#include "stdafx.h"
#include "SiaDokanDrive.h"
#include <dokan\dokan.h>
#include <bitset>

using namespace Sia::Api;
using namespace Sia::Api::Dokan;


class DokanImpl
{
private:
	static std::mutex _dokanMutex;
	static CSiaApi* _siaApi;
	static DOKAN_OPERATIONS _dokanOps;
	static String _cacheLocation;

private:
	static NTSTATUS DOKAN_CALLBACK SiaDrive_ZwCreateFile(
		LPCWSTR FileName,
		PDOKAN_IO_SECURITY_CONTEXT SecurityContext,
		ACCESS_MASK DesiredAccess,
		ULONG FileAttributes,
		ULONG ShareAccess,
		ULONG CreateDisposition,
		ULONG CreateOptions,
		PDOKAN_FILE_INFO DokanFileInfo)
	{
		SECURITY_ATTRIBUTES securityAttrib;
		securityAttrib.nLength = sizeof(securityAttrib);
		securityAttrib.lpSecurityDescriptor = SecurityContext->AccessState.SecurityDescriptor;
		securityAttrib.bInheritHandle = FALSE;

		DWORD fileAttributesAndFlags;
		DWORD creationDisposition;
		DokanMapKernelToUserCreateFileFlags(FileAttributes, CreateOptions, CreateDisposition, &fileAttributesAndFlags, &creationDisposition);
		
		ACCESS_MASK genericDesiredAccess = DokanMapStandardToGenericAccess(DesiredAccess);

		NTSTATUS ret = STATUS_SUCCESS;
		bool isFile = (fileAttributesAndFlags & FILE_NON_DIRECTORY_FILE);
		if (isFile)
		{
			// Formulate Sia path and cache path
			String siaPath = PathSkipRoot(FileName); // Strip drive letter to get Sia path

			String cacheFilePath;
			cacheFilePath.resize(MAX_PATH + 1);
			PathCombine(&cacheFilePath[0], _cacheLocation.c_str(), siaPath.c_str());

			// If cache file already exists and is a directory, file operation should fail
			if (GetFileAttributes(cacheFilePath.c_str()) & FILE_ATTRIBUTE_DIRECTORY)
			{
				ret = STATUS_OBJECT_NAME_COLLISION;
			}
			else
			{
				bool exists;
				if (API_SUCCESS(SiaApiError, _siaApi->GetRenter()->FileExists(siaPath, exists)))
				{
					bool isCreateOp = false;
					bool isReplaceOp = false;
					switch (creationDisposition)
					{
					case CREATE_ALWAYS:
					{
						isCreateOp = true;
						isReplaceOp = exists;
					}
					break;

					case CREATE_NEW:
					{
						if (exists)
						{
							ret = STATUS_OBJECT_NAME_EXISTS;
						}
						else
						{
							isCreateOp = true;
						}
					}
					break;

					case OPEN_ALWAYS:
					{
						if (!exists)
						{
							isCreateOp = true;
						}
					}
					break;

					case OPEN_EXISTING:
					{
						if (!exists)
						{
							ret = STATUS_NOT_FOUND;
						}
					}
					break;

					case TRUNCATE_EXISTING:
					{
						if (exists)
						{
							isCreateOp = isReplaceOp = true;
						}
						else
						{
							ret = STATUS_NOT_FOUND;
						}
					}
					break;
					}

					if (ret == STATUS_SUCCESS)
					{
						if (isReplaceOp)
						{
							if (!PathFileExists(cacheFilePath.c_str()) || ::DeleteFile(cacheFilePath.c_str()))
							{
								// Delete from Sia
								if (!API_SUCCESS(SiaApiError, _siaApi->GetRenter()->DeleteFile(siaPath)))
								{
									ret = STATUS_INVALID_SERVER_STATE;
								}
							}
							else
							{
								ret = DokanNtStatusFromWin32(GetLastError());
							}
						}

						if (ret == STATUS_SUCCESS)
						{
							// If file should exist, then check for it in cache location. If not found,
							//	it must be downloaded first and placed in cache
							if (!isCreateOp && !PathFileExists(cacheFilePath.c_str()))
							{
								// Download to temp location
								// Move to cache location
							}

