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

#include "ui_cmd.h"

#include "browser_launcher.h"
#include "zenserviceclient.h"

#include <zencore/except_fmt.h>
#include <zencore/fmtutils.h>
#include <zencore/logging.h>
#include <zencore/process.h>
#include <zenutil/consoletui.h>
#include <zenutil/zenserverprocess.h>

namespace zen {

namespace {

	struct RunningServerInfo
	{
		uint16_t	Port;
		uint32_t	Pid;
		std::string SessionId;
		std::string CmdLine;
	};

	static std::vector<RunningServerInfo> CollectRunningServers()
	{
		std::vector<RunningServerInfo> Servers;
		ZenServerState				   State;
		if (!State.InitializeReadOnly())
			return Servers;

		State.Snapshot([&](const ZenServerState::ZenServerEntry& Entry) {
			StringBuilder<25> SessionSB;
			Entry.GetSessionId().ToString(SessionSB);
			std::error_code CmdLineEc;
			std::string		CmdLine = GetProcessCommandLine(static_cast<int>(Entry.Pid.load()), CmdLineEc);
			Servers.push_back({Entry.EffectiveListenPort.load(), Entry.Pid.load(), std::string(SessionSB.c_str()), std::move(CmdLine)});
		});

		return Servers;
	}

}  // namespace

UiCommand::UiCommand()
{
	m_Options.add_options()("h,help", "Print help");
	m_Options.add_options()("a,all", "Open dashboard for all running instances", cxxopts::value(m_All)->default_value("false"));
	m_Options.add_option("", "u", "hosturl", kHostUrlHelp, cxxopts::value(m_HostName)->default_value(""), "<hosturl>");
	m_Options.add_option("",
						 "p",
						 "path",
						 "Dashboard path (default: /dashboard/)",
						 cxxopts::value(m_DashboardPath)->default_value("/dashboard/"),
						 "<path>");
	m_Options.parse_positional("path");
}

UiCommand::~UiCommand()
{
}

void
UiCommand::OpenBrowser(std::string_view HostName)
{
	// Allow shortcuts for specifying dashboard path, and ensure it is in a format we expect
	// (leading slash, trailing slash if no file extension)

	if (!m_DashboardPath.empty())
	{
		if (m_DashboardPath[0] != '/')
		{
			m_DashboardPath = "/dashboard/" + m_DashboardPath;
		}

		if (m_DashboardPath.find_last_of('.') == std::string::npos && m_DashboardPath.back() != '/')
		{
			m_DashboardPath += '/';
		}
	}

	ExtendableStringBuilder<256> FullUrl;
	FullUrl << HostName << m_DashboardPath;

	LaunchBrowser(std::string_view(FullUrl));
}

void
UiCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
{
	using namespace std::literals;

	ZEN_UNUSED(GlobalOptions);

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

	// Resolve target server
	uint16_t ServerPort = 0;

	if (m_HostName.empty())
	{
		// Auto-discover running instances.
		std::vector<RunningServerInfo> Servers = CollectRunningServers();

		if (m_All)
		{
			if (Servers.empty())
			{
				throw OptionParseException("No running Zen server instances found", m_Options.help());
			}

			for (const auto& Server : Servers)
			{
				OpenBrowser(fmt::format("http://localhost:{}", Server.Port));
			}
			return;
		}

		// If multiple are found and we have an interactive terminal, present a picker
		// instead of silently using the first one.
		if (Servers.size() > 1 && IsTuiAvailable())
		{
			std::vector<std::string> Labels;
			Labels.reserve(Servers.size() + 1);
			Labels.push_back(fmt::format("(all {} instances)", Servers.size()));

			const int32_t	  Cols		 = static_cast<int32_t>(TuiConsoleColumns());
			constexpr int32_t kIndicator = 3;  // " > " or "   " prefix
			constexpr int32_t kSeparator = 2;  // "  " before cmdline
			constexpr int32_t kEllipsis	 = 3;  // "..."

			for (const auto& Server : Servers)
			{
				std::string Label = fmt::format("port {:<5}  pid {:<7}  session {}", Server.Port, Server.Pid, Server.SessionId);

				if (!Server.CmdLine.empty())
				{
					int32_t Available = Cols - kIndicator - kSeparator - static_cast<int32_t>(Label.size());
					if (Available > kEllipsis)
					{
						Label += "  ";
						if (static_cast<int32_t>(Server.CmdLine.size()) <= Available)
						{
							Label += Server.CmdLine;
						}
						else
						{
							Label.append(Server.CmdLine, 0, static_cast<size_t>(Available - kEllipsis));
							Label += "...";
						}
					}
				}

				Labels.push_back(std::move(Label));
			}

			int SelectedIdx = TuiPickOne("Multiple Zen server instances found. Select one to open:", Labels);
			if (SelectedIdx < 0)
				return;	 // User cancelled

			if (SelectedIdx == 0)
			{
				// "All" selected
				for (const auto& Server : Servers)
				{
					OpenBrowser(fmt::format("http://localhost:{}", Server.Port));
				}
				return;
			}

			ServerPort = Servers[SelectedIdx - 1].Port;
			m_HostName = fmt::format("http://localhost:{}", ServerPort);
		}

		if (m_HostName.empty())
		{
			// Single or zero instances, or not an interactive terminal:
			// fall back to default resolution (picks first instance or returns empty)
			m_HostName = ResolveTargetHostSpec("", ServerPort);
		}
	}
	else
	{
		if (m_All)
		{
			throw OptionParseException("--all cannot be used together with --hosturl", m_Options.help());
		}
		m_HostName = ResolveTargetHostSpec(m_HostName, ServerPort);
	}

	ZenServiceClient Service({.HostSpec = m_HostName, .CommandName = Name});

	if (IsUnixSocketSpec(Service.HostSpec()))
	{
		throw std::runtime_error("Cannot open browser for a Unix domain socket connection");
	}

	OpenBrowser(Service.HostSpec());
}

}  // namespace zen