#pragma once

#include <QDate>
#include <QStyledItemDelegate>
#include <QUrl>

class QNetworkAccessManager;
class QNetworkReply;

namespace update
{
enum class State { NotAvailable, NotInstalled, UpdateAvailable, Actual };
enum class Action { NoAction, Remove, Install };

struct File {
  QUrl url;
  QString rawPath;
  QString expandedPath;
  QString downloadPath;
  QString md5;
  QDateTime versionDate;
};

using UserActions = std::multimap<Action, File>;

class ActionDelegate : public QStyledItemDelegate
{
  Q_OBJECT
public:
  explicit ActionDelegate(QObject* parent = nullptr);
  QWidget* createEditor(QWidget* parent, const QStyleOptionViewItem& option,
                        const QModelIndex& index) const override;
  void setEditorData(QWidget* editor, const QModelIndex& index) const override;
  void setModelData(QWidget* editor, QAbstractItemModel* model,
                    const QModelIndex& index) const override;
};

class Model : public QAbstractItemModel
{
  Q_OBJECT
public:
  enum class Column { Name, State, Action, Version, Files, Count };

  explicit Model(QObject* parent = nullptr);

  void parse(const QByteArray& data);
  void setExpansions(const std::map<QString, QString>& expansions);
  UserActions userActions() const;
  void updateStates();

  QModelIndex index(int row, int column,
                    const QModelIndex& parent) const override;
  QModelIndex parent(const QModelIndex& child) const override;
  int rowCount(const QModelIndex& parent) const override;
  int columnCount(const QModelIndex& parent) const override;
  QVariant headerData(int section, Qt::Orientation orientation,
                      int role) const override;
  QVariant data(const QModelIndex& index, int role) const override;
  Qt::ItemFlags flags(const QModelIndex& index) const override;
  bool setData(const QModelIndex& index, const QVariant& value,
               int role) override;

private:
  struct Component {
    QString name;
    State state{State::NotAvailable};
    Action action{Action::NoAction};
    QString version;
    std::vector<File> files;
    std::vector<std::unique_ptr<Component>> children;
    Component* parent{nullptr};
    int index{-1};
  };

  std::unique_ptr<Component> parse(const QJsonObject& json) const;
  void updateState(Component& component);
  void fillUserActions(UserActions& actions, Component& component) const;
  State currentState(const File& file) const;
  QString expanded(const QString& source) const;
  void emitColumnsChanged(const QModelIndex& parent);

  std::unique_ptr<Component> root_;
  std::map<QString, QString> expansions_;
};

class Installer
{
public:
  explicit Installer(const UserActions& actions);
  bool commit();
  QString errorString() const;

private:
  bool checkIsPossible();

  UserActions actions_;
  QStringList errors_;
};

class Loader : public QObject
{
  Q_OBJECT
public:
  explicit Loader(const QUrl& updateUrl, QObject* parent = nullptr);

  void checkForUpdates();
  void applyUserActions();
  Model* model() const;

signals:
  void updated();
  void error(const QString& error);

private:
  void handleReply(QNetworkReply* reply);
  QString toError(QNetworkReply& reply) const;
  void finishUpdate(const QString& error = {});
  void commitUpdate();

  QNetworkAccessManager* network_;
  Model* model_;
  QUrl updateUrl_;
  QString downloadPath_;
  std::map<QNetworkReply*, QString> componentReplyToPath_;
  std::unique_ptr<Installer> installer_;
};

}  // namespace update