/**
	This file is a part of rexy's general purpose library
	Copyright (C) 2020 rexy712

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

	This program 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 Affero General Public License for more details.

	You should have received a copy of the GNU Affero General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef REXY_CX_STRING_HPP
#define REXY_CX_STRING_HPP

namespace rexy::cx{
	template<size_t N, class Char>
	class string;
}

#include "../string_base.hpp"
#include "utility.hpp"
#include <type_traits>
#include <cstddef> //ptrdiff_t

//This is different from rexy::static_string in that this doesn't hold a pointer to a constant string array.
//This holds a mutable array of data which can be modified during compile time. static_string is
//designed to be a thin wrapper around a raw char*, this is designed to allow compile time string concatenation

namespace rexy::cx{

	template<size_t N, class Char = char>
	class string
	{
	public:
		using value_type = Char;
		using size_type = size_t;
		using difference_type = ptrdiff_t;
		using pointer = value_type*;
		using const_pointer = const value_type*;
		using reference = value_type&;
		using const_reference = const value_type&;
		using iterator = pointer;
		using const_iterator = const_pointer;

	public:
		static constexpr size_t max_size = N;
	private:
		value_type m_data[N] = {};
		size_type m_length = 0;

	public:
		constexpr string(void) = default;
		template<size_type M>
		constexpr string(const char(&data)[M])noexcept:
			m_length(M)
		{
			static_assert(M <= N);
			for(size_type i = 0;i < M;++i){
				m_data[i] = data[i];
			}
		}
		constexpr string(const_pointer data)noexcept:
			m_length(cx::strlen(data))
		{
			for(size_type i = 0;i < m_length;++i){
				m_data[i] = data[i];
			}
		}
		constexpr string(const_pointer data, size_type len)noexcept:
			m_length(len)
		{
			for(size_type i = 0;i < m_length;++i){
				m_data[i] = data[i];
			}
		}

		constexpr string(const rexy::static_string<value_type>& str)noexcept:
			m_length(str.length())
		{
			for(size_type i = 0;i < m_length;++i){
				m_data[i] = str[i];
			}
		}
		template<class Left, class Right>
		constexpr string(const rexy::string_cat_expr<Left,Right>& expr)
			noexcept(std::is_nothrow_invocable<rexy::detail::string_appender<cx::string<N>>, decltype(expr)>::value)
		{
			rexy::detail::string_appender<cx::string<N,value_type>> append(*this);
			append(expr);
		}

		constexpr string(const string&)noexcept = default;
		constexpr string(string&&)noexcept = default;
		~string(void)noexcept = default;

		constexpr string& operator=(const_pointer c)noexcept{
			m_length = cx::strlen(c);
			for(size_type i = 0;i < m_length;++i){
				m_data[i] = c[i];
			}
			return *this;
		}
		constexpr string& operator=(const string&)noexcept = default;
		constexpr string& operator=(string&&)noexcept = default;


		constexpr size_type length(void)const noexcept{
			return m_length;
		}
		constexpr size_type capacity(void)const noexcept{
			return max_size;
		}
		constexpr pointer c_str(void)noexcept{
			return m_data;
		}
		constexpr const_pointer c_str(void)const noexcept{
			return m_data;
		}
		constexpr pointer get(void)noexcept{
			return m_data;
		}
		constexpr const_pointer get(void)const noexcept{
			return m_data;
		}
		constexpr operator pointer(void)noexcept{
			return m_data;
		}
		constexpr operator const_pointer(void)const noexcept{
			return m_data;
		}

		constexpr bool valid(void)const noexcept{
			return m_length > 0;
		}
		constexpr reference operator[](size_type i)noexcept{
			return m_data[i];
		}
		constexpr const_reference operator[](size_type i)const noexcept{
			return m_data[i];
		}

		constexpr bool resize(size_type i)noexcept{
			if(i >= capacity())
				return false;
			m_length = i;
			m_data[m_length] = 0;
			return true;
		}

		constexpr void append(const_pointer data, size_type len)noexcept{
			for(size_type i = 0;i < len;++i){
				m_data[m_length++] = data[i];
			}
		}
		constexpr void append(const_pointer data)noexcept{
			append(data, cx::strlen(data));
		}
		constexpr void append(const string& s)noexcept{
			append(s.get(), s.length());
		}
		constexpr void append(const rexy::static_string<value_type>& s)noexcept{
			append(s.get(), s.length());
		}
	};

	namespace detail{
		template<class T>
		struct is_cx_string_helper{
			static constexpr bool value = false;
		};
		template<size_t N, class Char>
		struct is_cx_string_helper<cx::string<N,Char>>{
			static constexpr bool value = true;
		};
		template<class... Ts>
		struct is_cx_string{
			static constexpr bool value = (is_cx_string_helper<std::decay_t<Ts>>::value && ...);
		};
	}

	template<class Str1, class Str2, std::enable_if_t<detail::is_cx_string<Str1,Str2>::value,int> = 0>
	constexpr auto operator+(Str1&& l, Str2&& r)noexcept{
		return string_cat_expr(std::forward<Str1>(l), std::forward<Str2>(r));
	}
	template<class Str1, std::enable_if_t<detail::is_cx_string<Str1>::value,int> = 0>
	constexpr auto operator+(Str1&& l, const char* r)noexcept{
		return string_cat_expr(std::forward<Str1>(l), rexy::static_string<char>(r));
	}
	template<class Str1, std::enable_if_t<detail::is_cx_string<Str1>::value,int> = 0>
	constexpr auto operator+(const char* l, Str1&& r)noexcept{
		return string_cat_expr(rexy::static_string<char>(l), std::forward<Str1>(r));
	}
}

#ifdef REXY_CX_HASH_HPP
#include "cx_string_hash.hpp"
#endif

#endif