22 files changed, 1402 insertions, 772 deletions

diff --git a/api/gui/icons/IconList.cpp b/api/gui/icons/IconList.cpp
index 4f9fb09f..b6be007f 100644
--- a/api/gui/icons/IconList.cpp
+++ b/api/gui/icons/IconList.cpp
@@ -243,7 +243,7 @@ int IconList::rowCount(const QModelIndex &parent) const
 	return icons.size();
 }
 
-void IconList::installIcons(QStringList iconFiles)
+void IconList::installIcons(const QStringList &iconFiles)
 {
 	for (QString file : iconFiles)
 	{
@@ -261,7 +261,7 @@ void IconList::installIcons(QStringList iconFiles)
 	}
 }
 
-bool IconList::iconFileExists(QString key)
+bool IconList::iconFileExists(const QString &key) const
 {
 	auto iconEntry = icon(key);
 	if(!iconEntry)
@@ -271,7 +271,7 @@ bool IconList::iconFileExists(QString key)
 	return iconEntry->has(IconType::FileBased);
 }
 
-const MMCIcon *IconList::icon(QString key)
+const MMCIcon *IconList::icon(const QString &key) const
 {
 	int iconIdx = getIconIndex(key);
 	if (iconIdx == -1)
@@ -279,7 +279,7 @@ const MMCIcon *IconList::icon(QString key)
 	return &icons[iconIdx];
 }
 
-bool IconList::deleteIcon(QString key)
+bool IconList::deleteIcon(const QString &key)
 {
 	int iconIdx = getIconIndex(key);
 	if (iconIdx == -1)
diff --git a/api/gui/icons/IconList.h b/api/gui/icons/IconList.h
index 7aeb7067..24ff4454 100644
--- a/api/gui/icons/IconList.h
+++ b/api/gui/icons/IconList.h
@@ -44,18 +44,19 @@ public:
 	virtual QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
 	virtual int rowCount(const QModelIndex &parent = QModelIndex()) const override;
 
-	virtual bool addIcon(QString key, QString name, QString path, IconType type) override;
-	bool deleteIcon(QString key);
-	bool iconFileExists(QString key);
+	bool addIcon(const QString &key, const QString &name, const QString &path, const IconType type) override;
+	void saveIcon(const QString &key, const QString &path, const char * format) const override;
+	bool deleteIcon(const QString &key) override;
+	bool iconFileExists(const QString &key) const override;
 
 	virtual QStringList mimeTypes() const override;
 	virtual Qt::DropActions supportedDropActions() const override;
 	virtual bool dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent) override;
 	virtual Qt::ItemFlags flags(const QModelIndex &index) const override;
 
-	void installIcons(QStringList iconFiles);
+	void installIcons(const QStringList &iconFiles) override;
 
-	const MMCIcon * icon(QString key);
+	const MMCIcon * icon(const QString &key) const;
 
 	void startWatching();
 	void stopWatching();
diff --git a/api/logic/BaseInstance.cpp b/api/logic/BaseInstance.cpp
index 9dee2c38..452e657a 100644
--- a/api/logic/BaseInstance.cpp
+++ b/api/logic/BaseInstance.cpp
@@ -17,6 +17,7 @@
 
 #include <QFileInfo>
 #include <QDir>
+#include <QDebug>
 
 #include "settings/INISettingsObject.h"
 #include "settings/Setting.h"
@@ -74,10 +75,32 @@ void BaseInstance::iconUpdated(QString key)
 	}
 }
 
+void BaseInstance::invalidate()
+{
+	changeStatus(Status::Gone);
+	qDebug() << "Instance" << id() << "has been invalidated.";
+}
+
 void BaseInstance::nuke()
 {
+	changeStatus(Status::Gone);
+	qDebug() << "Instance" << id() << "has been deleted by MultiMC.";
 	FS::deletePath(instanceRoot());
-	emit nuked(this);
+}
+
+void BaseInstance::changeStatus(BaseInstance::Status newStatus)
+{
+	Status status = currentStatus();
+	if(status != newStatus)
+	{
+		m_status = newStatus;
+		emit statusChanged(status, newStatus);
+	}
+}
+
+BaseInstance::Status BaseInstance::currentStatus() const
+{
+	return m_status;
 }
 
