/**
	This file is a part of rexy's general purpose library
	Copyright (C) 2020-2022 rexy712

	This program 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.

	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 General Public License for more details.

	You should have received a copy of the GNU 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

#include <cstddef> //ptrdiff_t, size_t

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

#include "../string_base.hpp" //string_cat_expr
#include "../string_view.hpp"
#include "../utility.hpp" //strlen, strcmp
#include "../detail/string_appender.hpp"
#include "../traits.hpp" //remove_cvref
#include <type_traits> //nothrow_invocable, integral_constant, declval
#include <iterator> //reverse_iterator

#include "../compat/standard.hpp"
#include "../compat/string_base.hpp"

//This is different from rexy::string_view 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. string_view is
//designed to be a thin wrapper around a raw char*, this is designed to allow compile time string concatenation

namespace rexy::cx{

	template<std::size_t N, class Char = char>
	class string
	{
	public:
		using value_type = Char;
		using size_type = std::size_t;
		using difference_type = std::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;
		using reverse_iterator = std::reverse_iterator<iterator>;
		using const_reverse_iterator = std::reverse_iterator<const_iterator>;

	public:
		static constexpr size_type max_size = N;
		static constexpr size_type npos = size_type{-1};

	public:
		value_type m_data[N] = {};
		size_type m_length = 0;

	public:
		constexpr string(void) = default;
		template<size_type M>
		constexpr string(const value_type(&data)[M])noexcept:
			m_length(M)
		{
			static_assert(M <= N);
			for(size_type i = 0;i < M;++i){
				m_data[i] = data[i];
			}
			if(m_data[m_length - 1] == 0){
				--m_length; //exclude null terminator in length
			}
		}
		constexpr string(const_pointer data)noexcept:
			m_length(rexy::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::basic_string_view<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;
		REXY_CPP20_CONSTEXPR ~string(void)noexcept = default;

		constexpr string& operator=(const_pointer c)noexcept{
			m_length = rexy::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 bool operator==(const string& s)noexcept{return !rexy::strcmp(m_data, s.m_data);}
		constexpr bool operator!=(const string& s)noexcept{return rexy::strcmp(m_data, s.m_data);}

		constexpr size_type length(void)const noexcept{return m_length;}
		constexpr size_type size(void)const noexcept{return m_length;}
		constexpr size_type capacity(void)const noexcept{return max_size;}
		constexpr bool empty(void)const noexcept{return m_length == 0;}

		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 reference operator[](size_type i)noexcept{return m_data[i];}
		constexpr const_reference operator[](size_type i)const noexcept{return m_data[i];}
		constexpr reference at(size_type i)noexcept{return m_data[i];}
		constexpr const_reference at(size_type i)const noexcept{return m_data[i];}
		constexpr const_reference front(size_type i)const noexcept{return m_data[0];}
		constexpr const_reference back(size_type i)const noexcept{return m_data[m_length-1];}

		constexpr const_iterator search(const basic_string_view<value_type>& s)const{
			return two_way_search(cbegin(), cend(), s.cbegin(), s.cend());
		}
		constexpr const_iterator search(const_pointer c)const{
			return search(basic_string_view<value_type>{c});
		}
		template<class Searcher>
		constexpr const_iterator search(const basic_string_view<value_type>& s, Searcher&& searcher)const{
			return searcher(cbegin(), cend(), s.cbegin(), s.cend());
		}
		template<class Searcher>
		constexpr const_iterator search(const_pointer c, Searcher&& searcher)const{
			return search(basic_string_view<value_type>{c}, searcher);
		}

		constexpr iterator begin(void)noexcept{return m_data;}
		constexpr const_iterator begin(void)const noexcept{return m_data;}
		constexpr const_iterator cbegin(void)const noexcept{return m_data;}
		constexpr iterator end(void)noexcept{return m_data+m_length;}
		constexpr const_iterator end(void)const noexcept{return m_data+m_length;}
		constexpr const_iterator cend(void)const noexcept{return m_data+m_length;}

		constexpr const_reverse_iterator rbegin(void)const{return const_reverse_iterator(m_data+m_length);}
		constexpr const_reverse_iterator rend(void)const{return const_reverse_iterator(m_data-1);}
		constexpr const_reverse_iterator crbegin(void)const{return rbegin();}
		constexpr const_reverse_iterator crend(void)const{return rend();}

		constexpr bool valid(void)const noexcept{return m_length > 0;}

		constexpr bool compare(const string& s)const{return *this == s;}
		constexpr bool compare(const_pointer c)const{return *this == c;}

		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, rexy::strlen(data));}
		constexpr void append(const string& s)noexcept{append(s.get(), s.length());}
		constexpr void append(const rexy::basic_string_view<value_type>& s)noexcept{append(s.get(), s.length());}

		constexpr size_type find_first_of(value_type v, size_type start = 0)const{
			return rexy::find_first_of(*this, &v, start, 1);
		}
		constexpr size_type find_first_of(const_pointer c, size_type pos = 0)const{
			return rexy::find_first_of(*this, c, pos, rexy::strlen(c));
		}
		constexpr size_type find_first_of(const_pointer c, size_type start, size_type size)const{
			return rexy::find_first_of(*this, c, start, size);
		}
		constexpr size_type find_last_of(value_type v, size_type start = 0)const{
			return rexy::find_last_of(*this, &v, start, 1);
		}
		constexpr size_type find_last_of(const_pointer c, size_type start = 0)const{
			return rexy::find_last_of(*this, c, start, rexy::strlen(c));
		}
		constexpr size_type find_last_of(const_pointer c, size_type start, size_type size)const{
			return rexy::find_last_of(*this, c, start, size);
		}

	};
	template<class Char, std::size_t N>
	string(const Char(&data)[N]) -> string<N, Char>;

	template<class... Ts>
	struct is_cx_string{
		template<class Char, std::size_t N>
		static std::true_type check(cx::string<N,Char>);
		static std::false_type check(...);
		static constexpr bool value = (decltype(check(std::declval<remove_cvref_t<Ts>>()))::value && ...);
	};

}

#ifdef __cpp_concepts
	#include "../compat/cpp20/cx/string.hpp"
#else //__cpp_concepts
	#include "../compat/cpp17/cx/string.hpp"
#endif //__cpp_concepts

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

#endif