// SPDX-FileCopyrightText: 2002-2024 PCSX2 Dev Team
// SPDX-License-Identifier: GPL-3.0+

#include "common/Console.h"
#include "common/Assertions.h"
#include "common/FileSystem.h"
#include "common/SmallString.h"
#include "common/Timer.h"

#include "fmt/format.h"

#include <mutex>
#include <vector>

#ifdef _WIN32
#include "common/RedtapeWindows.h"
#else
#include <unistd.h>
#endif

using namespace std::string_view_literals;

// Dummy objects, need to get rid of them...
ConsoleLogWriter<LOGLEVEL_INFO> Console;
ConsoleLogWriter<LOGLEVEL_DEV> DevCon;

#ifdef _DEBUG
ConsoleLogWriter<LOGLEVEL_DEBUG> DbgConWriter;
#else
NullLogWriter DbgConWriter;
#endif

#define TIMESTAMP_FORMAT_STRING "[{:10.4f}] "
#define TIMESTAMP_PRINTF_STRING "[%10.4f] "

namespace Log
{
	static void WriteToConsole(LOGLEVEL level, ConsoleColors color, std::string_view message);
	static void WriteToDebug(LOGLEVEL level, ConsoleColors color, std::string_view message);
	static void WriteToFile(LOGLEVEL level, ConsoleColors color, std::string_view message);

	static void UpdateMaxLevel();

	static void ExecuteCallbacks(LOGLEVEL level, ConsoleColors color, std::string_view message);

	static Common::Timer::Value s_start_timestamp = Common::Timer::GetCurrentValue();

	static LOGLEVEL s_max_level = LOGLEVEL_NONE;
	static LOGLEVEL s_console_level = LOGLEVEL_NONE;
	static LOGLEVEL s_debug_level = LOGLEVEL_NONE;
	static LOGLEVEL s_file_level = LOGLEVEL_NONE;
	static LOGLEVEL s_host_level = LOGLEVEL_NONE;
	static bool s_log_timestamps = true;

	static FileSystem::ManagedCFilePtr s_file_handle;
	static std::string s_file_path;
	static std::mutex s_file_mutex;

	static HostCallbackType s_host_callback;

#ifdef _WIN32
	static HANDLE s_hConsoleStdIn = NULL;
	static HANDLE s_hConsoleStdOut = NULL;
	static HANDLE s_hConsoleStdErr = NULL;
#endif
} // namespace Log

float Log::GetCurrentMessageTime()
{
	return static_cast<float>(Common::Timer::ConvertValueToSeconds(Common::Timer::GetCurrentValue() - s_start_timestamp));
}

__ri void Log::WriteToConsole(LOGLEVEL level, ConsoleColors color, std::string_view message)
{
	static constexpr std::string_view s_ansi_color_codes[ConsoleColors_Count] = {
		"\033[0m"sv, // default
		"\033[30m\033[1m"sv, // black
		"\033[32m"sv, // green
		"\033[31m"sv, // red
		"\033[34m"sv, // blue
		"\033[35m"sv, // magenta
		"\033[35m"sv, // orange (FIXME)
		"\033[37m"sv, // gray
		"\033[36m"sv, // cyan
		"\033[33m"sv, // yellow
		"\033[37m"sv, // white
		"\033[30m\033[1m"sv, // strong black
		"\033[31m\033[1m"sv, // strong red
		"\033[32m\033[1m"sv, // strong green
		"\033[34m\033[1m"sv, // strong blue
		"\033[35m\033[1m"sv, // strong magenta
		"\033[35m\033[1m"sv, // strong orange (FIXME)
		"\033[37m\033[1m"sv, // strong gray
		"\033[36m\033[1m"sv, // strong cyan
		"\033[33m\033[1m"sv, // strong yellow
		"\033[37m\033[1m"sv, // strong white
	};

	static constexpr size_t BUFFER_SIZE = 512;

	SmallStackString<BUFFER_SIZE> buffer;
	buffer.reserve(32 + message.length());
	buffer.append(s_ansi_color_codes[color]);

	if (s_log_timestamps)
		buffer.append_format(TIMESTAMP_FORMAT_STRING, Log::GetCurrentMessageTime());

	buffer.append(message);
	buffer.append('\n');