 QString BaseInstance::id() const
@@ -278,3 +301,19 @@ std::shared_ptr<LaunchTask> BaseInstance::getLaunchTask()
 {
 	return m_launchProcess;
 }
+
+void BaseInstance::setProvider(BaseInstanceProvider* provider)
+{
+	// only once.
+	assert(!m_provider);
+	if(m_provider)
+	{
+		qWarning() << "Provider set more than once for instance" << id();
+	}
+	m_provider = provider;
+}
+
+BaseInstanceProvider* BaseInstance::provider() const
+{
+	return m_provider;
+}
diff --git a/api/logic/BaseInstance.h b/api/logic/BaseInstance.h
index ebaaeb83..56d3d6cb 100644
--- a/api/logic/BaseInstance.h
+++ b/api/logic/BaseInstance.h
@@ -14,6 +14,7 @@
  */
 
 #pragma once
+#include <cassert>
 
 #include <QObject>
 #include "QObjectPtr.h"
@@ -35,6 +36,7 @@ class QDir;
 class Task;
 class LaunchTask;
 class BaseInstance;
+class BaseInstanceProvider;
 
 // pointer for lazy people
 typedef std::shared_ptr<BaseInstance> InstancePtr;
@@ -54,6 +56,13 @@ protected:
 	/// no-touchy!
 	BaseInstance(SettingsObjectPtr globalSettings, SettingsObjectPtr settings, const QString &rootDir);
 
+public: /* types */
+	enum class Status
+	{
+		Present,
+		Gone // either nuked or invalidated
+	};
+
 public:
 	/// virtual destructor to make sure the destruction is COMPLETE
 	virtual ~BaseInstance() {};
@@ -66,6 +75,14 @@ public:
 	/// responsible of cleaning up the husk
 	void nuke();
 
+	/***
+	 * the instance has been invalidated - it is no longer tracked by MultiMC for some reason,
+	 * but it has not necessarily been deleted.
+	 *
+	 * Happens when the instance folder changes to some other location, or the instance is removed by external means.
+	 */
+	void invalidate();
+
 	/// The instance's ID. The ID SHALL be determined by MMC internally. The ID IS guaranteed to
 	/// be unique.
 	virtual QString id() const;
@@ -75,6 +92,9 @@ public:
 	int64_t totalTimePlayed() const;
 	void resetTimePlayed();
 
+	void setProvider(BaseInstanceProvider * provider);
+	BaseInstanceProvider * provider() const;
+
 	/// get the type of this instance
 	QString instanceType() const;
 
@@ -219,6 +239,11 @@ public:
 	 */
 	virtual QStringList verboseDescription(AuthSessionPtr session) = 0;
 
+	Status currentStatus() const;
+
+protected:
+	void changeStatus(Status newStatus);
+
 signals:
 	/*!
 	 * \brief Signal emitted when properties relevant to the instance view change
@@ -228,10 +253,6 @@ signals:
 	 * \brief Signal emitted when groups are affected in any way
 	 */
 	void groupChanged();
-	/*!
-	 * \brief The instance just got nuked. Hurray!
-	 */
-	void nuked(BaseInstance *inst);
 
 	void flagsChanged();
 
@@ -239,10 +260,12 @@ signals:
 
 	void runningStatusChanged(bool running);
 
+	void statusChanged(Status from, Status to);
+
 protected slots:
 	void iconUpdated(QString key);
 
-protected:
+protected: /* data */
 	QString m_rootDir;
 	QString m_group;
 	SettingsObjectPtr m_settings;
@@ -250,6 +273,10 @@ protected:
 	bool m_isRunning = false;
 	std::shared_ptr<LaunchTask> m_launchProcess;
 	QDateTime m_timeStarted;
+	BaseInstanceProvider * m_provider = nullptr;
+
+private: /* data */
+	Status m_status = Status::Present;
 };
 
