#ifndef REMOTEMODEL_H
#define REMOTEMODEL_H

#include <QAbstractItemModel>
#include <QStringList>

#include <json.hpp>

class RemoteDatabase;

// List of fields stored in the JSON data
enum RemoteModelColumns
{
 RemoteModelColumnName,
 RemoteModelColumnType,
 RemoteModelColumnUrl,
 RemoteModelColumnCommitId,
 RemoteModelColumnSize,
 RemoteModelColumnLastModified,

 RemoteModelColumnCount
};

class RemoteModelItem
{
public:
 explicit RemoteModelItem(RemoteModelItem* parent = nullptr);
 ~RemoteModelItem();

 QVariant value(RemoteModelColumns column) const;
 void setValue(RemoteModelColumns column, QVariant value);

 bool fetchedDirectoryList() const;
 void setFetchedDirectoryList(bool fetched);

 void appendChild(RemoteModelItem* item);
 RemoteModelItem* child(int row) const;
 RemoteModelItem* parent() const;
 int childCount() const;
 int row() const;

 // This function assumes the JSON value it's getting passed is an array ("[{...}, {...}, {...}, ...]"). It returns a list of model items, one
 // per array entry and each with the specified parent set.
 static std::vector<RemoteModelItem*> loadArray(const nlohmann::json& array, RemoteModelItem* parent = nullptr);

private:
 // These are just the fields from the json objects returned by the dbhub.io server
 QVariant m_values[RemoteModelColumnCount];

 // Child items and parent item
 std::vector<RemoteModelItem*> m_children;
 RemoteModelItem* m_parent;

 // Indicates whether we already tried fetching a directory listing for this item. This serves two purposes:
 // 1) When having an empty directory this allows us to remove the expandable flag for this item.
 // 2) Between sending a network request and getting the reply this flag is already set, avoiding a second or third request being sent in the meantime.
 bool m_fetchedDirectoryList;
};

class RemoteModel : public QAbstractItemModel
{
 Q_OBJECT

public:
 explicit RemoteModel(QObject* parent, RemoteDatabase& remote);
 ~RemoteModel() override;

 void setNewRootDir(const QString& url, const QString& cert);

 QModelIndex index(int row, int column,const QModelIndex& parent = QModelIndex()) const override;
 QModelIndex parent(const QModelIndex& index) const override;

 QVariant data(const QModelIndex& index, int role) const override;
 QVariant headerData(int section, Qt::Orientation orientation, int role) const override;

 int rowCount(const QModelIndex& parent = QModelIndex()) const override;
 int columnCount(const QModelIndex& parent = QModelIndex()) const override;
 bool hasChildren(const QModelIndex& parent) const override;

 bool canFetchMore(const QModelIndex& parent) const override;
 void fetchMore(const QModelIndex& parent) override;

 // This helper function takes a model index and returns the according model item. An invalid model index is used to indicate the
 // root item, so if the index is invalid the root item is returned. This means that if you need to check for actual invalid indices
 // this needs to be done prior to calling this function.
 const RemoteModelItem* modelIndexToItem(const QModelIndex& idx) const;

 // Returns the current client certificate
 const QString& currentClientCertificate() const;

signals:
 // This signal is emitted whenever a directory listing has been received and parsed
 void directoryListingParsed(QModelIndex parent);

private slots:
 // This is called whenever a network reply containing a directory listing arrives. json contains the reply data, userdata
 // contains some custom data passed to the request. In this case we expect this to be the model index of the parent tree item.
 void parseDirectoryListing(const QString& text, const QVariant& userdata);

private:
 // Pointer to the root item. This contains all the actual item data.
 RemoteModelItem* rootItem;

 // The header list is a list of column titles. It's a static list that's getting filled in the constructor.
 QStringList headerList;

 // Reference to the remote database object which is stored somewhere in the main window.
 RemoteDatabase& remoteDatabase;

 // This stores the currently used network identity so it can be used for further requests, e.g. for
 // lazy population.
 QString currentRootDirectory;
 QString currentClientCert;
 QString currentUserName;
};

#endif