Reorganize the version-related code.

18 files changed, 880 insertions, 849 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f070684d..229179cb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -414,31 +414,38 @@ logic/LegacyInstance.cpp
 logic/LegacyInstance_p.h
 logic/LegacyUpdate.h
 logic/LegacyUpdate.cpp
+
 logic/LegacyForge.h
 logic/LegacyForge.cpp
 
 # OneSix instances
 logic/OneSixUpdate.h
 logic/OneSixUpdate.cpp
-logic/OneSixVersion.h
-logic/OneSixVersion.cpp
+logic/OneSixInstance.h
+logic/OneSixInstance.cpp
+logic/OneSixInstance_p.h
+
+# OneSix version json infrastructure
+logic/OneSixVersionBuilder.h
+logic/OneSixVersionBuilder.cpp
+logic/VersionFile.h
+logic/VersionFile.cpp
+logic/VersionFinal.h
+logic/VersionFinal.cpp
 logic/OneSixLibrary.h
 logic/OneSixLibrary.cpp
 logic/OneSixRule.h
 logic/OneSixRule.cpp
 logic/OpSys.h
 logic/OpSys.cpp
+
+# Mod installers
 logic/BaseInstaller.h
 logic/BaseInstaller.cpp
 logic/ForgeInstaller.h
 logic/ForgeInstaller.cpp
 logic/LiteLoaderInstaller.h
 logic/LiteLoaderInstaller.cpp
-logic/OneSixInstance.h
-logic/OneSixInstance.cpp
-logic/OneSixInstance_p.h
-logic/OneSixVersionBuilder.h
-logic/OneSixVersionBuilder.cpp
 
 # Nostalgia
 logic/NostalgiaInstance.h
diff --git a/gui/dialogs/OneSixModEditDialog.cpp b/gui/dialogs/OneSixModEditDialog.cpp
index fe621a9a..67210217 100644
--- a/gui/dialogs/OneSixModEditDialog.cpp
+++ b/gui/dialogs/OneSixModEditDialog.cpp
@@ -34,7 +34,7 @@
 #include "gui/dialogs/ProgressDialog.h"
 
 #include "logic/ModList.h"
-#include "logic/OneSixVersion.h"
+#include "logic/VersionFinal.h"
 #include "logic/EnabledItemFilter.h"
 #include "logic/lists/ForgeVersionList.h"
 #include "logic/lists/LiteLoaderVersionList.h"
@@ -353,7 +353,7 @@ QMap<QString, int> OneSixModEditDialog::getExistingOrder() const
 	QMap<QString, int> order;
 	// default
 	{
-		for (OneSixVersion::VersionFile file : m_version->versionFiles)
+		for (VersionFinal::VersionFile file : m_version->versionFiles)
 		{
 			if (file.id.startsWith("org.multimc."))
 			{
diff --git a/gui/dialogs/OneSixModEditDialog.h b/gui/dialogs/OneSixModEditDialog.h
index f44b336b..1f3f9f67 100644
--- a/gui/dialogs/OneSixModEditDialog.h
+++ b/gui/dialogs/OneSixModEditDialog.h
@@ -60,7 +60,7 @@ protected:
 
 private:
 	Ui::OneSixModEditDialog *ui;
-	std::shared_ptr<OneSixVersion> m_version;
+	std::shared_ptr<VersionFinal> m_version;
 	std::shared_ptr<ModList> m_mods;
 	std::shared_ptr<ModList> m_resourcepacks;
 	EnabledItemFilter *main_model;
diff --git a/logic/BaseInstaller.cpp b/logic/BaseInstaller.cpp
index 92aa0c92..669fd0ac 100644
--- a/logic/BaseInstaller.cpp
+++ b/logic/BaseInstaller.cpp
@@ -17,7 +17,7 @@
 
 #include <QFile>
 
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 #include "OneSixLibrary.h"
 #include "OneSixInstance.h"
 
diff --git a/logic/ForgeInstaller.cpp b/logic/ForgeInstaller.cpp
index 3e18d17f..6f238c21 100644
--- a/logic/ForgeInstaller.cpp
+++ b/logic/ForgeInstaller.cpp
@@ -14,7 +14,7 @@
  */
 
 #include "ForgeInstaller.h"
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 #include "OneSixLibrary.h"
 #include "net/HttpMetaCache.h"
 #include <quazip.h>
@@ -33,7 +33,7 @@
 
 ForgeInstaller::ForgeInstaller(QString filename, QString universal_url)
 {
-	std::shared_ptr<OneSixVersion> newVersion;
+	std::shared_ptr<VersionFinal> newVersion;
 	m_universal_url = universal_url;
 
 	QuaZip zip(filename);
@@ -66,7 +66,7 @@ ForgeInstaller::ForgeInstaller(QString filename, QString universal_url)
 
 	// read the forge version info
 	{
-		newVersion = OneSixVersion::fromJson(versionInfoVal.toObject());
+		newVersion = VersionFinal::fromJson(versionInfoVal.toObject());
 		if (!newVersion)
 			return;
 	}
diff --git a/logic/ForgeInstaller.h b/logic/ForgeInstaller.h
index c5052092..df029f38 100644
--- a/logic/ForgeInstaller.h
+++ b/logic/ForgeInstaller.h
@@ -20,7 +20,7 @@
 #include <QString>
 #include <memory>
 
-class OneSixVersion;
+class VersionFinal;
 
 class ForgeInstaller : public BaseInstaller
 {
@@ -33,7 +33,7 @@ public:
 
 private:
 	// the version, read from the installer
-	std::shared_ptr<OneSixVersion> m_forge_version;
+	std::shared_ptr<VersionFinal> m_forge_version;
 	QString internalPath;
 	QString finalPath;
 	QString realVersionId;
diff --git a/logic/LiteLoaderInstaller.cpp b/logic/LiteLoaderInstaller.cpp
index 126027fb..44400e8a 100644
--- a/logic/LiteLoaderInstaller.cpp
+++ b/logic/LiteLoaderInstaller.cpp
@@ -20,7 +20,7 @@
 
 #include "logger/QsLog.h"
 
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 #include "OneSixLibrary.h"
 #include "OneSixInstance.h"
 
diff --git a/logic/OneSixFTBInstance.cpp b/logic/OneSixFTBInstance.cpp
index 8b8465b9..cdb3f53e 100644
--- a/logic/OneSixFTBInstance.cpp
+++ b/logic/OneSixFTBInstance.cpp
@@ -1,6 +1,6 @@
 #include "OneSixFTBInstance.h"
 
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 #include "OneSixLibrary.h"
 #include "tasks/SequentialTask.h"
 #include "ForgeInstaller.h"
diff --git a/logic/OneSixInstance.cpp b/logic/OneSixInstance.cpp
index 10411c56..bd5d559e 100644
--- a/logic/OneSixInstance.cpp
+++ b/logic/OneSixInstance.cpp
@@ -19,7 +19,7 @@
 
 #include "OneSixInstance_p.h"
 #include "OneSixUpdate.h"
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 #include "pathutils.h"
 #include "logger/QsLog.h"
 #include "assets/AssetsUtils.h"
@@ -34,8 +34,8 @@ OneSixInstance::OneSixInstance(const QString &rootDir, SettingsObject *settings,
 	I_D(OneSixInstance);
 	d->m_settings->registerSetting("IntendedVersion", "");
 	d->m_settings->registerSetting("ShouldUpdate", false);
-	d->version.reset(new OneSixVersion(this, this));
-	d->vanillaVersion.reset(new OneSixVersion(this, this));
+	d->version.reset(new VersionFinal(this, this));
+	d->vanillaVersion.reset(new VersionFinal(this, this));
 }
 
 void OneSixInstance::init()
@@ -79,7 +79,7 @@ QString replaceTokensIn(QString text, QMap<QString, QString> with)
 	return result;
 }
 
-QDir OneSixInstance::reconstructAssets(std::shared_ptr<OneSixVersion> version)
+QDir OneSixInstance::reconstructAssets(std::shared_ptr<VersionFinal> version)
 {
 	QDir assetsDir = QDir("assets/");
 	QDir indexDir = QDir(PathCombine(assetsDir.path(), "indexes"));
@@ -345,13 +345,13 @@ void OneSixInstance::clearVersion()
 	emit versionReloaded();
 }
 
-std::shared_ptr<OneSixVersion> OneSixInstance::getFullVersion() const
+std::shared_ptr<VersionFinal> OneSixInstance::getFullVersion() const
 {
 	I_D(const OneSixInstance);
 	return d->version;
 }
 
-std::shared_ptr<OneSixVersion> OneSixInstance::getVanillaVersion() const
+std::shared_ptr<VersionFinal> OneSixInstance::getVanillaVersion() const
 {
 	I_D(const OneSixInstance);
 	return d->vanillaVersion;
diff --git a/logic/OneSixInstance.h b/logic/OneSixInstance.h
index 06fd9de3..75edec1e 100644
--- a/logic/OneSixInstance.h
+++ b/logic/OneSixInstance.h
@@ -17,7 +17,7 @@
 
 #include "BaseInstance.h"
 