 Q_DECLARE_METATYPE(std::shared_ptr<BaseInstance>)
diff --git a/api/logic/BaseInstanceProvider.h b/api/logic/BaseInstanceProvider.h
new file mode 100644
index 00000000..f6833650
--- /dev/null
+++ b/api/logic/BaseInstanceProvider.h
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <QObject>
+#include <QString>
+#include "BaseInstance.h"
+#include "settings/SettingsObject.h"
+
+#include "multimc_logic_export.h"
+
+using InstanceId = QString;
+using InstanceLocator = std::pair<InstancePtr, int>;
+
+enum class InstCreateError
+{
+	NoCreateError = 0,
+	NoSuchVersion,
+	UnknownCreateError,
+	InstExists,
+	CantCreateDir
+};
+
+class MULTIMC_LOGIC_EXPORT BaseInstanceProvider : public QObject
+{
+	Q_OBJECT
+public:
+	BaseInstanceProvider(SettingsObjectPtr settings) : m_globalSettings(settings)
+	{
+		// nil
+	}
+public:
+	virtual QList<InstanceId> discoverInstances() = 0;
+	virtual InstancePtr loadInstance(const InstanceId &id) = 0;
+	virtual void loadGroupList() = 0;
+	virtual void saveGroupList() = 0;
+
+	virtual QString getStagedInstancePath()
+	{
+		return QString();
+	}
+	virtual bool commitStagedInstance(const QString & keyPath, const QString & path, const QString& instanceName, const QString & groupName)
+	{
+		return false;
+	}
+	virtual bool destroyStagingPath(const QString & path)
+	{
+		return true;
+	}
+
+signals:
+	// Emit this when the list of provided instances changed
+	void instancesChanged();
+	// Emit when the set of groups your provider supplies changes.
+	void groupsChanged(QSet<QString> groups);
+
+protected:
+	SettingsObjectPtr m_globalSettings;
+};
diff --git a/api/logic/CMakeLists.txt b/api/logic/CMakeLists.txt
index c430b53f..0741fb1a 100644
--- a/api/logic/CMakeLists.txt
+++ b/api/logic/CMakeLists.txt
@@ -8,8 +8,17 @@ set(CORE_SOURCES
 	BaseInstaller.cpp
 	BaseVersionList.h
 	BaseVersionList.cpp
+	InstanceCreationTask.h
+	InstanceCreationTask.cpp
+	InstanceCopyTask.h
+	InstanceCopyTask.cpp
+	InstanceImportTask.h
+	InstanceImportTask.cpp
 	InstanceList.h
 	InstanceList.cpp
+	BaseInstanceProvider.h
+	FolderInstanceProvider.h
+	FolderInstanceProvider.cpp
 	BaseVersion.h
 	BaseInstance.h
 	BaseInstance.cpp
@@ -276,6 +285,8 @@ set(MINECRAFT_SOURCES
 	minecraft/ftb/LegacyFTBInstance.cpp
 	minecraft/ftb/FTBProfileStrategy.h
 	minecraft/ftb/FTBProfileStrategy.cpp
+	minecraft/ftb/FTBInstanceProvider.cpp
+	minecraft/ftb/FTBInstanceProvider.h
 	minecraft/ftb/FTBPlugin.h
 	minecraft/ftb/FTBPlugin.cpp
 
