#include "util/types.hpp"
#include "util/sysinfo.hpp"
#include "JIT.h"
#include "StrFmt.h"
#include "File.h"
#include "util/logs.hpp"
#include "mutex.h"
#include "util/vm.hpp"
#include "util/asm.hpp"
#include "Crypto/unzip.h"

#include <charconv>

LOG_CHANNEL(jit_log, "JIT");

#ifdef LLVM_AVAILABLE

#include <unordered_map>

#ifdef _MSC_VER
#pragma warning(push, 0)
#else
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wall"
#pragma GCC diagnostic ignored "-Wextra"
#pragma GCC diagnostic ignored "-Wold-style-cast"
#pragma GCC diagnostic ignored "-Wunused-parameter"
#pragma GCC diagnostic ignored "-Wstrict-aliasing"
#pragma GCC diagnostic ignored "-Wredundant-decls"
#pragma GCC diagnostic ignored "-Weffc++"
#pragma GCC diagnostic ignored "-Wmissing-noreturn"
#endif
#include <llvm/Support/CodeGen.h>
#include "llvm/Support/TargetSelect.h"
#include "llvm/TargetParser/Host.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
#include "llvm/ExecutionEngine/ObjectCache.h"
#include "llvm/ExecutionEngine/JITEventListener.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Object/SymbolSize.h"
#ifdef _MSC_VER
#pragma warning(pop)
#else
#pragma GCC diagnostic pop
#endif

const bool jit_initialize = []() -> bool
{
	llvm::InitializeNativeTarget();
	llvm::InitializeNativeTargetAsmPrinter();
	llvm::InitializeNativeTargetAsmParser();
	LLVMLinkInMCJIT();
	return true;
}();

[[noreturn]] static void null(const char* name)
{
	fmt::throw_exception("Null function: %s", name);
}

namespace vm
{
	extern u8* const g_sudo_addr;
}

static shared_mutex null_mtx;

static std::unordered_map<std::string, u64> null_funcs;

static u64 make_null_function(const std::string& name)
{
	if (name.starts_with("__0x"))
	{
		u32 addr = -1;
		auto res = std::from_chars(name.c_str() + 4, name.c_str() + name.size(), addr, 16);

		if (res.ec == std::errc() && res.ptr == name.c_str() + name.size() && addr < 0x8000'0000)
		{
			// Point the garbage to reserved, non-executable memory
			return reinterpret_cast<u64>(vm::g_sudo_addr + addr);
		}
	}

	std::lock_guard lock(null_mtx);

	if (u64& func_ptr = null_funcs[name]) [[likely]]
	{
		// Already exists
		return func_ptr;
	}
	else
	{
		using namespace asmjit;

		// Build a "null" function that contains its name
		const auto func = build_function_asm<void (*)()>("NULL", [&](native_asm& c, auto& args)
		{
#if defined(ARCH_X64)
			Label data = c.newLabel();
			c.lea(args[0], x86::qword_ptr(data, 0));
			c.jmp(Imm(&null));
			c.align(AlignMode::kCode, 16);
			c.bind(data);

			// Copy function name bytes
			for (char ch : name)
				c.db(ch);
			c.db(0);
			c.align(AlignMode::kData, 16);
#else
			// AArch64 implementation
			Label jmp_address = c.newLabel();
			Label data = c.newLabel();
			// Force absolute jump to prevent out of bounds PC-rel jmp
			c.ldr(args[0], arm::ptr(jmp_address));
			c.br(args[0]);
			c.align(AlignMode::kCode, 16);

			c.bind(data);
			c.embed(name.c_str(), name.size());
			c.embedUInt8(0U);
			c.bind(jmp_address);
			c.embedUInt64(reinterpret_cast<u64>(&null));
			c.align(AlignMode::kData, 16);
#endif
		});

		func_ptr = reinterpret_cast<u64>(func);
		return func_ptr;
	}
}

struct JITAnnouncer : llvm::JITEventListener
{
	void notifyObjectLoaded(u64, const llvm::object::ObjectFile& obj, const llvm::RuntimeDyld::LoadedObjectInfo& info) override
	{
		using namespace llvm;

		object::OwningBinary<object::ObjectFile> debug_obj_ = info.getObjectForDebug(obj);
		if (!debug_obj_.getBinary())
		{
#ifdef __linux__
			jit_log.error("LLVM: Failed to announce JIT events (no debug object)");
#endif
			return;
		}

		const object::ObjectFile& debug_obj = *debug_obj_.getBinary();

		for (const auto& [sym, size] : computeSymbolSizes(debug_obj))
		{
			Expected<object::SymbolRef::Type> type_ = sym.getType();
			if (!type_ || *type_ != object::SymbolRef::ST_Function)
				continue;