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 #include "ModList.h"
 
 class OneSixInstance : public BaseInstance
@@ -58,9 +58,9 @@ public:
 	/// clears all version information in preparation for an update
 	void clearVersion();
 	/// get the current full version info
-	std::shared_ptr<OneSixVersion> getFullVersion() const;
+	std::shared_ptr<VersionFinal> getFullVersion() const;
 	/// gets the current version info, but only for version.json
-	std::shared_ptr<OneSixVersion> getVanillaVersion() const;
+	std::shared_ptr<VersionFinal> getVanillaVersion() const;
 	/// is the current version original, or custom?
 	virtual bool versionIsCustom() override;
 
@@ -80,5 +80,5 @@ signals:
 
 private:
 	QStringList processMinecraftArgs(AuthSessionPtr account);
-	QDir reconstructAssets(std::shared_ptr<OneSixVersion> version);
+	QDir reconstructAssets(std::shared_ptr<VersionFinal> version);
 };
diff --git a/logic/OneSixInstance_p.h b/logic/OneSixInstance_p.h
index 0cc46f33..2dffa62c 100644
--- a/logic/OneSixInstance_p.h
+++ b/logic/OneSixInstance_p.h
@@ -16,13 +16,13 @@
 #pragma once
 
 #include "BaseInstance_p.h"
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 #include "ModList.h"
 
 struct OneSixInstancePrivate : public BaseInstancePrivate
 {
-	std::shared_ptr<OneSixVersion> version;
-	std::shared_ptr<OneSixVersion> vanillaVersion;
+	std::shared_ptr<VersionFinal> version;
+	std::shared_ptr<VersionFinal> vanillaVersion;
 	std::shared_ptr<ModList> loader_mod_list;
 	std::shared_ptr<ModList> resource_pack_list;
 };
diff --git a/logic/OneSixUpdate.cpp b/logic/OneSixUpdate.cpp
index f87c65e7..750aeabb 100644
--- a/logic/OneSixUpdate.cpp
+++ b/logic/OneSixUpdate.cpp
@@ -25,7 +25,7 @@
 
 #include "BaseInstance.h"
 #include "lists/MinecraftVersionList.h"
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 #include "OneSixLibrary.h"
 #include "OneSixInstance.h"
 #include "net/ForgeMirrors.h"
@@ -150,7 +150,7 @@ void OneSixUpdate::assetIndexStart()
 {
 	setStatus(tr("Updating assets index..."));
 	OneSixInstance *inst = (OneSixInstance *)m_inst;
-	std::shared_ptr<OneSixVersion> version = inst->getFullVersion();
+	std::shared_ptr<VersionFinal> version = inst->getFullVersion();
 	QString assetName = version->assets;
 	QUrl indexUrl = "http://" + URLConstants::AWS_DOWNLOAD_INDEXES + assetName + ".json";
 	QString localPath = assetName + ".json";
@@ -174,7 +174,7 @@ void OneSixUpdate::assetIndexFinished()
 	AssetsIndex index;
 
 	OneSixInstance *inst = (OneSixInstance *)m_inst;
-	std::shared_ptr<OneSixVersion> version = inst->getFullVersion();
+	std::shared_ptr<VersionFinal> version = inst->getFullVersion();
 	QString assetName = version->assets;
 
 	QString asset_fname = "assets/indexes/" + assetName + ".json";
@@ -243,7 +243,7 @@ void OneSixUpdate::jarlibStart()
 	}
 
 	// Build a list of URLs that will need to be downloaded.
-	std::shared_ptr<OneSixVersion> version = inst->getFullVersion();
+	std::shared_ptr<VersionFinal> version = inst->getFullVersion();
 	// minecraft.jar for this version
 	{
 		QString version_id = version->id;
diff --git a/logic/OneSixVersionBuilder.cpp b/logic/OneSixVersionBuilder.cpp
index f6917697..0d4d66a2 100644
--- a/logic/OneSixVersionBuilder.cpp
+++ b/logic/OneSixVersionBuilder.cpp
@@ -26,806 +26,37 @@
 #include <QDir>
 #include <QDebug>
 
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 #include "OneSixInstance.h"
 #include "OneSixRule.h"
+#include "VersionFile.h"
 #include "modutils.h"
 #include "logger/QsLog.h"
 