							// Create file as specified
							HANDLE handle = CreateFile(
								cacheFilePath.c_str(),
								genericDesiredAccess,
								ShareAccess,
								&securityAttrib,
								creationDisposition,
								fileAttributesAndFlags,
								nullptr);
							if (handle == INVALID_HANDLE_VALUE)
							{
								ret = DokanNtStatusFromWin32(GetLastError());
							}
							else
							{
								DokanFileInfo->Context = reinterpret_cast<ULONG64>(handle); // save the file handle in Context
								/*if (creationDisposition == OPEN_ALWAYS ||
									  creationDisposition == CREATE_ALWAYS) {
									error = GetLastError();
									if (error == ERROR_ALREADY_EXISTS) {
									  DbgPrint(L"\tOpen an already existing file\n");
									  // Open succeed but we need to inform the driver
									  // that the file open and not created by returning STATUS_OBJECT_NAME_COLLISION
									  return STATUS_OBJECT_NAME_COLLISION;
									}
								  }*/
							}
						}
					}
				}
				else
				{
					ret = STATUS_INVALID_SERVER_STATE;
				}
			}
		}
		else // Folder Operation (cache operation only)
		{
			ret = STATUS_NOT_IMPLEMENTED;
		}
		
		return ret;
	}

	static NTSTATUS DOKAN_CALLBACK SiaDrive_FindFiles(
		LPCWSTR FileName,
		PFillFindData FillFindData,
		PDOKAN_FILE_INFO DokanFileInfo)
	{
		return 0;
	}

public:
	static void Initialize(CSiaApi* siaApi)
	{
		_siaApi = siaApi;
		_dokanOps.Cleanup = nullptr;
		_dokanOps.CloseFile = nullptr;
		_dokanOps.DeleteDirectory = nullptr;
		_dokanOps.DeleteFileW = nullptr;
		_dokanOps.FindFiles = SiaDrive_FindFiles;
		_dokanOps.FindFilesWithPattern = nullptr;
		_dokanOps.FindStreams = nullptr;
		_dokanOps.FlushFileBuffers = nullptr;
		_dokanOps.GetDiskFreeSpaceW = nullptr;
		_dokanOps.GetFileInformation = nullptr;
		_dokanOps.GetFileSecurityW = nullptr;
		_dokanOps.GetVolumeInformationW = nullptr;
		_dokanOps.LockFile = nullptr;
		_dokanOps.Mounted = nullptr;
		_dokanOps.MoveFileW = nullptr;
		_dokanOps.ReadFile = nullptr;
		_dokanOps.SetAllocationSize = nullptr;
		_dokanOps.SetEndOfFile = nullptr;
		_dokanOps.SetFileAttributesW = nullptr;
		_dokanOps.SetFileSecurityW = nullptr;
		_dokanOps.SetFileTime = nullptr;
		_dokanOps.UnlockFile = nullptr;
		_dokanOps.Unmounted = nullptr;
		_dokanOps.WriteFile = nullptr;
		_dokanOps.ZwCreateFile = SiaDrive_ZwCreateFile;
	}

	static void Shutdown()
	{
		_siaApi = nullptr;
		ZeroMemory(&_dokanOps, sizeof(_dokanOps));
	}

	static std::mutex& GetMutex()
	{
		return _dokanMutex;
	}

	static bool IsInitialized()
	{
		return _siaApi != nullptr;
	}
};
std::mutex DokanImpl::_dokanMutex;
CSiaApi* DokanImpl::_siaApi = nullptr;
DOKAN_OPERATIONS DokanImpl::_dokanOps;
String DokanImpl::_cacheLocation;


CSiaDokanDrive::CSiaDokanDrive(CSiaApi& siaApi) :
	_siaApi(siaApi),
	_Mounted(false)
{
	std::lock_guard<std::mutex> l(DokanImpl::GetMutex());
	if (DokanImpl::IsInitialized())
		throw SiaDokanDriveException("Sia drive has already been activated");
	
	DokanImpl::Initialize(&_siaApi);
}

CSiaDokanDrive::~CSiaDokanDrive()
{
	std::lock_guard<std::mutex> l(DokanImpl::GetMutex());
	Unmount();
	DokanImpl::Shutdown();
}

void CSiaDokanDrive::Mount(const wchar_t& driveLetter, const String& cacheLocation, const std::uint64_t& maxCacheSizeBytes)
{
}

void CSiaDokanDrive::Unmount(const bool& clearCache)
{
}