#ifdef _WIN32
	const HANDLE hOutput = (level <= LOGLEVEL_WARNING) ? s_hConsoleStdErr : s_hConsoleStdOut;

	// Convert to UTF-16 first so Unicode characters display correctly. NT is going to do it anyway...
	wchar_t wbuf[BUFFER_SIZE];
	wchar_t* wmessage_buf = wbuf;
	int wmessage_buflen = static_cast<int>(std::size(wbuf) - 1);
	if (buffer.length() >= std::size(wbuf))
	{
		wmessage_buflen = static_cast<int>(buffer.length());
		wmessage_buf = static_cast<wchar_t*>(std::malloc(static_cast<size_t>(wmessage_buflen) * sizeof(wchar_t)));
		if (!wmessage_buf)
			return;
	}

	const int wmessage_size = MultiByteToWideChar(CP_UTF8, 0, buffer.data(), static_cast<int>(buffer.length()), wmessage_buf, wmessage_buflen);
	if (wmessage_size <= 0)
		goto cleanup;

	DWORD chars_written;
	WriteConsoleW(hOutput, wmessage_buf, static_cast<DWORD>(wmessage_size), &chars_written, nullptr);

cleanup:
	if (wmessage_buf != wbuf)
		std::free(wmessage_buf);
#else
	const int fd = (level <= LOGLEVEL_WARNING) ? STDERR_FILENO : STDOUT_FILENO;
	write(fd, buffer.data(), buffer.length());
#endif
}

bool Log::IsConsoleOutputEnabled()
{
	return (s_console_level > LOGLEVEL_NONE);
}

void Log::SetConsoleOutputLevel(LOGLEVEL level)
{
	if (s_console_level == level)
		return;

	const bool was_enabled = (s_console_level > LOGLEVEL_NONE);
	const bool now_enabled = (level > LOGLEVEL_NONE);
	s_console_level = level;
	UpdateMaxLevel();

	if (was_enabled == now_enabled)
		return;

		// Worst that happens here is we write to a bad handle..

#if defined(_WIN32)
	static constexpr auto enable_virtual_terminal_processing = [](HANDLE hConsole) {
		DWORD old_mode;
		if (!GetConsoleMode(hConsole, &old_mode))
			return;

		// already enabled?
		if (old_mode & ENABLE_VIRTUAL_TERMINAL_PROCESSING)
			return;

		SetConsoleMode(hConsole, old_mode | ENABLE_VIRTUAL_TERMINAL_PROCESSING);
	};

	// On windows, no console is allocated by default on a windows based application
	static bool console_was_allocated = false;
	static HANDLE old_stdin = NULL;
	static HANDLE old_stdout = NULL;
	static HANDLE old_stderr = NULL;

	if (now_enabled)
	{
		old_stdin = GetStdHandle(STD_INPUT_HANDLE);
		old_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
		old_stderr = GetStdHandle(STD_ERROR_HANDLE);

		if (!old_stdout)
		{
			// Attach to the parent console if we're running from a command window
			if (!AttachConsole(ATTACH_PARENT_PROCESS) && !AllocConsole())
				return;

			s_hConsoleStdIn = GetStdHandle(STD_INPUT_HANDLE);
			s_hConsoleStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
			s_hConsoleStdErr = GetStdHandle(STD_ERROR_HANDLE);

			enable_virtual_terminal_processing(s_hConsoleStdOut);
			enable_virtual_terminal_processing(s_hConsoleStdErr);

			std::FILE* fp;
			freopen_s(&fp, "CONIN$", "r", stdin);
			freopen_s(&fp, "CONOUT$", "w", stdout);
			freopen_s(&fp, "CONOUT$", "w", stderr);

			console_was_allocated = true;
		}
		else
		{
			s_hConsoleStdIn = old_stdin;
			s_hConsoleStdOut = old_stdout;
			s_hConsoleStdErr = old_stderr;
		}
	}
	else
	{
		if (console_was_allocated)
		{
			console_was_allocated = false;

			std::FILE* fp;
			freopen_s(&fp, "NUL:", "w", stderr);
			freopen_s(&fp, "NUL:", "w", stdout);
			freopen_s(&fp, "NUL:", "w", stdin);

