// Copyright 2023 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

#include "pw_bluetooth_sapphire/internal/host/gap/bredr_connection.h"

#include <utility>

namespace bt::gap {

namespace {

const char* const kInspectPeerIdPropertyName = "peer_id";
const char* const kInspectPairingStateNodeName = "pairing_state";

}  // namespace

BrEdrConnection::BrEdrConnection(Peer::WeakPtr peer,
                                 std::unique_ptr<hci::BrEdrConnection> link,
                                 fit::closure send_auth_request_cb,
                                 fit::callback<void()> disconnect_cb,
                                 fit::closure on_peer_disconnect_cb,
                                 l2cap::ChannelManager* l2cap,
                                 hci::Transport::WeakPtr transport,
                                 std::optional<Request> request,
                                 pw::async::Dispatcher& dispatcher)
    : peer_id_(peer->identifier()),
      peer_(std::move(peer)),
      link_(std::move(link)),
      request_(std::move(request)),
      pairing_state_(std::make_unique<PairingState>(
          peer_,
          link_.get(),
          request_ && request_->AwaitingOutgoing(),
          std::move(send_auth_request_cb),
          fit::bind_member<&BrEdrConnection::OnPairingStateStatus>(this))),
      l2cap_(l2cap),
      sco_manager_(
          std::make_unique<sco::ScoConnectionManager>(peer_id_,
                                                      link_->handle(),
                                                      link_->peer_address(),
                                                      link_->local_address(),
                                                      transport)),
      interrogator_(new BrEdrInterrogator(
          peer_, link_->handle(), transport->command_channel()->AsWeakPtr())),
      create_time_(dispatcher.now()),
      disconnect_cb_(std::move(disconnect_cb)),
      peer_init_token_(request_->take_peer_init_token()),
      peer_conn_token_(peer_->MutBrEdr().RegisterConnection()),
      dispatcher_(dispatcher) {
  link_->set_peer_disconnect_callback(
      [peer_disconnect_cb = std::move(on_peer_disconnect_cb)](
          const auto& conn, auto /*reason*/) { peer_disconnect_cb(); });
}

BrEdrConnection::~BrEdrConnection() {
  if (auto request = std::exchange(request_, std::nullopt);
      request.has_value()) {
    // Connection never completed so signal the requester(s).
    request->NotifyCallbacks(ToResult(HostError::kNotSupported),
                             [] { return nullptr; });
  }

  sco_manager_.reset();
  pairing_state_.reset();
  link_.reset();
}

void BrEdrConnection::Interrogate(BrEdrInterrogator::ResultCallback callback) {
  interrogator_->Start(std::move(callback));
}

void BrEdrConnection::OnInterrogationComplete() {
  BT_ASSERT_MSG(!interrogation_complete(),
                "%s on a connection that's already been interrogated",
                __FUNCTION__);

  // Fulfill and clear request so that the dtor does not signal requester(s)
  // with errors.
  if (auto request = std::exchange(request_, std::nullopt);
      request.has_value()) {
    request->NotifyCallbacks(fit::ok(), [this] { return this; });
  }
}

void BrEdrConnection::AddRequestCallback(
    BrEdrConnection::Request::OnComplete cb) {
  if (!request_.has_value()) {
    cb(fit::ok(), this);
    return;
  }

  BT_ASSERT(request_);
  request_->AddCallback(std::move(cb));
}

void BrEdrConnection::OpenL2capChannel(l2cap::Psm psm,
                                       l2cap::ChannelParameters params,
                                       l2cap::ChannelCallback cb) {
  if (!interrogation_complete()) {
    // Connection is not yet ready for L2CAP; return a null channel.
    bt_log(INFO,
           "gap-bredr",
           "connection not ready; canceling connect to PSM %.4x (peer: %s)",
           psm,
           bt_str(peer_id_));
    cb(l2cap::Channel::WeakPtr());
    return;
  }

  bt_log(DEBUG,
         "gap-bredr",
         "opening l2cap channel on psm %#.4x (peer: %s)",
         psm,
         bt_str(peer_id_));
  l2cap_->OpenL2capChannel(link().handle(), psm, params, std::move(cb));
}

BrEdrConnection::ScoRequestHandle BrEdrConnection::OpenScoConnection(
    bt::StaticPacket<
        pw::bluetooth::emboss::SynchronousConnectionParametersWriter>
        parameters,
    sco::ScoConnectionManager::OpenConnectionCallback callback) {
  return sco_manager_->OpenConnection(std::move(parameters),
                                      std::move(callback));
}

BrEdrConnection::ScoRequestHandle BrEdrConnection::AcceptScoConnection(
    std::vector<bt::StaticPacket<
        pw::bluetooth::emboss::SynchronousConnectionParametersWriter>>
        parameters,
    sco::ScoConnectionManager::AcceptConnectionCallback callback) {
  return sco_manager_->AcceptConnection(std::move(parameters),
                                        std::move(callback));
}

void BrEdrConnection::AttachInspect(inspect::Node& parent, std::string name) {
  inspect_node_ = parent.CreateChild(name);
  inspect_properties_.peer_id = inspect_node_.CreateString(
      kInspectPeerIdPropertyName, peer_id_.ToString());

  pairing_state_->AttachInspect(inspect_node_, kInspectPairingStateNodeName);
}

void BrEdrConnection::OnPairingStateStatus(hci_spec::ConnectionHandle handle,
                                           hci::Result<> status) {
  if (bt_is_error(status,
                  DEBUG,
                  "gap-bredr",
                  "PairingState error status, disconnecting (peer id: %s)",
                  bt_str(peer_id_))) {
    if (disconnect_cb_) {
      disconnect_cb_();
    }
    return;
  }

  // Once pairing succeeds for the first time, the transition from Initializing
  // -> Connected can happen.
  peer_init_token_.reset();
}

pw::chrono::SystemClock::duration BrEdrConnection::duration() const {
  return dispatcher_.now() - create_time_;
}

}  // namespace bt::gap