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

#include "zenutil/logging.h"

#undef ZEN_USE_SENTRY
#define ZEN_USE_SENTRY 0

#if !defined(ZEN_USE_SENTRY)
#	if ZEN_PLATFORM_MAC && ZEN_ARCH_ARM64
// vcpkg's sentry-native port does not support Arm on Mac.
#		define ZEN_USE_SENTRY 0
#	else
#		define ZEN_USE_SENTRY 1
#	endif
#endif

ZEN_THIRD_PARTY_INCLUDES_START
#include <spdlog/async.h>
#include <spdlog/async_logger.h>
#include <spdlog/pattern_formatter.h>
#include <spdlog/sinks/ansicolor_sink.h>
#include <spdlog/sinks/basic_file_sink.h>
#include <spdlog/sinks/daily_file_sink.h>
#include <spdlog/sinks/msvc_sink.h>
#include <spdlog/sinks/rotating_file_sink.h>
#include <spdlog/sinks/stdout_color_sinks.h>
#if ZEN_USE_SENTRY
#	include <sentry.h>
#endif
ZEN_THIRD_PARTY_INCLUDES_END

#include <zencore/filesystem.h>
#include <zencore/string.h>

#include <chrono>
#include <memory>

// Custom logging -- test code, this should be tweaked

namespace zen::logging {

using namespace spdlog;
using namespace spdlog::details;
using namespace std::literals;

class full_formatter final : public spdlog::formatter
{
public:
	full_formatter(std::string_view LogId, std::chrono::time_point<std::chrono::system_clock> Epoch) : m_Epoch(Epoch), m_LogId(LogId) {}

	virtual std::unique_ptr<formatter> clone() const override { return std::make_unique<full_formatter>(m_LogId, m_Epoch); }

	static constexpr bool UseDate = false;

	virtual void format(const details::log_msg& msg, memory_buf_t& dest) override
	{
		using std::chrono::duration_cast;
		using std::chrono::milliseconds;
		using std::chrono::seconds;

		if constexpr (UseDate)
		{
			auto secs = std::chrono::duration_cast<seconds>(msg.time.time_since_epoch());
			if (secs != m_LastLogSecs)
			{
				m_CachedTm	  = os::localtime(log_clock::to_time_t(msg.time));
				m_LastLogSecs = secs;
			}
		}

		const auto& tm_time = m_CachedTm;

		// cache the date/time part for the next second.
		auto duration = msg.time - m_Epoch;
		auto secs	  = duration_cast<seconds>(duration);

		if (m_CacheTimestamp != secs || m_CachedDatetime.size() == 0)
		{
			m_CachedDatetime.clear();
			m_CachedDatetime.push_back('[');

			if constexpr (UseDate)
			{
				fmt_helper::append_int(tm_time.tm_year + 1900, m_CachedDatetime);
				m_CachedDatetime.push_back('-');

				fmt_helper::pad2(tm_time.tm_mon + 1, m_CachedDatetime);
				m_CachedDatetime.push_back('-');

				fmt_helper::pad2(tm_time.tm_mday, m_CachedDatetime);
				m_CachedDatetime.push_back(' ');

				fmt_helper::pad2(tm_time.tm_hour, m_CachedDatetime);
				m_CachedDatetime.push_back(':');

				fmt_helper::pad2(tm_time.tm_min, m_CachedDatetime);
				m_CachedDatetime.push_back(':');

				fmt_helper::pad2(tm_time.tm_sec, m_CachedDatetime);
			}
			else
			{
				int Count = int(secs.count());

				const int LogSecs = Count % 60;
				Count /= 60;

				const int LogMins = Count % 60;
				Count /= 60;

				const int LogHours = Count;

				fmt_helper::pad2(LogHours, m_CachedDatetime);
				m_CachedDatetime.push_back(':');
				fmt_helper::pad2(LogMins, m_CachedDatetime);
				m_CachedDatetime.push_back(':');
				fmt_helper::pad2(LogSecs, m_CachedDatetime);
			}

			m_CachedDatetime.push_back('.');

			m_CacheTimestamp = secs;
		}

		dest.append(m_CachedDatetime.begin(), m_CachedDatetime.end());

		auto millis = fmt_helper::time_fraction<milliseconds>(msg.time);
		fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
		dest.push_back(']');
		dest.push_back(' ');

		if (!m_LogId.empty())
		{
			dest.push_back('[');
			fmt_helper::append_string_view(m_LogId, dest);
			dest.push_back(']');
			dest.push_back(' ');
		}

