#include "WorkspacePanel.h"

#include <QAbstractItemView>
#include <QFrame>
#include <QGuiApplication>
#include <QHBoxLayout>
#include <QLabel>
#include <QListWidget>
#include <QListWidgetItem>
#include <QMouseEvent>
#include <QPushButton>
#include <QScreen>
#include <QSplitter>
#include <QTextEdit>
#include <QVBoxLayout>
#include <QtGlobal>

#include <limits>
#include <utility>

namespace
{
constexpr int PanelWidth = 780;
constexpr int PanelHeight = 560;
constexpr int PanelGap = 16;
constexpr int ScreenMargin = 8;
constexpr int MaxTextMatchesInDetails = 30;

int boundedCoordinate(int value, int minimum, int maximum)
{
    if (maximum < minimum)
    {
        return minimum;
    }
    return qBound(minimum, value, maximum);
}

qint64 overlapArea(const QRect &first, const QRect &second)
{
    const QRect intersection = first.intersected(second);
    if (intersection.isEmpty())
    {
        return 0;
    }
    return static_cast<qint64>(intersection.width()) * static_cast<qint64>(intersection.height());
}

qint64 squaredDistance(const QPoint &first, const QPoint &second)
{
    const qint64 dx = first.x() - second.x();
    const qint64 dy = first.y() - second.y();
    return dx * dx + dy * dy;
}

QString compactPath(const WorkspaceFileInfo &file)
{
    return file.relativePath + (file.isDirectory ? QStringLiteral(" [目录]") : QString());
}

QString fileTypeText(const WorkspaceFileInfo &file)
{
    if (file.isDirectory)
    {
        return QStringLiteral("目录");
    }
    if (file.isTextFile)
    {
        return QStringLiteral("文本文件");
    }
    return QStringLiteral("文件");
}

QString htmlLine(QString text)
{
    return text.toHtmlEscaped().replace(QStringLiteral("\n"), QStringLiteral("<br>"));
}

QFrame *card(QWidget *parent)
{
    auto *frame = new QFrame(parent);
    frame->setObjectName(QStringLiteral("WorkspaceCard"));
    auto *layout = new QVBoxLayout(frame);
    layout->setContentsMargins(14, 12, 14, 12);
    layout->setSpacing(8);
    return frame;
}

QLabel *cardTitle(const QString &text, QWidget *parent)
{
    auto *label = new QLabel(text, parent);
    label->setObjectName(QStringLiteral("CardTitle"));
    return label;
}

QTextEdit *readOnlyTextEdit(QWidget *parent)
{
    auto *edit = new QTextEdit(parent);
    edit->setReadOnly(true);
    edit->setFrameShape(QFrame::NoFrame);
    edit->setLineWrapMode(QTextEdit::WidgetWidth);
    return edit;
}
}

WorkspacePanel::WorkspacePanel(QWidget *parent)
    : QDialog(parent)
    , m_workspaceLabel(new QLabel(this))
    , m_scanLabel(new QLabel(this))
    , m_summaryLabel(new QLabel(this))
    , m_resultList(new QListWidget(this))
    , m_selectedDetailEdit(readOnlyTextEdit(this))
    , m_textMatchesEdit(readOnlyTextEdit(this))
    , m_recentReadEdit(readOnlyTextEdit(this))
    , m_readButton(new QPushButton(QStringLiteral("读取"), this))
    , m_openButton(new QPushButton(QStringLiteral("打开"), this))
    , m_revealButton(new QPushButton(QStringLiteral("位置"), this))
    , m_closeButton(new QPushButton(QStringLiteral("×"), this))
{
    setWindowTitle(QStringLiteral("本地工作区 Agent"));
    setWindowFlags(Qt::Tool | Qt::FramelessWindowHint | Qt::WindowStaysOnTopHint);
    setModal(false);
    resize(PanelWidth, PanelHeight);

