#include "DotNetHost.h"
#include "LogUtil.h"

#include <Windows.h>
#include <nethost.h>
#include <hostfxr.h>
#include <coreclr_delegates.h>

#include <cstring>
#include <string>

static hostfxr_initialize_for_runtime_config_fn init_fptr = nullptr;
static hostfxr_get_runtime_delegate_fn get_delegate_fptr = nullptr;
static hostfxr_close_fn close_fptr = nullptr;

typedef int (CORECLR_DELEGATE_CALLTYPE *managed_entry_fn)(void* args, int sizeBytes);

static managed_entry_fn fn_Initialize = nullptr;
static managed_entry_fn fn_DiscoverMods = nullptr;
static managed_entry_fn fn_PreInit = nullptr;
static managed_entry_fn fn_Init = nullptr;
static managed_entry_fn fn_PostInit = nullptr;
static managed_entry_fn fn_Tick = nullptr;
static managed_entry_fn fn_Shutdown = nullptr;

static bool LoadHostfxr()
{
    char_t buffer[MAX_PATH];
    size_t buffer_size = sizeof(buffer) / sizeof(char_t);

    int rc = get_hostfxr_path(buffer, &buffer_size, nullptr);
    if (rc != 0)
    {
        LogUtil::Log("[LegacyForge] get_hostfxr_path failed: 0x%x", rc);
        return false;
    }

    HMODULE lib = LoadLibraryW(buffer);
    if (!lib)
    {
        LogUtil::Log("[LegacyForge] Failed to load hostfxr");
        return false;
    }

    init_fptr = reinterpret_cast<hostfxr_initialize_for_runtime_config_fn>(
        GetProcAddress(lib, "hostfxr_initialize_for_runtime_config"));
    get_delegate_fptr = reinterpret_cast<hostfxr_get_runtime_delegate_fn>(
        GetProcAddress(lib, "hostfxr_get_runtime_delegate"));
    close_fptr = reinterpret_cast<hostfxr_close_fn>(
        GetProcAddress(lib, "hostfxr_close"));

    return init_fptr && get_delegate_fptr && close_fptr;
}

static load_assembly_and_get_function_pointer_fn GetDotNetLoadAssembly(const wchar_t* configPath)
{
    hostfxr_handle cxt = nullptr;
    int rc = init_fptr(configPath, nullptr, &cxt);
    if (rc != 0 || cxt == nullptr)
    {
        LogUtil::Log("[LegacyForge] hostfxr_initialize failed: 0x%x", rc);
        if (cxt) close_fptr(cxt);
        return nullptr;
    }

    void* load_fn = nullptr;
    rc = get_delegate_fptr(cxt, hdt_load_assembly_and_get_function_pointer, &load_fn);
    if (rc != 0 || load_fn == nullptr)
    {
        LogUtil::Log("[LegacyForge] hostfxr_get_runtime_delegate failed: 0x%x", rc);
    }

    close_fptr(cxt);
    return reinterpret_cast<load_assembly_and_get_function_pointer_fn>(load_fn);
}

static bool ResolveManagedMethod(
    load_assembly_and_get_function_pointer_fn load_fn,
    const wchar_t* assemblyPath,
    const wchar_t* methodName,
    managed_entry_fn* outFn)
{
    int rc = load_fn(
        assemblyPath,
        L"LegacyForge.Core.LegacyForgeCore, LegacyForge.Core",
        methodName,
        nullptr,
        nullptr,
        reinterpret_cast<void**>(outFn));

    return rc == 0 && *outFn != nullptr;
}

bool DotNetHost::Initialize()
{
    if (!LoadHostfxr())
    {
        LogUtil::Log("[LegacyForge] Failed to load hostfxr library");
        return false;
    }

    wchar_t modulePath[MAX_PATH];
    GetModuleFileNameW(nullptr, modulePath, MAX_PATH);

    std::wstring exeDir(modulePath);
    size_t lastSlash = exeDir.find_last_of(L"\\/");
    if (lastSlash != std::wstring::npos)
        exeDir = exeDir.substr(0, lastSlash + 1);
    else
        exeDir = L".\\";

    HMODULE hSelf = nullptr;
    GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
                       GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
                       reinterpret_cast<LPCWSTR>(&DotNetHost::Initialize), &hSelf);

    wchar_t selfPath[MAX_PATH];
    GetModuleFileNameW(hSelf, selfPath, MAX_PATH);
    std::wstring selfDir(selfPath);
    lastSlash = selfDir.find_last_of(L"\\/");
    if (lastSlash != std::wstring::npos)
        selfDir = selfDir.substr(0, lastSlash + 1);
    else
        selfDir = L".\\";

    std::wstring configPath = selfDir + L"LegacyForge.Core.runtimeconfig.json";
    std::wstring assemblyPath = selfDir + L"LegacyForge.Core.dll";

    auto load_fn = GetDotNetLoadAssembly(configPath.c_str());
    if (!load_fn)
    {
        LogUtil::Log("[LegacyForge] Failed to get load_assembly_and_get_function_pointer");
        return false;
    }

    bool ok = true;
    ok &= ResolveManagedMethod(load_fn, assemblyPath.c_str(), L"Initialize", &fn_Initialize);
    ok &= ResolveManagedMethod(load_fn, assemblyPath.c_str(), L"DiscoverMods", &fn_DiscoverMods);
    ok &= ResolveManagedMethod(load_fn, assemblyPath.c_str(), L"PreInit", &fn_PreInit);
    ok &= ResolveManagedMethod(load_fn, assemblyPath.c_str(), L"Init", &fn_Init);
    ok &= ResolveManagedMethod(load_fn, assemblyPath.c_str(), L"PostInit", &fn_PostInit);
    ok &= ResolveManagedMethod(load_fn, assemblyPath.c_str(), L"Tick", &fn_Tick);
    ok &= ResolveManagedMethod(load_fn, assemblyPath.c_str(), L"Shutdown", &fn_Shutdown);

    if (!ok)
    {
        LogUtil::Log("[LegacyForge] Failed to resolve one or more managed entry points");
        return false;
    }

    LogUtil::Log("[LegacyForge] All managed entry points resolved");
    return true;
}

void DotNetHost::CallManagedInit()
{
    if (fn_Initialize)
        fn_Initialize(nullptr, 0);
}

int DotNetHost::CallDiscoverMods(const char* modsPath)
{
    if (fn_DiscoverMods)
        return fn_DiscoverMods(const_cast<char*>(modsPath), static_cast<int>(strlen(modsPath)));
    return 0;
}

void DotNetHost::CallPreInit()
{
    if (fn_PreInit) fn_PreInit(nullptr, 0);
}

void DotNetHost::CallInit()
{
    if (fn_Init) fn_Init(nullptr, 0);
}

void DotNetHost::CallPostInit()
{
    if (fn_PostInit) fn_PostInit(nullptr, 0);
}

void DotNetHost::CallTick()
{
    if (fn_Tick) fn_Tick(nullptr, 0);
}

void DotNetHost::CallShutdown()
{
    if (fn_Shutdown) fn_Shutdown(nullptr, 0);
}

void DotNetHost::Cleanup()
{
}