			SetStdHandle(STD_ERROR_HANDLE, old_stderr);
			SetStdHandle(STD_OUTPUT_HANDLE, old_stdout);
			SetStdHandle(STD_INPUT_HANDLE, old_stdin);

			s_hConsoleStdIn = NULL;
			s_hConsoleStdOut = NULL;
			s_hConsoleStdErr = NULL;

			FreeConsole();
		}
	}
#endif
}

__ri void Log::WriteToDebug(LOGLEVEL level, ConsoleColors color, std::string_view message)
{
#ifdef _WIN32
	static constexpr size_t BUFFER_SIZE = 512;

	// Convert to UTF-16 first so Unicode characters display correctly. NT is going to do it anyway...
	wchar_t wbuf[BUFFER_SIZE];
	wchar_t* wmessage_buf = wbuf;
	int wmessage_buflen = static_cast<int>(std::size(wbuf) - 1);
	if (message.length() >= std::size(wbuf))
	{
		wmessage_buflen = static_cast<int>(message.length());
		wmessage_buf = static_cast<wchar_t*>(std::malloc((static_cast<size_t>(wmessage_buflen) + 2) * sizeof(wchar_t)));
		if (!wmessage_buf)
			return;
	}

	int wmessage_size = 0;
	if (!message.empty()) [[likely]]
	{
		wmessage_size = MultiByteToWideChar(CP_UTF8, 0, message.data(), static_cast<int>(message.length()), wmessage_buf, wmessage_buflen);
		if (wmessage_size <= 0)
			goto cleanup;
	}

	wmessage_buf[wmessage_size++] = L'\n';
	wmessage_buf[wmessage_size++] = 0;
	OutputDebugStringW(wmessage_buf);

cleanup:
	if (wmessage_buf != wbuf)
		std::free(wmessage_buf);
#endif
}

bool Log::IsDebugOutputAvailable()
{
#ifdef _WIN32
	return IsDebuggerPresent();
#else
	return false;
#endif
}

bool Log::IsDebugOutputEnabled()
{
	return (s_console_level > LOGLEVEL_NONE);
}

void Log::SetDebugOutputLevel(LOGLEVEL level)
{
	s_debug_level = level;
	UpdateMaxLevel();
}

__ri void Log::WriteToFile(LOGLEVEL level, ConsoleColors color, std::string_view message)
{
	std::unique_lock lock(s_file_mutex);
	if (!s_file_handle) [[unlikely]]
		return;

	if (!message.empty()) [[likely]]
	{
		if (s_log_timestamps)
		{
			std::fprintf(s_file_handle.get(), TIMESTAMP_PRINTF_STRING "%.*s\n", GetCurrentMessageTime(),
				static_cast<int>(message.size()), message.data());
		}
		else
		{
			std::fprintf(s_file_handle.get(), "%.*s\n", static_cast<int>(message.size()), message.data());
		}
	}
	else
	{
		if (s_log_timestamps)
		{
			std::fprintf(s_file_handle.get(), TIMESTAMP_PRINTF_STRING "\n", GetCurrentMessageTime());
		}
		else
		{
			std::fputc('\n', s_file_handle.get());
		}
	}

	std::fflush(s_file_handle.get());
}

bool Log::IsFileOutputEnabled()
{
	return (s_file_level > LOGLEVEL_NONE);
}

bool Log::SetFileOutputLevel(LOGLEVEL level, std::string path)
{
	std::unique_lock lock(s_file_mutex);

	const bool was_enabled = (s_file_level > LOGLEVEL_NONE);
	const bool new_enabled = (level > LOGLEVEL_NONE && !path.empty());
	if (was_enabled != new_enabled || (new_enabled && path == s_file_path))
	{
		if (new_enabled)
		{
			if (!s_file_handle || s_file_path != path)
			{
				s_file_handle.reset();
				s_file_handle = FileSystem::OpenManagedCFile(path.c_str(), "wb");
				if (s_file_handle)
				{
					s_file_path = std::move(path);
				}
				else
				{
					s_file_path = {};

					if (IsConsoleOutputEnabled())
						WriteToConsole(LOGLEVEL_ERROR, Color_StrongRed, TinyString::from_format("Failed to open log file '{}'", path));
				}
			}
		}
		else
		{
			s_file_handle.reset();
			s_file_path = {};
		}
	}

