#include <iostream>

#include "vdm.hpp"
#include "msrexec.hpp"
#include "theo.h"
#include "linker.hpp"

using extern_symbols_t = std::vector<std::pair<std::string, lnk::map_symbols_t>>;
using objs_buffer_t = std::vector<lnk::obj_buffer_t>;

auto get_mapping_info(int argc, char** argv) -> std::pair<objs_buffer_t, extern_symbols_t>
{
	auto maps_offset = 0u;
	std::vector<lnk::obj_buffer_t> image_objs;
	std::vector<std::pair<std::string, lnk::map_symbols_t>> extern_symbols;

	for (auto idx = 2; idx < argc; ++idx)
	{
		if (!strcmp(argv[idx], "--maps"))
		{
			maps_offset = idx + 1;
			break;
		}

		// another flag so we break...
		if (argv[idx][0] == '-' && argv[idx][1] == '-')
			break;

		if (!lnk::get_objs(argv[idx], image_objs))
		{
			std::printf("> failed to parse lib...\n");
			return {};
		}
	}

	if (maps_offset)
	{
		for (auto idx = maps_offset; idx <= argc - 1; ++idx)
		{
			extern_symbols.push_back
			({
				std::filesystem::path(argv[idx]).stem().string(),
				lnk::get_map_symbols(argv[idx])
			});
		}
	}

	return { image_objs, extern_symbols };
}

int main(int argc, char** argv)
{
	if (argc < 3 || strcmp(argv[1], "--libs"))
	{
		std::printf("[!] invalid usage... please use one of the following:\n");
		std::printf("		> theo.exe --libs one.lib two.lib three.lib\n");
		std::printf("		> theo.exe --libs one.lib --maps ntoskrnl.exe.map win32kbase.sys.map\n");
		return -1;
	}

	auto [image_objs, extern_symbols] = get_mapping_info(argc, argv);
	std::printf("[+] number of objs = %d\n", image_objs.size());

	if (!image_objs.size())
	{
		std::printf("[!] failed to parse .lib...\n");
		return -1;
	}

	const auto [drv_handle, drv_key, drv_status] = vdm::load_drv();
	if (drv_status != STATUS_SUCCESS || drv_handle == INVALID_HANDLE_VALUE)
	{
		std::printf("> failed to load driver... reason -> 0x%x\n", drv_status);
		return -1;
	}

	writemsr_t _write_msr =
		[&](std::uint32_t key, std::uint64_t value) -> bool
	{
		return vdm::writemsr(key, value);
	};

	vdm::msrexec_ctx msrexec(_write_msr);
	theo::malloc_t _kalloc = [&](std::size_t size) -> void*
	{
		void* alloc_base;
		msrexec.exec
		(
			[&](void* krnl_base, get_system_routine_t get_kroutine) -> void
			{
				using ex_alloc_pool_t =
					void* (*)(std::uint32_t, std::size_t);

				const auto ex_alloc_pool =
					reinterpret_cast<ex_alloc_pool_t>(
						get_kroutine(krnl_base, "ExAllocatePool"));

				alloc_base = ex_alloc_pool(NULL, size);
			}
		);
		return alloc_base;
	};

	theo::memcpy_t _kmemcpy =
		[&](void* dest, const void* src, std::size_t size) -> void*
	{
		void* result = nullptr;
		msrexec.exec
		(
			[&](void* krnl_base, get_system_routine_t get_kroutine) -> void
			{
				const auto kmemcpy =
					reinterpret_cast<decltype(&memcpy)>(
						get_kroutine(krnl_base, "memcpy"));

				result = kmemcpy(dest, src, size);
			}
		);
		return result;
	};

	theo::resolve_symbol_t resolve_symbol = 
		[&, &extern_symbols = extern_symbols](const char* symbol_name) -> std::uintptr_t
	{
		std::uintptr_t result = 0u;
		for (auto& [drv_name, drv_symbols] : extern_symbols)
		{
			// each kernel module... find a driver with a matching map file name...
			// I.E ntoskrnl.exe.map == ntoskrnl.exe...
			utils::kmodule::each_module
			(
				[&, &drv_name = drv_name, &drv_symbols = drv_symbols]
				(PRTL_PROCESS_MODULE_INFORMATION drv_info, const char* drv_path) -> bool
				{
					const auto _drv_name = 
						reinterpret_cast<const char*>(
							drv_info->OffsetToFileName + drv_info->FullPathName);

					// if this is the driver, load it, loop over its sections
					// calc the absolute virtual address of the symbol...
					if (!strcmp(_drv_name, drv_name.c_str()))
					{
						const auto drv_load_addr = 
							reinterpret_cast<std::uintptr_t>(
								LoadLibraryExA(drv_path, NULL, DONT_RESOLVE_DLL_REFERENCES));

						std::uint32_t section_count = 1u;
						utils::pe::each_section
						(
							[&, &drv_symbols = drv_symbols]
							(PIMAGE_SECTION_HEADER section_header, std::uintptr_t img_base) -> bool
							{
								if (section_count == drv_symbols[symbol_name].first)
								{
									result = reinterpret_cast<std::uintptr_t>(drv_info->ImageBase) + 
										section_header->VirtualAddress + drv_symbols[symbol_name].second;

									// we found the symbol...
									return false;
								}

								++section_count;
								// keep going over sections...
								return true;
							}, drv_load_addr
						);
					}

					// keep looping over modules until we resolve the symbol...
					return !result;
				}
			);
		}

		// if the symbol was not resolved in any of the map files then try 
		// to see if its an export from any other drivers...
		if (!result)
		{
			utils::kmodule::each_module
			(
				[&](PRTL_PROCESS_MODULE_INFORMATION drv_info, const char* drv_path) -> bool
				{
					const auto drv_name =
						reinterpret_cast<const char*>(
							drv_info->OffsetToFileName + drv_info->FullPathName);

					// false if we found the symbol...
					return (!(result = utils::kmodule::get_export(drv_name, symbol_name)));
				}
			);
		}

		return result;
	};

	theo::hmm_ctx drv_mapper({ _kalloc, _kmemcpy, resolve_symbol });
	if (!drv_mapper.map_objs(image_objs))
	{
		std::printf("[!] failed to map object files...\n");
		return -1;
	}

	const auto drv_entry = drv_mapper.get_symbol("DrvEntry");
	std::printf("\n\n> driver entry -> 0x%p\n", drv_entry);
	std::getchar();

	if(drv_entry)
	{
		int result;
		msrexec.exec([&result, drv_entry = drv_entry]
			(void* krnl_base, get_system_routine_t get_kroutine) -> void
		{
			using drv_entry_t = int(*)();
			result = reinterpret_cast<drv_entry_t>(drv_entry)();
		});
	}

	const auto unload_status = vdm::unload_drv(drv_handle, drv_key);
	if (unload_status != STATUS_SUCCESS)
	{
		std::printf("> failed to unload driver... reason -> 0x%x\n", unload_status);
		return -1;
	}

	std::printf("> press enter to close...\n");
	std::getchar();
}