			Expected<StringRef> name = sym.getName();
			if (!name)
				continue;

			Expected<u64> addr = sym.getAddress();
			if (!addr)
				continue;

			jit_announce(*addr, size, {name->data(), name->size()});
		}
	}
};

// Simple memory manager
struct MemoryManager1 : llvm::RTDyldMemoryManager
{
	// 256 MiB for code or data
	static constexpr u64 c_max_size = 0x20000000 / 2;

	// Allocation unit (2M)
	static constexpr u64 c_page_size = 2 * 1024 * 1024;

	// Reserve 512 MiB
	u8* const ptr = static_cast<u8*>(utils::memory_reserve(c_max_size * 2));

	u64 code_ptr = 0;
	u64 data_ptr = c_max_size;

	MemoryManager1() = default;

	MemoryManager1(const MemoryManager1&) = delete;

	MemoryManager1& operator=(const MemoryManager1&) = delete;

	~MemoryManager1() override
	{
		// Hack: don't release to prevent reuse of address space, see jit_announce
		utils::memory_decommit(ptr, c_max_size * 2);
	}

	llvm::JITSymbol findSymbol(const std::string& name) override
	{
		u64 addr = RTDyldMemoryManager::getSymbolAddress(name);

		if (!addr)
		{
			addr = make_null_function(name);

			if (!addr)
			{
				fmt::throw_exception("Failed to link '%s'", name);
			}
		}

		return {addr, llvm::JITSymbolFlags::Exported};
	}

	u8* allocate(u64& oldp, uptr size, uint align, utils::protection prot)
	{
		if (align > c_page_size)
		{
			jit_log.fatal("Unsupported alignment (size=0x%x, align=0x%x)", size, align);
			return nullptr;
		}

		const u64 olda = utils::align(oldp, align);
		const u64 newp = utils::align(olda + size, align);

		if ((newp - 1) / c_max_size != oldp / c_max_size)
		{
			jit_log.fatal("Out of memory (size=0x%x, align=0x%x)", size, align);
			return nullptr;
		}

		if ((oldp - 1) / c_page_size != (newp - 1) / c_page_size)
		{
			// Allocate pages on demand
			const u64 pagea = utils::align(oldp, c_page_size);
			const u64 psize = utils::align(newp - pagea, c_page_size);
			utils::memory_commit(this->ptr + pagea, psize, prot);
		}

		// Update allocation counter
		oldp = newp;

		return this->ptr + olda;
	}

	u8* allocateCodeSection(uptr size, uint align, uint /*sec_id*/, llvm::StringRef /*sec_name*/) override
	{
		return allocate(code_ptr, size, align, utils::protection::wx);
	}

	u8* allocateDataSection(uptr size, uint align, uint /*sec_id*/, llvm::StringRef /*sec_name*/, bool /*is_ro*/) override
	{
		return allocate(data_ptr, size, align, utils::protection::rw);
	}

	bool finalizeMemory(std::string* = nullptr) override
	{
		return false;
	}

	void registerEHFrames(u8*, u64, usz) override
	{
	}

	void deregisterEHFrames() override
	{
	}
};

// Simple memory manager
struct MemoryManager2 : llvm::RTDyldMemoryManager
{
	MemoryManager2() = default;

