#include <string>
#include <cstring>
#include <cassert>
#include <regex>
#include <unistd.h>
#include <dlfcn.h>

void *build_and_dlopen(const std::string &code)
{                                               
        //fprintf(stderr,">>%s<<\n",code.c_str());
        char filename[128];
        snprintf(filename,128,"/tmp/edgeXXXXXX.cpp");
        auto dot = strrchr(filename,'.');
        assert(dot);                    
        auto fd= mkstemps(filename, (&filename[strlen(filename)])-dot /*suffixlen*/);
        write(fd,code.c_str(),code.length());   
        //fprintf(stderr,"filename: %s\n", filename);     
        std::string object_filename = filename;         
        object_filename = std::regex_replace(object_filename,std::regex("cpp$"),"so");
        //fprintf(stderr,"object_filename: %s\n", object_filename.c_str()); 
                                                                
        // examples:                                            
        // clang++-9 -fPIC -shared -o /tmp/edgehELGdQ.so /tmp/edgehELGdQ.cpp
        // nm -gD /tmp/edgehELGdQ.so # show C-lang syms         
                                                        
        char cmd[384];                  
        snprintf(cmd,384,"clang++-9 -std=c++2a -O3 -fPIC -shared -o %s %s 2>&1", object_filename.c_str(), filename);
        auto p = popen(cmd,"r");        
        std::array<char, 1024> buffer;  
        std::string result;                     
        while(!feof(p))                         
                if (fgets(buffer.data(), 1024, p) != nullptr)
                        result += buffer.data();
        auto rc=pclose(p);              
        if(rc)                          
                fprintf(stderr,"%s\n", result.c_str());
        assert(0==rc);                  
        close(fd);                              
        unlink(filename);               
                                        
        // link filter into program
        auto handle=dlmopen(LM_ID_NEWLM,object_filename.c_str(), RTLD_NOW); // leak
        unlink(object_filename.c_str());
        assert(handle); 
        return handle;  
}                               

int main() {

	std::string code = R"(
	#include <iostream>
	extern "C" {
	void make_me_a_better_program()
	{
		std::cout << "stuffez" << std::endl;
	}
	}
	)";

	auto handle = build_and_dlopen(code);
	auto sym_handle=dlsym(handle,"make_me_a_better_program");
        assert(sym_handle);
        auto make_me_a_better_program = (void (*)())sym_handle;

	make_me_a_better_program();

	return 0;
}