#include "panels/DatasetListPanel.hpp"

#include <QColor>
#include <QListWidget>
#include <QListWidgetItem>
#include <QObject>
#include <QPainter>
#include <QPainterPath>
#include <QString>
#include <QStyledItemDelegate>

#include "Theme.hpp"

namespace geopro::app {

namespace {
QString humanSize(long long b) {
    if (b < 1024) return QStringLiteral("%1 B").arg(b);
    const double kb = b / 1024.0;
    if (kb < 1024.0) return QStringLiteral("%1 KB").arg(kb, 0, 'f', 1);
    return QStringLiteral("%1 MB").arg(kb / 1024.0, 0, 'f', 1);
}

// 数据/文件列表卡片委托：标题+元信息双行、悬停/选中圆角高亮 + 选中左 2px 强调竖条（规范§6.2）。
// 特殊行（加载更多 / 占位提示）退回为居中纯文本，不画卡片。
class DatasetCardDelegate : public QStyledItemDelegate {
public:
    using QStyledItemDelegate::QStyledItemDelegate;

    QSize sizeHint(const QStyleOptionViewItem&, const QModelIndex& idx) const override {
        const bool special =
            idx.data(kDsLoadMoreRole).toBool() || !(idx.flags() & Qt::ItemIsSelectable);
        return QSize(0, special ? 34 : 52);
    }

    void paint(QPainter* p, const QStyleOptionViewItem& opt, const QModelIndex& idx) const override {
        p->save();
        p->setRenderHint(QPainter::Antialiasing, true);
        const QString disp = idx.data(Qt::DisplayRole).toString();

        // 「加载更多」：居中强调色文本（hover 时加底）。
        if (idx.data(kDsLoadMoreRole).toBool()) {
            if (opt.state & QStyle::State_MouseOver) {
                QPainterPath bgp;
                bgp.addRoundedRect(opt.rect.adjusted(4, 2, -4, -2), 6, 6);
                p->fillPath(bgp, geopro::app::tokenColor("bg/hover"));
            }
            p->setPen(geopro::app::tokenColor("accent/primary"));
            p->drawText(opt.rect, Qt::AlignCenter, disp);
            p->restore();
            return;
        }
        // 占位提示行（不可选）：居中淡色文本。
        if (!(idx.flags() & Qt::ItemIsSelectable)) {
            p->setPen(geopro::app::tokenColor("text/disabled"));
            p->drawText(opt.rect, Qt::AlignCenter, disp);
            p->restore();
            return;
        }

        // 卡片
        const QRect r = opt.rect.adjusted(4, 2, -4, -2);
        const bool selected = opt.state & QStyle::State_Selected;
        const bool hover = opt.state & QStyle::State_MouseOver;
        if (selected || hover) {
            QPainterPath path;
            path.addRoundedRect(r, 6, 6);
            p->fillPath(path, geopro::app::tokenColor(selected ? "bg/selected" : "bg/hover"));
        }
        if (selected) {  // 左 2px 强调竖条（规范§6.2）
            p->fillRect(QRect(r.left(), r.top() + 4, 2, r.height() - 8),
                        geopro::app::tokenColor("accent/primary"));
        }

        QString title = disp, meta;
        const int nl = disp.indexOf(QLatin1Char('\n'));
        if (nl >= 0) {
            title = disp.left(nl);
            meta = disp.mid(nl + 1);
        }

        const QRect textR = r.adjusted(14, 6, -12, -6);
        // 标题
        QFont tf = opt.font;
        tf.setPixelSize(geopro::app::scaledPx(13));
        p->setFont(tf);
        p->setPen(geopro::app::tokenColor("text/primary"));
        const QRect titleR(textR.left(), textR.top(), textR.width(), textR.height() / 2);
        p->drawText(titleR, Qt::AlignLeft | Qt::AlignVCenter,
                    p->fontMetrics().elidedText(title, Qt::ElideRight, titleR.width()));
        // 元信息
        if (!meta.isEmpty()) {
            QFont mf = opt.font;
            mf.setPixelSize(geopro::app::scaledPx(11));
            p->setFont(mf);
            p->setPen(geopro::app::tokenColor("text/tertiary"));
            const QRect metaR(textR.left(), textR.center().y() + 1, textR.width(),
                              textR.height() / 2);
            p->drawText(metaR, Qt::AlignLeft | Qt::AlignVCenter,
                        p->fontMetrics().elidedText(meta, Qt::ElideRight, metaR.width()));
        }
        p->restore();
    }
};
}  // namespace

void populateDatasetList(QListWidget* list, const std::vector<geopro::data::DsRow>& rows, bool append) {
    if (!list) return;
    if (!append) list->clear();
    for (const auto& d : rows) {
        QString text = QString::fromStdString(d.dsName);
        QString sub = QString::fromStdString(d.createTime);  // 名称下先创建时间
        if (!d.typeName.empty())
            sub += QStringLiteral(" · %1").arg(QString::fromStdString(d.typeName));  // 再跟类型
        if (!sub.isEmpty()) text += QStringLiteral("\n%1").arg(sub);
        auto* item = new QListWidgetItem(text, list);
        item->setData(kDsIdRole, QString::fromStdString(d.id));
        item->setData(kDsDdTypeRole, QString::fromStdString(d.ddCode));
    }
}

void populateFileList(QListWidget* list, const std::vector<geopro::data::DsRow>& rows, bool append) {
    if (!list) return;
    if (!append) list->clear();
    if (!append && rows.empty()) {
        auto* hint = new QListWidgetItem(QStringLiteral("（暂无文件）"), list);
        hint->setFlags(Qt::NoItemFlags);
        hint->setTextAlignment(Qt::AlignCenter);
        return;
    }
    for (const auto& d : rows) {
        const QString fname =
            d.fileName.empty() ? QString::fromStdString(d.dsName) : QString::fromStdString(d.fileName);
        QString sub = QString::fromStdString(d.createTime);  // 名称下先创建时间
        sub += QStringLiteral(" · %1").arg(humanSize(d.fileSize));  // 再跟大小
        const QString text = fname + QStringLiteral("\n%1").arg(sub);
        auto* item = new QListWidgetItem(text, list);
        item->setData(kDsIdRole, QString::fromStdString(d.id));
        item->setData(kDsFileUrlRole, QString::fromStdString(d.fileUrl));
    }
}

void applyDatasetCardDelegate(QListWidget* list) {
    if (!list) return;
    list->setItemDelegate(new DatasetCardDelegate(list));
    list->setMouseTracking(true);  // 让委托收到 hover 状态
    list->setSpacing(0);           // 卡间距由委托内边距控制
    QObject::connect(&ThemeManager::instance(), &ThemeManager::changed, list,
                     [list]() { list->viewport()->update(); });
}

}  // namespace geopro::app