-#define CURRENT_MINIMUM_LAUNCHER_VERSION 14
-
-struct VersionFile
-{
-	int order;
-	QString name;
-	QString fileId;
-	QString version;
-	// TODO use the mcVersion to determine if a version file should be removed on update
-	QString mcVersion;
-	QString filename;
-	// TODO requirements
-	// QMap<QString, QString> requirements;
-	QString id;
-	QString mainClass;
-	QString overwriteMinecraftArguments;
-	QString addMinecraftArguments;
-	QString removeMinecraftArguments;
-	QString processArguments;
-	QString type;
-	QString releaseTime;
-	QString time;
-	QString assets;
-	int minimumLauncherVersion = -1;
-
-	bool shouldOverwriteTweakers = false;
-	QStringList overwriteTweakers;
-	QStringList addTweakers;
-	QStringList removeTweakers;
-
-	struct Library
-	{
-		QString name;
-		QString url;
-		QString hint;
-		QString absoluteUrl;
-		bool applyExcludes = false;
-		QStringList excludes;
-		bool applyNatives = false;
-		QList<QPair<OpSys, QString>> natives;
-		bool applyRules = false;
-		QList<std::shared_ptr<Rule>> rules;
-
-		// user for '+' libraries
-		enum InsertType
-		{
-			Apply,
-			Append,
-			Prepend,
-			Replace
-		};
-		InsertType insertType = Append;
-		QString insertData;
-		enum DependType
-		{
-			Soft,
-			Hard
-		};
-		DependType dependType = Soft;
-	};
-	bool shouldOverwriteLibs = false;
-	QList<Library> overwriteLibs;
-	QList<Library> addLibs;
-	QList<QString> removeLibs;
-
-	enum ApplyError
-	{
-		LauncherVersionError,
-		OtherError,
-		NoApplyError
-	};
-
-	static Library fromLibraryJson(const QJsonObject &libObj, const QString &filename,
-								   bool &isError)
-	{
-		isError = true;
-		Library out;
-		if (!libObj.contains("name"))
-		{
-			QLOG_ERROR() << filename << "contains a library that doesn't have a 'name' field";
-			return out;
-		}
-		out.name = libObj.value("name").toString();
-
-		auto readString = [libObj, filename](const QString &key, QString &variable)
-		{
-			if (libObj.contains(key))
-			{
-				QJsonValue val = libObj.value(key);
-				if (!val.isString())
-				{
-					QLOG_WARN() << key << "is not a string in" << filename << "(skipping)";
-				}
-				else
-				{
-					variable = val.toString();
-				}
-			}
-		};
-
-		readString("url", out.url);
-		readString("MMC-hint", out.hint);
-		readString("MMC-absulute_url", out.absoluteUrl);
-		readString("MMC-absoluteUrl", out.absoluteUrl);
-		if (libObj.contains("extract"))
-		{
-			if (!libObj.value("extract").isObject())
-			{
-				QLOG_ERROR()
-					<< filename
-					<< "contains a library with an 'extract' field that's not an object";
-				return out;
-			}
-			QJsonObject extractObj = libObj.value("extract").toObject();
-			if (!extractObj.contains("exclude") || !extractObj.value("exclude").isArray())
-			{
-				QLOG_ERROR() << filename
-							 << "contains a library with an invalid 'extract' field";
-				return out;
-			}
-			out.applyExcludes = true;
-			QJsonArray excludeArray = extractObj.value("exclude").toArray();
-			for (auto excludeVal : excludeArray)
-			{
-				if (!excludeVal.isString())
-				{
-					QLOG_WARN() << filename << "contains a library that contains an 'extract' "
-											   "field that contains an invalid 'exclude' entry "
-											   "(skipping)";
-				}
-				else
-				{
-					out.excludes.append(excludeVal.toString());
-				}
-			}
-		}
-		if (libObj.contains("natives"))
-		{
-			if (!libObj.value("natives").isObject())
-			{
-				QLOG_ERROR()
-					<< filename
-					<< "contains a library with a 'natives' field that's not an object";
-				return out;
-			}
-			out.applyNatives = true;
-			QJsonObject nativesObj = libObj.value("natives").toObject();
-			for (auto it = nativesObj.begin(); it != nativesObj.end(); ++it)
-			{
-				if (!it.value().isString())
-				{
-					QLOG_WARN() << filename << "contains an invalid native (skipping)";
-				}
-				OpSys opSys = OpSys_fromString(it.key());
-				if (opSys != Os_Other)
-				{
-					out.natives.append(qMakePair(opSys, it.value().toString()));
-				}
-			}
-		}
-		if (libObj.contains("rules"))
-		{
-			out.applyRules = true;
-			out.rules = rulesFromJsonV4(libObj);
-		}
-		isError = false;
-		return out;
-	}
-	static VersionFile fromJson(const QJsonDocument &doc, const QString &filename,
-								const bool requireOrder, bool &isError, const OneSixVersionBuilder::ParseFlags flags = OneSixVersionBuilder::NoFlags)
-	{
-		VersionFile out;
-		isError = true;
-		if (doc.isEmpty() || doc.isNull())
-		{
-			QLOG_ERROR() << filename << "is empty or null";
-			return out;
-		}
-		if (!doc.isObject())
-		{
-			QLOG_ERROR() << "The root of" << filename << "is not an object";
-			return out;
-		}
-
-		QJsonObject root = doc.object();
-
-		if (requireOrder)
-		{
-			if (root.contains("order"))
-			{
-				if (root.value("order").isDouble())
-				{
-					out.order = root.value("order").toDouble();
-				}
-				else
-				{
-					QLOG_ERROR() << "'order' field contains an invalid value in" << filename;
-					return out;
-				}
-			}
-			else
-			{
-				QLOG_ERROR() << filename << "doesn't contain an order field";
-			}
-		}
-
-		out.name = root.value("name").toString();
-		out.fileId = root.value("fileId").toString();
-		out.version = root.value("version").toString();
-		out.mcVersion = root.value("mcVersion").toString();
-		out.filename = filename;
-
-		auto readString = [root, filename](const QString &key, QString &variable)
-		{
-			if (root.contains(key))
-			{
-				QJsonValue val = root.value(key);
-				if (!val.isString())
-				{
-					QLOG_WARN() << key << "is not a string in" << filename << "(skipping)";
-				}
-				else
-				{
-					variable = val.toString();
-				}
-			}
-		};
-
-		if (!(flags & OneSixVersionBuilder::IsFTBPackJson))
-		{
-			readString("id", out.id);
-		}
-		readString("mainClass", out.mainClass);
-		readString("processArguments", out.processArguments);
-		readString("minecraftArguments", out.overwriteMinecraftArguments);
-		readString("+minecraftArguments", out.addMinecraftArguments);
-		readString("-minecraftArguments", out.removeMinecraftArguments);
-		readString("type", out.type);
-		readString("releaseTime", out.releaseTime);
-		readString("time", out.time);
-		readString("assets", out.assets);
-		if (root.contains("minimumLauncherVersion"))
-		{
-			QJsonValue val = root.value("minimumLauncherVersion");
-			if (!val.isDouble())
-			{
-				QLOG_WARN() << "minimumLauncherVersion is not an int in" << filename
-							<< "(skipping)";
-			}
-			else
-			{
-				out.minimumLauncherVersion = val.toDouble();
-			}
-		}
-
-		if (root.contains("tweakers"))
-		{
-			QJsonValue tweakersVal = root.value("tweakers");
-			if (!tweakersVal.isArray())
-			{
-				QLOG_ERROR() << filename
-							 << "contains a 'tweakers' field, but it's not an array";
-				return out;
-			}
-			out.shouldOverwriteTweakers = true;
-			QJsonArray tweakers = root.value("tweakers").toArray();
-			for (auto tweakerVal : tweakers)
-			{
-				if (!tweakerVal.isString())
-				{
-					QLOG_ERROR() << filename
-								 << "contains a 'tweakers' field entry that's not a string";
-					return out;
-				}
-				out.overwriteTweakers.append(tweakerVal.toString());
-			}
-		}
-		if (root.contains("+tweakers"))
-		{
-			QJsonValue tweakersVal = root.value("+tweakers");
-			if (!tweakersVal.isArray())
-			{
-				QLOG_ERROR() << filename
-							 << "contains a '+tweakers' field, but it's not an array";
-				return out;
-			}
-			QJsonArray tweakers = root.value("+tweakers").toArray();
-			for (auto tweakerVal : tweakers)
-			{
-				if (!tweakerVal.isString())
-				{
-					QLOG_ERROR() << filename
-								 << "contains a '+tweakers' field entry that's not a string";
-					return out;
-				}
-				out.addTweakers.append(tweakerVal.toString());
-			}
-		}
-		if (root.contains("-tweakers"))
-		{
-			QJsonValue tweakersVal = root.value("-tweakers");
-			if (!tweakersVal.isArray())
-			{
-				QLOG_ERROR() << filename
-							 << "contains a '-tweakers' field, but it's not an array";
-				return out;
-			}
-			out.shouldOverwriteTweakers = true;
-			QJsonArray tweakers = root.value("-tweakers").toArray();
-			for (auto tweakerVal : tweakers)
-			{
-				if (!tweakerVal.isString())
-				{
-					QLOG_ERROR() << filename
-								 << "contains a '-tweakers' field entry that's not a string";
-					return out;
-				}
-				out.removeTweakers.append(tweakerVal.toString());
-			}
-		}
-
-		if (root.contains("libraries"))
-		{
-			out.shouldOverwriteLibs = !(flags & OneSixVersionBuilder::IsFTBPackJson);
-			QJsonValue librariesVal = root.value("libraries");
-			if (!librariesVal.isArray())
-			{
-				QLOG_ERROR() << filename
-							 << "contains a 'libraries' field, but its not an array";
-				return out;
-			}
-			QJsonArray librariesArray = librariesVal.toArray();
-			for (auto libVal : librariesArray)
-			{
-				if (!libVal.isObject())
-				{
-					QLOG_ERROR() << filename << "contains a library that's not an object";
-					return out;
-				}
-				QJsonObject libObj = libVal.toObject();
-				bool error;
-				Library lib = fromLibraryJson(libObj, filename, error);
-				if (error)
-				{
-					QLOG_ERROR() << "Error while reading a library entry in" << filename;
-					return out;
-				}
-				if (flags & OneSixVersionBuilder::IsFTBPackJson)
-				{
-					lib.hint = "local";
-					lib.insertType = Library::Prepend;
-					out.addLibs.prepend(lib);
-				}
-				else
-				{
-					out.overwriteLibs.append(lib);
-				}
-			}
-		}
-		if (root.contains("+libraries"))
-		{
-			QJsonValue librariesVal = root.value("+libraries");
-			if (!librariesVal.isArray())
-			{
-				QLOG_ERROR() << filename
-							 << "contains a '+libraries' field, but its not an array";
-				return out;
-			}
-			QJsonArray librariesArray = librariesVal.toArray();
-			for (auto libVal : librariesArray)
-			{
-				if (!libVal.isObject())
-				{
-					QLOG_ERROR() << filename << "contains a library that's not an object";
-					return out;
-				}
-				QJsonObject libObj = libVal.toObject();
-				bool error;
-				Library lib = fromLibraryJson(libObj, filename, error);
