/*
	This file is part of c++script.

	c++script is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	c++script is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with c++script.  If not, see <https://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <string>
#include <cstring>
#include <vector>
#include <iostream>
#include <format>
#include "c++script.h"

using namespace std;

namespace cpps{
vector<string> args;
std::vector<class option_base*> options;
static std::string description;

option_base::option_base(const char _letter,
	std::string_view _longname,
	std::string_view _desc,
	bool _mandatory,
	bool _valueneeded,
	bool _mayrepeat)
	:letter(_letter), longname(_longname), desc(_desc)
	,mandatory(_mandatory), valueneeded(_valueneeded), mayrepeat(_mayrepeat)
{
}
option_base::~option_base()
{
	auto f = ranges::find(options,this);
	if (f != options.end()) options.erase (f);
}
bool option_base::addval (std::string_view val)
{
	nbseen++;
	bool ret = setval(val);
	if (nbseen > 1 && !mayrepeat){
		cerr << format ("option -{} --{} may not be repeated\n",letter,longname);
		ret = false;
	}
	return ret;
}

bool option_setval (std::string &val, std::string_view v, char letter, const string &longname)
{
	val = v;
	return true;
}
static bool option_validate (const std::from_chars_result &res, const char *end, std::string_view v, char letter, const string &longname)
{
	bool ret = false;
	if (res.ec == std::errc()){
		if (res.ptr <end){
			std::cerr << format("Option -{} --{}: value \"{}\" contains extra non numeric characters\n",letter,longname,v);
		}else{
			ret = true;
		}
	} else if (res.ec == std::errc::invalid_argument){
		std::cerr << format("Option -{} --{}: value \"{}\" is not a number.\n",letter,longname,v);
	}else if (res.ec == std::errc::result_out_of_range){
		std::cerr << format("Option -{} --{}: value \"{}\" is too large.\n",letter,longname,v);
	}
	return ret;
}

bool option_setval (int &val, std::string_view v, char letter, const string &longname)
{
	const char *end = v.data() + v.size();
	auto res = std::from_chars(v.data(), end, val);

	return option_validate (res,end,v,letter,longname);
}
bool option_setval (double &val, std::string_view v, char letter, const string &longname)
{
	const char *end = v.data() + v.size();
	auto res = std::from_chars(v.data(), end, val);
 
	return option_validate (res,end,v,letter,longname);
}

bool option_setval (unsigned &val, std::string_view v, char letter, const string &longname)
{
	bool ret = false;
	int tmpval;
	if (option_setval(tmpval,v,letter,longname)){
		if (tmpval < 0){
			std::cerr << format("Option -{} --{}: value \"{}\" can't be negative.\n",letter,longname,v);
		}else{
			val = tmpval;
			ret = true;
		}
	}
	return ret;
}
void usage()
{
	cout << '\n';
	cout << format ("{}\n\nOptions:\n",description);
	size_t maxlen = 0;
	for (auto o:options){
		if (o->longname.size() > maxlen) maxlen = o->longname.size();
	}
	for (auto o:options){
		if (o->letter == ' '){
			cout << format ("\t   --{:{}}  {}\n",o->longname,maxlen,o->desc);
		}else{
			cout << format ("\t-{} --{:{}}  {}\n",o->letter,o->longname,maxlen,o->desc);
		}
		if (o->mayrepeat){
			cout << format ("\t{:{}}  This option may be repeated\n"," ",maxlen+5);
		}
		if (o->defval.size() > 0){
			cout << format ("\t{:{}}  Default value is {}\n"," ",maxlen+5,o->defval);
		}
	}
	cout << '\n';
	exit (0);
}

void endoptions(int argc, char *argv[])
{
	for (int i=1; i<argc; i++) args.emplace_back(argv[i]);
	option<bool> opthelp (' ',"help","Show this help screen");
	bool some_errors = false;
	for (unsigned i=0; i<args.size(); i++){
		const string &arg = args[i];
		bool more = i < args.size()-1;
		if (arg == "--help"){
			usage();
			#if 0
			cout << '\n';
			cout << format ("{}\n\n",description);
			for (auto o:options){
				cout << format ("\t-{} --{} {}\n",o->letter,o->longname,o->desc);
			}
			cout << '\n';
			#endif
			exit (0);
		}else if (arg.size() > 0 && arg[0] == '-'){
			int remove = 0;
			if (arg.size() == 1){
				cerr << "Incomplete option -\n";
				some_errors = true;
				break;
			}else{
				char letter = arg[1];
				if (letter == '-'){
					if (arg.size() == 2){	
						// -- means end of options
						args.erase(args.begin()+i);
						break;
					}else{ // arg.size() > 2
						auto pos = arg.find('=');
						string optname,optvalue;
						if (pos == string::npos){
							optname = arg.substr(2);
						}else{
							optname = arg.substr(2,pos-2);
							optvalue = arg.substr(pos+1);
						}
						option_base *opt = nullptr;
						for (auto o:options){
							if (o->longname == optname){
								opt = o;
								break;
							}
						}
						if (opt == nullptr){
							cerr << format ("Unknown option {}, ending\n",optname);
							usage();
							exit (-1);
						}else if (!opt->valueneeded && optvalue.size()==0){
							opt->enable();
							remove = 1;
						}else if (optvalue.size() > 0){
							if (!opt->addval(optvalue)) some_errors = true;
							remove = 1;
						}else if (more){
							if (!opt->addval(args[i+1])) some_errors = true;
							remove = 2;
						}else{
							cerr << format ("option --{} incomplete\n",optname);
							some_errors = true;
							break;
						}
					}
				}else{
					option_base *opt = nullptr;
					for (auto o:options){
						if (o->letter == letter){
							opt = o;
							break;
						}
					}
					if (opt == nullptr){
						cerr << format ("Unknown option -{}, ending\n",letter);
						usage();
						exit (-1);
					}else if (!opt->valueneeded && arg.size()==2){
						opt->enable();
						remove = 1;
					}else if (arg.size() > 2){
						if (!opt->addval(arg.substr(2))) some_errors = true;
						remove = 1;
					}else if (more){
						if (!opt->addval(args[i+1])) some_errors = true;
						remove = 2;
					}else{
						cerr << format ("option -{} incomplete\n",letter);
						some_errors = true;
					}
				}
			}
			if (remove > 0){
				args.erase(args.begin()+i,args.begin()+i+remove);
				i--;
			}
		}else{
			break;
		}
	}
	if (some_errors) exit(-1);
	if (opthelp.val){
		usage();
	}else{
		for (auto o:options){
			if (o->mandatory && o->nbseen == 0){
				cerr << format ("Option -{} --{} is mandatory\n",o->letter,o->longname);
				some_errors = true;
			}
		}
		if (some_errors) usage();
	}
}
void progdesc(std::string_view desc)
{
	description = desc;
}

} // namespace cpps