#include "stdafx.h"
#include "util/types.hpp"
#include "util/logs.hpp"
#include "util/v128.hpp"
#include "util/simd.hpp"
#include "util/File.h"
#include "util/StrFmt.h"
#include "system_config.h"
#include "savestate_utils.hpp"

#include "System.h"

#include <set>
#include <span>

LOG_CHANNEL(sys_log, "SYS");

struct serial_ver_t
{
	std::string ver_name;
	bool used = false;
	u16 current_version = 0;
	std::set<u16> compatible_versions;
};

static std::array<serial_ver_t, 27> s_serial_versions;

#define SERIALIZATION_VER(name, identifier, ...)                \
                                                                \
	const bool s_##name##_serialization_fill = []() {           \
		auto& e = ::s_serial_versions[identifier];              \
		if (e.compatible_versions.empty())                      \
		{                                                       \
			e.compatible_versions = {__VA_ARGS__};              \
			e.ver_name = #name;                                 \
		}                                                       \
		return true;                                            \
	}();                                                        \
                                                                \
	extern void using_##name##_serialization()                  \
	{                                                           \
		ensure(Emu.IsStopped());                                \
		::s_serial_versions[identifier].used = true;            \
	}                                                           \
                                                                \
	extern s32 get_##name##_serialization_version()             \
	{                                                           \
		return ::s_serial_versions[identifier].current_version; \
	}

SERIALIZATION_VER(global_version, 0, 19) // For stuff not listed here
SERIALIZATION_VER(ppu, 1, 1, 2 /*PPU sleep order*/, 3 /*PPU FNID and module*/)
SERIALIZATION_VER(spu, 2, 1)
SERIALIZATION_VER(lv2_sync, 3, 1)
SERIALIZATION_VER(lv2_vm, 4, 1)
SERIALIZATION_VER(lv2_net, 5, 1, 2 /*TCP Feign conection loss*/)
SERIALIZATION_VER(lv2_fs, 6, 1, 2 /*NPDRM key saving*/)
SERIALIZATION_VER(lv2_prx_overlay, 7, 1)
SERIALIZATION_VER(lv2_memory, 8, 1)
SERIALIZATION_VER(lv2_config, 9, 1)

namespace rsx
{
	SERIALIZATION_VER(rsx, 10, 1, 2 /*Pending flip*/, 3 /*avconf scan_mode*/)
}

namespace np
{
	SERIALIZATION_VER(sceNp, 11, 1)
}

#ifdef _MSC_VER
// Compiler bug, lambda function body does seem to inherit used namespace atleast for function declaration
SERIALIZATION_VER(rsx, 10)
SERIALIZATION_VER(sceNp, 11)
#endif

SERIALIZATION_VER(cellVdec, 12, 1)
SERIALIZATION_VER(cellAudio, 13, 1)
SERIALIZATION_VER(cellCamera, 14, 1, 2 /*gem_camera_shared*/)
SERIALIZATION_VER(cellGem, 15, 1, 2 /*calibration_status_flags*/, 3 /*video_conversion*/)
SERIALIZATION_VER(sceNpTrophy, 16, 1)
SERIALIZATION_VER(cellMusic, 17, 1)
SERIALIZATION_VER(cellVoice, 18, 1)
SERIALIZATION_VER(cellGcm, 19, 1)
SERIALIZATION_VER(sysPrxForUser, 20, 1)
SERIALIZATION_VER(cellSaveData, 21, 1)
SERIALIZATION_VER(cellAudioOut, 22, 1)
SERIALIZATION_VER(sys_io, 23, 2)

// Misc versions for HLE/LLE not included so main version would not invalidated
SERIALIZATION_VER(LLE, 24, 1)
SERIALIZATION_VER(HLE, 25, 1)

