#pragma once

#include "common.hpp"
#include "data.hpp"

namespace saw {

template<>
class remote<rmt::Sycl>;

template<typename T>
class device;

template<typename Schema>
class data<Schema, encode::Native, rmt::Sycl> {
private:
	cl::sycl::buffer<data<Schema, encode::Native, storage::Default>> data_;
public:
	data(data<Schema, encode::Native, storage::Default>& data__):
		data_{&data__, 1u}
	{}

	auto& get_handle() {
		return data_;
	}

	template<cl::sycl::access::mode AccessMode>
	auto access(cl::sycl::handler& h){
		return data_.template get_access<AccessMode>(h);
	}
};

/**
 * Remote data class for the Sycl backend.
 */
template<typename T, typename Encoding, typename Storage>
class remote_data<T, Encoding, Storage, rmt::Sycl> final {
private:
	/**
	 * An identifier to the data being held on the remote
	 */
	id<T> data_id_;

	/**
	 * The sycl queue object
	 */
	cl::sycl::queue* queue_;
public:
	/**
	 * Main constructor
	 */
	remote_data(id<T> data_id__, cl::sycl::queue& queue__):
		data_id_{data_id__},
		queue_{&queue__}
	{}

	/**
	 * Destructor specifically designed to deallocate on the device.
	 */
	~remote_data(){}

	SAW_FORBID_COPY(remote_data);
	SAW_FORBID_MOVE(remote_data);
	/**
	remote_data(const id<T>& id, id_map<T, Encoding, rmt::Sycl>& map, cl::sycl::queue& queue__):
		id_{id},
		map_{&map}
	{}
	*/

	/**
	 * Wait for the data
	 */
	error_or<data<T,Encoding,Storage>> wait(){
		return make_error<err::not_implemented>();
	}

	/**
	 * Request data asynchronously
	 */
	// conveyor<data<T,Encoding,Storage>> on_receive(); /// Stopped here
};

/**
 * Meant to be a helper object which holds the allocated data on the sycl side
 */
template<typename Schema, typename Encoding, typename Backend>
class device_data;

/**
 * This class helps in regards to the ownership on the server side
 */
template<typename Schema, typename Encoding>
class device_data<Schema, Encoding, rmt::Sycl> {
private:
	/**
	 * The actual data
	 */
	data<Schema,Encoding,storage::Default>* device_data_;
	/**
	 * The sycl queue object
	 */
	cl::sycl::queue* queue_;
public:
	/**
	 * Main constructor
	 */
	device_data(data<Schema,Encoding,storage::Default>& device_data__, cl::sycl::queue& queue__):
		device_data_{&device_data__},
		queue_{&queue__}
	{}
	
	/**
	 * Destructor specifically designed to deallocate on the device.
	 */
	~device_data(){
		if(device_data_){
			cl::sycl::free(device_data_,queue_);
			device_data_ = nullptr;
		}
	}

	SAW_FORBID_COPY(device_data);
	SAW_FORBID_MOVE(device_data);
};

namespace impl {
template<typename Schema, typename Encoding, typename Backend>
struct device_id_map {
	std::vector<device_data<Schema, Encoding, Backend>> data;
};

template<typename Iface, typename Encoding, typename Storage>
struct rpc_id_map_helper {
	static_assert(always_false<Iface, Encoding,Storage>, "Only supports Interface schema types.");
};

template<typename... Members, typename Encoding, typename Storage>
struct rpc_id_map_helper<schema::Interface<Members...>, Encoding, Storage> {
	std::tuple<id_map<typename Members::ValueType::ResponseT, Encoding, Storage>...> maps;
};
}

}
// Maybe a helper impl tmpl file?
namespace saw {

/**
 * Represents a remote Sycl device.
 */
template<>
class device<rmt::Sycl> final {
private:
	cl::sycl::queue cmd_queue_;
public:
	device() = default;

	SAW_FORBID_COPY(device);
	SAW_FORBID_MOVE(device);

	/**
	 * Copy data to device
	 */
	template<typename Schema, typename Encoding, typename Storage>
	error_or<data<Schema, Encoding, rmt::Sycl>> copy_to_device(const data<Schema, Encoding, Storage>& host_data){
		return data<Schema, Encoding, rmt::Sycl>::copy_to_device(host_data, *this);
	}
	
	/**
	 * Copy data to host
	 */
	template<typename Schema, typename Encoding, typename Storage>
	error_or<data<Schema, Encoding, Storage>> copy_to_host(const data<Schema, Encoding, rmt::Sycl>& device_data){
		return device_data.copy_to_host();
	}
	
	/**
	 * Get a reference to the handle
	 */
	cl::sycl::queue& get_handle(){
		return cmd_queue_;
	}
};

/**
 * Rpc Client class for the Sycl backend.
 */
template<typename Iface, typename Encoding, typename Storage>
class rpc_client<Iface, Encoding, Storage, rmt::Sycl> {
public:
private:
	/**
	 * Server this client is tied to
	 */
	rpc_server<Iface, Encoding, rmt::Sycl>* srv_;

	/**
	 * Generated some sort of id for the request.
	 */
public:
	rpc_client(rpc_server<Iface, Encoding, rmt::Sycl>& srv):
		srv_{&srv}
	{}

	/**
	 * Rpc call
	 */
	template<string_literal Name>
	error_or<
		id<
			typename schema_member_type<Name, Iface>::type::ResponseT
		>
	> call(const data_or_id<typename schema_member_type<Name, Iface>::type::RequestT, Encoding, Storage>& input){
		auto next_free_id = srv_->template next_free_id<typename schema_member_type<Name, Iface>::type::ResponseT>();
		return srv_->template call<Name, Storage>(input, next_free_id);
	}

