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use std::marker::PhantomData;

#[allow(unused_imports)]
use log::{debug, error, info, warn};
use rustdds::{rpc::*, *};
use serde::{Deserialize, Serialize};

use crate::message::Message;
use super::{
  request_id::{RmwRequestId, SequenceNumber},
  ClientGeneric, ServerGeneric, Service, ServiceMapping,
};

// --------------------------------------------
// --------------------------------------------
// Basic mode header is specified in
// RPC over DDS Section "7.5.1.1.1 Common Types"

#[derive(Serialize, Deserialize)]
pub struct BasicRequestWrapper<R> {
  // "struct RequestHeader":
  request_id: SampleIdentity,
  instance_name: String, // This is apparenlty not used: Always sent as empty string.
  // ROS2 payload
  request: R,
}
impl<R: Message> Message for BasicRequestWrapper<R> {}

#[derive(Serialize, Deserialize)]
pub struct BasicResponseWrapper<R> {
  // "struct ReplyHeader":
  related_request_id: SampleIdentity,
  remote_exception_code: u32, /* It is uncertain if this is ever used. Transmitted as zero
                               * ("REMOTE_EX_OK"). */
  // ROS2 payload
  response: R,
}
impl<R: Message> Message for BasicResponseWrapper<R> {}

pub struct BasicServiceMapping<S> {
  phantom: PhantomData<S>,
}

pub type BasicServer<S> = ServerGeneric<S, BasicServiceMapping<S>>;
pub type BasicClient<S> = ClientGeneric<S, BasicServiceMapping<S>>;

pub struct BasicClientState {
  client_guid: GUID,
  sequence_number_counter: SequenceNumber,
}

impl BasicClientState {
  pub fn new(client_guid: GUID) -> BasicClientState {
    BasicClientState {
      client_guid,
      sequence_number_counter: SequenceNumber::default(),
    }
  }
}

impl<S> ServiceMapping<S> for BasicServiceMapping<S>
where
  S: Service,
  S::Request: Clone,
{
  type RequestWrapper = BasicRequestWrapper<S::Request>;
  type ResponseWrapper = BasicResponseWrapper<S::Response>;

  fn unwrap_request(
    wrapped: &Self::RequestWrapper,
    _sample_info: &SampleInfo,
  ) -> (RmwRequestId, S::Request) {
    (
      RmwRequestId::from(wrapped.request_id),
      wrapped.request.clone(),
    )
  }

  fn wrap_response(
    r_id: RmwRequestId,
    response: S::Response,
  ) -> (Self::ResponseWrapper, Option<SampleIdentity>) {
    (
      BasicResponseWrapper {
        related_request_id: SampleIdentity::from(r_id),
        remote_exception_code: 0,
        response,
      },
      Some(SampleIdentity::from(r_id)),
    )
  }

  type ClientState = BasicClientState;

  fn wrap_request(
    state: &mut Self::ClientState,
    request: S::Request,
  ) -> (Self::RequestWrapper, Option<RmwRequestId>) {
    state.sequence_number_counter = state.sequence_number_counter.next();

    let rmw_request_id = RmwRequestId {
      writer_guid: state.client_guid,
      sequence_number: state.sequence_number_counter,
    };

    (
      BasicRequestWrapper {
        request_id: SampleIdentity::from(rmw_request_id),
        instance_name: "".to_string(),
        request,
      },
      Some(rmw_request_id),
    )
  }

  fn request_id_after_wrap(
    state: &mut Self::ClientState,
    _write_result: SampleIdentity,
  ) -> RmwRequestId {
    // Request id is what we generated into header.
    // write_result is irrelevant, so we discard it.
    RmwRequestId {
      writer_guid: state.client_guid,
      sequence_number: state.sequence_number_counter,
    }
  }

  fn unwrap_response(
    _state: &mut Self::ClientState,
    wrapped: Self::ResponseWrapper,
    _sample_info: SampleInfo,
  ) -> (RmwRequestId, S::Response) {
    let r_id = RmwRequestId {
      writer_guid: wrapped.related_request_id.writer_guid,
      sequence_number: SequenceNumber::from(wrapped.related_request_id.sequence_number),
    };

    (r_id, wrapped.response)
  }

  fn new_client_state(request_sender: GUID) -> Self::ClientState {
    BasicClientState::new(request_sender)
  }
}