	~MemoryManager2() override
	{
	}

	llvm::JITSymbol findSymbol(const std::string& name) override
	{
		u64 addr = RTDyldMemoryManager::getSymbolAddress(name);

		if (!addr)
		{
			addr = make_null_function(name);

			if (!addr)
			{
				fmt::throw_exception("Failed to link '%s' (MM2)", name);
			}
		}

		return {addr, llvm::JITSymbolFlags::Exported};
	}

	u8* allocateCodeSection(uptr size, uint align, uint /*sec_id*/, llvm::StringRef /*sec_name*/) override
	{
		return jit_runtime::alloc(size, align, true);
	}

	u8* allocateDataSection(uptr size, uint align, uint /*sec_id*/, llvm::StringRef /*sec_name*/, bool /*is_ro*/) override
	{
		return jit_runtime::alloc(size, align, false);
	}

	bool finalizeMemory(std::string* = nullptr) override
	{
		return false;
	}

	void registerEHFrames(u8*, u64, usz) override
	{
	}

	void deregisterEHFrames() override
	{
	}
};

// Helper class
class ObjectCache final : public llvm::ObjectCache
{
	const std::string& m_path;
	const std::add_pointer_t<jit_compiler> m_compiler = nullptr;

public:
	ObjectCache(const std::string& path, jit_compiler* compiler = nullptr)
		: m_path(path)
		, m_compiler(compiler)
	{
	}

	~ObjectCache() override = default;

	void notifyObjectCompiled(const llvm::Module* _module, llvm::MemoryBufferRef obj) override
	{
		std::string name = m_path;

		name.append(_module->getName().data());
		//fs::file(name, fs::rewrite).write(obj.getBufferStart(), obj.getBufferSize());
		name.append(".gz");

		if (!obj.getBufferSize())
		{
			jit_log.error("LLVM: Nothing to write: %s", name);
			return;
		}

		ensure(m_compiler);

		fs::file module_file(name, fs::rewrite);

		if (!module_file)
		{
			jit_log.error("LLVM: Failed to create module file: %s (%s)", name, fs::g_tls_error);
			return;
		}

		// Bold assumption about upper limit of space consumption
		const usz max_size = obj.getBufferSize() * 4;

		if (!m_compiler->add_sub_disk_space(0 - max_size))
		{
			jit_log.error("LLVM: Failed to create module file: %s (not enough disk space left)", name);
			return;
		}

		if (!zip(obj.getBufferStart(), obj.getBufferSize(), module_file))
		{
			jit_log.error("LLVM: Failed to compress module: %s", _module->getName().data());
			module_file.close();
			fs::remove_file(name);
			return;
		}

		jit_log.notice("LLVM: Created module: %s", _module->getName().data());

		// Restore space that was overestimated
		ensure(m_compiler->add_sub_disk_space(max_size - module_file.size()));
	}

	static std::unique_ptr<llvm::MemoryBuffer> load(const std::string& path)
	{
		if (fs::file cached{path + ".gz", fs::read})
		{
			const std::vector<u8> cached_data = cached.to_vector<u8>();

			if (cached_data.empty()) [[unlikely]]
			{
				return nullptr;
			}

			const std::vector<u8> out = unzip(cached_data);

			if (out.empty())
			{
				jit_log.error("LLVM: Failed to unzip module: '%s'", path);
				return nullptr;
			}

			auto buf = llvm::WritableMemoryBuffer::getNewUninitMemBuffer(out.size());
			std::memcpy(buf->getBufferStart(), out.data(), out.size());
			return buf;
		}

		if (fs::file cached{path, fs::read})
		{
			if (cached.size() == 0) [[unlikely]]
			{
				return nullptr;
			}

			auto buf = llvm::WritableMemoryBuffer::getNewUninitMemBuffer(cached.size());
			cached.read(buf->getBufferStart(), buf->getBufferSize());
			return buf;
		}

		return nullptr;
	}

	std::unique_ptr<llvm::MemoryBuffer> getObject(const llvm::Module* _module) override
	{
		std::string path = m_path;
		path.append(_module->getName().data());

		if (auto buf = load(path))
		{
			jit_log.notice("LLVM: Loaded module: %s", _module->getName().data());
			return buf;
		}

		return nullptr;
	}
};

std::string jit_compiler::cpu(const std::string& _cpu)
{
	std::string m_cpu = _cpu;

	if (m_cpu.empty())
	{
		m_cpu = llvm::sys::getHostCPUName().str();