    m_workspaceLabel->setObjectName(QStringLiteral("WorkspaceTitle"));
    m_workspaceLabel->setWordWrap(true);
    m_scanLabel->setObjectName(QStringLiteral("MetaLabel"));
    m_summaryLabel->setObjectName(QStringLiteral("MetaLabel"));
    m_summaryLabel->setWordWrap(true);
    m_closeButton->setObjectName(QStringLiteral("TitleCloseButton"));
    m_closeButton->setFixedSize(30, 30);
    m_resultList->setObjectName(QStringLiteral("ResultList"));
    m_resultList->setSelectionMode(QAbstractItemView::SingleSelection);

    auto *titleLayout = new QHBoxLayout;
    titleLayout->setContentsMargins(0, 0, 0, 0);
    titleLayout->setSpacing(10);
    titleLayout->addWidget(m_workspaceLabel, 1);
    titleLayout->addWidget(m_closeButton);

    auto *headerLayout = new QVBoxLayout;
    headerLayout->setSpacing(6);
    headerLayout->addLayout(titleLayout);
    headerLayout->addWidget(m_scanLabel);
    headerLayout->addWidget(m_summaryLabel);

    auto *leftCard = card(this);
    leftCard->setMinimumWidth(260);
    leftCard->layout()->addWidget(cardTitle(QStringLiteral("上一轮结果"), leftCard));
    leftCard->layout()->addWidget(m_resultList);

    auto *selectedCard = card(this);
    selectedCard->layout()->addWidget(cardTitle(QStringLiteral("选中项"), selectedCard));
    selectedCard->layout()->addWidget(m_selectedDetailEdit);

    auto *matchesCard = card(this);
    matchesCard->layout()->addWidget(cardTitle(QStringLiteral("文本命中"), matchesCard));
    matchesCard->layout()->addWidget(m_textMatchesEdit);

    auto *recentReadCard = card(this);
    recentReadCard->layout()->addWidget(cardTitle(QStringLiteral("最近读取"), recentReadCard));
    recentReadCard->layout()->addWidget(m_recentReadEdit);

    auto *rightLayout = new QVBoxLayout;
    rightLayout->setContentsMargins(0, 0, 0, 0);
    rightLayout->setSpacing(12);
    rightLayout->addWidget(selectedCard, 1);
    rightLayout->addWidget(matchesCard, 2);
    rightLayout->addWidget(recentReadCard, 2);

    auto *rightContainer = new QWidget(this);
    rightContainer->setLayout(rightLayout);

    auto *splitter = new QSplitter(Qt::Horizontal, this);
    splitter->setObjectName(QStringLiteral("WorkspaceSplitter"));
    splitter->addWidget(leftCard);
    splitter->addWidget(rightContainer);
    splitter->setStretchFactor(0, 0);
    splitter->setStretchFactor(1, 1);
    splitter->setSizes({280, 470});

    auto *buttonLayout = new QHBoxLayout;
    buttonLayout->setSpacing(10);
    buttonLayout->addWidget(m_readButton);
    buttonLayout->addWidget(m_openButton);
    buttonLayout->addWidget(m_revealButton);
    buttonLayout->addStretch(1);
    auto *bottomCloseButton = new QPushButton(QStringLiteral("关闭"), this);
    buttonLayout->addWidget(bottomCloseButton);

    auto *layout = new QVBoxLayout(this);
    layout->setContentsMargins(16, 16, 16, 16);
    layout->setSpacing(14);
    layout->addLayout(headerLayout);
    layout->addWidget(splitter, 1);
    layout->addLayout(buttonLayout);