-				if (error)
-				{
-					QLOG_ERROR() << "Error while reading a library entry in" << filename;
-					return out;
-				}
-				if (!libObj.contains("insert"))
-				{
-					QLOG_ERROR() << "Missing 'insert' field in '+libraries' field in"
-								 << filename;
-					return out;
-				}
-				QJsonValue insertVal = libObj.value("insert");
-				QString insertString;
-				{
-					if (insertVal.isString())
-					{
-						insertString = insertVal.toString();
-					}
-					else if (insertVal.isObject())
-					{
-						QJsonObject insertObj = insertVal.toObject();
-						if (insertObj.isEmpty())
-						{
-							QLOG_ERROR() << "One library has an empty insert object in"
-										 << filename;
-							return out;
-						}
-						insertString = insertObj.keys().first();
-						lib.insertData = insertObj.value(insertString).toString();
-					}
-				}
-				if (insertString == "apply")
-				{
-					lib.insertType = Library::Apply;
-				}
-				else if (insertString == "prepend")
-				{
-					lib.insertType = Library::Prepend;
-				}
-				else if (insertString == "append")
-				{
-					lib.insertType = Library::Prepend;
-				}
-				else if (insertString == "replace")
-				{
-					lib.insertType = Library::Replace;
-				}
-				else
-				{
-					QLOG_ERROR() << "A '+' library in" << filename
-								 << "contains an invalid insert type";
-					return out;
-				}
-				if (libObj.contains("MMC-depend") && libObj.value("MMC-depend").isString())
-				{
-					const QString dependString = libObj.value("MMC-depend").toString();
-					if (dependString == "hard")
-					{
-						lib.dependType = Library::Hard;
-					}
-					else if (dependString == "soft")
-					{
-						lib.dependType = Library::Soft;
-					}
-					else
-					{
-						QLOG_ERROR() << "A '+' library in" << filename
-									 << "contains an invalid depend type";
-						return out;
-					}
-				}
-				out.addLibs.append(lib);
-			}
-		}
-		if (root.contains("-libraries"))
-		{
-			QJsonValue librariesVal = root.value("-libraries");
-			if (!librariesVal.isArray())
-			{
-				QLOG_ERROR() << filename
-							 << "contains a '-libraries' field, but its not an array";
-				return out;
-			}
-			QJsonArray librariesArray = librariesVal.toArray();
-			for (auto libVal : librariesArray)
-			{
-				if (!libVal.isObject())
-				{
-					QLOG_ERROR() << filename << "contains a library that's not an object";
-					return out;
-				}
-				QJsonObject libObj = libVal.toObject();
-				if (!libObj.contains("name"))
-				{
-					QLOG_ERROR() << filename << "contains a library without a name";
-					return out;
-				}
-				if (!libObj.value("name").isString())
-				{
-					QLOG_ERROR() << filename
-								 << "contains a library without a valid 'name' field";
-					return out;
-				}
-				out.removeLibs.append(libObj.value("name").toString());
-			}
-		}
-
-		isError = false;
-		return out;
-	}
-
-	static std::shared_ptr<OneSixLibrary> createLibrary(const Library &lib)
-	{
-		std::shared_ptr<OneSixLibrary> out(new OneSixLibrary(lib.name));
-		if (!lib.url.isEmpty())
-		{
-			out->setBaseUrl(lib.url);
-		}
-		out->setHint(lib.hint);
-		if (!lib.absoluteUrl.isEmpty())
-		{
-			out->setAbsoluteUrl(lib.absoluteUrl);
-		}
-		out->setAbsoluteUrl(lib.absoluteUrl);
-		out->extract_excludes = lib.excludes;
-		for (auto native : lib.natives)
-		{
-			out->addNative(native.first, native.second);
-		}
-		out->setRules(lib.rules);
-		out->finalize();
-		return out;
-	}
-	int findLibrary(QList<std::shared_ptr<OneSixLibrary>> haystack, const QString &needle)
-	{
-		for (int i = 0; i < haystack.size(); ++i)
-		{
-			if (QRegExp(needle, Qt::CaseSensitive, QRegExp::WildcardUnix)
-					.indexIn(haystack.at(i)->rawName()) != -1)
-			{
-				return i;
-			}
-		}
-		return -1;
-	}
-	ApplyError applyTo(OneSixVersion *version)
-	{
-		if (minimumLauncherVersion != -1)
-		{
-			if (minimumLauncherVersion > CURRENT_MINIMUM_LAUNCHER_VERSION)
-			{
-				QLOG_ERROR() << filename << "is for a different launcher version ("
-							 << minimumLauncherVersion << "), current supported is"
-							 << CURRENT_MINIMUM_LAUNCHER_VERSION;
-				return LauncherVersionError;
-			}
-		}
-
-		if (!version->id.isNull() && !mcVersion.isNull())
-		{
-			if (QRegExp(mcVersion, Qt::CaseInsensitive, QRegExp::Wildcard)
-					.indexIn(version->id) == -1)
-			{
-				QLOG_ERROR() << filename << "is for a different version of Minecraft";
-				return OtherError;
-			}
-		}
-
-		if (!id.isNull())
-		{
-			version->id = id;
-		}
-		if (!mainClass.isNull())
-		{
-			version->mainClass = mainClass;
-		}
-		if (!processArguments.isNull())
-		{
-			version->processArguments = processArguments;
-		}
-		if (!type.isNull())
-		{
-			version->type = type;
-		}
-		if (!releaseTime.isNull())
-		{
-			version->releaseTime = releaseTime;
-		}
-		if (!time.isNull())
-		{
-			version->time = time;
-		}
-		if (!assets.isNull())
-		{
-			version->assets = assets;
-		}
-		if (minimumLauncherVersion >= 0)
-		{
-			version->minimumLauncherVersion = minimumLauncherVersion;
-		}
-		if (!overwriteMinecraftArguments.isNull())
-		{
-			version->minecraftArguments = overwriteMinecraftArguments;
-		}
-		if (!addMinecraftArguments.isNull())
-		{
-			version->minecraftArguments += addMinecraftArguments;
-		}
-		if (!removeMinecraftArguments.isNull())
-		{
-			version->minecraftArguments.remove(removeMinecraftArguments);
-		}
-		if (shouldOverwriteTweakers)
-		{
-			version->tweakers = overwriteTweakers;
-		}
-		for (auto tweaker : addTweakers)
-		{
-			version->tweakers += tweaker;
-		}
-		for (auto tweaker : removeTweakers)
-		{
-			version->tweakers.removeAll(tweaker);
-		}
-		if (shouldOverwriteLibs)
-		{
-			version->libraries.clear();
-			for (auto lib : overwriteLibs)
-			{
-				version->libraries.append(createLibrary(lib));
-			}
-		}
-		for (auto lib : addLibs)
-		{
-			switch (lib.insertType)
-			{
-			case Library::Apply:
-			{
-
-				int index = findLibrary(version->libraries, lib.name);
-				if (index >= 0)
-				{
-					auto library = version->libraries[index];
-					if (!lib.url.isNull())
-					{
-						library->setBaseUrl(lib.url);
-					}
-					if (!lib.hint.isNull())
-					{
-						library->setHint(lib.hint);
-					}
-					if (!lib.absoluteUrl.isNull())
-					{
-						library->setAbsoluteUrl(lib.absoluteUrl);
-					}
-					if (lib.applyExcludes)
-					{
-						library->extract_excludes = lib.excludes;
-					}
-					if (lib.applyNatives)
-					{
-						library->clearSuffixes();
-						for (auto native : lib.natives)
-						{
-							library->addNative(native.first, native.second);
-						}
-					}
-					if (lib.applyRules)
-					{
-						library->setRules(lib.rules);
-					}
-					library->finalize();
-				}
-				else
-				{
-					QLOG_WARN() << "Couldn't find" << lib.insertData << "(skipping)";
-				}
-				break;
-			}
-			case Library::Append:
-			case Library::Prepend:
-			{
-
-				const int startOfVersion = lib.name.lastIndexOf(':') + 1;
-				const int index =
-					findLibrary(version->libraries,
-								QString(lib.name).replace(startOfVersion, INT_MAX, '*'));
-				if (index < 0)
-				{
-					if (lib.insertType == Library::Append)
-					{
-						version->libraries.append(createLibrary(lib));
-					}
-					else
-					{
-						version->libraries.prepend(createLibrary(lib));
-					}
-				}
-				else
-				{
-					auto otherLib = version->libraries.at(index);
-					const Util::Version ourVersion = lib.name.mid(startOfVersion, INT_MAX);
-					const Util::Version otherVersion = otherLib->version();
-					// if the existing version is a hard dependency we can either use it or
-					// fail, but we can't change it
-					if (otherLib->dependType == OneSixLibrary::Hard)
-					{
-						// we need a higher version, or we're hard to and the versions aren't
-						// equal
-						if (ourVersion > otherVersion ||
-							(lib.dependType == Library::Hard && ourVersion != otherVersion))
-						{
-							QLOG_ERROR() << "Error resolving library dependencies between"
-										 << otherLib->rawName() << "and" << lib.name << "in"
-										 << filename;
-							return OtherError;
-						}
-						else
-						{
-							// the library is already existing, so we don't have to do anything
-						}
-					}
-					else if (otherLib->dependType == OneSixLibrary::Soft)
-					{
-						// if we are higher it means we should update
-						if (ourVersion > otherVersion)
-						{
-							auto library = createLibrary(lib);
-							if (Util::Version(otherLib->minVersion) < ourVersion)
-							{
-								library->minVersion = ourVersion.toString();
-							}
-							version->libraries.replace(index, library);
-						}
-						else
-						{
-							// our version is smaller than the existing version, but we require
-							// it: fail
-							if (lib.dependType == Library::Hard)
-							{
-								QLOG_ERROR() << "Error resolving library dependencies between"
-											 << otherLib->rawName() << "and" << lib.name << "in"
-											 << filename;
-								return OtherError;
-							}
-						}
-					}
-				}
-				break;
-			}
-			case Library::Replace:
-			{
-				int index = findLibrary(version->libraries, lib.insertData);
-				if (index >= 0)
-				{
-					version->libraries.replace(index, createLibrary(lib));
-				}
-				else
-				{
-					QLOG_WARN() << "Couldn't find" << lib.insertData << "(skipping)";
-				}
-				break;
-			}
-			}
-		}
-		for (auto lib : removeLibs)
-		{
-			int index = findLibrary(version->libraries, lib);
-			if (index >= 0)
-			{
-				version->libraries.removeAt(index);
-			}
-			else
-			{
-				QLOG_WARN() << "Couldn't find" << lib << "(skipping)";
-			}
-		}
-
-		OneSixVersion::VersionFile versionFile;
-		versionFile.name = name;
-		versionFile.id = fileId;
-		versionFile.version = this->version;
-		versionFile.mcVersion = mcVersion;
-		versionFile.filename = filename;
-		versionFile.order = order;
-		version->versionFiles.append(versionFile);
-
-		return NoApplyError;
-	}
-};
-
 OneSixVersionBuilder::OneSixVersionBuilder()
 {
 }
 
