// Copyright Epic Games, Inc. All Rights Reserved.

#include "up_cmd.h"

#include <zencore/basicfile.h>
#include <zencore/compactbinary.h>
#include <zencore/compactbinaryutil.h>
#include <zencore/filesystem.h>
#include <zencore/fmtutils.h>
#include <zencore/logging.h>
#include <zencore/process.h>
#include <zenutil/zenserverprocess.h>

namespace zen {

namespace {

	bool TryShutdownByPid(ZenServerState& Instance, uint32_t Pid, const std::filesystem::path& ProgramBaseDir, bool ForceTerminate)
	{
		Instance.Sweep();

		uint16_t DesiredPort = 0;
		Instance.Snapshot([&](const ZenServerState::ZenServerEntry& Entry) {
			if (Entry.Pid.load() == Pid)
			{
				DesiredPort = Entry.DesiredListenPort.load();
			}
		});

		ZenServerState::ZenServerEntry* Entry = (DesiredPort != 0) ? Instance.Lookup(DesiredPort) : nullptr;
		if (Entry && Entry->Pid.load() != Pid)
		{
			Entry = nullptr;
		}

		if (Entry)
		{
			if (ShutdownZenServer(ConsoleLog(), Instance, Entry, ProgramBaseDir))
			{
				return true;
			}
		}

		std::error_code Ec;
		ProcessHandle	Proc;
		Proc.Initialize(int(Pid), Ec);
		if (!Ec && Proc.IsValid() && !Proc.IsRunning())
		{
			return true;
		}

		if (ForceTerminate && !Ec && Proc.IsValid() && Proc.IsRunning())
		{
			ZEN_CONSOLE_WARN("Hard terminating zen process with pid ({})", Pid);
			if (Proc.Terminate(0))
			{
				ZEN_CONSOLE("Terminate complete");
				return true;
			}
		}

		return false;
	}

}  // namespace

UpCommand::UpCommand()
{
	m_Options.add_option("", "p", "port", "Host port", cxxopts::value(m_Port)->default_value("0"), "<hostport>");
	m_Options.add_option("", "b", "base-dir", "Parent folder of server executable", cxxopts::value(m_ProgramBaseDir), "<directory>");
	m_Options.add_option("", "c", "show-console", "Open a console window for the zenserver process", cxxopts::value(m_ShowConsole), "");
	m_Options.add_option("",
						 "l",
						 "show-log",
						 "Show the output log of the zenserver process after successful start",
						 cxxopts::value(m_ShowLog),
						 "");
}

UpCommand::~UpCommand() = default;

void
UpCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
{
	if (!ParseOptions(argc, argv))
	{
		return;
	}

	if (m_ShowConsole && m_ShowLog)
	{
		throw OptionParseException("'--show-console' conflicts with '--show-log'", m_Options.help());
	}

	if (m_ProgramBaseDir.empty())
	{
		m_ProgramBaseDir = GetRunningExecutablePath().parent_path();
	}
	MakeSafeAbsolutePathInPlace(m_ProgramBaseDir);

	std::optional<int> StartResult = StartupZenServer(ConsoleLog(),
													  {.ProgramBaseDir		   = m_ProgramBaseDir,
													   .Port				   = m_Port,
													   .OpenConsole			   = m_ShowConsole,
													   .ShowLog				   = m_ShowLog,
													   .ExtraArgs			   = GlobalOptions.PassthroughCommandLine,
													   .EnableExecutionHistory = GlobalOptions.EnableExecutionHistory});
	if (!StartResult.has_value())
	{
		ZEN_CONSOLE("Zen server already running");
		return;
	}
	if (*StartResult != 0)
	{
		throw ErrorWithReturnCode("Zen server failed to start", *StartResult);
	}

	ZEN_CONSOLE("Zen server up");
}

//////////////////////////////////////////////////////////////////////////

AttachCommand::AttachCommand()
{
	m_Options.add_option("", "p", "port", "Host port", cxxopts::value(m_Port)->default_value("8558"), "<hostport>");
	m_Options.add_option("lifetime", "", "owner-pid", "Specify owning process id", cxxopts::value(m_OwnerPid), "<identifier>");
	m_Options.add_option("", "", "data-dir", "Path to data directory to inspect for running server", cxxopts::value(m_DataDir), "<file>");
}

