#include "Log.h"
#include "File.h"
#include "StrFmt.h"

#include <cstdarg>
#include <string>

// Thread-specific log prefix provider
thread_local std::string(*g_tls_log_prefix)() = nullptr;

namespace _log
{
	struct listener
	{
		listener() = default;

		virtual ~listener() = default;

		virtual void log(const channel& ch, level sev, const std::string& text) = 0;
	};

	class file_writer
	{
		// Could be memory-mapped file
		fs::file m_file;

	public:
		file_writer(const std::string& name);

		virtual ~file_writer() = default;

		// Append raw data
		void log(const std::string& text);

		// Get current file size (may be used by secondary readers)
		std::size_t size() const;
	};

	struct file_listener : public file_writer, public listener
	{
		file_listener(const std::string& name)
			: file_writer(name)
			, listener()
		{
		}

		// Encode level, current thread name, channel name and write log message
		virtual void log(const channel& ch, level sev, const std::string& text) override;
	};

	static file_listener& get_logger()
	{
		// Use magic static
		static file_listener logger("RPCS3.log");
		return logger;
	}

	channel GENERAL(nullptr, level::notice);
	channel LOADER("LDR", level::notice);
	channel MEMORY("MEM", level::notice);
	channel RSX("RSX", level::notice);
	channel HLE("HLE", level::notice);
	channel PPU("PPU", level::notice);
	channel SPU("SPU", level::notice);
	channel ARMv7("ARMv7");
}

void _log::channel::broadcast(const _log::channel& ch, _log::level sev, const char* fmt...)
{
	va_list args;
	va_start(args, fmt);
	get_logger().log(ch, sev, fmt::unsafe_vformat(fmt, args));
	va_end(args);
}

[[noreturn]] extern void catch_all_exceptions();

_log::file_writer::file_writer(const std::string& name)
{
	try
	{
		if (!m_file.open(fs::get_config_dir() + name, fs::rewrite + fs::append))
		{
			throw fmt::exception("Can't create log file %s (error %d)", name, fs::error);
		}
	}
	catch (...)
	{
		catch_all_exceptions();
	}
}

void _log::file_writer::log(const std::string& text)
{
	m_file.write(text);
}

std::size_t _log::file_writer::size() const
{
	return m_file.pos();
}

void _log::file_listener::log(const _log::channel& ch, _log::level sev, const std::string& text)
{
	std::string msg; msg.reserve(text.size() + 200);

	// Used character: U+00B7 (Middle Dot)
	switch (sev)
	{
	case level::always:  msg = u8"·A "; break;
	case level::fatal:   msg = u8"·F "; break;
	case level::error:   msg = u8"·E "; break;
	case level::todo:    msg = u8"·U "; break;
	case level::success: msg = u8"·S "; break;
	case level::warning: msg = u8"·W "; break;
	case level::notice:  msg = u8"·! "; break;
	case level::trace:   msg = u8"·T "; break;
	}

	// TODO: print time?

	if (auto prefix = g_tls_log_prefix)
	{
		msg += '{';
		msg += prefix();
		msg += "} ";
	}
	
	if (ch.name)
	{
		msg += ch.name;
		msg += sev == level::todo ? " TODO: " : ": ";
	}
	else if (sev == level::todo)
	{
		msg += "TODO: ";
	}
	
	msg += text;
	msg += '\n';

	file_writer::log(msg);
}