#include "panels/chart/TablePager.hpp"

#include <algorithm>

#include <QComboBox>
#include <QHBoxLayout>
#include <QIntValidator>
#include <QLabel>
#include <QLineEdit>
#include <QSignalBlocker>
#include <QToolButton>

namespace geopro::app {

namespace {
// 每页条数选项（实测原版 vxe-pager 下拉：50/100/500/1000，默认 50）。
const int kPageSizes[] = {50, 100, 500, 1000};
constexpr int kPagerCount = 7;  // 页码窗口（>此值用 … 折叠，对齐 vxe 默认）
constexpr int kJumpStep = 5;    // 点击 … 的跳页步长

// 分页器样式：常态不设字色（跟随主题/全局样式表）；边框用半透明灰（两主题通用）；
// hover/选中页用强调蓝 #409EFF（与 DataTableView 开关同色）。
const char* kPagerQss = R"(
QToolButton {
  border: 1px solid rgba(128,128,128,0.35);
  border-radius: 3px;
  padding: 1px 6px;
  min-width: 16px;
  min-height: 20px;
  background: transparent;
}
QToolButton:hover:enabled { color: #409EFF; border-color: #409EFF; }
QToolButton[active="true"] { color: #409EFF; border-color: #409EFF; font-weight: bold; }
QToolButton:disabled { color: rgba(128,128,128,0.55); }
)";
}  // namespace

TablePager::TablePager(QWidget* parent) : QWidget(parent) {
    setStyleSheet(QString::fromUtf8(kPagerQss));

    auto* lay = new QHBoxLayout(this);
    lay->setContentsMargins(8, 6, 8, 6);
    lay->setSpacing(6);
    lay->addStretch(1);  // 右对齐

    prevBtn_ = new QToolButton(this);
    prevBtn_->setText(QStringLiteral("‹"));
    prevBtn_->setCursor(Qt::PointingHandCursor);
    connect(prevBtn_, &QToolButton::clicked, this,
            [this] { emit pageRequested(pageNo_ - 1, pageSize_); });
    lay->addWidget(prevBtn_);

    numHost_ = new QWidget(this);
    numLay_ = new QHBoxLayout(numHost_);
    numLay_->setContentsMargins(0, 0, 0, 0);
    numLay_->setSpacing(6);
    lay->addWidget(numHost_);

    nextBtn_ = new QToolButton(this);
    nextBtn_->setText(QStringLiteral("›"));
    nextBtn_->setCursor(Qt::PointingHandCursor);
    connect(nextBtn_, &QToolButton::clicked, this,
            [this] { emit pageRequested(pageNo_ + 1, pageSize_); });
    lay->addWidget(nextBtn_);

    auto* gotoLabel = new QLabel(QStringLiteral("前往"), this);
    lay->addWidget(gotoLabel);

    jumpEdit_ = new QLineEdit(this);
    jumpEdit_->setFixedWidth(40);
    jumpEdit_->setAlignment(Qt::AlignCenter);
    jumpValidator_ = new QIntValidator(1, 1, jumpEdit_);
    jumpEdit_->setValidator(jumpValidator_);
    connect(jumpEdit_, &QLineEdit::returnPressed, this, [this] {
        bool ok = false;
        int p = jumpEdit_->text().toInt(&ok);
        const int pc = pageCount();
        if (!ok) {
            jumpEdit_->setText(QString::number(pageNo_));
            return;
        }
        p = std::min(std::max(1, p), std::max(1, pc));
        if (p == pageNo_) {
            jumpEdit_->setText(QString::number(pageNo_));
            return;
        }
        emit pageRequested(p, pageSize_);
    });
    lay->addWidget(jumpEdit_);

    lay->addWidget(new QLabel(QStringLiteral("页"), this));

    sizeCombo_ = new QComboBox(this);
    for (int s : kPageSizes)
        sizeCombo_->addItem(QStringLiteral("%1条/页").arg(s), s);
    connect(sizeCombo_, &QComboBox::activated, this, [this](int i) {
        emit pageRequested(1, sizeCombo_->itemData(i).toInt());  // 改每页条数 → 回第 1 页
    });
    lay->addWidget(sizeCombo_);

    totalLabel_ = new QLabel(this);
    lay->addWidget(totalLabel_);

    setState(0, 1, pageSize_);
}

int TablePager::pageCount() const {
    if (pageSize_ <= 0) return 1;
    return std::max(1, (total_ + pageSize_ - 1) / pageSize_);
}

void TablePager::setState(int total, int pageNo, int pageSize) {
    total_ = std::max(0, total);
    if (pageSize > 0) pageSize_ = pageSize;
    const int pc = pageCount();
    pageNo_ = std::min(std::max(1, pageNo), pc);

    prevBtn_->setEnabled(pageNo_ > 1);
    nextBtn_->setEnabled(pageNo_ < pc);

    jumpValidator_->setTop(pc);
    {
        QSignalBlocker b(jumpEdit_);
        jumpEdit_->setText(QString::number(pageNo_));
    }
    {
        QSignalBlocker b(sizeCombo_);
        int idx = sizeCombo_->findData(pageSize_);
        if (idx < 0) {  // 非预设条数（兜底）：补一项再选中
            sizeCombo_->addItem(QStringLiteral("%1条/页").arg(pageSize_), pageSize_);
            idx = sizeCombo_->findData(pageSize_);
        }
        sizeCombo_->setCurrentIndex(idx);
    }
    totalLabel_->setText(QStringLiteral("共 %1 条记录").arg(total_));

    rebuildNumbers();
}

void TablePager::rebuildNumbers() {
    // 清空旧页码按钮。
    while (QLayoutItem* it = numLay_->takeAt(0)) {
        if (QWidget* w = it->widget()) w->deleteLater();
        delete it;
    }

    const int pc = pageCount();
    auto addNum = [this](int p, bool active) {
        auto* b = new QToolButton(numHost_);
        b->setText(QString::number(p));
        b->setCursor(Qt::PointingHandCursor);
        b->setProperty("active", active);
        b->setEnabled(!active);  // 当前页不可再点
        connect(b, &QToolButton::clicked, this, [this, p] { emit pageRequested(p, pageSize_); });
        numLay_->addWidget(b);
    };
    auto addDots = [this](int target) {
        auto* b = new QToolButton(numHost_);
        b->setText(QStringLiteral("..."));
        b->setCursor(Qt::PointingHandCursor);
        connect(b, &QToolButton::clicked, this,
                [this, target] { emit pageRequested(target, pageSize_); });
        numLay_->addWidget(b);
    };

    if (pc <= kPagerCount) {
        for (int p = 1; p <= pc; ++p) addNum(p, p == pageNo_);
        return;
    }
    // 折叠窗口：首页 [ … ] 中段(当前±2) [ … ] 末页。
    addNum(1, pageNo_ == 1);
    int left = pageNo_ - 2;
    int right = pageNo_ + 2;
    if (left < 2) {
        left = 2;
        right = 5;
    }
    if (right > pc - 1) {
        right = pc - 1;
        left = pc - 4;
    }
    if (left > 2) addDots(std::max(1, pageNo_ - kJumpStep));
    for (int p = left; p <= right; ++p) addNum(p, p == pageNo_);
    if (right < pc - 1) addDots(std::min(pc, pageNo_ + kJumpStep));
    addNum(pc, pageNo_ == pc);
}

}  // namespace geopro::app