diff --git a/api/logic/FolderInstanceProvider.cpp b/api/logic/FolderInstanceProvider.cpp
new file mode 100644
index 00000000..a1f3f1f2
--- /dev/null
+++ b/api/logic/FolderInstanceProvider.cpp
@@ -0,0 +1,356 @@
+#include "FolderInstanceProvider.h"
+#include "settings/INISettingsObject.h"
+#include "FileSystem.h"
+#include "minecraft/onesix/OneSixInstance.h"
+#include "minecraft/legacy/LegacyInstance.h"
+#include "NullInstance.h"
+
+#include <QDir>
+#include <QDirIterator>
+#include <QFileSystemWatcher>
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QJsonArray>
+#include <QUuid>
+
+const static int GROUP_FILE_FORMAT_VERSION = 1;
+
+struct WatchLock
+{
+	WatchLock(QFileSystemWatcher * watcher, const QString& instDir)
+		: m_watcher(watcher), m_instDir(instDir)
+	{
+		m_watcher->removePath(m_instDir);
+	}
+	~WatchLock()
+	{
+		m_watcher->addPath(m_instDir);
+	}
+	QFileSystemWatcher * m_watcher;
+	QString m_instDir;
+};
+
+FolderInstanceProvider::FolderInstanceProvider(SettingsObjectPtr settings, const QString& instDir)
+	: BaseInstanceProvider(settings)
+{
+	m_instDir = instDir;
+	if (!QDir::current().exists(m_instDir))
+	{
+		QDir::current().mkpath(m_instDir);
+	}
+	m_watcher = new QFileSystemWatcher(this);
+	connect(m_watcher, &QFileSystemWatcher::directoryChanged, this, &FolderInstanceProvider::instanceDirContentsChanged);
+	m_watcher->addPath(m_instDir);
+}
+
+QList< InstanceId > FolderInstanceProvider::discoverInstances()
+{
+	QList<InstanceId> out;
+	QDirIterator iter(m_instDir, QDir::Dirs | QDir::NoDot | QDir::NoDotDot | QDir::Readable, QDirIterator::FollowSymlinks);
+	while (iter.hasNext())
+	{
+		QString subDir = iter.next();
+		QFileInfo dirInfo(subDir);
+		if (!QFileInfo(FS::PathCombine(subDir, "instance.cfg")).exists())
+			continue;
+		// if it is a symlink, ignore it if it goes to the instance folder
+		if(dirInfo.isSymLink())
+		{
+			QFileInfo targetInfo(dirInfo.symLinkTarget());
+			QFileInfo instDirInfo(m_instDir);
+			if(targetInfo.canonicalPath() == instDirInfo.canonicalFilePath())
+			{
+				qDebug() << "Ignoring symlink" << subDir << "that leads into the instances folder";
+				continue;
+			}
+		}
+		auto id = dirInfo.fileName();
+		out.append(id);
+		qDebug() << "Found instance ID" << id;
+	}
+	return out;
+}
+
+InstancePtr FolderInstanceProvider::loadInstance(const InstanceId& id)
+{
+	if(!m_groupsLoaded)
+	{
+		loadGroupList();
+	}
+
+	auto instanceRoot = FS::PathCombine(m_instDir, id);
+	auto instanceSettings = std::make_shared<INISettingsObject>(FS::PathCombine(instanceRoot, "instance.cfg"));
+	InstancePtr inst;
+
+	instanceSettings->registerSetting("InstanceType", "Legacy");
+
+	QString inst_type = instanceSettings->get("InstanceType").toString();
+
+	if (inst_type == "OneSix" || inst_type == "Nostalgia")
+	{
+		inst.reset(new OneSixInstance(m_globalSettings, instanceSettings, instanceRoot));
+	}
+	else if (inst_type == "Legacy")
+	{
+		inst.reset(new LegacyInstance(m_globalSettings, instanceSettings, instanceRoot));
+	}
+	else
+	{
+		inst.reset(new NullInstance(m_globalSettings, instanceSettings, instanceRoot));
+	}
+	inst->init();
+	inst->setProvider(this);
+	auto iter = groupMap.find(id);
+	if (iter != groupMap.end())
+	{
+		inst->setGroupInitial((*iter));
+	}
+	connect(inst.get(), &BaseInstance::groupChanged, this, &FolderInstanceProvider::groupChanged);
+	qDebug() << "Loaded instance " << inst->name() << " from " << inst->instanceRoot();
+	return inst;
+}
+
+#include "InstanceImportTask.h"
+Task * FolderInstanceProvider::zipImportTask(const QUrl sourceUrl, const QString& instName, const QString& instGroup, const QString& instIcon)
+{
+	return new InstanceImportTask(m_globalSettings, sourceUrl, this, instName, instGroup, instIcon);
+}
+
+#include "InstanceCreationTask.h"
