#define WIN32_LEAN_AND_MEAN

#include <Geode/DefaultInclude.hpp>

#ifdef GEODE_IS_WINDOWS

#include <crashlog.hpp>
#include <Geode/loader/Dirs.hpp>
#include <Geode/loader/Loader.hpp>
#include <Geode/loader/Mod.hpp>
#include <DbgHelp.h>
#include <Geode/utils/casts.hpp>
#include <Geode/utils/file.hpp>
#include <Windows.h>
#include <chrono>
#include <ctime>
#include <errhandlingapi.h>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <string>

USE_GEODE_NAMESPACE();

static bool g_lastLaunchCrashed = false;
static bool g_symbolsInitialized = false;

static std::string getDateString(bool filesafe) {
    auto const now = std::time(nullptr);
    auto const tm = *std::localtime(&now);
    std::ostringstream oss;
    if (filesafe) {
        oss << std::put_time(&tm, "%F_%H-%M-%S");
    }
    else {
        oss << std::put_time(&tm, "%FT%T%z"); // ISO 8601
    }
    return oss.str();
}

static std::string getModuleName(HMODULE module, bool fullPath = true) {
    char buffer[MAX_PATH];
    if (!GetModuleFileNameA(module, buffer, MAX_PATH)) {
        return "<Unknown>";
    }
    if (fullPath) {
        return buffer;
    }
    return ghc::filesystem::path(buffer).filename().string();
}

static char const* getExceptionCodeString(DWORD code) {
    #define EXP_STR(c) \
        case c: return #c
    switch (code) {
        EXP_STR(EXCEPTION_ACCESS_VIOLATION);
        EXP_STR(EXCEPTION_ARRAY_BOUNDS_EXCEEDED);
        EXP_STR(EXCEPTION_STACK_OVERFLOW);
        EXP_STR(EXCEPTION_ILLEGAL_INSTRUCTION);
        EXP_STR(EXCEPTION_IN_PAGE_ERROR);
        EXP_STR(EXCEPTION_BREAKPOINT);
        EXP_STR(EXCEPTION_DATATYPE_MISALIGNMENT);
        EXP_STR(EXCEPTION_FLT_DENORMAL_OPERAND);
        EXP_STR(EXCEPTION_FLT_DIVIDE_BY_ZERO);
        EXP_STR(EXCEPTION_FLT_INEXACT_RESULT);
        EXP_STR(EXCEPTION_FLT_INVALID_OPERATION);
        EXP_STR(EXCEPTION_FLT_OVERFLOW);
        EXP_STR(EXCEPTION_INT_DIVIDE_BY_ZERO);
        default: return "<Unknown>";
    }
    #undef EXP_STR
}

static HMODULE handleFromAddress(void const* addr) {
    HMODULE module = nullptr;
    GetModuleHandleEx(
        GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
        (LPCTSTR)addr, &module
    );
    return module;
}

static Mod* modFromAddress(PVOID exceptionAddress) {
    auto modulePath = getModuleName(handleFromAddress(exceptionAddress), true);
    for (auto& mod : Loader::get()->getAllMods()) {
        if (mod->getBinaryPath() == modulePath) {
            return mod;
        }
    }
    return nullptr;
}

static void printAddr(std::ostream& stream, void const* addr, bool fullPath = true) {
    HMODULE module = nullptr;

    if (GetModuleHandleEx(
            GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
            (LPCTSTR)addr, &module
        )) {
        // calculate base + [address]
        auto const diff = reinterpret_cast<uintptr_t>(addr) - reinterpret_cast<uintptr_t>(module);
        stream << getModuleName(module, fullPath) << " + " << std::hex << diff << std::dec;

        // log symbol if possible
        if (g_symbolsInitialized) {
            // https://docs.microsoft.com/en-us/windows/win32/debug/retrieving-symbol-information-by-address

            DWORD64 displacement;

            char buffer[sizeof(SYMBOL_INFO) + MAX_SYM_NAME * sizeof(TCHAR)];
            PSYMBOL_INFO symbolInfo = reinterpret_cast<PSYMBOL_INFO>(buffer);

            symbolInfo->SizeOfStruct = sizeof(SYMBOL_INFO);
            symbolInfo->MaxNameLen = MAX_SYM_NAME;

            auto proc = GetCurrentProcess();

            if (SymFromAddr(
                    proc, static_cast<DWORD64>(reinterpret_cast<uintptr_t>(addr)), &displacement,
                    symbolInfo
                )) {
                stream << " (" << std::string(symbolInfo->Name, symbolInfo->NameLen) << " + "
                       << displacement;

                IMAGEHLP_LINE64 line;
                line.SizeOfStruct = sizeof(IMAGEHLP_LINE64);

                DWORD displacement2;

                if (SymGetLineFromAddr64(
                        proc, static_cast<DWORD64>(reinterpret_cast<uintptr_t>(addr)),
                        &displacement2, &line
                    )) {
                    stream << " | " << line.FileName << ":" << line.LineNumber;
                }

                stream << ")";
            }
        }
    }
    else {
        stream << addr;
    }
}

// https://stackoverflow.com/a/50208684/9124836
static void walkStack(std::ostream& stream, PCONTEXT context) {
    STACKFRAME64 stack;
    memset(&stack, 0, sizeof(STACKFRAME64));

    auto process = GetCurrentProcess();
    auto thread = GetCurrentThread();
    stack.AddrPC.Offset = context->Eip;
    stack.AddrPC.Mode = AddrModeFlat;
    stack.AddrStack.Offset = context->Esp;
    stack.AddrStack.Mode = AddrModeFlat;
    stack.AddrFrame.Offset = context->Ebp;
    stack.AddrFrame.Mode = AddrModeFlat;