-bool OneSixVersionBuilder::build(OneSixVersion *version, OneSixInstance *instance,
+bool OneSixVersionBuilder::build(VersionFinal *version, OneSixInstance *instance,
 								 QWidget *widgetParent, const bool onlyVanilla, const QStringList &external)
 {
 	OneSixVersionBuilder builder;
 	builder.m_version = version;
 	builder.m_instance = instance;
 	builder.m_widgetParent = widgetParent;
-	return builder.build(onlyVanilla, external);
+	return builder.buildInternal(onlyVanilla, external);
 }
 
-bool OneSixVersionBuilder::read(OneSixVersion *version, const QJsonObject &obj)
+bool OneSixVersionBuilder::readJsonAndApplyToVersion(VersionFinal *version, const QJsonObject &obj)
 {
 	OneSixVersionBuilder builder;
 	builder.m_version = version;
 	builder.m_instance = 0;
 	builder.m_widgetParent = 0;
-	return builder.read(obj);
+	return builder.readJsonAndApply(obj);
 }
 
-bool OneSixVersionBuilder::build(const bool onlyVanilla, const QStringList &external)
+bool OneSixVersionBuilder::buildInternal(const bool onlyVanilla, const QStringList &external)
 {
 	m_version->clear();
 
@@ -837,8 +68,7 @@ bool OneSixVersionBuilder::build(const bool onlyVanilla, const QStringList &exte
 	{
 		QLOG_INFO() << "Reading" << fileName;
 		VersionFile file;
-		ParseFlags flags = fileName.endsWith("pack.json") ? IsFTBPackJson : NoFlags;
-		if (!read(QFileInfo(fileName), false, &file, flags))
+		if (!parseJsonFile(QFileInfo(fileName), false, &file, fileName.endsWith("pack.json") ? IsFTBPackJson : NoFlags))
 		{
 			return false;
 		}
@@ -856,7 +86,7 @@ bool OneSixVersionBuilder::build(const bool onlyVanilla, const QStringList &exte
 	{
 		QLOG_INFO() << "Reading custom.json";
 		VersionFile file;
-		if (!read(QFileInfo(root.absoluteFilePath("custom.json")), false, &file))
+		if (!parseJsonFile(QFileInfo(root.absoluteFilePath("custom.json")), false, &file))
 		{
 			return false;
 		}
@@ -876,7 +106,7 @@ bool OneSixVersionBuilder::build(const bool onlyVanilla, const QStringList &exte
 		// version.json
 		QLOG_INFO() << "Reading version.json";
 		VersionFile file;
-		if (!read(QFileInfo(root.absoluteFilePath("version.json")), false, &file))
+		if (!parseJsonFile(QFileInfo(root.absoluteFilePath("version.json")), false, &file))
 		{
 			return false;
 		}
@@ -907,7 +137,7 @@ bool OneSixVersionBuilder::build(const bool onlyVanilla, const QStringList &exte
 		{
 			QLOG_INFO() << "Reading" << info.fileName();
 			VersionFile file;
-			if (!read(info, true, &file))
+			if (!parseJsonFile(info, true, &file))
 			{
 				return false;
 			}
@@ -968,7 +198,7 @@ bool OneSixVersionBuilder::build(const bool onlyVanilla, const QStringList &exte
 	return true;
 }
 
-bool OneSixVersionBuilder::read(const QJsonObject &obj)
+bool OneSixVersionBuilder::readJsonAndApply(const QJsonObject &obj)
 {
 	m_version->clear();
 
@@ -1000,7 +230,7 @@ bool OneSixVersionBuilder::read(const QJsonObject &obj)
 	return true;
 }
 
-bool OneSixVersionBuilder::read(const QFileInfo &fileInfo, const bool requireOrder,
+bool OneSixVersionBuilder::parseJsonFile(const QFileInfo &fileInfo, const bool requireOrder,
 								VersionFile *out, const ParseFlags flags)
 {
 	QFile file(fileInfo.absoluteFilePath());
@@ -1072,6 +302,7 @@ QMap<QString, int> OneSixVersionBuilder::readOverrideOrders(OneSixInstance *inst
 	}
 	return out;
 }
+
 bool OneSixVersionBuilder::writeOverrideOrders(const QMap<QString, int> &order,
 											   OneSixInstance *instance)
 {
diff --git a/logic/OneSixVersionBuilder.h b/logic/OneSixVersionBuilder.h
index 8cf6f32f..8ca2551a 100644
--- a/logic/OneSixVersionBuilder.h
+++ b/logic/OneSixVersionBuilder.h
@@ -18,7 +18,7 @@
 #include <QString>
 #include <QMap>
 
-class OneSixVersion;
+class VersionFinal;
 class OneSixInstance;
 class QWidget;
 class QJsonObject;
@@ -29,8 +29,9 @@ class OneSixVersionBuilder
 {
 	OneSixVersionBuilder();
 public:
-	static bool build(OneSixVersion *version, OneSixInstance *instance, QWidget *widgetParent, const bool onlyVanilla, const QStringList &external);
-	static bool read(OneSixVersion *version, const QJsonObject &obj);
+	static bool build(VersionFinal *version, OneSixInstance *instance, QWidget *widgetParent, const bool onlyVanilla, const QStringList &external);
+	static bool readJsonAndApplyToVersion(VersionFinal *version, const QJsonObject &obj);
+
 	static QMap<QString, int> readOverrideOrders(OneSixInstance *instance);
 	static bool writeOverrideOrders(const QMap<QString, int> &order, OneSixInstance *instance);
 
@@ -42,14 +43,14 @@ public:
 	Q_DECLARE_FLAGS(ParseFlags, ParseFlag)
 
 private:
-	OneSixVersion *m_version;
+	VersionFinal *m_version;
 	OneSixInstance *m_instance;
 	QWidget *m_widgetParent;
 
-	bool build(const bool onlyVanilla, const QStringList &external);
-	bool read(const QJsonObject &obj);
+	bool buildInternal(const bool onlyVanilla, const QStringList &external);
+	bool readJsonAndApply(const QJsonObject &obj);
 
