#include <forstio/core/error.h>
#include <forstio/codec/schema.h>

#include <string>
#include <sstream>
#include <map>

#include <iostream>

namespace saw {

namespace impl {

template<typename Schema>
struct c_primitive_string {
	static_assert(always_false<Schema>, "Not supported");
};

template<>
struct c_primitive_string<schema::Int8> {
	static constexpr std::string_view value = "int8_t";
};

template<>
struct c_primitive_string<schema::Int16> {
	static constexpr std::string_view value = "int16_t";
};

template<>
struct c_primitive_string<schema::Int32> {
	static constexpr std::string_view value = "int32_t";
};

template<>
struct c_primitive_string<schema::Int64> {
	static constexpr std::string_view value = "int64_t";
};

template<>
struct c_primitive_string<schema::UInt8> {
	static constexpr std::string_view value = "uint8_t";
};

template<>
struct c_primitive_string<schema::UInt16> {
	static constexpr std::string_view value = "uint16_t";
};

template<>
struct c_primitive_string<schema::UInt32> {
	static constexpr std::string_view value = "uint32_t";
};

template<>
struct c_primitive_string<schema::UInt64> {
	static constexpr std::string_view value = "uint64_t";
};

template<>
struct c_primitive_string<schema::Float32> {
	static constexpr std::string_view value = "float";
};

template<>
struct c_primitive_string<schema::Float64> {
	static constexpr std::string_view value = "double";
};

template<typename Schema>
struct c_data_translater {
	static_assert(always_false<Schema>, "Not supported");
};

template<typename T, size_t N>
struct c_data_translater<schema::Primitive<T,N>> {
	using Schema = schema::Primitive<T,N>;
	static error_or<void> generate(std::map<std::string,std::string>& map_str, std::string& str, const std::string& prefix){
		str += c_primitive_string<Schema>::value;
		return void_t{};
	}
};

template<typename T, size_t Dim>
struct c_data_translater<schema::Array<T,Dim>> {
	static error_or<void> generate(std::map<std::string, std::string>& map_str, std::string& type_str, const std::string& prefix){
		type_str = prefix + "_";
		type_str += "array_";

		std::string inner_type_str;
		auto eov = impl::c_data_translater<T>::generate(map_str, inner_type_str, prefix);
		if(eov.is_error()){
			return eov;
		}

		type_str += inner_type_str;

		if(Dim > 1){
			type_str += "_";
			type_str += std::to_string(Dim);
			type_str += "d";
		}

		if(map_str.find(type_str) != map_str.end()){
			return void_t{};
		}

		std::string str = "struct ";
		str += type_str;

		str += " {\n";

		str += "\t" + inner_type_str + "* data;\n";
		str += "\tsize_t size;\n";
		if( Dim > 1 ){
			str += "\tsize_t dims["+std::to_string(Dim)+"];\n";
		}

		str += "};\n";

		map_str.insert(std::make_pair(std::move(type_str), std::move(str)));
		return void_t{};
	}
};

template<typename Interface>
struct c_rpc_translater {
	static_assert(always_false<Interface>,"Not supported");
};

template<class Request, class Response>
struct c_rpc_translater<schema::Function<Request, Response>> {
	using Map = std::map<std::string, std::string>;

	static error_or<void> generate(const std::string& prefix, Map& type_map, Map& func_map){
		
		return void_t{};
	}
};

template<class... Requests, class... Responses, string_literal... Names>
struct c_rpc_translater<schema::Interface<schema::Member<schema::Function<Requests, Responses>, Names>...>> {
	using Map = std::map<std::string, std::string>;

	template<size_t i>
	static error_or<void> generate_member(const std::string& prefix, Map& type_map, Map& func_map){
		using Req = typename parameter_pack_type<i,Requests...>::type;
		using Resp = typename parameter_pack_type<i,Responses...>::type;
		constexpr string_literal lit = parameter_key_pack_type<i, Names...>::literal;

		std::string func_name{lit.view()};
		if(func_map.find(func_name) != func_map.end()){
			return make_error<err::already_exists>();
		}

		{
			std::string type_str;
			auto eov = c_rpc_translater<schema::Function<Req, Resp>>::generate(prefix, type_map, func_map);
			if(eov.is_error()){
				return eov;
			}
		}

		if constexpr ((i+1) < sizeof...(Requests) ){
			return generate_member<i+1>(prefix, type_map, func_map);
		}
		return void_t{};
	}

	static error_or<void> generate(const std::string& prefix){
		Map type_map, func_map;

		if constexpr ( sizeof...(Requests) > 0 ){
			return generate_member<0>(prefix, type_map, func_map);
		}

		return void_t{};
	}
};
}

template<typename Interface>
error_or<std::string> generate_c_rpc_interface(){
	std::stringstream iss;
	auto eov = impl::c_rpc_translater<Interface>::generate(iss, "c_saw");

	if(eov.is_error()){
		return std::move(eov.get_error());
	}

	try {
		return iss.str();
	}catch(const std::exception& e){
		// Do nothing for now
	}
	return make_error<err::out_of_memory>();
}

error_or<void> generate_array_example(){
	using Schema = schema::Array<schema::Int32,2>;
	
	using Schema2 = schema::Array<schema::Float64,5>;
	
	using Schema3 = schema::Array<schema::UInt16,1>;

	std::string prefix = "c_saw";
	std::map<std::string,std::string> map_str;
	{
		std::string type_str;
		auto eov = impl::c_data_translater<Schema>::generate(map_str, type_str, prefix);
		if(eov.is_error()){
			return eov;
		}
	}
	{
		std::string type_str;
		auto eov = impl::c_data_translater<Schema2>::generate(map_str, type_str, prefix);
		if(eov.is_error()){
			return eov;
		}
	}
	{
		std::string type_str;
		auto eov = impl::c_data_translater<Schema3>::generate(map_str, type_str, prefix);
		if(eov.is_error()){
			return eov;
		}
	}

	std::cout<<"Prefix: "<<prefix<<std::endl;

	for(auto& iter : map_str){
		std::cout<<"\nType: \""<<iter.first<<"\""<<std::endl;
		std::cout<<"Definition:\n\"\"\"\n";
		std::cout<<iter.second;
		std::cout<<"\"\"\""<<std::endl;
	}

	return void_t{};
}
}