#ifndef SCIQLOP_VARIABLESTATES_H
#define SCIQLOP_VARIABLESTATES_H

#include "CoreGlobal.h"

#include <Common/MetaTypes.h>

#include <memory>
#include <tuple>

#include <QVariantMap>

using StateData = QVariantMap;
SCIQLOP_REGISTER_META_TYPE(STATEDATA_REGISTRY, StateData)

/**
 * @brief The IVariableState class is the representation interface of a state in which a variable
 * may be. It proposes different methods to represent the variable according to its current state
 * @sa Variable
 */
struct SCIQLOP_CORE_EXPORT IVariableState {
    virtual ~IVariableState() noexcept = default;

    virtual std::unique_ptr<IVariableState> clone() const = 0;

    /// @return the data associated with the state
    virtual StateData data() const = 0;
};

/// Default implementation of @sa IVariableState
class AbstractVariableState : public IVariableState {
public:
    /// @sa IVariableState::data()
    StateData data() const override;

protected:
    explicit AbstractVariableState(StateData data);

private:
    StateData m_Data;
};

/**
 * State when a variable is fully loaded (i.e. the last request on the variable has been
 * successfully completed)
 */
class LoadedState : public AbstractVariableState {
public:
    explicit LoadedState();
    std::unique_ptr<IVariableState> clone() const override;
};

/**
 * State when a variable is loading (i.e. there's pending requests for the variable)
 */
class LoadingState : public AbstractVariableState {
public:
    explicit LoadingState();
    std::unique_ptr<IVariableState> clone() const override;
};

/**
 * State when a variable is canceled (i.e. the last request on the variable has been canceled)
 */
class CanceledState : public AbstractVariableState {
public:
    explicit CanceledState();
    std::unique_ptr<IVariableState> clone() const override;
};

#endif // SCIQLOP_VARIABLESTATES_H