-	bool read(const QFileInfo &fileInfo, const bool requireOrder, VersionFile *out, const ParseFlags flags = NoFlags);
+	bool parseJsonFile(const QFileInfo &fileInfo, const bool requireOrder, VersionFile *out, const ParseFlags flags = NoFlags);
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(OneSixVersionBuilder::ParseFlags)
diff --git a/logic/VersionFile.cpp b/logic/VersionFile.cpp
new file mode 100644
index 00000000..76cf9279
--- /dev/null
+++ b/logic/VersionFile.cpp
@@ -0,0 +1,702 @@
+#include <QJsonArray>
+#include <QJsonDocument>
+
+#include <modutils.h>
+
+#include "logger/QsLog.h"
+#include "logic/VersionFile.h"
+#include "logic/OneSixLibrary.h"
+#include "logic/VersionFinal.h"
+
+
+#define CURRENT_MINIMUM_LAUNCHER_VERSION 14
+
+VersionFile::Library VersionFile::Library::fromJson(const QJsonObject &libObj,
+													const QString &filename, bool &isError)
+{
+	isError = true;
+	Library out;
+	if (!libObj.contains("name"))
+	{
+		QLOG_ERROR() << filename << "contains a library that doesn't have a 'name' field";
+		return out;
+	}
+	out.name = libObj.value("name").toString();
+
+	auto readString = [libObj, filename](const QString & key, QString & variable)
+	{
+		if (libObj.contains(key))
+		{
+			QJsonValue val = libObj.value(key);
+			if (!val.isString())
+			{
+				QLOG_WARN() << key << "is not a string in" << filename << "(skipping)";
+			}
+			else
+			{
+				variable = val.toString();
+			}
+		}
+	};
+
+	readString("url", out.url);
+	readString("MMC-hint", out.hint);
+	readString("MMC-absulute_url", out.absoluteUrl);
+	readString("MMC-absoluteUrl", out.absoluteUrl);
+	if (libObj.contains("extract"))
+	{
+		if (!libObj.value("extract").isObject())
+		{
+			QLOG_ERROR() << filename
+						 << "contains a library with an 'extract' field that's not an object";
+			return out;
+		}
+		QJsonObject extractObj = libObj.value("extract").toObject();
+		if (!extractObj.contains("exclude") || !extractObj.value("exclude").isArray())
+		{
+			QLOG_ERROR() << filename << "contains a library with an invalid 'extract' field";
+			return out;
+		}
+		out.applyExcludes = true;
+		QJsonArray excludeArray = extractObj.value("exclude").toArray();
+		for (auto excludeVal : excludeArray)
+		{
+			if (!excludeVal.isString())
+			{
+				QLOG_WARN() << filename << "contains a library that contains an 'extract' "
+										   "field that contains an invalid 'exclude' entry "
+										   "(skipping)";
+			}
+			else
+			{
+				out.excludes.append(excludeVal.toString());
+			}
+		}
+	}
+	if (libObj.contains("natives"))
+	{
+		if (!libObj.value("natives").isObject())
+		{
+			QLOG_ERROR() << filename
+						 << "contains a library with a 'natives' field that's not an object";
+			return out;
+		}
+		out.applyNatives = true;
+		QJsonObject nativesObj = libObj.value("natives").toObject();
+		for (auto it = nativesObj.begin(); it != nativesObj.end(); ++it)
+		{
+			if (!it.value().isString())
+			{
+				QLOG_WARN() << filename << "contains an invalid native (skipping)";
+			}
+			OpSys opSys = OpSys_fromString(it.key());
+			if (opSys != Os_Other)
+			{
+				out.natives.append(qMakePair(opSys, it.value().toString()));
+			}
+		}
+	}
+	if (libObj.contains("rules"))
+	{
+		out.applyRules = true;
+		out.rules = rulesFromJsonV4(libObj);
+	}
+	isError = false;
+	return out;
+}
+
+VersionFile VersionFile::fromJson(const QJsonDocument &doc, const QString &filename,
+								  const bool requireOrder, bool &isError, const bool isFTB)
+{
+	VersionFile out;
+	isError = true;
+	if (doc.isEmpty() || doc.isNull())
+	{
+		QLOG_ERROR() << filename << "is empty or null";
+		return out;
+	}
+	if (!doc.isObject())
+	{
+		QLOG_ERROR() << "The root of" << filename << "is not an object";
+		return out;
+	}
+
+	QJsonObject root = doc.object();
+
+	if (requireOrder)
+	{
+		if (root.contains("order"))
+		{
+			if (root.value("order").isDouble())
+			{
+				out.order = root.value("order").toDouble();
+			}
+			else
+			{
+				QLOG_ERROR() << "'order' field contains an invalid value in" << filename;
+				return out;
+			}
+		}
+		else
+		{
+			QLOG_ERROR() << filename << "doesn't contain an order field";
+		}
+	}
+
+	out.name = root.value("name").toString();
+	out.fileId = root.value("fileId").toString();
+	out.version = root.value("version").toString();
+	out.mcVersion = root.value("mcVersion").toString();
+	out.filename = filename;
+
+	auto readString = [root, filename](const QString & key, QString & variable)
+	{
+		if (root.contains(key))
+		{
+			QJsonValue val = root.value(key);
+			if (!val.isString())
+			{
+				QLOG_WARN() << key << "is not a string in" << filename << "(skipping)";
+			}
+			else
+			{
+				variable = val.toString();
+			}
+		}
+	};
+
+	// FTB id attribute is completely bogus. We ignore it.
+	if (!isFTB)
+	{
+		readString("id", out.id);
+	}
+
+	readString("mainClass", out.mainClass);
+	readString("processArguments", out.processArguments);
+	readString("minecraftArguments", out.overwriteMinecraftArguments);
+	readString("+minecraftArguments", out.addMinecraftArguments);
+	readString("-minecraftArguments", out.removeMinecraftArguments);
+	readString("type", out.type);
+	readString("releaseTime", out.releaseTime);
+	readString("time", out.time);
+	readString("assets", out.assets);
+	if (root.contains("minimumLauncherVersion"))
+	{
+		QJsonValue val = root.value("minimumLauncherVersion");
+		if (!val.isDouble())
+		{
+			QLOG_WARN() << "minimumLauncherVersion is not an int in" << filename
+						<< "(skipping)";
+		}
+		else
+		{
+			out.minimumLauncherVersion = val.toDouble();
+		}
+	}
+
+	if (root.contains("tweakers"))
+	{
+		QJsonValue tweakersVal = root.value("tweakers");
+		if (!tweakersVal.isArray())
+		{
+			QLOG_ERROR() << filename << "contains a 'tweakers' field, but it's not an array";
+			return out;
+		}
+		out.shouldOverwriteTweakers = true;
+		QJsonArray tweakers = root.value("tweakers").toArray();
+		for (auto tweakerVal : tweakers)
+		{
+			if (!tweakerVal.isString())
+			{
+				QLOG_ERROR() << filename
+							 << "contains a 'tweakers' field entry that's not a string";
+				return out;
+			}
+			out.overwriteTweakers.append(tweakerVal.toString());
+		}
+	}
+	if (root.contains("+tweakers"))
+	{
+		QJsonValue tweakersVal = root.value("+tweakers");
+		if (!tweakersVal.isArray())
+		{
+			QLOG_ERROR() << filename << "contains a '+tweakers' field, but it's not an array";
+			return out;
+		}
+		QJsonArray tweakers = root.value("+tweakers").toArray();
+		for (auto tweakerVal : tweakers)
+		{
+			if (!tweakerVal.isString())
+			{
+				QLOG_ERROR() << filename
+							 << "contains a '+tweakers' field entry that's not a string";
+				return out;
+			}
+			out.addTweakers.append(tweakerVal.toString());
+		}
+	}
+	if (root.contains("-tweakers"))
+	{
+		QJsonValue tweakersVal = root.value("-tweakers");
+		if (!tweakersVal.isArray())
+		{
+			QLOG_ERROR() << filename << "contains a '-tweakers' field, but it's not an array";
+			return out;
+		}
+		out.shouldOverwriteTweakers = true;
+		QJsonArray tweakers = root.value("-tweakers").toArray();
+		for (auto tweakerVal : tweakers)
+		{
+			if (!tweakerVal.isString())
+			{
+				QLOG_ERROR() << filename
+							 << "contains a '-tweakers' field entry that's not a string";
+				return out;
+			}
+			out.removeTweakers.append(tweakerVal.toString());
+		}
+	}
+
+	if (root.contains("libraries"))
+	{
+		out.shouldOverwriteLibs = !isFTB;
+		QJsonValue librariesVal = root.value("libraries");
+		if (!librariesVal.isArray())
+		{
+			QLOG_ERROR() << filename << "contains a 'libraries' field, but its not an array";
+			return out;
+		}
+		QJsonArray librariesArray = librariesVal.toArray();
+		for (auto libVal : librariesArray)
+		{
+			if (!libVal.isObject())
+			{
+				QLOG_ERROR() << filename << "contains a library that's not an object";
+				return out;
+			}
+			QJsonObject libObj = libVal.toObject();
+			bool error;
+			Library lib = Library::fromJson(libObj, filename, error);
+			if (error)
+			{
+				QLOG_ERROR() << "Error while reading a library entry in" << filename;
+				return out;
+			}
+			if (isFTB)
+			{
+				lib.hint = "local";
+				lib.insertType = Library::Prepend;
+				out.addLibs.prepend(lib);
+			}
+			else
+			{
+				out.overwriteLibs.append(lib);
+			}
+		}
+	}
+	if (root.contains("+libraries"))
+	{
+		QJsonValue librariesVal = root.value("+libraries");
+		if (!librariesVal.isArray())
+		{
+			QLOG_ERROR() << filename << "contains a '+libraries' field, but its not an array";
+			return out;
+		}
+		QJsonArray librariesArray = librariesVal.toArray();
+		for (auto libVal : librariesArray)
+		{
+			if (!libVal.isObject())
+			{
+				QLOG_ERROR() << filename << "contains a library that's not an object";
+				return out;
+			}
+			QJsonObject libObj = libVal.toObject();
+			bool error;
+			Library lib = Library::fromJson(libObj, filename, error);
+			if (error)
+			{
+				QLOG_ERROR() << "Error while reading a library entry in" << filename;
+				return out;
+			}
+			if (!libObj.contains("insert"))
+			{
+				QLOG_ERROR() << "Missing 'insert' field in '+libraries' field in" << filename;
+				return out;
+			}
+			QJsonValue insertVal = libObj.value("insert");
+			QString insertString;
+			{
+				if (insertVal.isString())
+				{
+					insertString = insertVal.toString();
+				}
+				else if (insertVal.isObject())
+				{
+					QJsonObject insertObj = insertVal.toObject();
+					if (insertObj.isEmpty())
+					{
+						QLOG_ERROR() << "One library has an empty insert object in" << filename;
+						return out;
+					}
+					insertString = insertObj.keys().first();
+					lib.insertData = insertObj.value(insertString).toString();
+				}
+			}
+			if (insertString == "apply")
+			{
+				lib.insertType = Library::Apply;
+			}
+			else if (insertString == "prepend")
+			{
+				lib.insertType = Library::Prepend;
+			}
+			else if (insertString == "append")
+			{
+				lib.insertType = Library::Prepend;
+			}
+			else if (insertString == "replace")
+			{
+				lib.insertType = Library::Replace;
+			}
+			else
+			{
+				QLOG_ERROR() << "A '+' library in" << filename
+							 << "contains an invalid insert type";
+				return out;
+			}
+			if (libObj.contains("MMC-depend") && libObj.value("MMC-depend").isString())
+			{
+				const QString dependString = libObj.value("MMC-depend").toString();
+				if (dependString == "hard")
+				{
+					lib.dependType = Library::Hard;
+				}
+				else if (dependString == "soft")
+				{