SERIALIZATION_VER(cellSysutil, 26, 1, 2 /*AVC2 Muting,Volume*/)

template <>
void fmt_class_string<std::remove_cvref_t<decltype(s_serial_versions)>>::format(std::string& out, u64 arg)
{
	bool is_first = true;

	const auto& serials = get_object(arg);

	out += "{ ";

	for (auto& entry : serials)
	{
		if (entry.current_version)
		{
			if (!is_first)
			{
				out += ", ";
			}

			is_first = false;
			fmt::append(out, "%s=%d", entry.ver_name, entry.current_version);
		}
	}

	out += " }";
}

std::vector<version_entry> get_savestate_versioning_data(fs::file&& file, std::string_view filepath)
{
	if (!file)
	{
		return {};
	}

	file.seek(0);

	utils::serial ar;
	ar.set_reading_state({}, true);

	if (filepath.ends_with(".zst"))
	{
		ar.m_file_handler = make_compressed_zstd_serialization_file_handler(std::move(file));
	}
	else if (filepath.ends_with(".gz"))
	{
		ar.m_file_handler = make_compressed_serialization_file_handler(std::move(file));
	}
	else
	{
		ar.m_file_handler = make_uncompressed_serialization_file_handler(std::move(file));
	}

	if (u64 r = 0; ar.try_read(r) != 0 || r != "RPCS3SAV"_u64)
	{
		return {};
	}

	ar.pos = 10;

	u64 offs = ar.try_read<u64>().second;

	const usz fsize = ar.get_size(offs);

	if (!offs || fsize <= offs)
	{
		return {};
	}

	ar.seek_pos(offs);
	ar.breathe(true);

	std::vector<version_entry> ver_data = ar.pop<std::vector<version_entry>>();
	return ver_data;
}

std::shared_ptr<utils::serial> make_savestate_reader(const std::string& path)
{
	std::shared_ptr<utils::serial> ar;

	fs::file save{path, fs::isfile + fs::read};

	if (!save)
	{
		return ar;
	}

	if (path.ends_with(".SAVESTAT") && save.size() >= 8 && save.read<u64>() == "RPCS3SAV"_u64)
	{
		ar = std::make_shared<utils::serial>();
		ar->set_reading_state();

		ar->m_file_handler = make_uncompressed_serialization_file_handler(std::move(save));
	}
	else if (path.ends_with(".zst"))
	{
		ar = std::make_shared<utils::serial>();
		ar->set_reading_state();

		ar->m_file_handler = make_compressed_zstd_serialization_file_handler(std::move(save));

		if (ar->try_read<u64>().second != "RPCS3SAV"_u64)
		{
			ar.reset();
		}
		else
		{
			ar->pos = 0;
		}
	}
	else if (path.ends_with(".gz"))
	{
		ar = std::make_shared<utils::serial>();
		ar->set_reading_state();

		ar->m_file_handler = make_compressed_serialization_file_handler(std::move(save));

		if (ar->try_read<u64>().second != "RPCS3SAV"_u64)
		{
			ar.reset();
		}
		else
		{
			ar->pos = 0;
		}
	}

	return ar;
}

bool is_savestate_version_compatible(const std::vector<version_entry>& data, bool is_boot_check)
{
	if (data.empty())
	{
		return false;
	}

	bool ok = true;

	if (is_boot_check)
	{
		for (auto& entry : s_serial_versions)
		{
			// Version 0 means that the entire constructor using the version should be skipped
			entry.current_version = 0;
		}
	}

	auto& channel = (is_boot_check ? sys_log.error : sys_log.trace);

	for (const auto& entry : data)
	{
		if (entry.type >= s_serial_versions.size())
		{
			channel("Savestate version identifier is unknown! (category=%u, version=%u)", entry.type, entry.version);
			ok = false; // Log all mismatches
		}
		else if (!s_serial_versions[entry.type].compatible_versions.count(entry.version))
		{
			channel("Savestate version is not supported. (category=%u, version=%u)", entry.type, entry.version);
			ok = false;
		}
		else if (is_boot_check)
		{
			s_serial_versions[entry.type].current_version = entry.version;
		}
	}

