#include "panels/DatasetListPanel.hpp"

#include <QAbstractItemView>
#include <QApplication>
#include <QColor>
#include <QHash>
#include <QKeyEvent>
#include <QListWidget>
#include <QListWidgetItem>
#include <QMouseEvent>
#include <QObject>
#include <QPainter>
#include <QPainterPath>
#include <QString>
#include <QStyle>
#include <QStyledItemDelegate>
#include <QTreeWidget>
#include <QTreeWidgetItem>
#include <QTreeWidgetItemIterator>

#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"));
        }

        // 可勾选项：左侧画复选框(用当前 style 的指示器),文本整体右移。
        int textLeftPad = 14;
        const bool checkable = (idx.flags() & Qt::ItemIsUserCheckable);
        if (checkable) {
            const int box = 16;
            QRect checkRect(r.left() + 12, r.top() + (r.height() - box) / 2, box, box);
            const auto cs = static_cast<Qt::CheckState>(idx.data(Qt::CheckStateRole).toInt());
            QStyleOptionViewItem o(opt);
            o.rect = checkRect;
            o.state &= ~QStyle::State_HasFocus;
            o.state |= (cs == Qt::Checked ? QStyle::State_On : QStyle::State_Off);
            const QWidget* w = opt.widget;
            QStyle* st = w ? w->style() : QApplication::style();
            st->drawPrimitive(QStyle::PE_IndicatorItemViewItemCheck, &o, p, w);
            textLeftPad = 12 + box + 8;  // 复选框右侧留白后再放文本
        }

        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(textLeftPad, 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();
    }

    bool editorEvent(QEvent* ev, QAbstractItemModel* model, const QStyleOptionViewItem& opt,
                     const QModelIndex& idx) override {
        if (!(idx.flags() & Qt::ItemIsUserCheckable))
            return QStyledItemDelegate::editorEvent(ev, model, opt, idx);
        const QRect r = opt.rect.adjusted(4, 2, -4, -2);
        const int box = 16;
        // 命中区放宽到复选框左侧整段(含一点文本起始),便于点击。
        const QRect hit(r.left(), r.top(), 12 + box + 8, r.height());
        auto toggle = [&]() {
            const auto cur = static_cast<Qt::CheckState>(idx.data(Qt::CheckStateRole).toInt());
            model->setData(idx, cur == Qt::Checked ? Qt::Unchecked : Qt::Checked, Qt::CheckStateRole);
        };
        if (ev->type() == QEvent::MouseButtonRelease) {
            auto* me = static_cast<QMouseEvent*>(ev);
            if (me->button() == Qt::LeftButton && hit.contains(me->pos())) {
                toggle();
                return true;
            }
        } else if (ev->type() == QEvent::KeyPress) {
            auto* ke = static_cast<QKeyEvent*>(ev);
            if (ke->key() == Qt::Key_Space || ke->key() == Qt::Key_Select) {
                toggle();
                return true;
            }
        }
        return QStyledItemDelegate::editorEvent(ev, model, opt, idx);
    }
};
}  // namespace

namespace {
// 建一条数据集树项（不挂载）：列0 文本 = dsName +「创建时间 · 类型名」，data 存各角色。
QTreeWidgetItem* makeDatasetItem(const geopro::data::DsRow& d, const QString& tmObjectId) {
    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 QTreeWidgetItem();
    item->setText(0, text);
    item->setData(0, kDsIdRole, QString::fromStdString(d.id));
    item->setData(0, kDsDdTypeRole, QString::fromStdString(d.ddCode));
    item->setData(0, kDsDdCodeRole, QString::fromStdString(d.ddCode));
    item->setData(0, kDsNameRole, QString::fromStdString(d.dsName));
    item->setData(0, kDsTypeNameRole, QString::fromStdString(d.typeName));
    item->setData(0, kDsCreateTimeRole, QString::fromStdString(d.createTime));
    item->setData(0, kDsTmObjectIdRole, tmObjectId);  // 所属 TM 对象 id（白化 structParentId）
    // 单击 tip：显示数据集主要属性（名称 / 类型 / 创建时间），对齐菜单文档「tip显示ds的主要属性」。
    QString tip = QStringLiteral("名称：%1").arg(QString::fromStdString(d.dsName));
    if (!d.typeName.empty()) tip += QStringLiteral("\n类型：%1").arg(QString::fromStdString(d.typeName));
    if (!d.createTime.empty())
        tip += QStringLiteral("\n创建时间：%1").arg(QString::fromStdString(d.createTime));
    item->setToolTip(0, tip);
    return item;
}
}  // namespace

void populateDatasetList(QTreeWidget* tree, const std::vector<geopro::data::DsRow>& rows, bool append,
                         const QString& tmObjectId) {
    if (!tree) return;
    if (!append) tree->clear();