+Task * FolderInstanceProvider::creationTask(BaseVersionPtr version, const QString& instName, const QString& instGroup, const QString& instIcon)
+{
+	return new InstanceCreationTask(m_globalSettings, this, version, instName, instIcon, instGroup);
+}
+
+#include "InstanceCopyTask.h"
+Task * FolderInstanceProvider::copyTask(const InstancePtr& oldInstance, const QString& instName, const QString& instGroup, const QString& instIcon, bool copySaves)
+{
+	return new InstanceCopyTask(m_globalSettings, this, oldInstance, instName, instIcon, instGroup, copySaves);
+}
+
+void FolderInstanceProvider::saveGroupList()
+{
+	WatchLock foo(m_watcher, m_instDir);
+	QString groupFileName = m_instDir + "/instgroups.json";
+	QMap<QString, QSet<QString>> reverseGroupMap;
+	for (auto iter = groupMap.begin(); iter != groupMap.end(); iter++)
+	{
+		QString id = iter.key();
+		QString group = iter.value();
+		if (group.isEmpty())
+			continue;
+
+		if (!reverseGroupMap.count(group))
+		{
+			QSet<QString> set;
+			set.insert(id);
+			reverseGroupMap[group] = set;
+		}
+		else
+		{
+			QSet<QString> &set = reverseGroupMap[group];
+			set.insert(id);
+		}
+	}
+	QJsonObject toplevel;
+	toplevel.insert("formatVersion", QJsonValue(QString("1")));
+	QJsonObject groupsArr;
+	for (auto iter = reverseGroupMap.begin(); iter != reverseGroupMap.end(); iter++)
+	{
+		auto list = iter.value();
+		auto name = iter.key();
+		QJsonObject groupObj;
+		QJsonArray instanceArr;
+		groupObj.insert("hidden", QJsonValue(QString("false")));
+		for (auto item : list)
+		{
+			instanceArr.append(QJsonValue(item));
+		}
+		groupObj.insert("instances", instanceArr);
+		groupsArr.insert(name, groupObj);
+	}
+	toplevel.insert("groups", groupsArr);
+	QJsonDocument doc(toplevel);
+	try
+	{
+		FS::write(groupFileName, doc.toJson());
+	}
+	catch(FS::FileSystemException & e)
+	{
+		qCritical() << "Failed to write instance group file :" << e.cause();
+	}
+}
+
+void FolderInstanceProvider::loadGroupList()
+{
+	QSet<QString> groupSet;
+
+	QString groupFileName = m_instDir + "/instgroups.json";
+
+	// if there's no group file, fail
+	if (!QFileInfo(groupFileName).exists())
+		return;
+
+	QByteArray jsonData;
+	try
+	{
+		jsonData = FS::read(groupFileName);
+	}
+	catch (FS::FileSystemException & e)
+	{
+		qCritical() << "Failed to read instance group file :" << e.cause();
+		return;
+	}
+
+	QJsonParseError error;
+	QJsonDocument jsonDoc = QJsonDocument::fromJson(jsonData, &error);
+
+	// if the json was bad, fail
+	if (error.error != QJsonParseError::NoError)
+	{
+		qCritical() << QString("Failed to parse instance group file: %1 at offset %2")
+							.arg(error.errorString(), QString::number(error.offset))
+							.toUtf8();
+		return;
+	}
+
+	// if the root of the json wasn't an object, fail
+	if (!jsonDoc.isObject())
+	{
+		qWarning() << "Invalid group file. Root entry should be an object.";
+		return;
+	}
+
+	QJsonObject rootObj = jsonDoc.object();
+
+	// Make sure the format version matches, otherwise fail.
+	if (rootObj.value("formatVersion").toVariant().toInt() != GROUP_FILE_FORMAT_VERSION)
+		return;
+
+	// Get the groups. if it's not an object, fail
+	if (!rootObj.value("groups").isObject())
+	{
+		qWarning() << "Invalid group list JSON: 'groups' should be an object.";
+		return;
+	}
+
+	groupMap.clear();
+
+	// Iterate through all the groups.
+	QJsonObject groupMapping = rootObj.value("groups").toObject();
+	for (QJsonObject::iterator iter = groupMapping.begin(); iter != groupMapping.end(); iter++)
+	{
+		QString groupName = iter.key();
+
+		// If not an object, complain and skip to the next one.
+		if (!iter.value().isObject())
+		{
+			qWarning() << QString("Group '%1' in the group list should "
+								   "be an object.")
+							   .arg(groupName)