	if (is_boot_check)
	{
		if (ok)
		{
			sys_log.success("Savestate versions: %s", s_serial_versions);
		}
		else
		{
			for (auto& entry : s_serial_versions)
			{
				entry.current_version = 0;
			}
		}
	}

	return ok;
}

std::string get_savestate_file(std::string_view title_id, std::string_view boot_path, s64 abs_id, s64 rel_id)
{
	const std::string title = std::string{title_id.empty() ? boot_path.substr(boot_path.find_last_of(fs::delim) + 1) : title_id};

	if (abs_id == -1 && rel_id == -1)
	{
		// Return directory
		return fs::get_config_dir() + "savestates/" + title + "/";
	}

	ensure(rel_id < 0 || abs_id >= 0, "Unimplemented!");

	const std::string save_id = fmt::format("%d", abs_id);

	// Make sure that savestate file with higher IDs are placed at the bottom of "by name" file ordering in directory view by adding a single character prefix which tells the ID length
	// While not needing to keep a 59 chars long suffix at all times for this purpose
	const char prefix = ::at32("0123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"sv, save_id.size());

	std::string path = fs::get_config_dir() + "/savestates/" + title + "/" + title + '_' + prefix + '_' + save_id + ".SAVESTAT";

	if (std::string path_compressed = path + ".zst"; fs::is_file(path_compressed))
	{
		return path_compressed;
	}

	if (std::string path_compressed = path + ".gz"; fs::is_file(path_compressed))
	{
		return path_compressed;
	}

	return path;
}

bool is_savestate_compatible(fs::file&& file, std::string_view filepath)
{
	return is_savestate_version_compatible(get_savestate_versioning_data(std::move(file), filepath), false);
}

bool is_savestate_compatible(const std::string& filepath)
{
	if (fs::file file{filepath, fs::isfile + fs::read})
	{
		return is_savestate_compatible(std::move(file), filepath);
	}
	return false;
}

std::vector<version_entry> read_used_savestate_versions()
{
	std::vector<version_entry> used_serial;
	used_serial.reserve(s_serial_versions.size());

	for (serial_ver_t& ver : s_serial_versions)
	{
		if (std::exchange(ver.used, false))
		{
			used_serial.push_back(version_entry{static_cast<u16>(&ver - s_serial_versions.data()), *ver.compatible_versions.rbegin()});
		}

		ver.current_version = 0;
	}

	return used_serial;
}

bool boot_last_savestate(bool testing)
{
	if (!g_cfg.savestate.suspend_emu && !Emu.GetTitleID().empty() && (Emu.IsRunning() || Emu.GetStatus() == system_state::paused))
	{
		const std::string save_dir = get_savestate_file(Emu.GetTitleID(), Emu.GetBoot(), -1, -1);

		std::string savestate_path;
		s64 mtime = smin;

		for (auto&& entry : fs::dir(save_dir))
		{
			if (entry.is_directory)
			{
				continue;
			}

			// Find the latest savestate file compatible with the game (TODO: Check app version and anything more)
			if (entry.name.find(Emu.GetTitleID()) != umax && mtime <= entry.mtime)
			{
				if (std::string path = save_dir + entry.name + ".zst"; is_savestate_compatible(fs::file(path), path))
				{
					savestate_path = std::move(path);
					mtime = entry.mtime;
				}
				else if (std::string path = save_dir + entry.name + ".gz"; is_savestate_compatible(fs::file(path), path))
				{
					savestate_path = std::move(path);
					mtime = entry.mtime;
				}
				else if (std::string path = save_dir + entry.name; is_savestate_compatible(fs::file(path), path))
				{
					savestate_path = std::move(path);
					mtime = entry.mtime;
				}
			}
		}

		const bool result = fs::is_file(savestate_path);

		if (testing)
		{
			sys_log.trace("boot_last_savestate(true) returned %s.", result);
			return result;
		}

		if (result)
		{
			sys_log.success("Booting the most recent savestate \'%s\' using the Reload shortcut.", savestate_path);