		if (m_cpu == "sandybridge" ||
			m_cpu == "ivybridge" ||
			m_cpu == "haswell" ||
			m_cpu == "broadwell" ||
			m_cpu == "skylake" ||
			m_cpu == "skylake-avx512" ||
			m_cpu == "cascadelake" ||
			m_cpu == "cooperlake" ||
			m_cpu == "cannonlake" ||
			m_cpu == "icelake" ||
			m_cpu == "icelake-client" ||
			m_cpu == "icelake-server" ||
			m_cpu == "tigerlake" ||
			m_cpu == "rocketlake" ||
			m_cpu == "alderlake" ||
			m_cpu == "raptorlake" ||
			m_cpu == "meteorlake")
		{
			// Downgrade if AVX is not supported by some chips
			if (!utils::has_avx())
			{
				m_cpu = "nehalem";
			}
		}

		if (m_cpu == "skylake-avx512" ||
			m_cpu == "cascadelake" ||
			m_cpu == "cooperlake" ||
			m_cpu == "cannonlake" ||
			m_cpu == "icelake" ||
			m_cpu == "icelake-client" ||
			m_cpu == "icelake-server" ||
			m_cpu == "tigerlake" ||
			m_cpu == "rocketlake")
		{
			// Downgrade if AVX-512 is disabled or not supported
			if (!utils::has_avx512())
			{
				m_cpu = "skylake";
			}
		}

		if (m_cpu == "znver1" && utils::has_clwb())
		{
			// Upgrade
			m_cpu = "znver2";
		}

		if ((m_cpu == "znver3" || m_cpu == "goldmont" || m_cpu == "alderlake" || m_cpu == "raptorlake" || m_cpu == "meteorlake") && utils::has_avx512_icl())
		{
			// Upgrade
			m_cpu = "icelake-client";
		}

		if (m_cpu == "goldmont" && utils::has_avx2())
		{
			// Upgrade
			m_cpu = "alderlake";
		}
	}

	return m_cpu;
}

std::string jit_compiler::triple1()
{
#if defined(_WIN32)
	return llvm::Triple::normalize(llvm::sys::getProcessTriple());
#elif defined(__APPLE__) && defined(ARCH_X64)
	return llvm::Triple::normalize("x86_64-unknown-linux-gnu");
#elif defined(__APPLE__) && defined(ARCH_ARM64)
	return llvm::Triple::normalize("aarch64-unknown-linux-gnu");
#else
	return llvm::Triple::normalize(llvm::sys::getProcessTriple());
#endif
}

std::string jit_compiler::triple2()
{
#if defined(_WIN32) && defined(ARCH_X64)
	return llvm::Triple::normalize("x86_64-unknown-linux-gnu");
#elif defined(_WIN32) && defined(ARCH_ARM64)
	return llvm::Triple::normalize("aarch64-unknown-linux-gnu");
#elif defined(__APPLE__) && defined(ARCH_X64)
	return llvm::Triple::normalize("x86_64-unknown-linux-gnu");
#elif defined(__APPLE__) && defined(ARCH_ARM64)
	return llvm::Triple::normalize("aarch64-unknown-linux-gnu");
#else
	return llvm::Triple::normalize(llvm::sys::getProcessTriple());
#endif
}

bool jit_compiler::add_sub_disk_space(ssz space)
{
	if (space >= 0)
	{
		ensure(m_disk_space.fetch_add(space) < ~static_cast<usz>(space));
		return true;
	}

	return m_disk_space.fetch_op([sub_size = static_cast<usz>(0 - space)](usz& val)
	{
		if (val >= sub_size)
		{
			val -= sub_size;
			return true;
		}

		return false;
	}).second;
}

jit_compiler::jit_compiler(const std::unordered_map<std::string, u64>& _link, const std::string& _cpu, u32 flags)
	: m_context(new llvm::LLVMContext)
	, m_cpu(cpu(_cpu))
{
	std::string result;

	auto null_mod = std::make_unique<llvm::Module> ("null_", *m_context);
	null_mod->setTargetTriple(jit_compiler::triple1());

	std::unique_ptr<llvm::RTDyldMemoryManager> mem;

	if (_link.empty())
	{
		// Auxiliary JIT (does not use custom memory manager, only writes the objects)
		if (flags & 0x1)
		{
			mem = std::make_unique<MemoryManager1>();
		}
		else
		{
			mem = std::make_unique<MemoryManager2>();
			null_mod->setTargetTriple(jit_compiler::triple2());
		}
	}
	else
	{
		mem = std::make_unique<MemoryManager1>();
	}

