feat(RD): add texture pack downloader

This extends the resource pack downloader, with the custom behavior of
filtering the versions that shows up, to those <= 1.6. As always, Flame
is funky and requires a bit more workarounds than average.

This will also get a nice improvement when the Version parsing and
comparison PR gets merged! :D

Signed-off-by: flow <flowlnlnln@gmail.com>

launcher/ui/pages/modplatform/TexturePackModel.cpp

@@ -0,0 +1,80 @@
+#include "TexturePackModel.h"
+
+#include "Application.h"
+
+#include "meta/Index.h"
+#include "meta/Version.h"
+
+static std::list<Version> s_availableVersions = {};
+
+namespace ResourceDownload {
+TexturePackResourceModel::TexturePackResourceModel(BaseInstance const& inst, ResourceAPI* api)
+    : ResourcePackResourceModel(inst, api), m_version_list(APPLICATION->metadataIndex()->get("net.minecraft"))
+{
+    if (!m_version_list->isLoaded()) {
+        qDebug() << "Loading version list...";
+        auto task = m_version_list->getLoadTask();
+        if (!task->isRunning())
+            task->start();
+    }
+}
+
+void waitOnVersionListLoad(Meta::VersionList::Ptr version_list)
+{
+    QEventLoop load_version_list_loop;
+
+    QTimer time_limit_for_list_load;
+    time_limit_for_list_load.setTimerType(Qt::TimerType::CoarseTimer);
+    time_limit_for_list_load.setSingleShot(true);
+    time_limit_for_list_load.callOnTimeout(&load_version_list_loop, &QEventLoop::quit);
+    time_limit_for_list_load.start(4000);
+
+    auto task = version_list->getLoadTask();
+    QObject::connect(task.get(), &Task::finished, &load_version_list_loop, &QEventLoop::quit);
+
+    load_version_list_loop.exec();
+    if (time_limit_for_list_load.isActive())
+        time_limit_for_list_load.stop();
+}
+
+ResourceAPI::SearchArgs TexturePackResourceModel::createSearchArguments()
+{
+    if (s_availableVersions.empty())
+        waitOnVersionListLoad(m_version_list);
+
+    auto args = ResourcePackResourceModel::createSearchArguments();
+
+    if (!m_version_list->isLoaded()) {
+        qCritical() << "The version list could not be loaded. Falling back to showing all entries.";
+        return args;
+    }
+
+    if (s_availableVersions.empty()) {
+        for (auto&& version : m_version_list->versions()) {
+            // FIXME: This duplicates the logic in meta for the 'texturepacks' trait. However, we don't have access to that
+            //        information from the index file alone. Also, downloading every version's file isn't a very good idea.
+            if (auto ver = version->toComparableVersion(); ver <= maximumTexturePackVersion())
+                s_availableVersions.push_back(ver);
+        }
+    }
+
+    Q_ASSERT(!s_availableVersions.empty());
+
+    args.versions = s_availableVersions;
+
+    return args;
+}
+
+ResourceAPI::VersionSearchArgs TexturePackResourceModel::createVersionsArguments(QModelIndex& entry)
+{
+    auto args = ResourcePackResourceModel::createVersionsArguments(entry);
+    if (!m_version_list->isLoaded()) {
+        qCritical() << "The version list could not be loaded. Falling back to showing all entries.";
+        return args;
+    }
+
+    args.mcVersions = s_availableVersions;
+    return args;
+}
+
+}  // namespace ResourceDownload