#ifndef CRUDMODEL_H
#define CRUDMODEL_H

#include "BaseTableModel.h"
#include "ASyncDBConnection.h"
#include "PgClass.h"
#include "Pgsql_Connection.h"
#include <memory>
#include <vector>
#include <boost/optional.hpp>

class PgConstraint;
class OpenDatase;

/**
 * @brief The CrudModel class
 *
 * Features
 * - order by one or more user selectable columns
 * - user filter condition
 * - user limit and offset
 * - hide columns (will not be retrieved can greatly speed up things when you disable wide columns)
 * - can use foreign keys to display dropdown
 *
 * How to load data?
 * - 2D array of QVariants won't be efficient
 * - 2D array of strings
 * - We do know the type of a single column is fixed
 * - Keep data in Result and only load data in replacement rows
 * std::string has short string optimization so this probably means
 *  that a two dimensional array of std::string objects could actually be quite efficient!
 */
class CrudModel: public BaseTableModel {
	Q_OBJECT
public:
	CrudModel();
	~CrudModel();

	QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;
	void setData(std::shared_ptr<OpenDatabase> db, const PgClass &table);


	// Basic functionality:
	int rowCount(const QModelIndex &parent = QModelIndex()) const override;
	int columnCount(const QModelIndex &parent = QModelIndex()) const override;

protected:
	virtual Oid getType(int column) const override;
	virtual QVariant getData(const QModelIndex &index) const override;

private:
	std::shared_ptr<OpenDatabase> m_database;
	PgClass m_table;
	boost::optional<PgConstraint> m_primaryKey;
	ASyncDBConnection m_dbConn;


	using RowData = std::vector<std::string>;
	using RowDataPtr = std::unique_ptr<RowData>;
	/** Choosen for a vector of pointers while vector is relatively slow with insertion and removal in the middle
	 * I hope the small size of the elements will make this not much of an issue while the simple linear and sequential
	 * nature of a vector will keep memory allocation fairly efficient.
	using RowList = std::vector<RowDataPtr>;

};

#endif // CRUDMODEL_H