};

/**
 * Rpc Server class for the Sycl backend.
 */
template<typename Iface, typename Encoding>
class rpc_server<Iface, Encoding, rmt::Sycl> {
public:
	using InterfaceCtxT = cl::sycl::queue*;
	using InterfaceT = interface<Iface, Encoding, storage::Default, InterfaceCtxT>;
private:
	/**
	 * Device instance enabling the use of the remote device.
	 */
	device<rmt::Sycl>* device_;

	/**
	 * The interface including the relevant context class.
	 */
	interface<Iface, Encoding, storage::Default, InterfaceCtxT> cl_interface_;

	/**
	 * Basic storage for response data.
	 */
	impl::rpc_id_map_helper<Iface, Encoding, rmt::Sycl> storage_;
public:

	/**
	 * Main constructor
	 */
	rpc_server(device<rmt::Sycl>& dev__, InterfaceT cl_iface):
		device_{&dev__},
		cl_interface_{std::move(cl_iface)},
		storage_{}
	{}
	
	/**
	 * Ask which id the server prefers as the next one. Only available for fast requests on no roundtrip setups.
	 */
	/**
	template<typename T>
	id<T> next_free_id() const {
		return std::get<id_map<T,Encoding,rmt::Sycl>>(storage_.maps).next_free_id();
	}
	*/

	/**
	template<typename IdT, typename Storage>
	remote_data<IdT, Encoding, Storage, rmt::Sycl> request_data(id<IdT> dat_id){
		return {dat_id, std::get<id_map<IdT,Encoding,rmt::Sycl>>(storage_.maps), device_->get_handle()};
	}
	*/

	/**
	 * Rpc call based on the name
	 */
	template<string_literal Name>
	error_or<
		id<
			typename schema_member_type<Name, Iface>::type::ResponseT
		>
	> call(data_or_id<typename schema_member_type<Name, Iface>::type::RequestT, Encoding, storage::Default> input, id<typename schema_member_type<Name,Iface>::type::ResponseT> rpc_id){
		using FuncT = typename schema_member_type<Name, Iface>::type;

		/**
		 * Object needed if and only if the provided data type is not an id
		 */
		own<device_data<typename FuncT::RequestT, Encoding, rmt::Sycl>> dev_tmp_inp = nullptr;
		/**
		 * First check if it's data or an id.
		 * If it's an id, check if it's registered within the storage and retrieve it.
		 */
		auto eoinp = [&,this]() -> error_or<data<typename FuncT::RequestT, Encoding, rmt::Sycl>* > {
			if(input.is_id()){
				// storage_.maps
				auto& inner_map = std::get<id_map<typename FuncT::RequestT, Encoding, rmt::Sycl>> (storage_.maps);
				auto eov = inner_map.find(input.get_id());
				if(eov.is_error()){
					return std::move(eov.get_error());
				}
				return eov.get_value();
			} else {
				auto& client_data = input.get_data();

				auto eov = device_->template copy_to_device(client_data);
				if(eov.is_error()){
					return std::move(eov.get_error());
				}
				auto& val = eov.get_value();

				dev_tmp_inp = heap<data<typename FuncT::RequestT, Encoding, rmt::Sycl>>(std::move(val));
				device_->get_handle().wait();
				return dev_tmp_inp.get();
			}
		}();
		if(eoinp.is_error()){
			return std::move(eoinp.get_error());
		}
		auto& inp = *(eoinp.get_value());

		auto eod = cl_interface_.template call<Name>(inp, &(device_->get_handle()));

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

		auto& val = eod.get_value();
		/**
		 * Store returned data in rpc storage
		 */
		auto& inner_map = std::get<id_map<typename schema_member_type<Name, Iface>::type::RequestT, Encoding,rmt::Sycl>> (storage_.maps);
		auto eoid = inner_map.insert_as(std::move(val), rpc_id);
		if(eoid.is_error()){
			return std::move(eoid.get_error());
		}
		return rpc_id;
	}
};


template<>
struct remote_address<rmt::Sycl> {
private:
	remote<rmt::Sycl>* ctx_;

	SAW_FORBID_COPY(remote_address);
	SAW_FORBID_MOVE(remote_address);
public:
	remote_address(remote<rmt::Sycl>& r_ctx):
		ctx_{&r_ctx}
	{}
};

template<>
class remote<rmt::Sycl> {
private:
	SAW_FORBID_COPY(remote);
	SAW_FORBID_MOVE(remote);

public:
	/**
	 * Default constructor
	 */
	remote(){}

	/**
	 * For now we don't need to specify the location since
	 * we just create a default.
	 */
	conveyor<own<remote_address<rmt::Sycl>>> resolve_address(){
		return heap<remote_address<rmt::Sycl>>(*this);
	}

	/**
	 * Connect to a device
	 */
	device<rmt::Sycl> connect_device(const remote_address<rmt::Sycl>&){
		return {};
	}

	/**
	 * Spin up a rpc server
	 */
	template<typename Iface, typename Encoding>
	rpc_server<Iface, Encoding, rmt::Sycl> listen(device<rmt::Sycl>& dev, typename rpc_server<Iface, Encoding, rmt::Sycl>::InterfaceT iface){
		using RpcServerT = rpc_server<Iface, Encoding, rmt::Sycl>;
		using InterfaceT = typename RpcServerT::InterfaceT;
		return {dev, std::move(iface)};
	}
};

}