	{
		m_engine.reset(llvm::EngineBuilder(std::move(null_mod))
			.setErrorStr(&result)
			.setEngineKind(llvm::EngineKind::JIT)
			.setMCJITMemoryManager(std::move(mem))
#if LLVM_VERSION_MAJOR < 18
			.setOptLevel(llvm::CodeGenOpt::Aggressive)
#else
			.setOptLevel(llvm::CodeGenOptLevel::Aggressive)
#endif
			.setCodeModel(flags & 0x2 ? llvm::CodeModel::Large : llvm::CodeModel::Small)
#ifdef __APPLE__
			//.setCodeModel(llvm::CodeModel::Large)
#endif
			.setRelocationModel(llvm::Reloc::Model::PIC_)
			.setMCPU(m_cpu)
			.create());
	}

	if (!_link.empty())
	{
		for (auto&& [name, addr] : _link)
		{
			m_engine->updateGlobalMapping(name, addr);
		}
	}

	if (!_link.empty() || !(flags & 0x1))
	{
		m_engine->RegisterJITEventListener(llvm::JITEventListener::createIntelJITEventListener());
		m_engine->RegisterJITEventListener(new JITAnnouncer);
	}

	if (!m_engine)
	{
		fmt::throw_exception("LLVM: Failed to create ExecutionEngine: %s", result);
	}

	fs::device_stat stats{};

	if (fs::statfs(fs::get_cache_dir(), stats))
	{
		m_disk_space = stats.avail_free / 4;
	}
}

jit_compiler::~jit_compiler()
{
}

void jit_compiler::add(std::unique_ptr<llvm::Module> _module, const std::string& path)
{
	ObjectCache cache{path, this};
	m_engine->setObjectCache(&cache);

	const auto ptr = _module.get();
	m_engine->addModule(std::move(_module));
	m_engine->generateCodeForModule(ptr);
	m_engine->setObjectCache(nullptr);

	for (auto& func : ptr->functions())
	{
		// Delete IR to lower memory consumption
		func.deleteBody();
	}
}

void jit_compiler::add(std::unique_ptr<llvm::Module> _module)
{
	const auto ptr = _module.get();
	m_engine->addModule(std::move(_module));
	m_engine->generateCodeForModule(ptr);

	for (auto& func : ptr->functions())
	{
		// Delete IR to lower memory consumption
		func.deleteBody();
	}
}

bool jit_compiler::add(const std::string& path)
{
	auto cache = ObjectCache::load(path);

	if (!cache)
	{
		jit_log.error("ObjectCache: Failed to read file. (path='%s', error=%s)", path, fs::g_tls_error);
		return false;		
	}

	if (auto object_file = llvm::object::ObjectFile::createObjectFile(*cache))
	{
		m_engine->addObjectFile(llvm::object::OwningBinary<llvm::object::ObjectFile>(std::move(*object_file), std::move(cache)));
		jit_log.trace("ObjectCache: Successfully added %s", path);
		return true;
	}
	else
	{
		jit_log.error("ObjectCache: Adding failed: %s", path);
		return false;
	}
}

bool jit_compiler::check(const std::string& path)
{
	if (auto cache = ObjectCache::load(path))
	{
		if (auto object_file = llvm::object::ObjectFile::createObjectFile(*cache))
		{
			return true;
		}

		if (fs::remove_file(path))
		{
			jit_log.error("ObjectCache: Removed damaged file: %s", path);
		}
	}

	return false;
}

void jit_compiler::update_global_mapping(const std::string& name, u64 addr)
{
	m_engine->updateGlobalMapping(name, addr);
}

void jit_compiler::fin()
{
	m_engine->finalizeObject();
}

u64 jit_compiler::get(const std::string& name)
{
	return m_engine->getGlobalValueAddress(name);
}

#endif // LLVM_AVAILABLE