+							   .toUtf8();
+			continue;
+		}
+
+		QJsonObject groupObj = iter.value().toObject();
+		if (!groupObj.value("instances").isArray())
+		{
+			qWarning() << QString("Group '%1' in the group list is invalid. "
+								   "It should contain an array "
+								   "called 'instances'.")
+							   .arg(groupName)
+							   .toUtf8();
+			continue;
+		}
+
+		// keep a list/set of groups for choosing
+		groupSet.insert(groupName);
+
+		// Iterate through the list of instances in the group.
+		QJsonArray instancesArray = groupObj.value("instances").toArray();
+
+		for (QJsonArray::iterator iter2 = instancesArray.begin(); iter2 != instancesArray.end();
+			 iter2++)
+		{
+			groupMap[(*iter2).toString()] = groupName;
+		}
+	}
+	m_groupsLoaded = true;
+	emit groupsChanged(groupSet);
+}
+
+void FolderInstanceProvider::groupChanged()
+{
+	// save the groups. save all of them.
+	auto instance = (BaseInstance *) QObject::sender();
+	auto id = instance->id();
+	groupMap[id] = instance->group();
+	emit groupsChanged({instance->group()});
+	saveGroupList();
+}
+
+
+void FolderInstanceProvider::instanceDirContentsChanged(const QString& path)
+{
+	Q_UNUSED(path);
+	emit instancesChanged();
+}
+
+void FolderInstanceProvider::on_InstFolderChanged(const Setting &setting, QVariant value)
+{
+	QString newInstDir = value.toString();
+	if(newInstDir != m_instDir)
+	{
+		if(m_groupsLoaded)
+		{
+			saveGroupList();
+		}
+		m_instDir = newInstDir;
+		m_groupsLoaded = false;
+		emit instancesChanged();
+	}
+}
+
+QString FolderInstanceProvider::getStagedInstancePath()
+{
+	QString key = QUuid::createUuid().toString();
+	QString relPath = FS::PathCombine("_MMC_TEMP/" , key);
+	QDir rootPath(m_instDir);
+	auto path = FS::PathCombine(m_instDir, relPath);
+	if(!rootPath.mkpath(relPath))
+	{
+		return QString();
+	}
+	return path;
+}
+
+bool FolderInstanceProvider::commitStagedInstance(const QString& keyPath, const QString& path, const QString& instanceName,
+	const QString& groupName)
+{
+	if(!path.contains(keyPath))
+	{
+		qWarning() << "It is not possible to commit" << path << "because it is not in" << keyPath;
+		return false;
+	}
+	QDir dir;
+	QString instID = FS::DirNameFromString(instanceName, m_instDir);
+	{
+		WatchLock lock(m_watcher, m_instDir);
+		if(!dir.rename(path, FS::PathCombine(m_instDir, instID)))
+		{
+			destroyStagingPath(keyPath);
+			return false;
+		}
+		groupMap[instID] = groupName;
+		emit groupsChanged({groupName});
+		emit instancesChanged();
+	}
+	saveGroupList();
+	return destroyStagingPath(keyPath);
+}
+
+bool FolderInstanceProvider::destroyStagingPath(const QString& keyPath)
+{
+	return FS::deletePath(keyPath);
+}
+
diff --git a/api/logic/FolderInstanceProvider.h b/api/logic/FolderInstanceProvider.h
new file mode 100644
index 00000000..f350a96d
--- /dev/null
+++ b/api/logic/FolderInstanceProvider.h
@@ -0,0 +1,63 @@
+#pragma once
+
+#include "BaseInstanceProvider.h"
+#include <QMap>
+
+class QFileSystemWatcher;
+
+class MULTIMC_LOGIC_EXPORT FolderInstanceProvider : public BaseInstanceProvider
+{
+	Q_OBJECT
+public:
+	FolderInstanceProvider(SettingsObjectPtr settings, const QString & instDir);
+
+public:
+	/// used by InstanceList to @return a list of plausible IDs to probe for
+	QList<InstanceId> discoverInstances() override;
+
+	/// used by InstanceList to (re)load an instance with the given @id.
+	InstancePtr loadInstance(const InstanceId& id) override;
+
+
+	// create instance in this provider
+	Task * creationTask(BaseVersionPtr version, const QString &instName, const QString &instGroup, const QString &instIcon);
+
+	// copy instance to this provider
+	Task * copyTask(const InstancePtr &oldInstance, const QString& instName, const QString& instGroup, const QString& instIcon, bool copySaves);
+