			// Make sure we keep the game window opened
			Emu.SetContinuousMode(true);
			Emu.GracefulShutdown(false, false, false, true);

			if (game_boot_result error = Emu.BootGame(savestate_path, "", true); error != game_boot_result::no_errors)
			{
				sys_log.error("Failed to boot savestate \'%s\' using the Reload shortcut. (error: %s)", savestate_path, error);
			}
			else
			{
				return true;
			}
		}

		sys_log.error("No compatible savestate file found in \'%s\''", save_dir);
	}

	return false;
}

bool load_and_check_reserved(utils::serial& ar, usz size)
{
	u8 bytes[4096];
	ensure(size < std::size(bytes));
	std::memset(&bytes[size & (0 - sizeof(v128))], 0, sizeof(v128));

	const usz old_pos = ar.pos;
	ar(std::span<u8>(bytes, size));

	// Check if all are 0
	for (usz i = 0; i < size; i += sizeof(v128))
	{
		if (v128::loadu(&bytes[i]) != v128{})
		{
			return false;
		}
	}

	return old_pos + size == ar.pos;
}

namespace stx
{
	extern u16 serial_breathe_and_tag(utils::serial& ar, std::string_view name, bool tag_bit)
	{
		thread_local std::string_view s_tls_object_name = "none";
		thread_local u64 s_tls_call_count = 1, s_tls_current_pos = 0;

		if (s_tls_current_pos >= ar.pos)
		{
			// Reset, probably a new utils::serial object
			s_tls_call_count = 1;
			s_tls_object_name = "none"sv;
		}

		s_tls_current_pos = ar.pos;

		constexpr u16 data_mask = 0x7fff;

		if (ar.m_file_handler && ar.m_file_handler->is_null())
		{
			return (tag_bit ? data_mask + 1 : 0);
		}

		u16 tag = static_cast<u16>((static_cast<u16>(ar.pos / 2) & data_mask) | (tag_bit ? data_mask + 1 : 0));
		u16 saved = tag;
		ar(saved);

		sys_log.trace("serial_breathe_and_tag(%u): %s, object: '%s', next-object: '%s', expected/tag: 0x%x == 0x%x", s_tls_call_count, ar, s_tls_object_name, name, tag, saved);

		if ((saved ^ tag) & data_mask)
		{
			ensure(!ar.is_writing());
			fmt::throw_exception("serial_breathe_and_tag(%u): %s\nobject: '%s', next-object: '%s', expected/tag: 0x%x != 0x%x,", s_tls_call_count, ar, s_tls_object_name, name, tag, saved);
		}

		s_tls_object_name = name;
		s_tls_call_count++;
		ar.breathe();
		return saved;
	}
} // namespace stx

// MSVC bug workaround, see above similar case
extern u16 serial_breathe_and_tag(utils::serial& ar, std::string_view name, bool tag_bit)
{
	return ::stx::serial_breathe_and_tag(ar, name, tag_bit);
}

[[noreturn]] void hle_locks_t::lock()
{
	// Unreachable
	fmt::throw_exception("Unreachable");
}

bool hle_locks_t::try_lock()
{
	while (true)
	{
		auto [old, success] = lock_val.fetch_op([](s64& value)
			{
				if (value >= 0)
				{
					value++;
					return true;
				}

				return false;
			});

		if (success)
		{
			return true;
		}

		if (old == finalized)
		{
			break;
		}

		lock_val.wait(old);
	}

	return false;
}

void hle_locks_t::unlock()
{
	lock_val--;
}

bool hle_locks_t::try_finalize(std::function<bool()> test)
{
	if (!test())
	{
		return false;
	}

	if (!lock_val.compare_and_swap_test(0, waiting_for_evaluation))
	{
		return false;
	}

	if (!test())
	{
		// Failed
		ensure(lock_val.compare_and_swap_test(waiting_for_evaluation, 0));
		return false;
	}

	ensure(lock_val.compare_and_swap_test(waiting_for_evaluation, finalized));

	// Sanity check when debugging (the result is not expected to change after finalization)
	// ensure(test());

	lock_val.notify_all();
	return true;
}