#include "multiselectcombobox.h"
#include <QListView>
#include <QMouseEvent>
#include <QCheckBox>

MultiSelectComboBox::MultiSelectComboBox(QWidget *parent)
    : QComboBox(parent)
    , suppressUpdate(false)
{
    model = new QStandardItemModel(this);
    setModel(model);
    
    // Use list view for better checkbox display
    QListView *listView = new QListView(this);
    setView(listView);
    
    // Create a line edit to display the text (read-only)
    displayLabel = new QLineEdit(this);
    displayLabel->setReadOnly(true);
    setLineEdit(displayLabel);
    
    // Install event filter to keep popup open on click
    view()->viewport()->installEventFilter(this);
    
    connect(view(), &QAbstractItemView::pressed, this, &MultiSelectComboBox::onItemPressed);
}

void MultiSelectComboBox::addItem(const QString &text)
{
    // First item is "Select All"
    if (model->rowCount() == 0) {
        QStandardItem *selectAllItem = new QStandardItem("Select All");
        selectAllItem->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled);
        selectAllItem->setData(Qt::Checked, Qt::CheckStateRole);
        selectAllItem->setData(true, Qt::UserRole); // Mark as "Select All" item
        model->appendRow(selectAllItem);
    }
    
    QStandardItem *item = new QStandardItem(text);
    item->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled);
    item->setData(Qt::Checked, Qt::CheckStateRole);
    item->setData(false, Qt::UserRole); // Regular item
    model->appendRow(item);
}

void MultiSelectComboBox::addItems(const QStringList &texts)
{
    for (const QString &text : texts) {
        addItem(text);
    }
    updateText();
}

QStringList MultiSelectComboBox::getSelectedItems() const
{
    QStringList selected;
    for (int i = 1; i < model->rowCount(); ++i) { // Skip "Select All" at index 0
        QStandardItem *item = model->item(i);
        if (item && item->checkState() == Qt::Checked) {
            selected.append(item->text());
        }
    }
    return selected;
}

void MultiSelectComboBox::setSelectedItems(const QStringList &items)
{
    suppressUpdate = true;
    
    for (int i = 1; i < model->rowCount(); ++i) { // Skip "Select All" at index 0
        QStandardItem *item = model->item(i);
        if (item) {
            bool shouldCheck = items.contains(item->text());
            item->setCheckState(shouldCheck ? Qt::Checked : Qt::Unchecked);
        }
    }
    
    // Update "Select All" checkbox
    if (model->rowCount() > 1) {
        QStandardItem *selectAllItem = model->item(0);
        if (selectAllItem) {
            selectAllItem->setCheckState(allSelected() ? Qt::Checked : Qt::Unchecked);
        }
    }
    
    suppressUpdate = false;
    updateText();
}

bool MultiSelectComboBox::allSelected() const
{
    for (int i = 1; i < model->rowCount(); ++i) { // Skip "Select All" at index 0
        QStandardItem *item = model->item(i);
        if (item && item->checkState() == Qt::Unchecked) {
            return false;
        }
    }
    return model->rowCount() > 1;
}

void MultiSelectComboBox::clear()
{
    model->clear();
    QComboBox::clear();
}

void MultiSelectComboBox::hidePopup()
{
    // Don't hide on item click - only when clicking outside
    QComboBox::hidePopup();
    updateText();
    emit selectionChanged();
}

bool MultiSelectComboBox::eventFilter(QObject *watched, QEvent *event)
{
    if (watched == view()->viewport()) {
        if (event->type() == QEvent::MouseButtonRelease) {
            return true; // Prevent popup from closing
        }
    }
    return QComboBox::eventFilter(watched, event);
}

void MultiSelectComboBox::onItemPressed(const QModelIndex &index)
{
    QStandardItem *item = model->itemFromIndex(index);
    if (item) {
        // Check if this is the "Select All" item
        bool isSelectAll = item->data(Qt::UserRole).toBool();
        
        if (isSelectAll) {
            // Toggle all items
            Qt::CheckState newState = (item->checkState() == Qt::Checked) ? Qt::Unchecked : Qt::Checked;
            suppressUpdate = true;
            for (int i = 0; i < model->rowCount(); ++i) {
                QStandardItem *childItem = model->item(i);
                if (childItem) {
                    childItem->setCheckState(newState);
                }
            }
            suppressUpdate = false;
        } else {
            // Toggle individual item
            Qt::CheckState newState = (item->checkState() == Qt::Checked) ? Qt::Unchecked : Qt::Checked;
            item->setCheckState(newState);
            
            // Update "Select All" state
            if (model->rowCount() > 1) {
                QStandardItem *selectAllItem = model->item(0);
                if (selectAllItem) {
                    selectAllItem->setCheckState(allSelected() ? Qt::Checked : Qt::Unchecked);
                }
            }
        }
        updateText();
    }
}

void MultiSelectComboBox::updateText()
{
    if (suppressUpdate) return;
    
    QStringList selected = getSelectedItems();
    
    if (selected.isEmpty()) {
        displayLabel->setText("No Accounts");
    } else if (allSelected()) {
        displayLabel->setText("All Accounts");
    } else if (selected.size() == 1) {
        displayLabel->setText(selected.first());
    } else {
        displayLabel->setText(QString("%1 Accounts Selected").arg(selected.size()));
    }
}