+	// import zipped instance into this provider
+	Task * zipImportTask(const QUrl sourceUrl, const QString &instName, const QString &instGroup, const QString &instIcon);
+
+	/**
+	 * Create a new empty staging area for instance creation and @return a path/key top commit it later.
+	 * Used by instance manipulation tasks.
+	 */
+	QString getStagedInstancePath() override;
+	/**
+	 * Commit the staging area given by @keyPath to the provider - used when creation succeeds.
+	 * Used by instance manipulation tasks.
+	 */
+	bool commitStagedInstance(const QString & keyPath, const QString & path, const QString& instanceName, const QString & groupName) override;
+	/**
+	 * Destroy a previously created staging area given by @keyPath - used when creation fails.
+	 * Used by instance manipulation tasks.
+	 */
+	bool destroyStagingPath(const QString & keyPath) override;
+
+public slots:
+	void on_InstFolderChanged(const Setting &setting, QVariant value);
+
+private slots:
+	void instanceDirContentsChanged(const QString &path);
+	void groupChanged();
+
+private: /* methods */
+	void loadGroupList() override;
+	void saveGroupList() override;
+
+private: /* data */
+	QString m_instDir;
+	QFileSystemWatcher * m_watcher;
+	QMap<QString, QString> groupMap;
+	bool m_groupsLoaded = false;
+};
diff --git a/api/logic/InstanceCopyTask.cpp b/api/logic/InstanceCopyTask.cpp
new file mode 100644
index 00000000..1e231478
--- /dev/null
+++ b/api/logic/InstanceCopyTask.cpp
@@ -0,0 +1,53 @@
+#include "InstanceCopyTask.h"
+#include "BaseInstanceProvider.h"
+#include "settings/INISettingsObject.h"
+#include "FileSystem.h"
+#include "NullInstance.h"
+#include "pathmatcher/RegexpMatcher.h"
+
+InstanceCopyTask::InstanceCopyTask(SettingsObjectPtr settings, BaseInstanceProvider* target, InstancePtr origInstance, const QString& instName, const QString& instIcon, const QString& instGroup, bool copySaves)
+{
+	m_globalSettings = settings;
+	m_target = target;
+	m_origInstance = origInstance;
+	m_instName = instName;
+	m_instIcon = instIcon;
+	m_instGroup = instGroup;
+	m_copySaves = copySaves;
+}
+
+void InstanceCopyTask::executeTask()
+{
+	setStatus(tr("Copying instance %1").arg(m_origInstance->name()));
+	std::unique_ptr<IPathMatcher> matcher;
+	if(!m_copySaves)
+	{
+		// FIXME: get this from the original instance type...
+		auto matcherReal = new RegexpMatcher("[.]?minecraft/saves");
+		matcherReal->caseSensitive(false);
+		matcher.reset(matcherReal);
+	}
+
+	QString stagingPath = m_target->getStagedInstancePath();
+	FS::copy folderCopy(m_origInstance->instanceRoot(), stagingPath);
+	folderCopy.followSymlinks(false).blacklist(matcher.get());
+	if (!folderCopy())
+	{
+		m_target->destroyStagingPath(stagingPath);
+		emitFailed(tr("Instance folder copy failed."));
+		return;
+	}
+
+	// FIXME: shouldn't this be able to report errors?
+	auto instanceSettings = std::make_shared<INISettingsObject>(FS::PathCombine(stagingPath, "instance.cfg"));
+	instanceSettings->registerSetting("InstanceType", "Legacy");
+
+	// FIXME: and this too? errors???
+	m_origInstance->copy(stagingPath);
+
+	InstancePtr inst(new NullInstance(m_globalSettings, instanceSettings, stagingPath));
+	inst->setName(m_instName);
+	inst->setIconKey(m_instIcon);
+	m_target->commitStagedInstance(stagingPath, stagingPath, m_instName, m_instGroup);
+	emitSucceeded();
+}
diff --git a/api/logic/InstanceCopyTask.h b/api/logic/InstanceCopyTask.h
new file mode 100644
index 00000000..a663ddbd
--- /dev/null
+++ b/api/logic/InstanceCopyTask.h
@@ -0,0 +1,34 @@
+#pragma once
+
+#include "tasks/Task.h"
+#include "multimc_logic_export.h"
+#include "net/NetJob.h"
+#include <QUrl>
+#include "settings/SettingsObject.h"
+#include "BaseVersion.h"
+#include "BaseInstance.h"
+
+class BaseInstanceProvider;