    // size_t frame = 0;
    while (true) {
        if (!StackWalk64(
                IMAGE_FILE_MACHINE_I386, process, thread, &stack, context, nullptr,
                SymFunctionTableAccess64, SymGetModuleBase64, nullptr
            ))
            break;

        stream << " - ";
        printAddr(stream, reinterpret_cast<void*>(stack.AddrPC.Offset));
        stream << std::endl;
    }
}

static void printRegisters(std::ostream& stream, PCONTEXT context) {
    stream << std::hex << "EAX: " << context->Eax << "\n"
           << "EBX: " << context->Ebx << "\n"
           << "ECX: " << context->Ecx << "\n"
           << "EDX: " << context->Edx << "\n"
           << "EBP: " << context->Ebp << "\n"
           << "ESP: " << context->Esp << "\n"
           << "EDI: " << context->Edi << "\n"
           << "ESI: " << context->Esi << "\n"
           << "EIP: " << context->Eip << "\n"
           << std::dec;
}

static void printInfo(std::ostream& stream, LPEXCEPTION_POINTERS info, Mod* faultyMod) {
    stream << "Faulty Module: "
           << getModuleName(handleFromAddress(info->ExceptionRecord->ExceptionAddress), true)
           << "\n"
           << "Faulty Mod: " << (faultyMod ? faultyMod->getID() : "<Unknown>") << "\n"
           << "Exception Code: " << std::hex << info->ExceptionRecord->ExceptionCode << " ("
           << getExceptionCodeString(info->ExceptionRecord->ExceptionCode) << ")" << std::dec
           << "\n"
           << "Exception Flags: " << info->ExceptionRecord->ExceptionFlags << "\n"
           << "Exception Address: " << info->ExceptionRecord->ExceptionAddress << " (";
    printAddr(stream, info->ExceptionRecord->ExceptionAddress, false);
    stream << ")"
           << "\n"
           << "Number Parameters: " << info->ExceptionRecord->NumberParameters << "\n";
}

static void printGeodeInfo(std::ostream& stream) {
    stream << "Loader Version: " << Loader::get()->getVersion().toString() << "\n"
           << "Installed mods: " << Loader::get()->getAllMods().size() << "\n"
           << "Failed mods: " << Loader::get()->getFailedMods().size() << "\n";
}

static void printMods(std::ostream& stream) {
    auto mods = Loader::get()->getAllMods();
    if (!mods.size()) {
        stream << "<None>\n";
    }
    for (auto& mod : mods) {
        stream << mod->getID() << " | " << mod->getDeveloper() << " | "
               << mod->getVersion().toString() << " | "
               << (mod->isEnabled() ? "Enabled" : "Disabled") << " | "
               << (mod->isLoaded() ? "Loaded" : "Unloaded") << " | "
               << "\n";
    }
}

static LONG WINAPI exceptionHandler(LPEXCEPTION_POINTERS info) {
    // make sure crashlog directory exists
    (void)utils::file::createDirectoryAll(crashlog::getCrashLogDirectory());

    // add a file to let Geode know on next launch that it crashed previously
    // this could also be done by saving a loader setting or smth but eh.
    (void)utils::file::writeBinary(crashlog::getCrashLogDirectory() / "last-crashed", {});

    SymSetOptions(SYMOPT_UNDNAME | SYMOPT_DEFERRED_LOADS | SYMOPT_LOAD_LINES);

    std::stringstream file;

    // init symbols so we can get some juicy debug info
    g_symbolsInitialized = SymInitialize(static_cast<HMODULE>(GetCurrentProcess()), nullptr, true);

    auto faultyMod = modFromAddress(info->ExceptionRecord->ExceptionAddress);

    file << getDateString(false) << "\n"
         << std::showbase << "Whoopsies! An exception has occurred while running Geode.\n";

    if (faultyMod) {
        file << "It appears that the crash occurred while executing code from "
             << "the \"" << faultyMod->getID() << "\" mod. "
             << "Please submit this crash report to its developer (" << faultyMod->getDeveloper()
             << ") for assistance.\n";
    }

    // geode info
    file << "\n== Geode Information ==\n";
    printGeodeInfo(file);

    // exception info
    file << "\n== Exception Information ==\n";
    printInfo(file, info, faultyMod);

    // registers
    file << "\n== Register States ==\n";
    printRegisters(file, info->ContextRecord);

    // stack trace
    file << "\n== Stack Trace ==\n";
    walkStack(file, info->ContextRecord);

    // mods
    file << "\n== Installed Mods ==\n";
    printMods(file);

    // show message box on debug mode
    #ifdef GEODE_DEBUG
    MessageBoxA(nullptr, file.str().c_str(), "Geode Crashed", MB_ICONERROR);
    #endif

    // save actual file
    std::ofstream actualFile;
    actualFile.open(
        crashlog::getCrashLogDirectory() / (getDateString(true) + ".log"), std::ios::app
    );
    actualFile << file.rdbuf() << std::flush;
    actualFile.close();

    return EXCEPTION_CONTINUE_SEARCH;
}

bool crashlog::setupPlatformHandler() {
    SetUnhandledExceptionFilter(exceptionHandler);
    auto lastCrashedFile = crashlog::getCrashLogDirectory() / "last-crashed";
    if (ghc::filesystem::exists(lastCrashedFile)) {
        g_lastLaunchCrashed = true;
        try {
            ghc::filesystem::remove(lastCrashedFile);
        }
        catch (...) {
        }
    }
    return true;
}

bool crashlog::didLastLaunchCrash() {
    return g_lastLaunchCrashed;
}

ghc::filesystem::path crashlog::getCrashLogDirectory() {
    return dirs::getGeodeDir() / "crashlogs";
}

#endif