		// append logger name if exists
		if (msg.logger_name.size() > 0)
		{
			dest.push_back('[');
			fmt_helper::append_string_view(msg.logger_name, dest);
			dest.push_back(']');
			dest.push_back(' ');
		}

		dest.push_back('[');
		// wrap the level name with color
		msg.color_range_start = dest.size();
		fmt_helper::append_string_view(level::to_string_view(msg.level), dest);
		msg.color_range_end = dest.size();
		dest.push_back(']');
		dest.push_back(' ');

		// add source location if present
		if (!msg.source.empty())
		{
			dest.push_back('[');
			const char* filename = details::short_filename_formatter<details::null_scoped_padder>::basename(msg.source.filename);
			fmt_helper::append_string_view(filename, dest);
			dest.push_back(':');
			fmt_helper::append_int(msg.source.line, dest);
			dest.push_back(']');
			dest.push_back(' ');
		}

		fmt_helper::append_string_view(msg.payload, dest);
		fmt_helper::append_string_view("\n"sv, dest);
	}

private:
	std::chrono::time_point<std::chrono::system_clock> m_Epoch;
	std::tm											   m_CachedTm;
	std::chrono::seconds							   m_LastLogSecs;
	std::chrono::seconds							   m_CacheTimestamp{0};
	memory_buf_t									   m_CachedDatetime;
	std::string										   m_LogId;
};

class json_formatter final : public spdlog::formatter
{
public:
	json_formatter(std::string_view LogId) : m_LogId(LogId) {}

	virtual std::unique_ptr<formatter> clone() const override { return std::make_unique<json_formatter>(m_LogId); }

	virtual void format(const details::log_msg& msg, memory_buf_t& dest) override
	{
		using std::chrono::duration_cast;
		using std::chrono::milliseconds;
		using std::chrono::seconds;

		auto secs = std::chrono::duration_cast<seconds>(msg.time.time_since_epoch());
		if (secs != m_LastLogSecs)
		{
			m_CachedTm	  = os::localtime(log_clock::to_time_t(msg.time));
			m_LastLogSecs = secs;
		}

		const auto& tm_time = m_CachedTm;

		// cache the date/time part for the next second.

		if (m_CacheTimestamp != secs || m_CachedDatetime.size() == 0)
		{
			m_CachedDatetime.clear();

			fmt_helper::append_int(tm_time.tm_year + 1900, m_CachedDatetime);
			m_CachedDatetime.push_back('-');

			fmt_helper::pad2(tm_time.tm_mon + 1, m_CachedDatetime);
			m_CachedDatetime.push_back('-');

			fmt_helper::pad2(tm_time.tm_mday, m_CachedDatetime);
			m_CachedDatetime.push_back(' ');

			fmt_helper::pad2(tm_time.tm_hour, m_CachedDatetime);
			m_CachedDatetime.push_back(':');

			fmt_helper::pad2(tm_time.tm_min, m_CachedDatetime);
			m_CachedDatetime.push_back(':');

			fmt_helper::pad2(tm_time.tm_sec, m_CachedDatetime);

			m_CachedDatetime.push_back('.');

			m_CacheTimestamp = secs;
		}
		dest.append("{"sv);
		dest.append("\"time\": \""sv);
		dest.append(m_CachedDatetime.begin(), m_CachedDatetime.end());
		auto millis = fmt_helper::time_fraction<milliseconds>(msg.time);
		fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
		dest.append("\", "sv);

		dest.append("\"status\": \""sv);
		dest.append(level::to_string_view(msg.level));
		dest.append("\", "sv);

		dest.append("\"source\": \""sv);
		dest.append("zenserver"sv);
		dest.append("\", "sv);

		dest.append("\"service\": \""sv);
		dest.append("zencache"sv);
		dest.append("\", "sv);