+
+class MULTIMC_LOGIC_EXPORT InstanceCopyTask : public Task
+{
+	Q_OBJECT
+public:
+	explicit InstanceCopyTask(SettingsObjectPtr settings, BaseInstanceProvider * target, InstancePtr origInstance, const QString &instName,
+		const QString &instIcon, const QString &instGroup, bool copySaves);
+
+protected:
+	//! Entry point for tasks.
+	virtual void executeTask() override;
+
+private: /* data */
+	SettingsObjectPtr m_globalSettings;
+	BaseInstanceProvider * m_target = nullptr;
+	InstancePtr m_origInstance;
+	QString m_instName;
+	QString m_instIcon;
+	QString m_instGroup;
+	bool m_copySaves = false;
+};
+
+
diff --git a/api/logic/InstanceCreationTask.cpp b/api/logic/InstanceCreationTask.cpp
new file mode 100644
index 00000000..00156701
--- /dev/null
+++ b/api/logic/InstanceCreationTask.cpp
@@ -0,0 +1,46 @@
+#include "InstanceCreationTask.h"
+#include "BaseInstanceProvider.h"
+#include "settings/INISettingsObject.h"
+#include "FileSystem.h"
+
+//FIXME: remove this
+#include "minecraft/MinecraftVersion.h"
+#include "minecraft/onesix/OneSixInstance.h"
+
+InstanceCreationTask::InstanceCreationTask(SettingsObjectPtr settings, BaseInstanceProvider* target, BaseVersionPtr version,
+	const QString& instName, const QString& instIcon, const QString& instGroup)
+{
+	m_globalSettings = settings;
+	m_target = target;
+	m_instName = instName;
+	m_instIcon = instIcon;
+	m_instGroup = instGroup;
+	m_version = version;
+}
+
+void InstanceCreationTask::executeTask()
+{
+	setStatus(tr("Creating instance from version %1").arg(m_version->name()));
+	auto minecraftVersion = std::dynamic_pointer_cast<MinecraftVersion>(m_version);
+	if(!minecraftVersion)
+	{
+		emitFailed(tr("The supplied version is not a Minecraft version."));
+		return ;
+	}
+
+	QString stagingPath = m_target->getStagedInstancePath();
+	QDir rootDir(stagingPath);
+
+	auto instanceSettings = std::make_shared<INISettingsObject>(FS::PathCombine(stagingPath, "instance.cfg"));
+	instanceSettings->registerSetting("InstanceType", "Legacy");
+
+	auto mcVer = std::dynamic_pointer_cast<MinecraftVersion>(m_version);
+	instanceSettings->set("InstanceType", "OneSix");
+	InstancePtr inst(new OneSixInstance(m_globalSettings, instanceSettings, stagingPath));
+	inst->setIntendedVersionId(m_version->descriptor());
+	inst->setName(m_instName);
+	inst->setIconKey(m_instIcon);
+	inst->init();
+	m_target->commitStagedInstance(stagingPath, stagingPath, m_instName, m_instGroup);
+	emitSucceeded();
+}
diff --git a/api/logic/InstanceCreationTask.h b/api/logic/InstanceCreationTask.h
new file mode 100644
index 00000000..b4ade320
--- /dev/null
+++ b/api/logic/InstanceCreationTask.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include "tasks/Task.h"
+#include "multimc_logic_export.h"
+#include "net/NetJob.h"
+#include <QUrl>
+#include "settings/SettingsObject.h"
+#include "BaseVersion.h"
+
+class BaseInstanceProvider;
+
+class MULTIMC_LOGIC_EXPORT InstanceCreationTask : public Task
+{
+	Q_OBJECT
+public:
+	explicit InstanceCreationTask(SettingsObjectPtr settings, BaseInstanceProvider * target, BaseVersionPtr version, const QString &instName,
+		const QString &instIcon, const QString &instGroup);
+
+protected:
+	//! Entry point for tasks.
+	virtual void executeTask() override;
+
+private: /* data */
+	SettingsObjectPtr m_globalSettings;
+	BaseInstanceProvider * m_target;
+	BaseVersionPtr m_version;
+	QString m_instName;
+	QString m_instIcon;
+	QString m_instGroup;
+};
+
diff --git a/api/logic/InstanceImportTask.cpp b/api/logic/InstanceImportTask.cpp
new file mode 100644
index 00000000..99f2553f
--- /dev/null
+++ b/api/logic/InstanceImportTask.cpp
@@ -0,0 +1,146 @@
+
+#include "InstanceImportTask.h"
+#include "BaseInstance.h"
+#include "BaseInstanceProvider.h"
+#include "FileSystem.h"