+					lib.dependType = Library::Soft;
+				}
+				else
+				{
+					QLOG_ERROR() << "A '+' library in" << filename
+								 << "contains an invalid depend type";
+					return out;
+				}
+			}
+			out.addLibs.append(lib);
+		}
+	}
+	if (root.contains("-libraries"))
+	{
+		QJsonValue librariesVal = root.value("-libraries");
+		if (!librariesVal.isArray())
+		{
+			QLOG_ERROR() << filename << "contains a '-libraries' field, but its not an array";
+			return out;
+		}
+		QJsonArray librariesArray = librariesVal.toArray();
+		for (auto libVal : librariesArray)
+		{
+			if (!libVal.isObject())
+			{
+				QLOG_ERROR() << filename << "contains a library that's not an object";
+				return out;
+			}
+			QJsonObject libObj = libVal.toObject();
+			if (!libObj.contains("name"))
+			{
+				QLOG_ERROR() << filename << "contains a library without a name";
+				return out;
+			}
+			if (!libObj.value("name").isString())
+			{
+				QLOG_ERROR() << filename << "contains a library without a valid 'name' field";
+				return out;
+			}
+			out.removeLibs.append(libObj.value("name").toString());
+		}
+	}
+
+	isError = false;
+	return out;
+}
+
+std::shared_ptr<OneSixLibrary> VersionFile::createLibrary(const VersionFile::Library &lib)
+{
+	std::shared_ptr<OneSixLibrary> out(new OneSixLibrary(lib.name));
+	if (!lib.url.isEmpty())
+	{
+		out->setBaseUrl(lib.url);
+	}
+	out->setHint(lib.hint);
+	if (!lib.absoluteUrl.isEmpty())
+	{
+		out->setAbsoluteUrl(lib.absoluteUrl);
+	}
+	out->setAbsoluteUrl(lib.absoluteUrl);
+	out->extract_excludes = lib.excludes;
+	for (auto native : lib.natives)
+	{
+		out->addNative(native.first, native.second);
+	}
+	out->setRules(lib.rules);
+	out->finalize();
+	return out;
+}
+
+int VersionFile::findLibrary(QList<std::shared_ptr<OneSixLibrary>> haystack,
+							 const QString &needle)
+{
+	for (int i = 0; i < haystack.size(); ++i)
+	{
+		if (QRegExp(needle, Qt::CaseSensitive, QRegExp::WildcardUnix)
+				.indexIn(haystack.at(i)->rawName()) != -1)
+		{
+			return i;
+		}
+	}
+	return -1;
+}
+
+VersionFile::ApplyError VersionFile::applyTo(VersionFinal *version)
+{
+	if (minimumLauncherVersion != -1)
+	{
+		if (minimumLauncherVersion > CURRENT_MINIMUM_LAUNCHER_VERSION)
+		{
+			QLOG_ERROR() << filename << "is for a different launcher version ("
+						 << minimumLauncherVersion << "), current supported is"
+						 << CURRENT_MINIMUM_LAUNCHER_VERSION;
+			return LauncherVersionError;
+		}
+	}
+
+	if (!version->id.isNull() && !mcVersion.isNull())
+	{
+		if (QRegExp(mcVersion, Qt::CaseInsensitive, QRegExp::Wildcard).indexIn(version->id) ==
+			-1)
+		{
+			QLOG_ERROR() << filename << "is for a different version of Minecraft";
+			return OtherError;
+		}
+	}
+
+	if (!id.isNull())
+	{
+		version->id = id;
+	}
+	if (!mainClass.isNull())
+	{
+		version->mainClass = mainClass;
+	}
+	if (!processArguments.isNull())
+	{
+		version->processArguments = processArguments;
+	}
+	if (!type.isNull())
+	{
+		version->type = type;
+	}
+	if (!releaseTime.isNull())
+	{
+		version->releaseTime = releaseTime;
+	}
+	if (!time.isNull())
+	{
+		version->time = time;
+	}
+	if (!assets.isNull())
+	{
+		version->assets = assets;
+	}
+	if (minimumLauncherVersion >= 0)
+	{
+		version->minimumLauncherVersion = minimumLauncherVersion;
+	}
+	if (!overwriteMinecraftArguments.isNull())
+	{
+		version->minecraftArguments = overwriteMinecraftArguments;
+	}
+	if (!addMinecraftArguments.isNull())
+	{
+		version->minecraftArguments += addMinecraftArguments;
+	}
+	if (!removeMinecraftArguments.isNull())
+	{
+		version->minecraftArguments.remove(removeMinecraftArguments);
+	}
+	if (shouldOverwriteTweakers)
+	{
+		version->tweakers = overwriteTweakers;
+	}
+	for (auto tweaker : addTweakers)
+	{
+		version->tweakers += tweaker;
+	}
+	for (auto tweaker : removeTweakers)
+	{
+		version->tweakers.removeAll(tweaker);
+	}
+	if (shouldOverwriteLibs)
+	{
+		version->libraries.clear();
+		for (auto lib : overwriteLibs)
+		{
+			version->libraries.append(createLibrary(lib));
+		}
+	}
+	for (auto lib : addLibs)
+	{
+		switch (lib.insertType)
+		{
+		case Library::Apply:
+		{
+
+			int index = findLibrary(version->libraries, lib.name);
+			if (index >= 0)
+			{
+				auto library = version->libraries[index];
+				if (!lib.url.isNull())
+				{
+					library->setBaseUrl(lib.url);
+				}
+				if (!lib.hint.isNull())
+				{
+					library->setHint(lib.hint);
+				}
+				if (!lib.absoluteUrl.isNull())
+				{
+					library->setAbsoluteUrl(lib.absoluteUrl);
+				}
+				if (lib.applyExcludes)
+				{
+					library->extract_excludes = lib.excludes;
+				}
+				if (lib.applyNatives)
+				{
+					library->clearSuffixes();
+					for (auto native : lib.natives)
+					{
+						library->addNative(native.first, native.second);
+					}
+				}
+				if (lib.applyRules)
+				{
+					library->setRules(lib.rules);
+				}
+				library->finalize();
+			}
+			else
+			{
+				QLOG_WARN() << "Couldn't find" << lib.insertData << "(skipping)";
+			}
+			break;
+		}
+		case Library::Append:
+		case Library::Prepend:
+		{
+
+			const int startOfVersion = lib.name.lastIndexOf(':') + 1;
+			const int index = findLibrary(
+				version->libraries, QString(lib.name).replace(startOfVersion, INT_MAX, '*'));
+			if (index < 0)
+			{
+				if (lib.insertType == Library::Append)
+				{
+					version->libraries.append(createLibrary(lib));
+				}
+				else
+				{
+					version->libraries.prepend(createLibrary(lib));
+				}
+			}
+			else
+			{
+				auto otherLib = version->libraries.at(index);
+				const Util::Version ourVersion = lib.name.mid(startOfVersion, INT_MAX);
+				const Util::Version otherVersion = otherLib->version();
+				// if the existing version is a hard dependency we can either use it or
+				// fail, but we can't change it
+				if (otherLib->dependType == OneSixLibrary::Hard)
+				{
+					// we need a higher version, or we're hard to and the versions aren't
+					// equal
+					if (ourVersion > otherVersion ||
+						(lib.dependType == Library::Hard && ourVersion != otherVersion))
+					{
+						QLOG_ERROR() << "Error resolving library dependencies between"
+									 << otherLib->rawName() << "and" << lib.name << "in"
+									 << filename;
+						return OtherError;
+					}
+					else
+					{
+						// the library is already existing, so we don't have to do anything
+					}
+				}
+				else if (otherLib->dependType == OneSixLibrary::Soft)
+				{
+					// if we are higher it means we should update
+					if (ourVersion > otherVersion)
+					{
+						auto library = createLibrary(lib);
+						if (Util::Version(otherLib->minVersion) < ourVersion)
+						{
+							library->minVersion = ourVersion.toString();
+						}
+						version->libraries.replace(index, library);
+					}
+					else
+					{
+						// our version is smaller than the existing version, but we require
+						// it: fail
+						if (lib.dependType == Library::Hard)
+						{
+							QLOG_ERROR() << "Error resolving library dependencies between"
+										 << otherLib->rawName() << "and" << lib.name << "in"
+										 << filename;
+							return OtherError;
+						}
+					}
+				}
+			}
+			break;
+		}
+		case Library::Replace:
+		{
+			int index = findLibrary(version->libraries, lib.insertData);
+			if (index >= 0)
+			{
+				version->libraries.replace(index, createLibrary(lib));
+			}
+			else
+			{
+				QLOG_WARN() << "Couldn't find" << lib.insertData << "(skipping)";
+			}
+			break;
+		}
+		}
+	}
+	for (auto lib : removeLibs)
+	{
+		int index = findLibrary(version->libraries, lib);
+		if (index >= 0)
+		{
+			version->libraries.removeAt(index);
+		}
+		else
+		{
+			QLOG_WARN() << "Couldn't find" << lib << "(skipping)";
+		}
+	}
+
+	VersionFinal::VersionFile versionFile;
+	versionFile.name = name;
+	versionFile.id = fileId;
+	versionFile.version = this->version;
+	versionFile.mcVersion = mcVersion;
+	versionFile.filename = filename;
+	versionFile.order = order;
+	version->versionFiles.append(versionFile);
+
+	return NoApplyError;
+}
diff --git a/logic/VersionFile.h b/logic/VersionFile.h
new file mode 100644
index 00000000..04694999
--- /dev/null
+++ b/logic/VersionFile.h
@@ -0,0 +1,90 @@
+#pragma once
+
+#include <QString>
+#include <QStringList>
+#include <memory>
+#include "logic/OpSys.h"
+#include "logic/OneSixRule.h"
+class VersionFinal;
+
+struct VersionFile
+{
+	int order;
+	QString name;
+	QString fileId;
+	QString version;
+	// TODO use the mcVersion to determine if a version file should be removed on update
+	QString mcVersion;
+	QString filename;
+	// TODO requirements
+	// QMap<QString, QString> requirements;
+	QString id;
+	QString mainClass;
+	QString overwriteMinecraftArguments;
+	QString addMinecraftArguments;
+	QString removeMinecraftArguments;
+	QString processArguments;
+	QString type;
+	QString releaseTime;
+	QString time;
+	QString assets;
+	int minimumLauncherVersion = -1;
+
+	bool shouldOverwriteTweakers = false;
+	QStringList overwriteTweakers;
+	QStringList addTweakers;
+	QStringList removeTweakers;
+
+	struct Library
+	{
+		QString name;
+		QString url;
+		QString hint;
+		QString absoluteUrl;
+		bool applyExcludes = false;
+		QStringList excludes;
+		bool applyNatives = false;
+		QList<QPair<OpSys, QString>> natives;
+		bool applyRules = false;
+		QList<std::shared_ptr<Rule>> rules;
+
+		// user for '+' libraries
+		enum InsertType
+		{
+			Apply,
+			Append,
+			Prepend,
+			Replace
+		};
+		InsertType insertType = Append;
+		QString insertData;
+		enum DependType
+		{
+			Soft,
+			Hard
+		};
+		DependType dependType = Soft;
+
+		static Library fromJson(const QJsonObject &libObj, const QString &filename,
+								bool &isError);
+	};
+	bool shouldOverwriteLibs = false;
+	QList<Library> overwriteLibs;
+	QList<Library> addLibs;
+	QList<QString> removeLibs;
+
+	enum ApplyError
+	{
+		LauncherVersionError,
+		OtherError,
+		NoApplyError
+	};
+
+	static VersionFile fromJson(const QJsonDocument &doc, const QString &filename,
+								const bool requireOrder, bool &isError,
+								const bool isFTB = false);
+
+	static std::shared_ptr<OneSixLibrary> createLibrary(const Library &lib);
+	int findLibrary(QList<std::shared_ptr<OneSixLibrary>> haystack, const QString &needle);
+	ApplyError applyTo(VersionFinal *version);
+};
\ No newline at end of file
diff --git a/logic/OneSixVersion.cpp b/logic/VersionFinal.cpp
index 06e748bd..ce78e8e3 100644
--- a/logic/OneSixVersion.cpp
+++ b/logic/VersionFinal.cpp
@@ -13,20 +13,20 @@
  * limitations under the License.
  */
 