		if (!m_LogId.empty())
		{
			dest.append("\"id\": \""sv);
			dest.append(m_LogId);
			dest.append("\", "sv);
		}

		if (msg.logger_name.size() > 0)
		{
			dest.append("\"logger.name\": \""sv);
			dest.append(msg.logger_name);
			dest.append("\", "sv);
		}

		if (msg.thread_id != 0)
		{
			dest.append("\"logger.thread_name\": \""sv);
			fmt_helper::pad_uint(msg.thread_id, 0, dest);
			dest.append("\", "sv);
		}

		if (!msg.source.empty())
		{
			dest.append("\"file\": \""sv);
			WriteEscapedString(dest, details::short_filename_formatter<details::null_scoped_padder>::basename(msg.source.filename));
			dest.append("\","sv);

			dest.append("\"line\": \""sv);
			dest.append(fmt::format("{}", msg.source.line));
			dest.append("\","sv);

			dest.append("\"logger.method_name\": \""sv);
			WriteEscapedString(dest, msg.source.funcname);
			dest.append("\", "sv);
		}

		dest.append("\"message\": \""sv);
		WriteEscapedString(dest, msg.payload);
		dest.append("\""sv);

		dest.append("}\n"sv);
	}

private:
	static inline const std::unordered_map<char, std::string_view> SpecialCharacterMap{{'\b', "\\b"sv},
																					   {'\f', "\\f"sv},
																					   {'\n', "\\n"sv},
																					   {'\r', "\\r"sv},
																					   {'\t', "\\t"sv},
																					   {'"', "\\\""sv},
																					   {'\\', "\\\\"sv}};

	static void WriteEscapedString(memory_buf_t& dest, const spdlog::string_view_t& payload)
	{
		const char* RangeStart = payload.begin();
		for (const char* It = RangeStart; It != payload.end(); ++It)
		{
			if (auto SpecialIt = SpecialCharacterMap.find(*It); SpecialIt != SpecialCharacterMap.end())
			{
				if (RangeStart != It)
				{
					dest.append(RangeStart, It);
				}
				dest.append(SpecialIt->second);
				RangeStart = It + 1;
			}
		}
		if (RangeStart != payload.end())
		{
			dest.append(RangeStart, payload.end());
		}
	};

	std::tm				 m_CachedTm{0, 0, 0, 0, 0, 0, 0, 0, 0};
	std::chrono::seconds m_LastLogSecs{0};
	std::chrono::seconds m_CacheTimestamp{0};
	memory_buf_t		 m_CachedDatetime;
	std::string			 m_LogId;
};
}  // namespace zen::logging

bool
EnableVTMode()
{
#if ZEN_PLATFORM_WINDOWS
	// Set output mode to handle virtual terminal sequences
	HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
	if (hOut == INVALID_HANDLE_VALUE)
	{
		return false;
	}

	DWORD dwMode = 0;
	if (!GetConsoleMode(hOut, &dwMode))
	{
		return false;
	}

	dwMode |= ENABLE_VIRTUAL_TERMINAL_PROCESSING;
	if (!SetConsoleMode(hOut, dwMode))
	{
		return false;
	}
#endif

	return true;
}

#if ZEN_USE_SENTRY

class sentry_sink final : public spdlog::sinks::base_sink<spdlog::details::null_mutex>
{
public:
	sentry_sink() {}

protected:
	static constexpr sentry_level_t MapToSentryLevel[spdlog::level::level_enum::n_levels] = {SENTRY_LEVEL_DEBUG,
																							 SENTRY_LEVEL_DEBUG,
																							 SENTRY_LEVEL_INFO,
																							 SENTRY_LEVEL_WARNING,
																							 SENTRY_LEVEL_ERROR,
																							 SENTRY_LEVEL_FATAL,
																							 SENTRY_LEVEL_DEBUG};

	void sink_it_(const spdlog::details::log_msg& msg) override
	{
		if (msg.level >= SPDLOG_LEVEL_ERROR && msg.level <= SPDLOG_LEVEL_CRITICAL)
		{
			sentry_value_t event = sentry_value_new_message_event(
				/*   level */ MapToSentryLevel[msg.level],
				/*  logger */ nullptr,
				/* message */ std::string(msg.payload.data(), msg.payload.size()).c_str());
			sentry_event_value_add_stacktrace(event, NULL, 0);
			sentry_capture_event(event);
		}
	}
	void flush_() override {}
};
#endif

namespace zen {

void
InitializeLogging(const LoggingOptions& LogOptions)
{
	zen::logging::InitializeLogging();

