#pragma once

#include <QAbstractTableModel>
#include <QApplication>
#include <QClipboard>
#include <QFutureWatcher>
#include <QHeaderView>
#include <QLabel>
#include <QLineEdit>
#include <QMenu>
#include <QObject>
#include <QPainter>
#include <QVector>
#include <QString>
#include <QStyledItemDelegate>
#include <QTableView>
#include <QTimer>
#include <QVBoxLayout>
#include <QtConcurrent/QtConcurrentRun>

#include "uitypes.h"
#include "warp.h"

// Will search in batches of 50 items.
constexpr auto SEARCH_PAGE_SIZE = 50;
// Will debounce the search for 350 MS.
constexpr auto SEARCH_DEBOUNCE_MS = 350;

// Table model showing a paginated list of SearchItem.
class WarpSearchModel final : public QAbstractTableModel
{
	Q_OBJECT

public:
	enum Columns : int
	{
		DisplayCol = 0,
		KindCol,
		SourceCol,
		ColumnCount
	};

	explicit WarpSearchModel(QObject* parent = nullptr) : QAbstractTableModel(parent) {}

	int rowCount(const QModelIndex& parent) const override
	{
		if (parent.isValid())
			return 0;
		return m_items.size();
	}

	int columnCount(const QModelIndex& parent) const override
	{
		Q_UNUSED(parent);
		return ColumnCount;
	}

	QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;

	QVariant headerData(int section, Qt::Orientation orientation, int role) const override;

	// Begin a new search session: clears all current items and resets counters.
	Q_INVOKABLE void beginNewSearch(std::size_t pageSize = SEARCH_PAGE_SIZE)
	{
		beginResetModel();
		m_items.clear();
		m_total = 0;
		m_pageSize = pageSize;
		endResetModel();
		emit cleared();
		// Immediately ask for the first page from offset 0
		emit fetchMoreRequested(0, m_pageSize);
	}

	// Append results from a Warp::ContainerSearchResponse (infinite scroll, no replacement).
	void appendResponse(const Warp::ContainerSearchResponse& resp)
	{
		// Update total first (so canFetchMore reflects new value)
		m_total = resp.total;
		if (resp.items.empty())
		{
			emit responseUpdated(currentCount(), m_total);
			return;
		}
		const int begin = m_items.size();
		const int end = begin + static_cast<int>(resp.items.size()) - 1;
		beginInsertRows(QModelIndex(), begin, end);
		for (const auto& refItem : resp.items)
			m_items.push_back(refItem);
		endInsertRows();
		emit responseUpdated(currentCount(), m_total);
	}

	// Qt's infinite scroll hooks: the view will call these when near the end.
	bool canFetchMore(const QModelIndex& parent) const override
	{
		Q_UNUSED(parent);
		return static_cast<std::size_t>(m_items.size()) < m_total;
	}

	void fetchMore(const QModelIndex& parent) override
	{
		Q_UNUSED(parent);
		if (!canFetchMore({}))
			return;
		const std::size_t nextOffset = m_items.size();
		emit fetchMoreRequested(nextOffset, m_pageSize);
	}

	// Convenience accessors.
	std::size_t total() const { return m_total; }
	int currentCount() const { return m_items.size(); }
	void setPageSize(std::size_t pageSize) { m_pageSize = pageSize; }

	Q_INVOKABLE Warp::Ref<Warp::ContainerSearchItem> itemAt(int row) const
	{
		if (row < 0 || row >= m_items.size())
			return {};
		return m_items[row];
	}

signals:
	// Emitted when model is cleared for a new query.
	void cleared();

	// Emitted after items are appended or totals updated.
	void responseUpdated(int currentCount, std::size_t total);

	// Request the next page; connect this to your async search runner.
	void fetchMoreRequested(std::size_t offset, std::size_t limit);

private:
	QVector<Warp::Ref<Warp::ContainerSearchItem>> m_items;
	std::size_t m_total = 0;
	std::size_t m_pageSize = SEARCH_PAGE_SIZE;
};

// A delegate to render the DisplayCol text with an icon (mapped from KindCol) on the right.
class WarpSearchDelegate final : public QStyledItemDelegate
{
	Q_OBJECT

public:
	explicit WarpSearchDelegate(QObject* parent = nullptr) : QStyledItemDelegate(parent) {}

	QSize sizeHint(const QStyleOptionViewItem& option, const QModelIndex& index) const override
	{
		// Base text size + space for an icon on the right
		const QSize base = QStyledItemDelegate::sizeHint(option, index);
		const int iconSide = 16;
		return QSize(base.width(), qMax(base.height(), iconSide + 4));  // keep row height >= icon
	}

	void paint(QPainter* p, const QStyleOptionViewItem& option, const QModelIndex& index) const override;

private:
	static QString kindToIcon(const QString& kind)
	{
		// Example mapping; extend as needed
		if (kind.compare(QStringLiteral("Function"), Qt::CaseInsensitive) == 0)
			return QStringLiteral("ƒ");
		if (kind.compare(QStringLiteral("Type"), Qt::CaseInsensitive) == 0)
			return QStringLiteral("𝑇");
		if (kind.compare(QStringLiteral("Source"), Qt::CaseInsensitive) == 0)
			return QStringLiteral("📦");
		// Default: no icon
		return {};
	}
};

class WarpSearchRunner : public QObject
{
	Q_OBJECT

public:
	explicit WarpSearchRunner(Warp::Ref<Warp::Container> container, QObject* parent = nullptr) :
		QObject(parent), m_container(std::move(container))
	{}

signals:
	// Emitted on the UI thread after the worker finishes
	void pageReady(std::uint64_t sessionId, Warp::ContainerSearchResponse resp);

	void pageError(std::uint64_t sessionId, QString message);

public slots:
	// Start a new logical search session (new query or new filters)
	void startSession(QString queryText, const std::optional<Warp::Source>& source)
	{
		m_queryText = std::move(queryText);
		m_source = source;
		m_sessionId.fetchAndAddRelaxed(1);
	}

	// Fetch a page for the current session. Safe to call multiple times (infinite scroll).
	void fetchPage(std::size_t offset, std::size_t limit);

private:
	std::uint64_t currentSession() const { return m_sessionId.loadRelaxed(); }

	Warp::Ref<Warp::Container> m_container;
	QAtomicInteger<quint64> m_sessionId {0};
	QString m_queryText;
	std::optional<Warp::Source> m_source;
};

class WarpSearchWidget : public QWidget
{
	Q_OBJECT

public:
	explicit WarpSearchWidget(Warp::Ref<Warp::Container> container, QWidget* parent = nullptr);

	void setSourceFilter(const std::optional<Warp::Source>& src)
	{
		m_source = src;
		m_debounce.start();
	}

private:
	WarpSearchModel* m_model;
	WarpSearchRunner* m_runner;
	QLineEdit* m_query;
	QLabel* m_status;
	QTableView* m_view;
	QTimer m_debounce;
	// Source to filter for if no source is provided in the search.
	std::optional<Warp::Source> m_source;
};