/*
 * ================================
 * eli960@qq.com
 * http://linuxmail.cn/
 * 2026年02月22日
 * ================================
 */

#include "zcc/zcc_stdlib.h"
#include "zcc/zcc_win64.h"

#ifdef _WIN64
#include <shlwapi.h>
#include <tlhelp32.h>
#pragma comment(lib, "shlwapi.lib")
#else
#include <dlfcn.h>
#include <link.h>
#include <unistd.h>
#endif

zcc_namespace_begin;

void *dlopen_auto(const std::string &lib_pathname_or_name, const std::string &symbol_to_check)
{
 void *libhandle = nullptr;
 libhandle = dlopen("");
 if (libhandle)
 {
 if (dlsym(libhandle, symbol_to_check))
 {
 return libhandle;
 }
 dlclose(libhandle);
 libhandle = nullptr;
 }
 //
 if (lib_pathname_or_name.empty())
 {
 return nullptr;
 }
 //
 libhandle = dlopen(lib_pathname_or_name);
 if (libhandle)
 {
 return libhandle;
 }
 //
 std::string name;
#ifdef _WIN32
 name = lib_pathname_or_name + ".dll";
#else
 name = "lib" + lib_pathname_or_name + ".so";
#endif
 libhandle = dlopen(name);
 if (libhandle)
 {
 return libhandle;
 }
 //
 return nullptr;
}

#ifdef _WIN64
static HMODULE g_mainModule = nullptr;

// 获取主模块句柄,使用缓存并考虑多线程安全
static HMODULE getMainModule()
{
 if (g_mainModule)
 {
 return g_mainModule;
 }
 global_low_level_mutex_lock();
 if (g_mainModule == nullptr)
 {
 g_mainModule = GetModuleHandleA(nullptr);
 }
 global_low_level_mutex_unlock();
 return g_mainModule;
}
#endif // _WIN64

// 加载动态库,支持全局符号表
void *dlopen(const std::string &lib_name)
{
 if (lib_name.empty())
 {
#ifdef _WIN32
 // 返回一个特殊标记表示全局符号表
 return reinterpret_cast<void *>(-1);
#else
 return ::dlopen(nullptr, RTLD_GLOBAL | RTLD_LAZY);
#endif
 }
#ifdef _WIN32
 wchar_t lib_name_w[Z_MAX_PATH + 1];
 if (Utf8ToWideChar(lib_name, lib_name_w, Z_MAX_PATH) < 1)
 {
 return nullptr;
 }
 return LoadLibraryW(lib_name_w);
#else
 return ::dlopen(lib_name.c_str(), RTLD_GLOBAL | RTLD_LAZY);
#endif
}

// 获取符号地址,支持全局符号表
void *dlsym(void *handle, const std::string &symbol_name)
{
 if (!handle)
 {
 return nullptr;
 }
#ifdef _WIN32
 if (handle == reinterpret_cast<void *>(-1))
 {
 // 查找全局符号表
 HMODULE mainModule = getMainModule();
 void *addr = GetProcAddress(mainModule, symbol_name.c_str());
 if (addr != nullptr)
 return addr;

 HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, GetCurrentProcessId());
 if (snapshot == INVALID_HANDLE_VALUE)
 return nullptr;

 MODULEENTRY32 modEntry;
 modEntry.dwSize = sizeof(MODULEENTRY32);
 if (Module32First(snapshot, &modEntry))
 {
 do
 {
 if (modEntry.hModule == mainModule)
 continue;
 addr = GetProcAddress(modEntry.hModule, symbol_name.c_str());
 if (addr != nullptr)
 {
 CloseHandle(snapshot);
 return addr;
 }
 } while (Module32Next(snapshot, &modEntry));
 }
 CloseHandle(snapshot);
 return nullptr;
 }
 else
 {
 return reinterpret_cast<void *>(GetProcAddress(static_cast<HMODULE>(handle), symbol_name.c_str()));
 }
#else
 return ::dlsym(handle, symbol_name.c_str());
#endif
}

// 卸载动态库,处理全局符号表特殊情况
bool dlclose(void *handle)
{
 if (!handle)
 {
 return true;
 }
#ifdef _WIN32
 if (handle != reinterpret_cast<void *>(-1))
 {
 return FreeLibrary(static_cast<HMODULE>(handle)) != 0;
 }
 return true;
#else
 return ::dlclose(handle) == 0;
#endif
}

zcc_namespace_end;