	EnableVTMode();

	bool					  IsAsync  = true;
	spdlog::level::level_enum LogLevel = spdlog::level::info;

	if (LogOptions.IsDebug)
	{
		LogLevel = spdlog::level::debug;
		IsAsync	 = false;
	}

	if (LogOptions.IsTest)
	{
		LogLevel = spdlog::level::trace;
		IsAsync	 = false;
	}

	if (IsAsync)
	{
		const int QueueSize	  = 8192;
		const int ThreadCount = 1;
		spdlog::init_thread_pool(QueueSize, ThreadCount);

		auto AsyncLogger = spdlog::create_async<spdlog::sinks::ansicolor_stdout_sink_mt>("main");
		zen::logging::SetDefault(AsyncLogger);
	}

	// Sinks

	auto ConsoleSink = std::make_shared<spdlog::sinks::ansicolor_stdout_sink_mt>();

	spdlog::sink_ptr FileSink;
	spdlog::sink_ptr SentrySink;

	// spdlog can't create directories that starts with `\\?\` so we make sure the folder exists before creating the logger instance

	if (!LogOptions.AbsLogFile.empty())
	{
		if (LogOptions.AbsLogFile.has_parent_path())
		{
			zen::CreateDirectories(LogOptions.AbsLogFile.parent_path());
		}

#if 0
		FileSink = std::make_shared<spdlog::sinks::daily_file_sink_mt>(	zen::PathToUtf8(GlobalOptions.AbsLogFile),
																		0,
																		0,
																		/* truncate */ false,
																		uint16_t(/* max files */ 14));
#else
		FileSink = std::make_shared<spdlog::sinks::rotating_file_sink_mt>(zen::PathToUtf8(LogOptions.AbsLogFile),
																		  /* max size */ 128 * 1024 * 1024,
																		  /* max files */ 16,
																		  /* rotate on open */ true);
#endif
	}

#if ZEN_USE_SENTRY
	SentrySink = std::make_shared<sentry_sink>();
#endif

	std::set_terminate([]() { ZEN_CRITICAL("Program exited abnormally via std::terminate()"); });

	// Default

	auto& DefaultLogger = zen::logging::Default();
	auto& Sinks			= DefaultLogger.sinks();

	Sinks.clear();
	Sinks.push_back(ConsoleSink);

	if (FileSink)
	{
		Sinks.push_back(FileSink);
	}

	if (SentrySink)
	{
		Sinks.push_back(SentrySink);
	}

#if ZEN_PLATFORM_WINDOWS
	if (zen::IsDebuggerPresent() && LogOptions.IsDebug)
	{
		auto DebugSink = std::make_shared<spdlog::sinks::msvc_sink_mt>();
		DebugSink->set_level(spdlog::level::debug);
		Sinks.push_back(DebugSink);
	}
#endif

	// Configure all registered loggers according to settings

	spdlog::set_level(LogLevel);
	spdlog::flush_on(spdlog::level::err);
	spdlog::flush_every(std::chrono::seconds{2});
	spdlog::set_formatter(std::make_unique<logging::full_formatter>(LogOptions.LogId, std::chrono::system_clock::now()));

	if (FileSink)
	{
		if (LogOptions.AbsLogFile.extension() == ".json")
		{
			FileSink->set_formatter(std::make_unique<logging::json_formatter>(LogOptions.LogId));
		}
		else
		{
			FileSink->set_pattern("[%C-%m-%d.%e %T] [%n] [%l] %v");
		}
	}
	DefaultLogger.info("log starting at {:%FT%T%z}", std::chrono::system_clock::now());
}

void
ShutdownLogging()
{
	auto& DefaultLogger = zen::logging::Default();
	DefaultLogger.info("log ending at {:%FT%T%z}", std::chrono::system_clock::now());
	zen::logging::ShutdownLogging();
}

}  // namespace zen