-#include "OneSixVersion.h"
+#include "VersionFinal.h"
 
 #include <QDebug>
 #include <QFile>
 
 #include "OneSixVersionBuilder.h"
 
-OneSixVersion::OneSixVersion(OneSixInstance *instance, QObject *parent)
+VersionFinal::VersionFinal(OneSixInstance *instance, QObject *parent)
 	: QAbstractListModel(parent), m_instance(instance)
 {
 	clear();
 }
 
-bool OneSixVersion::reload(QWidget *widgetParent, const bool onlyVanilla, const QStringList &external)
+bool VersionFinal::reload(QWidget *widgetParent, const bool onlyVanilla, const QStringList &external)
 {
 	beginResetModel();
 	bool ret = OneSixVersionBuilder::build(this, m_instance, widgetParent, onlyVanilla, external);
@@ -34,7 +34,7 @@ bool OneSixVersion::reload(QWidget *widgetParent, const bool onlyVanilla, const
 	return ret;
 }
 
-void OneSixVersion::clear()
+void VersionFinal::clear()
 {
 	beginResetModel();
 	id.clear();
@@ -52,9 +52,9 @@ void OneSixVersion::clear()
 	endResetModel();
 }
 
-void OneSixVersion::dump() const
+void VersionFinal::dump() const
 {
-	qDebug().nospace() << "OneSixVersion("
+	qDebug().nospace() << "VersionFinal("
 				  << "\n\tid=" << id
 				  << "\n\ttime=" << time
 				  << "\n\treleaseTime=" << releaseTime
@@ -72,7 +72,7 @@ void OneSixVersion::dump() const
 	qDebug().nospace() << "\n)";
 }
 
-bool OneSixVersion::canRemove(const int index) const
+bool VersionFinal::canRemove(const int index) const
 {
 	if (index < versionFiles.size())
 	{
@@ -81,7 +81,7 @@ bool OneSixVersion::canRemove(const int index) const
 	return false;
 }
 
-QString OneSixVersion::versionFileId(const int index) const
+QString VersionFinal::versionFileId(const int index) const
 {
 	if (index < 0 || index >= versionFiles.size())
 	{
@@ -90,7 +90,7 @@ QString OneSixVersion::versionFileId(const int index) const
 	return versionFiles.at(index).id;
 }
 
-bool OneSixVersion::remove(const int index)
+bool VersionFinal::remove(const int index)
 {
 	if (canRemove(index))
 	{
@@ -99,7 +99,7 @@ bool OneSixVersion::remove(const int index)
 	return false;
 }
 
-QList<std::shared_ptr<OneSixLibrary> > OneSixVersion::getActiveNormalLibs()
+QList<std::shared_ptr<OneSixLibrary> > VersionFinal::getActiveNormalLibs()
 {
 	QList<std::shared_ptr<OneSixLibrary> > output;
 	for (auto lib : libraries)
@@ -112,7 +112,7 @@ QList<std::shared_ptr<OneSixLibrary> > OneSixVersion::getActiveNormalLibs()
 	return output;
 }
 
-QList<std::shared_ptr<OneSixLibrary> > OneSixVersion::getActiveNativeLibs()
+QList<std::shared_ptr<OneSixLibrary> > VersionFinal::getActiveNativeLibs()
 {
 	QList<std::shared_ptr<OneSixLibrary> > output;
 	for (auto lib : libraries)
@@ -125,17 +125,17 @@ QList<std::shared_ptr<OneSixLibrary> > OneSixVersion::getActiveNativeLibs()
 	return output;
 }
 
-std::shared_ptr<OneSixVersion> OneSixVersion::fromJson(const QJsonObject &obj)
+std::shared_ptr<VersionFinal> VersionFinal::fromJson(const QJsonObject &obj)
 {
-	std::shared_ptr<OneSixVersion> version(new OneSixVersion(0));
-	if (OneSixVersionBuilder::read(version.get(), obj))
+	std::shared_ptr<VersionFinal> version(new VersionFinal(0));
+	if (OneSixVersionBuilder::readJsonAndApplyToVersion(version.get(), obj))
 	{
 		return version;
 	}
 	return 0;
 }
 
-QVariant OneSixVersion::data(const QModelIndex &index, int role) const
+QVariant VersionFinal::data(const QModelIndex &index, int role) const
 {
 	if (!index.isValid())
 		return QVariant();
@@ -161,7 +161,7 @@ QVariant OneSixVersion::data(const QModelIndex &index, int role) const
 	return QVariant();
 }
 
-QVariant OneSixVersion::headerData(int section, Qt::Orientation orientation, int role) const
+QVariant VersionFinal::headerData(int section, Qt::Orientation orientation, int role) const
 {
 	if (orientation == Qt::Horizontal)
 	{
@@ -181,24 +181,24 @@ QVariant OneSixVersion::headerData(int section, Qt::Orientation orientation, int
 	return QVariant();
 }
 
-Qt::ItemFlags OneSixVersion::flags(const QModelIndex &index) const
+Qt::ItemFlags VersionFinal::flags(const QModelIndex &index) const
 {
 	if (!index.isValid())
 		return Qt::NoItemFlags;
 	return Qt::ItemIsSelectable | Qt::ItemIsEnabled;
 }
 
-int OneSixVersion::rowCount(const QModelIndex &parent) const
+int VersionFinal::rowCount(const QModelIndex &parent) const
 {
 	return versionFiles.size();
 }
 
-int OneSixVersion::columnCount(const QModelIndex &parent) const
+int VersionFinal::columnCount(const QModelIndex &parent) const
 {
 	return 2;
 }
 
-QDebug operator<<(QDebug &dbg, const OneSixVersion *version)
+QDebug operator<<(QDebug &dbg, const VersionFinal *version)
 {
 	version->dump();
 	return dbg.maybeSpace();
diff --git a/logic/OneSixVersion.h b/logic/VersionFinal.h
index fee47fa3..c9a5f469 100644
--- a/logic/OneSixVersion.h
+++ b/logic/VersionFinal.h
@@ -25,11 +25,11 @@
 
 class OneSixInstance;
 
-class OneSixVersion : public QAbstractListModel
+class VersionFinal : public QAbstractListModel
 {
 	Q_OBJECT
 public:
-	explicit OneSixVersion(OneSixInstance *instance, QObject *parent = 0);
+	explicit VersionFinal(OneSixInstance *instance, QObject *parent = 0);
 
 	virtual QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
 	virtual QVariant headerData(int section, Qt::Orientation orientation, int role) const;
@@ -54,7 +54,7 @@ public:
 	QList<std::shared_ptr<OneSixLibrary>> getActiveNormalLibs();
 	QList<std::shared_ptr<OneSixLibrary>> getActiveNativeLibs();
 
-	static std::shared_ptr<OneSixVersion> fromJson(const QJsonObject &obj);
+	static std::shared_ptr<VersionFinal> fromJson(const QJsonObject &obj);
 
 	// data members
 public:
@@ -133,5 +133,5 @@ private:
 	OneSixInstance *m_instance;
 };
 
-QDebug operator<<(QDebug &dbg, const OneSixVersion *version);
+QDebug operator<<(QDebug &dbg, const VersionFinal *version);
 QDebug operator<<(QDebug &dbg, const OneSixLibrary *library);