#include <filezilla.h>

#include "logging_private.h"

#ifdef __WXMSW__
#include <wx/filename.h>
#endif
#include <wx/log.h>

#include <errno.h>

bool CLogging::m_logfile_initialized = false;
#ifdef __WXMSW__
HANDLE CLogging::m_log_fd = INVALID_HANDLE_VALUE;
#else
int CLogging::m_log_fd = -1;
#endif
wxString CLogging::m_prefixes[static_cast<int>(MessageType::count)];
unsigned int CLogging::m_pid;
int CLogging::m_max_size;
wxString CLogging::m_file;

int CLogging::m_refcount = 0;
fz::mutex CLogging::mutex_(false);

thread_local int CLogging::debug_level_{};
thread_local int CLogging::raw_listing_{};

CLogging::CLogging(CFileZillaEnginePrivate & engine)
	: engine_(engine)
{
	fz::scoped_lock l(mutex_);
	m_refcount++;
}

CLogging::~CLogging()
{
	fz::scoped_lock l(mutex_);
	m_refcount--;

	if (!m_refcount) {
#ifdef __WXMSW__
		if (m_log_fd != INVALID_HANDLE_VALUE) {
			CloseHandle(m_log_fd);
			m_log_fd = INVALID_HANDLE_VALUE;
		}
#else
		if (m_log_fd != -1) {
			close(m_log_fd);
			m_log_fd = -1;
		}
#endif
		m_logfile_initialized = false;
	}
}

bool CLogging::ShouldLog(MessageType nMessageType) const
{
	switch (nMessageType) {
	case MessageType::Debug_Warning:
		if (!debug_level_)
			return false;
		break;
	case MessageType::Debug_Info:
		if (debug_level_ < 2)
			return false;
		break;
	case MessageType::Debug_Verbose:
		if (debug_level_ < 3)
			return false;
		break;
	case MessageType::Debug_Debug:
		if (debug_level_ != 4)
			return false;
		break;
	case MessageType::RawList:
		if (!raw_listing_)
			return false;
		break;
	default:
		break;
	}
	return true;
}

bool CLogging::InitLogFile(fz::scoped_lock& l) const
{
	if (m_logfile_initialized)
		return true;

	m_logfile_initialized = true;

	m_file = engine_.GetOptions().GetOption(OPTION_LOGGING_FILE);
	if (m_file.empty())
		return false;

#ifdef __WXMSW__
	m_log_fd = CreateFile(m_file.wc_str(), FILE_APPEND_DATA, FILE_SHARE_DELETE | FILE_SHARE_WRITE | FILE_SHARE_READ, 0, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
	if (m_log_fd == INVALID_HANDLE_VALUE)
#else
	m_log_fd = open(m_file.fn_str(), O_WRONLY | O_APPEND | O_CREAT | O_CLOEXEC, 0644);
	if (m_log_fd == -1)
#endif
	{
		l.unlock(); //Avoid recursion
		LogMessage(MessageType::Error, _("Could not open log file: %s"), wxSysErrorMsg());
		return false;
	}

	m_prefixes[static_cast<int>(MessageType::Status)] = _("Status:");
	m_prefixes[static_cast<int>(MessageType::Error)] = _("Error:");
	m_prefixes[static_cast<int>(MessageType::Command)] = _("Command:");
	m_prefixes[static_cast<int>(MessageType::Response)] = _("Response:");
	m_prefixes[static_cast<int>(MessageType::Debug_Warning)] = _("Trace:");
	m_prefixes[static_cast<int>(MessageType::Debug_Info)] = m_prefixes[static_cast<int>(MessageType::Debug_Warning)];
	m_prefixes[static_cast<int>(MessageType::Debug_Verbose)] = m_prefixes[static_cast<int>(MessageType::Debug_Warning)];
	m_prefixes[static_cast<int>(MessageType::Debug_Debug)] = m_prefixes[static_cast<int>(MessageType::Debug_Warning)];
	m_prefixes[static_cast<int>(MessageType::RawList)] = _("Listing:");

	m_pid = wxGetProcessId();

	m_max_size = engine_.GetOptions().GetOptionVal(OPTION_LOGGING_FILE_SIZELIMIT);
	if (m_max_size < 0)
		m_max_size = 0;
	else if (m_max_size > 2000)
		m_max_size = 2000;
	m_max_size *= 1024 * 1024;

	return true;
}

void CLogging::LogToFile(MessageType nMessageType, const wxString& msg) const
{
	fz::scoped_lock l(mutex_);

	if (!m_logfile_initialized) {
		if (!InitLogFile(l)) {
			return;
		}
	}
#ifdef __WXMSW__
	if (m_log_fd == INVALID_HANDLE_VALUE)
		return;
#else
	if (m_log_fd == -1)
		return;
#endif

	fz::datetime now = fz::datetime::now();
	wxString out(wxString::Format(_T("%s %u %d %s %s")
#ifdef __WXMSW__
		_T("\r\n"),
#else
		_T("\n"),
#endif
		now.format(_T("%Y-%m-%d %H:%M:%S"), fz::datetime::local), m_pid, engine_.GetEngineId(), m_prefixes[static_cast<int>(nMessageType)], msg));

	const wxWX2MBbuf utf8 = out.mb_str(wxConvUTF8);
	if (utf8) {
#ifdef __WXMSW__
		if (m_max_size) {
			LARGE_INTEGER size;
			if (!GetFileSizeEx(m_log_fd, &size) || size.QuadPart > m_max_size) {
				CloseHandle(m_log_fd);
				m_log_fd = INVALID_HANDLE_VALUE;

