#include "SampleManager.h"

#include "ExecutionTime.h"
#include "Misc/AronaConfig.h"

FArchive& operator<<(FArchive& Ar, FSamplePathNode* In)
{
	return *In << Ar;
}

FSamplePathNode* FSamplePathNode::Create(const FString& Path)
{
	if (!FPaths::DirectoryExists(Path))
		return nullptr;

	FSamplePathNode* Root = new FSamplePathNode();
	Root->Value = Path;
	Root->NodeType = Type::Directory;
	Root->Parent = nullptr;

	class FSamplePathVisitor : public IPlatformFile::FDirectoryStatVisitor
	{
	public:
		FSamplePathVisitor(FSamplePathNode* InRoot) : Root(InRoot)
		{
			
		}
		virtual bool Visit(const TCHAR* FilenameOrDirectory, const FFileStatData& StatData) override
		{
			if (!StatData.bIsDirectory)
			{
				const FString& FilePath = FPaths::GetPath(FilenameOrDirectory);
				auto* PathNode = Root->GetNodeByPath(FilePath);
				if (!PathNode)
				{
					PathNode = Root->CreateNodeByPath(FilePath);
				}
				FSamplePathNode* SamplePathNode = PathNode->AddChild();
				SamplePathNode->NodeType = Type::File;
				SamplePathNode->Value = FPaths::GetCleanFilename(FilenameOrDirectory);
				return true;
			}
			Root->CreateNodeByPath(FilenameOrDirectory);
			return true;
		}
		FSamplePathNode* Root;
	} Visitor(Root);
	
	IPlatformFile::GetPlatformPhysical().IterateDirectoryStatRecursively(*Path, Visitor);
	return Root;
}

FSamplePathNode* FSamplePathNode::AddChild()
{
	FSamplePathNode* ChildNode = new FSamplePathNode();
	ChildNode->Parent = this;
	Child.Add(ChildNode);
	return ChildNode;
}

FSamplePathNode* FSamplePathNode::GetNodeByPath(const FString& Path)
{
	if (FPaths::IsSamePath(Path, GetFullPath()))
		return this;
	if (FSamplePathNode** Node = GetRootNode()->ChildMap.Find(Path))
		return *Node;
	return nullptr;
}

FSamplePathNode* FSamplePathNode::CreateNodeByPath(FString Path)
{
	const FString& FullPath = GetFullPath();
	if (FullPath == Path)
		return this;
	TArray<FString> Paths;
	FString Leaf;
	do
	{
		FString Temp = FPaths::GetPathLeaf(Path);
		if (Temp == Leaf)
			break;
		Leaf = Temp;
		Paths.Add(Path);
		Path = FPaths::GetPath(Path);
		if (Path == FullPath)
			break;
	}
	while (true);
	Algo::Reverse(Paths);
	return CreateNodeByPathInternal(Paths);
}

FSamplePathNode* FSamplePathNode::CreateNodeByPathInternal(const TArray<FString>& Paths)
{
	FSamplePathNode* RootNode = GetRootNode();
	for (auto Str : Paths)
	{
		FSamplePathNode* PathNode = GetNodeByPath(Str);
		if (!PathNode)
		{
			PathNode = AddChild();
			PathNode->Value = FPaths::GetPathLeaf(Str);
			PathNode->NodeType = Directory;
			RootNode->ChildMap.Add(Str, PathNode);
		}
	}
	return GetNodeByPath(Paths[0]);
}

bool FSampleDirectoryCache::NeedRefresh()
{
	if (!FPaths::FileExists(*GetCachePath()))
		return true;
	TArray<FString> PathsStr;
	FAronaConfig::GetValueArray("Sample", "Path", PathsStr);
	if (PathsStr.Num() != SamplePathNodes.Num())
		return true;
	// TODO: 比较路径是否相同
	return false;
}

void FSampleDirectoryCache::Init()
{
	Reload();
	if (NeedRefresh())
	{
		Refresh();
	}
}

void FSampleDirectoryCache::Reload()
{
	Clear();
	TArray<uint8> Data;
	if (!FFileHelper::LoadFileToArray(Data, *GetCachePath()))
		return;
	FMemoryReader MemoryReader(Data);
	Serialize(MemoryReader);
	Save();
}

void FSampleDirectoryCache::Refresh()
{
	if (Loading || !NeedRefresh())
		return;
	
	Async(EAsyncExecution::Thread, [this]()
	{
		Loading = true;
		RegenCache();
		Loading = false;
	});
}

void FSampleDirectoryCache::RegenCache()
{
	DeleteCache();
	
	FAronaConfig::GetValueArray("Sample", "Path", SamplePaths);
	for (auto Str : SamplePaths)
	{
		if (FSamplePathNode* SamplePathNode = FSamplePathNode::Create(Str))
			SamplePathNodes.Add(SamplePathNode);
	}
	Save();
}

bool FSampleDirectoryCache::Save()
{
	TArray<uint8> Data;
	FMemoryWriter MemoryWriter(Data);
	Serialize(MemoryWriter);
	return FFileHelper::SaveArrayToFile(Data, *GetCachePath()); 
}

void FSampleDirectoryCache::Clear()
{
	for (const auto PathNode : SamplePathNodes)
	{
		delete PathNode;
	}
	SamplePathNodes.Empty();
}

void FSampleManager::Init()
{
	Cache.Init();
}

void FSampleManager::Refresh()
{
	Cache.Refresh();
}

void FSampleDirectoryCache::DeleteCache()
{
	IPlatformFile::GetPlatformPhysical().DeleteFile(*GetCachePath());
}

FString FSampleDirectoryCache::GetCachePath()
{
	return FPaths::ProjectSavedDir() / TEXT("SampleCache");
}