#pragma once

#include <forstio/core/common.h>
#include <forstio/core/templates.h>

#include <cassert>

#include <array>
#include <concepts>
#include <variant>
#include <vector>

#include "schema.h"

namespace saw {
namespace encode {
struct Native {};
}
template<typename Schema, typename Encode>
class codec;
/*
 * Helper for the basic message container, so the class doesn't have to be
 * specialized 10 times.
 */
template <class T> struct native_data_type;

template <>
struct native_data_type<schema::Primitive<schema::SignedInteger, 1>> {
	using type = int8_t;
};

template <>
struct native_data_type<schema::Primitive<schema::SignedInteger, 2>> {
	using type = int16_t;
};

template <>
struct native_data_type<schema::Primitive<schema::SignedInteger, 4>> {
	using type = int32_t;
};

template <>
struct native_data_type<schema::Primitive<schema::SignedInteger, 8>> {
	using type = int64_t;
};

template <>
struct native_data_type<schema::Primitive<schema::UnsignedInteger, 1>> {
	using type = uint8_t;
};

template <>
struct native_data_type<schema::Primitive<schema::UnsignedInteger, 2>> {
	using type = uint16_t;
};

template <>
struct native_data_type<schema::Primitive<schema::UnsignedInteger, 4>> {
	using type = uint32_t;
};

template <>
struct native_data_type<schema::Primitive<schema::UnsignedInteger, 8>> {
	using type = uint64_t;
};

template <>
struct native_data_type<schema::Primitive<schema::FloatingPoint, 4>> {
	using type = float;
};

template <>
struct native_data_type<schema::Primitive<schema::FloatingPoint, 8>> {
	using type = double;
};

template<typename T, typename Encoding = encode::Native>
class data {
private:
	static_assert(always_false<T>, "Type not supported");
};

template<typename... T, string_literal... literals>
class data<schema::Union<schema::Member<T, literals>...>, encode::Native> {
private:
	std::variant<data<T,encode::Native>...> value_;
public:
	data() = default;

	SAW_DEFAULT_COPY(data);
	SAW_DEFAULT_MOVE(data);

	template<string_literal lit>
	void set(data<typename parameter_pack_type<parameter_key_pack_index<lit, literals...>::value, T...>::type, encode::Native> val){
		value_ = std::move(val);
	}

	template<string_literal lit>
	bool holds_alternative() const {
		return (parameter_key_pack_index<lit, literals...>::value == value_.index());
	}

	template<string_literal lit>
	data<typename parameter_pack_type<parameter_key_pack_index<lit, literals...>::value, T...>::type, encode::Native>& get(){
		return std::get<parameter_key_pack_index<lit, literals...>::value>(value_);
	}
	
	template<string_literal lit>
	const data<typename parameter_pack_type<parameter_key_pack_index<lit, literals...>::value, T...>::type, encode::Native>& get() const{
		return std::get<parameter_key_pack_index<lit, literals...>::value>(value_);
	}
};

template<typename... T, string_literal... literals>
class data<schema::Struct<schema::Member<T, literals>...>, encode::Native> {
private:
	std::tuple<data<T,encode::Native>...> value_;
public:
	data() = default;
	SAW_DEFAULT_COPY(data);
	SAW_DEFAULT_MOVE(data);
	
	template<string_literal literal>
	data<
		typename parameter_pack_type<
			parameter_key_pack_index<
				literal, literals...
			>::value
		, T...>::type
	, encode::Native>& get(){
		return std::get<parameter_key_pack_index<literal, literals...>::value>(value_);
	}
	
	template<string_literal literal>
	const data<
		typename parameter_pack_type<
			parameter_key_pack_index<
				literal, literals...
			>::value
		, T...>::type
	, encode::Native>& get() const {
		return std::get<parameter_key_pack_index<literal, literals...>::value>(value_);
	}

	constexpr size_t size() const {
		return sizeof...(T);
	}
};