AttachCommand::~AttachCommand() = default;

void
AttachCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
{
	ZEN_UNUSED(GlobalOptions);

	if (!ParseOptions(argc, argv))
	{
		return;
	}

	if (!m_DataDir.empty())
	{
		MakeSafeAbsolutePathInPlace(m_DataDir);
	}

	ZenServerState Instance;
	Instance.Initialize();
	Instance.Sweep();
	ZenServerState::ZenServerEntry* Entry = Instance.Lookup(m_Port);

	if (!m_DataDir.empty())
	{
		if (!LockFile::IsHeldLive(m_DataDir / ".lock", /*AttemptCleanup*/ false))
		{
			throw std::runtime_error(fmt::format("No live zen server holding lock file in directory '{}'", m_DataDir));
		}
		CbValidateError ValidateResult = CbValidateError::None;
		if (CbObject LockFileObject =
				ValidateAndReadCompactBinaryObject(IoBufferBuilder::MakeFromFile(m_DataDir / ".lock"), ValidateResult);
			ValidateResult == CbValidateError::None && LockFileObject)
		{
			LockFileInfo Info = ReadLockFilePayload(LockFileObject);
			std::string	 Reason;
			if (!ValidateLockFileInfo(Info, Reason))
			{
				throw std::runtime_error(fmt::format("Lock file in directory '{}' is not valid. Reason: '{}'", m_DataDir, Reason));
			}
			Entry = Instance.LookupByEffectivePort(Info.EffectiveListenPort);
		}
		else
		{
			throw std::runtime_error(
				fmt::format("Lock file in directory '{}' is malformed. Reason: '{}'", m_DataDir, ToString(ValidateResult)));
		}
	}

	if (!Entry)
	{
		throw std::runtime_error("No zen server instance to add sponsor process to");
	}

	// Sponsor processes are checked every second, so 2 second wait time should be enough
	if (!Entry->AddSponsorProcess(m_OwnerPid, 2000))
	{
		throw std::runtime_error("Unable to add sponsor process to running zen server instance");
	}

	ZEN_CONSOLE("Added sponsor process {} to running instance {} on port {}", m_OwnerPid, Entry->Pid.load(), m_Port);
}

//////////////////////////////////////////////////////////////////////////

DownCommand::DownCommand()
{
	m_Options.add_option("", "p", "port", "Host port", cxxopts::value(m_Port)->default_value("0"), "<hostport>");
	m_Options.add_option("", "a", "all", "Shut down all running zen server instances", cxxopts::value(m_All), "");
	m_Options.add_option("", "f", "force", "Force terminate if graceful shutdown fails", cxxopts::value(m_ForceTerminate), "<force>");
	m_Options.add_option("", "b", "base-dir", "Parent folder of server executable", cxxopts::value(m_ProgramBaseDir), "<directory>");
	m_Options.add_option("", "", "data-dir", "Path to data directory to inspect for running server", cxxopts::value(m_DataDir), "<file>");
	m_Options.add_option("", "", "pid", "Shut down zen server process by PID", cxxopts::value(m_Pid)->default_value("0"), "<pid>");
	m_Options.add_option("",
						 "",
						 "executable",
						 "Shut down all zen server processes matching executable path",
						 cxxopts::value(m_ExecutablePath),
						 "<path>");
}

DownCommand::~DownCommand() = default;

void
DownCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
{
	ZEN_UNUSED(GlobalOptions);

	if (!ParseOptions(argc, argv))
	{
		return;
	}

	const bool HasPid		 = m_Pid != 0;
	const bool HasExecutable = !m_ExecutablePath.empty();
	const bool HasDataDir	 = !m_DataDir.empty();
	const int  SelectorCount = int(m_All) + int(HasPid) + int(HasExecutable) + int(HasDataDir);
	if (SelectorCount > 1)
	{
		throw OptionParseException("--all, --pid, --executable, and --data-dir are mutually exclusive", m_Options.help());
	}

	if (m_ProgramBaseDir.empty())
	{
		std::filesystem::path ExePath = GetRunningExecutablePath();
		m_ProgramBaseDir			  = ExePath.parent_path();
	}
	MakeSafeAbsolutePathInPlace(m_ProgramBaseDir);
	if (!m_DataDir.empty())
	{
		MakeSafeAbsolutePathInPlace(m_DataDir);
	}
	if (!m_ExecutablePath.empty() && m_ExecutablePath.has_parent_path())
	{
		MakeSafeAbsolutePathInPlace(m_ExecutablePath);
	}

