// Copyright 2013 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "lorgnette/daemon.h"

#include <sysexits.h>

#include <string>
#include <utility>

#include <base/functional/bind.h>
#include <base/logging.h>
#include <base/run_loop.h>
#include <base/task/single_thread_task_runner.h>
#include <base/time/time.h>
#include <chromeos/dbus/service_constants.h>

#include "lorgnette/dbus_service_adaptor.h"
#include "lorgnette/libsane_wrapper_impl.h"
#include "lorgnette/sane_client.h"
#include "lorgnette/sane_client_impl.h"
#include "lorgnette/usb/libusb_wrapper.h"
#include "lorgnette/usb/libusb_wrapper_impl.h"

using std::string;

namespace lorgnette {

// static
const char Daemon::kScanGroupName[] = "scanner";
const char Daemon::kScanUserName[] = "saned";

namespace {

constexpr base::TimeDelta kMaxDiscoverySessionTime = base::Minutes(60);
constexpr base::TimeDelta kMaxScannerHandleIdleTime = base::Minutes(60);
constexpr base::TimeDelta kTimeoutCheckInterval = base::Seconds(2);

}  // namespace

Daemon::Daemon() : DBusServiceDaemon(kManagerServiceName, "/ObjectManager") {}

Daemon::~Daemon() {}

int Daemon::OnInit() {
  int return_code = brillo::DBusServiceDaemon::OnInit();
  if (return_code != EX_OK) {
    return return_code;
  }

  PostponeShutdown(kNormalShutdownTimeout);

  return EX_OK;
}

void Daemon::RegisterDBusObjectsAsync(
    brillo::dbus_utils::AsyncEventSequencer* sequencer) {
  libsane_ = LibsaneWrapperImpl::Create();
  sane_client_ = SaneClientImpl::Create(libsane_.get());
  libusb_ = LibusbWrapperImpl::Create();
  auto manager =
      std::make_unique<Manager>(base::BindRepeating(&Daemon::PostponeShutdown,
                                                    weak_factory_.GetWeakPtr()),
                                sane_client_.get());
  device_tracker_.reset(new DeviceTracker(sane_client_.get(), libusb_.get()));
  dbus_service_.reset(
      new DBusServiceAdaptor(std::move(manager), device_tracker_.get(),
                             base::BindRepeating(&Daemon::OnDebugChanged,
                                                 weak_factory_.GetWeakPtr())));
  dbus_service_->RegisterAsync(object_manager_.get(), sequencer);
}

void Daemon::OnShutdown(int* return_code) {
  LOG(INFO) << "Shutting down";
  dbus_service_.reset();
  brillo::DBusServiceDaemon::OnShutdown(return_code);
}

void Daemon::OnTimeout() {
  // While there are active discovery sessions, they get a long timeout.  Once
  // there are no active sessions, the normal short timeout from the last
  // discovery session activity applies.
  base::TimeDelta idle_time =
      base::Time::Now() - device_tracker_->LastDiscoverySessionActivity();
  base::TimeDelta discovery_timeout =
      device_tracker_->NumActiveDiscoverySessions() > 0
          ? kMaxDiscoverySessionTime
          : kTimeoutCheckInterval;
  if (idle_time < discovery_timeout) {
    PostponeShutdown(kTimeoutCheckInterval);
    return;
  }

  // TODO(b/276909624): Change this logic to match the discovery session logic
  // above.
  if (device_tracker_->NumOpenScanners() > 0) {
    base::TimeDelta idle_time =
        base::Time::Now() - device_tracker_->LastOpenScannerActivity();
    if (idle_time < kMaxScannerHandleIdleTime) {
      PostponeShutdown(kTimeoutCheckInterval);
      return;
    }
  }

  LOG(INFO) << "Exiting after timeout";
  Quit();
}

void Daemon::OnDebugChanged() {
  LOG(INFO) << "Exiting after debug config changed.";
  Quit();
}

void Daemon::PostponeShutdown(base::TimeDelta delay) {
  shutdown_callback_.Reset(
      base::BindOnce(&Daemon::OnTimeout, weak_factory_.GetWeakPtr()));
  base::SingleThreadTaskRunner::GetCurrentDefault()->PostDelayedTask(
      FROM_HERE, shutdown_callback_.callback(), delay);
}

}  // namespace lorgnette