	s_file_level = s_file_handle ? level : LOGLEVEL_NONE;
	return IsFileOutputEnabled();
}

std::FILE* Log::GetFileLogHandle()
{
	std::unique_lock lock(s_file_mutex);
	return s_file_handle.get();
}

bool Log::IsHostOutputEnabled()
{
	return (s_host_level > LOGLEVEL_NONE);
}

void Log::SetHostOutputLevel(LOGLEVEL level, HostCallbackType callback)
{
	s_host_callback = callback;
	s_host_level = callback ? level : LOGLEVEL_NONE;
	UpdateMaxLevel();
}

bool Log::AreTimestampsEnabled()
{
	return s_log_timestamps;
}

void Log::SetTimestampsEnabled(bool enabled)
{
	s_log_timestamps = enabled;
}

LOGLEVEL Log::GetMaxLevel()
{
	return s_max_level;
}

__ri void Log::UpdateMaxLevel()
{
	s_max_level = std::max(s_console_level, std::max(s_debug_level, std::max(s_file_level, s_host_level)));
}

void Log::ExecuteCallbacks(LOGLEVEL level, ConsoleColors color, std::string_view message)
{
	// TODO: Cache the message time.

	// Split newlines into separate messages.
	std::string_view::size_type start_pos = 0;
	if (std::string_view::size_type end_pos = message.find('\n'); end_pos != std::string::npos) [[unlikely]]
	{
		for (;;)
		{
			std::string_view message_line;
			if (start_pos != end_pos)
				message_line = message.substr(start_pos, (end_pos == std::string_view::npos) ? end_pos : end_pos - start_pos);

			ExecuteCallbacks(level, color, message_line);

			if (end_pos == std::string_view::npos)
				return;

			start_pos = end_pos + 1;
			end_pos = message.find('\n', start_pos);
		}
		return;
	}

	pxAssert(level > LOGLEVEL_NONE);
	if (level <= s_console_level)
		WriteToConsole(level, color, message);

	if (level <= s_debug_level)
		WriteToDebug(level, color, message);

	if (level <= s_file_level)
		WriteToFile(level, color, message);

	if (level <= s_host_level)
	{
		// double check in case of race here
		const HostCallbackType callback = s_host_callback;
		if (callback)
			s_host_callback(level, color, message);
	}
}

void Log::Write(LOGLEVEL level, ConsoleColors color, std::string_view message)
{
	if (level > s_max_level)
		return;

	ExecuteCallbacks(level, color, message);
}

void Log::Writef(LOGLEVEL level, ConsoleColors color, const char* format, ...)
{
	std::va_list ap;
	va_start(ap, format);
	Writev(level, color, format, ap);
	va_end(ap);
}

void Log::Writev(LOGLEVEL level, ConsoleColors color, const char* format, va_list ap)
{
	if (level > s_max_level)
		return;

	std::va_list ap_copy;
	va_copy(ap_copy, ap);

#ifdef _WIN32
	const u32 required_size = static_cast<u32>(_vscprintf(format, ap_copy));
#else
	const u32 required_size = std::vsnprintf(nullptr, 0, format, ap_copy);
#endif
	va_end(ap_copy);

	if (required_size < 512)
	{
		char buffer[512];
		const int len = std::vsnprintf(buffer, std::size(buffer), format, ap);
		if (len > 0)
			ExecuteCallbacks(level, color, std::string_view(buffer, static_cast<size_t>(len)));
	}
	else
	{
		char* buffer = new char[required_size + 1];
		const int len = std::vsnprintf(buffer, required_size + 1, format, ap);
		if (len > 0)
			ExecuteCallbacks(level, color, std::string_view(buffer, static_cast<size_t>(len)));
		delete[] buffer;
	}
}

void Log::WriteFmtArgs(LOGLEVEL level, ConsoleColors color, fmt::string_view fmt, fmt::format_args args)
{
	if (level > s_max_level)
		return;

	fmt::memory_buffer buffer;
	fmt::vformat_to(std::back_inserter(buffer), fmt, args);

	ExecuteCallbacks(level, color, std::string_view(buffer.data(), buffer.size()));
}