	// Discover executing instances
	ZenServerState Instance;
	Instance.Initialize();

	if (HasPid)
	{
		if (!TryShutdownByPid(Instance, m_Pid, m_ProgramBaseDir, m_ForceTerminate))
		{
			throw std::runtime_error(fmt::format("Failed to shut down zen process with pid {}, use --force to hard terminate", m_Pid));
		}
		ZEN_CONSOLE("Zen server with pid {} is down", m_Pid);
		return;
	}

	if (HasExecutable)
	{
		int ShutdownCount = 0;
		while (true)
		{
			ProcessHandle	Proc;
			std::error_code Ec = FindProcess(m_ExecutablePath, Proc, /*IncludeSelf*/ false);
			if (Ec)
			{
				throw std::system_error(Ec, fmt::format("FindProcess failed for '{}'", m_ExecutablePath));
			}
			if (!Proc.IsValid())
			{
				break;
			}
			const uint32_t Pid = uint32_t(Proc.Pid());
			if (!TryShutdownByPid(Instance, Pid, m_ProgramBaseDir, m_ForceTerminate))
			{
				throw std::runtime_error(fmt::format("Failed to shut down zen process with pid {}, use --force to hard terminate", Pid));
			}
			++ShutdownCount;
		}
		if (ShutdownCount == 0)
		{
			ZEN_CONSOLE("No zen server processes matching executable '{}'", m_ExecutablePath);
		}
		else
		{
			ZEN_CONSOLE("Shut down {} zen server instance(s) matching executable '{}'", ShutdownCount, m_ExecutablePath);
		}
		return;
	}

	if (m_All)
	{
		struct EntryInfo
		{
			uint16_t Port = 0;
			uint32_t Pid  = 0;
		};
		std::vector<EntryInfo> Entries;
		Instance.Snapshot([&Entries](const ZenServerState::ZenServerEntry& Entry) {
			uint16_t Port = Entry.DesiredListenPort.load();
			uint32_t Pid  = Entry.Pid.load();
			if (Port != 0 && Pid != 0)
			{
				Entries.push_back({Port, Pid});
			}
		});

		if (Entries.empty())
		{
			ZEN_CONSOLE("No zen server instances to bring down");
			return;
		}

		int FailCount = 0;
		for (const EntryInfo& Info : Entries)
		{
			if (!TryShutdownByPid(Instance, Info.Pid, m_ProgramBaseDir, m_ForceTerminate))
			{
				ZEN_CONSOLE_WARN("Failed to shutdown server on port {} (pid {})", Info.Port, Info.Pid);
				++FailCount;
			}
		}

		if (FailCount > 0 && !m_ForceTerminate)
		{
			throw std::runtime_error(fmt::format("Failed to shutdown {} instance(s), use --force to hard terminate", FailCount));
		}
		return;
	}

	ZenServerState::ZenServerEntry* Entry = Instance.Lookup(m_Port);

	if (!m_DataDir.empty())
	{
		if (!LockFile::IsHeldLive(m_DataDir / ".lock", /*AttemptCleanup*/ true))
		{
			ZEN_CONSOLE("No live zen server holding lock file in '{}', nothing to do", m_DataDir);
			return;
		}
		CbValidateError ValidateResult = CbValidateError::None;
		if (CbObject LockFileObject =
				ValidateAndReadCompactBinaryObject(IoBufferBuilder::MakeFromFile(m_DataDir / ".lock"), ValidateResult);
			ValidateResult == CbValidateError::None && LockFileObject)
		{
			LockFileInfo Info = ReadLockFilePayload(LockFileObject);
			std::string	 Reason;
			if (!ValidateLockFileInfo(Info, Reason))
			{
				throw std::runtime_error(fmt::format("Lock file in directory '{}' is not valid. Reason: '{}'", m_DataDir, Reason));
			}
			Entry = Instance.LookupByEffectivePort(Info.EffectiveListenPort);
		}
		else
		{
			throw std::runtime_error(
				fmt::format("Lock file in directory '{}' is malformed. Reason: '{}'", m_DataDir, ToString(ValidateResult)));
		}
	}

	if (Entry)
	{
		if (ShutdownZenServer(ConsoleLog(), Instance, Entry, m_ProgramBaseDir))
		{
			return;
		}
	}

	if (m_ForceTerminate)
	{
		// Try to find the running executable by path name
		std::filesystem::path ServerExePath = m_ProgramBaseDir / "zenserver" ZEN_EXE_SUFFIX_LITERAL;
		ProcessHandle		  RunningProcess;
		if (std::error_code Ec = FindProcess(ServerExePath, RunningProcess, /*IncludeSelf*/ false); !Ec)
		{
			ZEN_CONSOLE_WARN("Attempting hard terminate of zen process with pid ({})", RunningProcess.Pid());
			if (RunningProcess.Terminate(0))
			{
				ZEN_CONSOLE("Terminate complete");
				return;
			}
			throw std::runtime_error("Failed to terminate server, still running");
		}
		else
		{
			ZEN_CONSOLE_WARN("Failed to find process '{}', reason: {}", ServerExePath.string(), Ec.message());
		}
	}
	else if (Entry)
	{
		throw std::runtime_error(
			fmt::format("Failed to shut down server on port {}, use --force to hard terminate process", Entry->DesiredListenPort.load()));
	}

	ZEN_CONSOLE("No zen server to bring down");
}

}  // namespace zen