    // id→已在树中的项：!append 时为空；append（分页）时含已加载行，使新行能挂到既有父下。
    QHash<QString, QTreeWidgetItem*> byId;
    for (QTreeWidgetItemIterator it(tree); *it; ++it) {
        const QString id = (*it)->data(0, kDsIdRole).toString();
        if (!id.isEmpty()) byId.insert(id, *it);
    }

    // 第一遍：本批全部建项（不挂载）并登记 id，使同批内的父子也能互相找到。
    std::vector<QTreeWidgetItem*> batch;
    batch.reserve(rows.size());
    for (const auto& d : rows) {
        auto* item = makeDatasetItem(d, tmObjectId);
        byId.insert(QString::fromStdString(d.id), item);
        batch.push_back(item);
    }
    // 第二遍：按 parentId 挂载。父在集合内→作其子；否则（父是源文件节点/不在本批）→作树根。
    for (std::size_t i = 0; i < rows.size(); ++i) {
        const QString pid = QString::fromStdString(rows[i].parentId);
        QTreeWidgetItem* parent = pid.isEmpty() ? nullptr : byId.value(pid, nullptr);
        if (parent && parent != batch[i])
            parent->addChild(batch[i]);
        else
            tree->addTopLevelItem(batch[i]);
    }
    // 默认折叠（对齐原版：仅显源数据根行，派生数据收在展开箭头内）。
}

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

QStringList collectDatasetTypeNames(QTreeWidget* tree) {
    QStringList types;
    if (!tree) return types;
    QSet<QString> seen;
    for (QTreeWidgetItemIterator it(tree); *it; ++it) {
        if ((*it)->data(0, kDsLoadMoreRole).toBool()) continue;
        const QString t = (*it)->data(0, kDsTypeNameRole).toString();
        if (t.isEmpty() || seen.contains(t)) continue;
        seen.insert(t);
        types << t;
    }
    return types;
}

namespace {
// 解析创建时间字符串为日期（容忍 "yyyy-MM-dd HH:mm:ss" / "yyyy-MM-dd" / "yyyy/MM/dd"）。
QDate parseRowDate(const QString& s) {
    if (s.isEmpty()) return {};
    const QString d = s.left(10);
    for (const char* fmt : {"yyyy-MM-dd", "yyyy/MM/dd"}) {
        QDate v = QDate::fromString(d, QString::fromLatin1(fmt));
        if (v.isValid()) return v;
    }
    return {};
}

// 递归判定项是否匹配（类型在集合内 且 创建日期 >= minDate）。
bool rowMatches(QTreeWidgetItem* item, const QSet<QString>& visibleTypes, const QDate& minDate) {
    const QString t = item->data(0, kDsTypeNameRole).toString();
    if (!t.isEmpty() && !visibleTypes.contains(t)) return false;
    if (minDate.isValid()) {
        const QDate d = parseRowDate(item->data(0, kDsCreateTimeRole).toString());
        if (d.isValid() && d < minDate) return false;
    }
    return true;
}

// 返回该项（或其任一后代）是否可见；据此 setHidden。父项只要有可见后代即保留。
bool applyFilterRec(QTreeWidgetItem* item, const QSet<QString>& visibleTypes, const QDate& minDate) {
    if (item->data(0, kDsLoadMoreRole).toBool()) return true;  // 「加载更多」行恒显
    bool anyChildVisible = false;
    for (int i = 0; i < item->childCount(); ++i)
        anyChildVisible |= applyFilterRec(item->child(i), visibleTypes, minDate);
    const bool selfMatch = rowMatches(item, visibleTypes, minDate);
    const bool visible = selfMatch || anyChildVisible;
    item->setHidden(!visible);
    return visible;
}
}  // namespace

void applyDatasetFilter(QTreeWidget* tree, const QSet<QString>& visibleTypes, const QDate& minDate) {
    if (!tree) return;
    for (int i = 0; i < tree->topLevelItemCount(); ++i)
        applyFilterRec(tree->topLevelItem(i), visibleTypes, minDate);
}

}  // namespace geopro::app