#include "nossmooth.h"

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

// Standard headers
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <iostream>
#include "nethost.h"
#include "coreclr_delegates.h"
#include "hostfxr.h"

#include <cassert>

#define STR(s) L ## s
#define CH(c) L ## c
#define DIR_SEPARATOR L'\\'

using string_t = std::basic_string<char_t>;

// Globals to hold hostfxr exports
hostfxr_initialize_for_runtime_config_fn init_fptr;
hostfxr_get_runtime_delegate_fn get_delegate_fptr;
hostfxr_close_fn close_fptr;

// Forward declarations
bool load_hostfxr();
load_assembly_and_get_function_pointer_fn get_dotnet_load_assembly(const char_t* assembly);

/********************************************************************************************
 * Function used to load and activate .NET Core
 ********************************************************************************************/

 // Forward declarations
void* load_library(const char_t*);
void* get_export(void*, const char*);

void* load_library(const char_t* path)
{
    HMODULE h = ::LoadLibraryW(path);
    assert(h != nullptr);
    return (void*)h;
}
void* get_export(void* h, const char* name)
{
    void* f = ::GetProcAddress((HMODULE)h, name);
    assert(f != nullptr);
    return f;
}

// Using the nethost library, discover the location of hostfxr and get exports
bool load_hostfxr()
{
    // Pre-allocate a large buffer for the path to hostfxr
    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)
        return false;

    // Load hostfxr and get desired exports
    void* lib = load_library(buffer);
    init_fptr = (hostfxr_initialize_for_runtime_config_fn)get_export(lib, "hostfxr_initialize_for_runtime_config");
    get_delegate_fptr = (hostfxr_get_runtime_delegate_fn)get_export(lib, "hostfxr_get_runtime_delegate");
    close_fptr = (hostfxr_close_fn)get_export(lib, "hostfxr_close");

    return (init_fptr && get_delegate_fptr && close_fptr);
}

// Load and initialize .NET Core and get desired function pointer for scenario
load_assembly_and_get_function_pointer_fn get_dotnet_load_assembly(const char_t* config_path)
{
    // Load .NET Core
    void* load_assembly_and_get_function_pointer = nullptr;
    hostfxr_handle cxt = nullptr;
    int rc = init_fptr(config_path, nullptr, &cxt);
    if (rc != 0 || cxt == nullptr)
    {
        std::cerr << "Init failed: " << std::hex << std::showbase << rc << std::endl;
        close_fptr(cxt);
        return nullptr;
    }

    // Get the load assembly function pointer
    rc = get_delegate_fptr(
        cxt,
        hdt_load_assembly_and_get_function_pointer,
        &load_assembly_and_get_function_pointer);
    if (rc != 0 || load_assembly_and_get_function_pointer == nullptr)
        std::cerr << "Get delegate failed: " << std::hex << std::showbase << rc << std::endl;

    close_fptr(cxt);
    return (load_assembly_and_get_function_pointer_fn)load_assembly_and_get_function_pointer;
}

int LoadAndCallMethod(LoadParams* params)
{
    if (!load_hostfxr())
    {
        assert(false && "Failure: load_hostfxr()");
        return 0;
    }

    load_assembly_and_get_function_pointer_fn load_assembly_and_get_function_pointer = nullptr;
    load_assembly_and_get_function_pointer = get_dotnet_load_assembly(params->runtimeConfigPath);
    assert(load_assembly_and_get_function_pointer != nullptr && "Failure: get_dotnet_load_assembly()");

    typedef void (CORECLR_DELEGATE_CALLTYPE* main_entry_point_fn)();
    main_entry_point_fn main = nullptr;
    int rc = load_assembly_and_get_function_pointer(
        params->libraryPath,
        params->typePath,
        params->methodName,
        UNMANAGEDCALLERSONLY_METHOD,
        nullptr,
        (void**)&main);
    assert(rc == 0 && main != nullptr && "Failure: load_assembly_and_get_function_pointer()");
    main();
    return 1;
}