				// m_log_fd might no longer be the original file.
				// Recheck on a new handle. Proteced with a mutex against other processes
				HANDLE hMutex = ::CreateMutex(0, true, _T("FileZilla 3 Logrotate Mutex"));
				if (!hMutex) {
					wxString error = wxSysErrorMsg();
					l.unlock();
					LogMessage(MessageType::Error, _("Could not create logging mutex: %s"), error);
					return;
				}

				HANDLE hFile = CreateFile(m_file.wc_str(), FILE_APPEND_DATA, FILE_SHARE_DELETE | FILE_SHARE_WRITE | FILE_SHARE_READ, 0, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
				if (hFile == INVALID_HANDLE_VALUE) {
					wxString error = wxSysErrorMsg();

					// Oh dear..
					ReleaseMutex(hMutex);
					CloseHandle(hMutex);

					l.unlock(); // Avoid recursion
					LogMessage(MessageType::Error, _("Could not open log file: %s"), error);
					return;
				}

				wxString error;
				if (GetFileSizeEx(hFile, &size) && size.QuadPart > m_max_size) {
					CloseHandle(hFile);

					// MoveFileEx can fail if trying to access a deleted file for which another process still has
					// a handle. Move it far away first.
					// Todo: Handle the case in which logdir and tmpdir are on different volumes.
					// (Why is everthing so needlessly complex on MSW?)
					wxString tmp = wxFileName::CreateTempFileName(_T("fz3"));
					MoveFileEx((m_file + _T(".1")).wc_str(), tmp.wc_str(), MOVEFILE_REPLACE_EXISTING);
					DeleteFile(tmp.wc_str());
					MoveFileEx(m_file.wc_str(), (m_file + _T(".1")).wc_str(), MOVEFILE_REPLACE_EXISTING);
					m_log_fd = CreateFile(m_file.wc_str(), FILE_APPEND_DATA, FILE_SHARE_DELETE | FILE_SHARE_WRITE | FILE_SHARE_READ, 0, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
					if (m_log_fd == INVALID_HANDLE_VALUE) {
						// If this function would return bool, I'd return FILE_NOT_FOUND here.
						error = wxSysErrorMsg();
					}
				}
				else
					m_log_fd = hFile;

				if (hMutex) {
					ReleaseMutex(hMutex);
					CloseHandle(hMutex);
				}

				if (!error.empty()) {
					l.unlock(); // Avoid recursion
					LogMessage(MessageType::Error, _("Could not open log file: %s"), error);
					return;
				}
			}
		}
		DWORD len = (DWORD)strlen((const char*)utf8);
		DWORD written;
		BOOL res = WriteFile(m_log_fd, (const char*)utf8, len, &written, 0);
		if (!res || written != len) {
			CloseHandle(m_log_fd);
			m_log_fd = INVALID_HANDLE_VALUE;
			l.unlock(); // Avoid recursion
			LogMessage(MessageType::Error, _("Could not write to log file: %s"), wxSysErrorMsg());
		}
#else
		if (m_max_size) {
			struct stat buf;
			int rc = fstat(m_log_fd, &buf);
			while (!rc && buf.st_size > m_max_size) {
				struct flock lock = {};
				lock.l_type = F_WRLCK;
				lock.l_whence = SEEK_SET;
				lock.l_start = 0;
				lock.l_len = 1;

				int rc;

				// Retry through signals
				while ((rc = fcntl(m_log_fd, F_SETLKW, &lock)) == -1 && errno == EINTR);

				// Ignore any other failures
				int fd = open(m_file.fn_str(), O_WRONLY | O_APPEND | O_CREAT | O_CLOEXEC, 0644);
				if (fd == -1) {
					wxString error = wxSysErrorMsg();

					close(m_log_fd);
					m_log_fd = -1;

					l.unlock(); // Avoid recursion
					LogMessage(MessageType::Error, error);
					return;
				}
				struct stat buf2;
				rc = fstat(fd, &buf2);

				// Different files
				if (!rc && buf.st_ino != buf2.st_ino) {
					close(m_log_fd); // Releases the lock
					m_log_fd = fd;
					buf = buf2;
					continue;
				}

				// The file is indeed the log file and we are holding a lock on it.

				// Rename it
				rc = rename(m_file.fn_str(), (m_file + _T(".1")).fn_str());
				close(m_log_fd);
				close(fd);

				// Get the new file
				m_log_fd = open(m_file.fn_str(), O_WRONLY | O_APPEND | O_CREAT | O_CLOEXEC, 0644);
				if (m_log_fd == -1) {
					l.unlock(); // Avoid recursion
					LogMessage(MessageType::Error, wxSysErrorMsg());
					return;
				}

				if (!rc) // Rename didn't fail
					rc = fstat(m_log_fd, &buf);
			}
		}
		size_t len = strlen((const char*)utf8);
		size_t written = write(m_log_fd, (const char*)utf8, len);
		if (written != len) {
			close(m_log_fd);
			m_log_fd = -1;

			l.unlock(); // Avoid recursion
			LogMessage(MessageType::Error, _("Could not write to log file: %s"), wxSysErrorMsg());
		}
#endif
	}
}

void CLogging::UpdateLogLevel(COptionsBase & options)
{
	debug_level_ = options.GetOptionVal(OPTION_LOGGING_DEBUGLEVEL);
	raw_listing_ = options.GetOptionVal(OPTION_LOGGING_RAWLISTING);
}