template<typename... T>
class data<schema::Tuple<T...>, encode::Native> {
private:
	std::tuple<data<T,encode::Native>...> value_;
public:
	data() = default;
	SAW_DEFAULT_COPY(data);
	SAW_DEFAULT_MOVE(data);
	
	template<size_t i>
	data<typename parameter_pack_type<i,T...>::type, encode::Native>& get(){
		return std::get<i>(value_);
	}
	
	template<size_t i>
	const data<typename parameter_pack_type<i,T...>::type, encode::Native>& get() const{
		return std::get<i>(value_);
	}

	constexpr size_t size() const {
		return sizeof...(T);
	}
};

template<typename T, size_t Dim>
class data<schema::Array<T,Dim>, encode::Native> {
	private:
		std::array<std::size_t, Dim> dims_;
		std::vector<data<T, encode::Native>> value_;

		std::size_t get_full_size() const {
			std::size_t s = 1;

			for(std::size_t iter = 0; iter < Dim; ++iter){
				assert(dims_.at(iter) > 0);
				s *= dims_.at(iter);
			}

			return s;
		}
	public:
		data() = default;
		SAW_DEFAULT_COPY(data);
		SAW_DEFAULT_MOVE(data);

		data(const std::array<std::size_t, Dim>& i):
			dims_{i},
			value_{}
		{
			value_.resize(get_full_size());
		}

		template<std::integral... Dims>
		data(Dims... size_):
			data{{size_...}}
		{
			static_assert(sizeof...(Dims)==Dim, "Argument size must be equal to the Dimension");
		}

		data<T, encode::Native>& at(const std::array<std::size_t, Dim>& ind){
			return value_.at(this->get_flat_index(ind));
		}
		
		const data<T, encode::Native>& at(const std::array<std::size_t, Dim>& ind) const {
			return value_.at(this->get_flat_index(ind));
		}

		template<std::integral... Dims>
		data<T, encode::Native>& at(Dims... i){
			return value_.at(this->get_flat_index({i...}));
		}
		
		template<std::integral... Dims>
		const data<T, encode::Native>& at(Dims... i) const {
			return value_.at(this->get_flat_index({i...}));
		}
		
		std::size_t get_dim_size(std::size_t i) const {
			return dims_.at(i);
		}

		size_t size() const { return value_.size();}

private:	
		std::size_t get_flat_index(const std::array<std::size_t, Dim>& i) const {
			std::size_t s = 0;

			std::size_t stride = 1;

			for(std::size_t iter = 0; iter < Dim; ++iter){
				s += i.at(iter) * stride;
				stride *= dims_.at(iter);
			}

			return s;
		}
};

template<>
class data<schema::String, encode::Native> {
private:
	std::string value_;
public:
	data() = default;
	SAW_DEFAULT_COPY(data);
	SAW_DEFAULT_MOVE(data);

	data(std::string value__):value_{std::move(value__)}{}
	data(std::size_t size_){
		value_.resize(size_);
	}

	std::size_t size() const {
		return value_.size();
	}

	void set(std::string str){
		value_ = std::move(str);
	}

	char& at(size_t i) {
		return value_.at(i);
	}

	const char& at(size_t i) const {
		return value_.at(i);
	}

	char get_at(size_t i) const{
		return value_.at(i);
	}

	void set_at(size_t i, char val){
		value_.at(i) = val;
	}

	bool operator==(const std::string_view& val)const{
		return value_ == val;
	}
};

template<typename T, size_t N>
class data<schema::Primitive<T,N>, encode::Native> {
private:
	typename native_data_type<schema::Primitive<T,N>>::type value_;
public:
	data():value_{{}}{};
	SAW_DEFAULT_COPY(data);
	SAW_DEFAULT_MOVE(data);

	data(typename native_data_type<schema::Primitive<T,N>>::type value__):
		value_{std::move(value__)}{}

	void set(typename native_data_type<schema::Primitive<T,N>>::type val){
		value_ = val;
	}

	typename native_data_type<schema::Primitive<T,N>>::type get() const {return value_;}
};


}