    setStyleSheet(QStringLiteral(
        "QDialog { background: #111827; color: #e5e7eb; }"
        "QLabel#WorkspaceTitle { color: #f8fafc; font-size: 17px; font-weight: 700; }"
        "QLabel#MetaLabel { color: #93a4bd; font-size: 12px; }"
        "QLabel#CardTitle { color: #dbeafe; font-size: 13px; font-weight: 700; }"
        "QFrame#WorkspaceCard { background: #172235; border: 1px solid #2a3a55; border-radius: 8px; }"
        "QListWidget#ResultList { background: #0f172a; color: #dbe4f0; border: 1px solid #26364f; border-radius: 6px; padding: 4px; }"
        "QListWidget#ResultList::item { min-height: 28px; padding: 6px 8px; border-radius: 5px; }"
        "QListWidget#ResultList::item:selected { background: #1d4ed8; color: #ffffff; }"
        "QTextEdit { background: #0f172a; color: #dbe4f0; border: 1px solid #26364f; border-radius: 6px; padding: 8px; selection-background-color: #2563eb; }"
        "QPushButton {"
        "background: #1f2d44;"
        "border: 1px solid #35506f;"
        "border-radius: 6px;"
        "padding: 5px 14px;"
        "min-height: 30px;"
        "color: #e5e7eb;"
        "}"
        "QPushButton:hover:enabled { background: #263b5f; }"
        "QPushButton:disabled { color: #64748b; background: #162033; border-color: #243247; }"
        "QPushButton#TitleCloseButton { min-width: 30px; max-width: 30px; min-height: 30px; max-height: 30px; border-radius: 15px; padding: 0; font-size: 18px; }"
        "QPushButton#TitleCloseButton:hover:enabled { background: #7f1d1d; border-color: #991b1b; }"
        "QSplitter::handle { background: transparent; width: 8px; }"));

    connect(m_resultList, &QListWidget::currentRowChanged, this, [this]() {
        updateDetails();
        updateActionButtons();
    });
    connect(m_readButton, &QPushButton::clicked, this, [this]() {
        const int index = selectedResultIndex();
        if (index >= 0 && m_readCallback)
        {
            m_readCallback(index);
        }
    });
    connect(m_openButton, &QPushButton::clicked, this, [this]() {
        const int index = selectedResultIndex();
        if (index >= 0 && m_openCallback)
        {
            m_openCallback(index);
        }
    });
    connect(m_revealButton, &QPushButton::clicked, this, [this]() {
        const int index = selectedResultIndex();
        if (index >= 0 && m_revealCallback)
        {
            m_revealCallback(index);
        }
    });
    connect(m_closeButton, &QPushButton::clicked, this, &QDialog::hide);
    connect(bottomCloseButton, &QPushButton::clicked, this, &QDialog::hide);
    updateDetails();
    updateActionButtons();
}

void WorkspacePanel::setSnapshot(const WorkspacePanelSnapshot &snapshot)
{
    m_snapshot = snapshot;
    updateSummary();
    updateResults();
    updateDetails();
    updateActionButtons();
}

void WorkspacePanel::showNear(const QRect &avoidRect)
{
    move(smartTopLeftNear(avoidRect));
    show();
    raise();
    activateWindow();
}

void WorkspacePanel::setReadCallback(ResultActionCallback callback)
{
    m_readCallback = std::move(callback);
}

void WorkspacePanel::setOpenCallback(ResultActionCallback callback)
{
    m_openCallback = std::move(callback);
}

void WorkspacePanel::setRevealCallback(ResultActionCallback callback)
{
    m_revealCallback = std::move(callback);
}

void WorkspacePanel::mousePressEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton && event->position().y() <= 72)
    {
        m_dragging = true;
        m_dragStartPosition = event->globalPosition().toPoint();
        m_dragWindowPosition = pos();
        event->accept();
        return;
    }

    QDialog::mousePressEvent(event);
}

void WorkspacePanel::mouseMoveEvent(QMouseEvent *event)
{
    if (m_dragging && (event->buttons() & Qt::LeftButton))
    {
        move(m_dragWindowPosition + (event->globalPosition().toPoint() - m_dragStartPosition));
        event->accept();
        return;
    }

    QDialog::mouseMoveEvent(event);
}

void WorkspacePanel::mouseReleaseEvent(QMouseEvent *event)
{
    m_dragging = false;
    QDialog::mouseReleaseEvent(event);
}

