        }
    }

    void paint(QPainter* p, const QStyleOptionViewItem& opt,
               const QModelIndex& ix) const override {
        QStyleOptionViewItem padded = opt;
        padded.rect.adjust(kCellPadding, 0, 0, 0);
        QStyledItemDelegate::paint(p, padded, ix);
        if (!ix.model()) return;

        p->save();
        p->setPen(opt.palette.color(QPalette::Mid));
        p->drawLine(opt.rect.bottomLeft(), opt.rect.bottomRight());
        if (ix.column() != ix.model()->columnCount() - 1)
            p->drawLine(opt.rect.topRight(), opt.rect.bottomRight());
        p->restore();
    }

    bool editorEvent(QEvent* e, QAbstractItemModel* model,
                     const QStyleOptionViewItem& opt,
                     const QModelIndex& ix) override {
        QStyleOptionViewItem padded = opt;
        padded.rect.adjust(kCellPadding, 0, 0, 0);
        return QStyledItemDelegate::editorEvent(e, model, padded, ix);
    }

    QSize sizeHint(const QStyleOptionViewItem& opt,
                   const QModelIndex& ix) const override {
        QSize s = QStyledItemDelegate::sizeHint(opt, ix);
        s.rwidth() += kCellPadding;
        if (ix.flags() & Qt::ItemIsUserCheckable) s.rwidth() += kCheckGap;
        return s;
    }

};

class CheckGapStyle : public QProxyStyle {
public:
    QRect subElementRect(SubElement se, const QStyleOption* opt,
                         const QWidget* w) const override {
        QRect r = QProxyStyle::subElementRect(se, opt, w);
        if (se == SE_ItemViewItemText)
            if (const auto* vi = qstyleoption_cast<const QStyleOptionViewItem*>(opt))
                if (vi->features & QStyleOptionViewItem::HasCheckIndicator)
                    r.adjust(kCheckGap, 0, 0, 0);
        return r;
    }
};

} 

PanelTableView::PanelTableView(QWidget* parent) : QTableView(parent) {
    setShowGrid(false);
    setItemDelegate(new CellSeparatorDelegate(this));
    auto* gapStyle = new CheckGapStyle;
    gapStyle->setParent(this);
    setStyle(gapStyle);

    setSelectionMode(QAbstractItemView::NoSelection);
    setFocusPolicy(Qt::NoFocus);
    setEditTriggers(QAbstractItemView::NoEditTriggers);

    auto* hh = horizontalHeader();
    hh->setStretchLastSection(false);
    hh->setSectionResizeMode(QHeaderView::Interactive);
    hh->setHighlightSections(false);
    verticalHeader()->setVisible(false);

    connect(hh, &QHeaderView::sectionResized, this, [this](int, int, int) {
        if (!m_applying) m_userSized = true;
    });
}

void PanelTableView::resetColumnProportions() {
    m_userSized = false;
    applyProportions();
}

void PanelTableView::resizeEvent(QResizeEvent* e) {
    QTableView::resizeEvent(e);
    applyProportions();
}

void PanelTableView::applyProportions() {
    if (m_userSized || !model()) return;
    if (model()->columnCount() < DiffTableModel::ColumnCount) return;

    const int w = viewport()->width();
    if (w <= 0) return;

    const int name = w * 50 / 100;
    const int size = w * 13 / 100;
    const int mod  = w * 24 / 100;

    m_applying = true;
    setColumnWidth(DiffTableModel::Name,     name);
    setColumnWidth(DiffTableModel::Size,     size);
    setColumnWidth(DiffTableModel::Modified, mod);
    setColumnWidth(DiffTableModel::TimeDiff, w - name - size - mod);
    m_applying = false;
}

}