#include "ehs/io/FileMonitor_W32.h"
#include "ehs/Log.h"
#include "ehs/UTF.h"

#include <chrono>

namespace ehs
{
	FileMonitor::~FileMonitor()
	{
		if (!IsInitialized())
			return;

		if (!CloseHandle(hdl))
			EHS_LOG_INT(LogType::ERR, 0, "Failed to close file at file path, \"" + filePath + "\", with error #" + GetLastError() + ".");
	}

	FileMonitor::FileMonitor()
		: hdl(INVALID_HANDLE_VALUE), time{}
	{
	}

	FileMonitor::FileMonitor(Str_8 filePath)
		: BaseFileMonitor((Str_8&&)filePath), hdl(INVALID_HANDLE_VALUE), time{}
	{
		FileMonitor::Initialize();
	}

	FileMonitor::FileMonitor(FileMonitor&& fm) noexcept
		: BaseFileMonitor((BaseFileMonitor&&)fm), hdl(fm.hdl), time(fm.time)
	{
		fm.hdl = INVALID_HANDLE_VALUE;
		fm.time = {};
	}

	FileMonitor::FileMonitor(const FileMonitor& fm)
		: BaseFileMonitor(fm), hdl(INVALID_HANDLE_VALUE), time{}
	{
		FileMonitor::Initialize();
	}

	FileMonitor& FileMonitor::operator=(FileMonitor&& fm) noexcept
	{
		if (this == &fm)
			return *this;

		Release();

		BaseFileMonitor::operator=((BaseFileMonitor&&)fm);

		hdl = fm.hdl;
		time = fm.time;

		fm.hdl = INVALID_HANDLE_VALUE;
		fm.time = {};

		return *this;
	}

	FileMonitor& FileMonitor::operator=(const FileMonitor& fm)
	{
		if (this == &fm)
			return *this;

		Release();

		BaseFileMonitor::operator=(fm);

		hdl = INVALID_HANDLE_VALUE;
		time = {};

		Initialize();

		return *this;
	}

	void FileMonitor::Initialize()
	{
		if (!IsValid() || IsInitialized())
			return;

		hdl = CreateFileW(UTF::To_16(filePath), GENERIC_READ, FILE_SHARE_READ,
			nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
		if (hdl == INVALID_HANDLE_VALUE)
			EHS_LOG_INT(LogType::ERR, 0, "Failed to open file at file path, \"" + filePath + "\", with error #" + GetLastError() + ".");
	}

	void FileMonitor::Release()
	{
		if (!IsValid() || !IsInitialized())
			return;

		if (!CloseHandle(hdl))
			EHS_LOG_INT(LogType::ERR, 0, "Failed to close file at file path, \"" + filePath + "\", with error #" + GetLastError() + ".");

		hdl = INVALID_HANDLE_VALUE;
	}

	UInt_8 FileMonitor::Poll()
	{
		UInt_8 mask = EHS_FE_NONE;

		FILETIME lastWriteTime = {};
		if (!GetFileTime(hdl, nullptr, nullptr, &lastWriteTime))
		{
			Release();
			return mask;
		}

		if (time.dwLowDateTime == lastWriteTime.dwLowDateTime && time.dwHighDateTime == lastWriteTime.dwHighDateTime)
			return mask;

		time = lastWriteTime;
		mask = EHS_FE_MODIFIED;

		return mask;
	}

	bool FileMonitor::IsInitialized() const
	{
		return hdl != INVALID_HANDLE_VALUE;
	}
}