/// @file dpf/protocol_roles.hpp
/// @brief Thin helpers for dealer, preprocess, and online roles.
/// @details Three modes:
///          - **Dealer** — sample prep and write per-party views (files or streams).
///          - **Preprocess** — exchange dealer output over the network (e.g. mux TCP).
///          - **Online** — parties read prep and run interactive rounds on peer streams.
#ifndef LIBDPF_INCLUDE_DPF_PROTOCOL_ROLES_HPP__
#define LIBDPF_INCLUDE_DPF_PROTOCOL_ROLES_HPP__

#include <cstddef>
#include <string>
#include <utility>
#include <vector>

#include "hedley/hedley.h"

#include "dpf/net/channel.hpp"
#include "dpf/net/stream_array.hpp"
#include "dpf/prep_source.hpp"

namespace dpf
{
namespace roles
{

/// @brief Dealer mode: write `basename-p0`, `basename-p1` prep blobs.
inline void dealer_write_files(const std::string & basename,
    const prep::demand & d)
{
    auto views = prep::deal_views(d);
    prep::write_file(basename + "-p0", views.first);
    prep::write_file(basename + "-p1", views.second);
}

/// @brief Preprocess mode: party 0 deals into mux streams; party 1 receives.
/// @details Party 0 writes its view locally and ships party 1's view on stream 0.
inline std::vector<std::uint8_t> preprocess_from_dealer_mux(net::channel & ch,
    unsigned party, const prep::demand & d, net::stream_array & local_out)
{
    if (local_out.size() < 1)
        throw std::invalid_argument("preprocess_from_dealer_mux: need stream 0");
    if (party == 0)
    {
        auto views = prep::deal_views(d);
        local_out.write(0, views.first.data(), views.first.size());
        local_out.flush(0);
        ch.send_vec(views.second, net::msg::beaver_tape);
        return std::move(views.first);
    }
    auto got = ch.recv_vec<std::uint8_t>(net::msg::beaver_tape);
    local_out.write(0, got.data(), got.size());
    local_out.flush(0);
    return got;
}

/// @brief Online mode: open prep cursors from dealer files (`basename-p0/p1`).
HEDLEY_WARN_UNUSED_RESULT
inline std::pair<prep::cursor, prep::cursor> online_open_file_array(
    const std::string & basename)
{
    return {prep::cursor(prep::read_file(basename + "-p0")),
        prep::cursor(prep::read_file(basename + "-p1"))};
}

}  // namespace roles
}  // namespace dpf

#endif