QRect WorkspacePanel::availableGeometryForRect(const QRect &rect) const
{
    const QScreen *screen = QGuiApplication::screenAt(rect.center());
    if (screen == nullptr)
    {
        screen = QGuiApplication::screenAt(rect.topLeft());
    }
    if (screen == nullptr)
    {
        screen = QGuiApplication::primaryScreen();
    }
    return screen == nullptr ? QRect() : screen->availableGeometry();
}

QPoint WorkspacePanel::constrainedTopLeft(const QPoint &preferredTopLeft, const QRect &availableGeometry) const
{
    if (!availableGeometry.isValid())
    {
        return preferredTopLeft;
    }

    return QPoint(
        boundedCoordinate(preferredTopLeft.x(), availableGeometry.left() + ScreenMargin, availableGeometry.right() - width() - ScreenMargin),
        boundedCoordinate(preferredTopLeft.y(), availableGeometry.top() + ScreenMargin, availableGeometry.bottom() - height() - ScreenMargin));
}

QPoint WorkspacePanel::smartTopLeftNear(const QRect &avoidRect) const
{
    if (!avoidRect.isValid())
    {
        return pos();
    }

    const QRect availableGeometry = availableGeometryForRect(avoidRect);
    const QVector<QPoint> preferredTopLefts = {
        QPoint(avoidRect.right() + 1 + PanelGap, avoidRect.top()),
        QPoint(avoidRect.left() - PanelGap - width(), avoidRect.top()),
        QPoint(avoidRect.center().x() - width() / 2, avoidRect.top() - PanelGap - height()),
        QPoint(avoidRect.center().x() - width() / 2, avoidRect.bottom() + 1 + PanelGap),
    };

    QPoint bestTopLeft = constrainedTopLeft(preferredTopLefts.first(), availableGeometry);
    qint64 bestOverlap = std::numeric_limits<qint64>::max();
    qint64 bestDistance = std::numeric_limits<qint64>::max();
    int bestIndex = preferredTopLefts.size();
    for (int index = 0; index < preferredTopLefts.size(); ++index)
    {
        const QPoint candidateTopLeft = constrainedTopLeft(preferredTopLefts.at(index), availableGeometry);
        const QRect candidateRect(candidateTopLeft, size());
        const qint64 candidateOverlap = overlapArea(candidateRect, avoidRect);
        const qint64 candidateDistance = squaredDistance(candidateTopLeft, preferredTopLefts.at(index));
        if (candidateOverlap < bestOverlap
            || (candidateOverlap == bestOverlap && candidateDistance < bestDistance)
            || (candidateOverlap == bestOverlap && candidateDistance == bestDistance && index < bestIndex))
        {
            bestTopLeft = candidateTopLeft;
            bestOverlap = candidateOverlap;
            bestDistance = candidateDistance;
            bestIndex = index;
        }
    }
    return bestTopLeft;
}

void WorkspacePanel::updateSummary()
{
    const QString workspaceText = m_snapshot.workspaceRoot.trimmed().isEmpty()
        ? QStringLiteral("未选择工作区")
        : m_snapshot.workspaceRoot;
    const QString scanText = m_snapshot.lastScanAt.isValid()
        ? m_snapshot.lastScanAt.toString(QStringLiteral("yyyy-MM-dd HH:mm:ss"))
        : QStringLiteral("尚未扫描");
    m_workspaceLabel->setText(QStringLiteral("本地工作区 Agent"));
    m_scanLabel->setText(QStringLiteral("工作区：%1").arg(workspaceText));
    m_summaryLabel->setText(QStringLiteral("索引项：%1    最近扫描：%2")
        .arg(m_snapshot.indexedItemCount)
        .arg(scanText));
}

void WorkspacePanel::updateResults()
{
    const int currentRow = m_resultList->currentRow();
    m_resultList->clear();
    if (m_snapshot.lastResults.isEmpty())
    {
        auto *item = new QListWidgetItem(QStringLiteral("暂无上一轮结果"));
        item->setFlags(Qt::NoItemFlags);
        m_resultList->addItem(item);
        return;
    }

