#ifndef DLANG_LIBS_STRING_HPP
#define DLANG_LIBS_STRING_HPP

#include <chrono>
#include <thread>
#include "../vm.hpp"
#include "../helpers.hpp"

static void NativeSubString(DlangVM* vm)
{
	double to = -1;
	if (dlang_top(vm) > 2)
		to = dlang_tonumber(vm);

	auto from = dlang_tonumber(vm);
	auto str = dlang_tostring(vm);

	if (to == -1)
		dlang_pushstring(vm, str.substr(from));
	else
		dlang_pushstring(vm, str.substr(from, to));
}

static void NativeContains(DlangVM* vm)
{
	auto needle = dlang_tostring(vm);
	auto haystack = dlang_tostring(vm);

	auto found = haystack.find(needle);
	dlang_pushboolean(vm, found != std::string::npos);
}

static void NativeReplace(DlangVM* vm)
{
	auto to = dlang_tostring(vm);
	auto from = dlang_tostring(vm);
	auto str = dlang_tostring(vm);

	size_t startPos = 0;
	if (!from.empty())
	{
		while ((startPos = str.find(from, startPos)) != std::string::npos)
		{
			str.replace(startPos, from.length(), to);
			startPos += to.length();
		}
	}

	dlang_pushstring(vm, str);
}

static void NativeLower(DlangVM* vm)
{
	auto str = dlang_tostring(vm);

	std::transform(
		str.begin(), str.end(),
		str.begin(), ::tolower
	);

	dlang_pushstring(vm, str);
}

static void NativeUpper(DlangVM* vm)
{
	auto str = dlang_tostring(vm);

	std::transform(
		str.begin(), str.end(),
		str.begin(), ::toupper
	);

	dlang_pushstring(vm, str);
}

static void NativeSplit(DlangVM* vm)
{
	auto delimiter = dlang_tostring(vm);
	auto str = dlang_tostring(vm);

	std::vector<std::string> parts;

	if (delimiter.empty()) {
		for (char c : str) {
			parts.push_back(std::string(1, c));
		}
	}
	else {
		size_t pos = 0;
		size_t delimSize = delimiter.size();

		while ((pos = str.find(delimiter)) != std::string::npos) {
			parts.push_back(str.substr(0, pos));
			str.erase(0, pos + delimSize);
		}

		parts.push_back(str);
	}

	dlang_newlist(vm);
	for (size_t i = 0; i < parts.size(); ++i)
	{
		dlang_pushstring(vm, parts[i]);
		dlang_pushindex(vm);
	}
}

static void NativeFind(DlangVM* vm)
{
	auto needle = dlang_tostring(vm);
	auto str = dlang_tostring(vm);

	size_t pos = str.find(needle);

	dlang_pushnumber(vm, static_cast<double>(pos));
}

inline void openlib_string(DlangVM* vm)
{
	dlang_newtable(vm);

	dlang_pushcfunction(vm, NativeSubString);
	dlang_setfield(vm, "substr");

	dlang_pushcfunction(vm, NativeContains);
	dlang_setfield(vm, "contains");

	dlang_pushcfunction(vm, NativeReplace);
	dlang_setfield(vm, "replace");

	dlang_pushcfunction(vm, NativeLower);
	dlang_setfield(vm, "lower");

	dlang_pushcfunction(vm, NativeUpper);
	dlang_setfield(vm, "upper");

	dlang_pushcfunction(vm, NativeSplit);
	dlang_setfield(vm, "split");

	dlang_pushcfunction(vm, NativeFind);
	dlang_setfield(vm, "find");

	dlang_setglobal(vm, "string");
}

#endif