    for (int index = 0; index < m_snapshot.lastResults.size(); ++index)
    {
        m_resultList->addItem(QStringLiteral("%1. %2").arg(index + 1).arg(compactPath(m_snapshot.lastResults.at(index))));
    }
    if (currentRow >= 0 && currentRow < m_resultList->count())
    {
        m_resultList->setCurrentRow(currentRow);
    }
    else
    {
        m_resultList->setCurrentRow(0);
    }
}

void WorkspacePanel::updateSelectedDetails()
{
    const int index = selectedResultIndex();
    if (index < 0)
    {
        m_selectedDetailEdit->setHtml(QStringLiteral("<div style=\"color:#93a4bd;\">请选择左侧结果。</div>"));
        return;
    }

    const WorkspaceFileInfo &file = m_snapshot.lastResults.at(index);
    const QString html = QStringLiteral(
        "<div style=\"font-weight:700; color:#f8fafc; margin-bottom:8px;\">%1</div>"
        "<div style=\"color:#cbd5e1;\">类型：%2<br>大小：%3 字节<br>修改时间：%4</div>")
        .arg(htmlLine(compactPath(file)))
        .arg(fileTypeText(file))
        .arg(file.sizeBytes)
        .arg(file.lastModified.isValid() ? file.lastModified.toString(QStringLiteral("yyyy-MM-dd HH:mm:ss")) : QStringLiteral("未知"));
    m_selectedDetailEdit->setHtml(html);
}

void WorkspacePanel::updateTextMatches()
{
    if (m_snapshot.lastTextMatches.isEmpty())
    {
        m_textMatchesEdit->setHtml(QStringLiteral("<div style=\"color:#93a4bd;\">暂无文本搜索命中。</div>"));
        return;
    }

    QString html;
    const int matchCount = qMin(m_snapshot.lastTextMatches.size(), MaxTextMatchesInDetails);
    for (int i = 0; i < matchCount; ++i)
    {
        const WorkspaceTextMatch &match = m_snapshot.lastTextMatches.at(i);
        html += QStringLiteral("<div style=\"margin-bottom:9px;\"><b style=\"color:#bfdbfe;\">%1:%2</b><br><span style=\"color:#dbe4f0;\">%3</span></div>")
            .arg(htmlLine(match.relativePath))
            .arg(match.lineNumber)
            .arg(htmlLine(match.lineText));
    }
    if (m_snapshot.lastTextMatches.size() > matchCount)
    {
        html += QStringLiteral("<div style=\"color:#93a4bd;\">仅显示前 %1 条文本命中。</div>").arg(matchCount);
    }
    m_textMatchesEdit->setHtml(html);
}

void WorkspacePanel::updateRecentRead()
{
    if (!m_snapshot.hasLastReadFile)
    {
        m_recentReadEdit->setHtml(QStringLiteral("<div style=\"color:#93a4bd;\">暂无最近读取文件。</div>"));
        return;
    }

    const QString html = QStringLiteral(
        "<div style=\"font-weight:700; color:#f8fafc; margin-bottom:8px;\">%1</div>"
        "<pre style=\"white-space:pre-wrap; color:#dbe4f0; font-family:Consolas,'Microsoft YaHei',monospace; font-size:12px; margin:0;\">%2</pre>")
        .arg(htmlLine(m_snapshot.lastReadFile.relativePath))
        .arg(m_snapshot.lastReadPreview.toHtmlEscaped());
    m_recentReadEdit->setHtml(html);
}

void WorkspacePanel::updateDetails()
{
    updateSelectedDetails();
    updateTextMatches();
    updateRecentRead();
}

void WorkspacePanel::updateActionButtons()
{
    const int index = selectedResultIndex();
    const bool hasSelection = index >= 0;
    m_openButton->setEnabled(hasSelection);
    m_revealButton->setEnabled(hasSelection);
    m_readButton->setEnabled(hasSelection && !m_snapshot.lastResults.at(index).isDirectory);
}

int WorkspacePanel::selectedResultIndex() const
{
    const int row = m_resultList->currentRow();
    if (row < 0 || row >= m_snapshot.lastResults.size())
    {
        return -1;
    }
    return row;
}