// Copyright 2017 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#include "DolphinQt/Config/Mapping/MappingCommon.h"

#include <deque>
#include <memory>

#include <QTimer>

#include "DolphinQt/Config/Mapping/MappingButton.h"
#include "DolphinQt/Config/Mapping/MappingWindow.h"

#include "InputCommon/ControlReference/ControlReference.h"
#include "InputCommon/ControllerEmu/ControllerEmu.h"
#include "InputCommon/ControllerInterface/ControllerInterface.h"
#include "InputCommon/ControllerInterface/MappingCommon.h"

namespace MappingCommon
{
constexpr auto INPUT_DETECT_INITIAL_TIME = std::chrono::seconds(3);
constexpr auto INPUT_DETECT_CONFIRMATION_TIME = std::chrono::milliseconds(0);
constexpr auto INPUT_DETECT_MAXIMUM_TIME = std::chrono::seconds(5);

class MappingProcessor : public QWidget
{
public:
  MappingProcessor(MappingWindow* parent) : QWidget{parent}, m_parent{parent}
  {
    using MW = MappingWindow;
    using MP = MappingProcessor;

    connect(parent, &MW::Update, this, &MP::ProcessMappingButtons);
    connect(parent, &MW::ConfigChanged, this, &MP::CancelMapping);

    connect(parent, &MW::UnQueueInputDetection, this, &MP::UnQueueInputDetection);
    connect(parent, &MW::QueueInputDetection, this, &MP::QueueInputDetection);
    connect(parent, &MW::CancelMapping, this, &MP::CancelMapping);

    m_input_detection_start_timer = new QTimer(this);
    m_input_detection_start_timer->setSingleShot(true);
    connect(m_input_detection_start_timer, &QTimer::timeout, this, &MP::StartInputDetection);
  }

  void StartInputDetection()
  {
    const auto& default_device = m_parent->GetController()->GetDefaultDevice();
    auto& button = m_clicked_mapping_buttons.front();

    button->StartMapping();

    std::vector device_strings{default_device.ToString()};
    if (m_parent->IsMappingAllDevices())
      device_strings = g_controller_interface.GetAllDeviceStrings();

    m_input_detector = std::make_unique<ciface::Core::InputDetector>();
    const auto lock = m_parent->GetController()->GetStateLock();
    m_input_detector->Start(g_controller_interface, device_strings);
  }

  void ProcessMappingButtons()
  {
    if (!m_input_detector)
      return;

    m_input_detector->Update(INPUT_DETECT_INITIAL_TIME, INPUT_DETECT_CONFIRMATION_TIME,
                             INPUT_DETECT_MAXIMUM_TIME);

    if (m_input_detector->IsComplete())
    {
      auto detections = m_input_detector->TakeResults();
      ciface::MappingCommon::RemoveSpuriousTriggerCombinations(&detections);

      // No inputs detected. Cancel this and any other queued mappings.
      if (detections.empty())
      {
        CancelMapping();
        return;
      }

      const auto& default_device = m_parent->GetController()->GetDefaultDevice();
      auto& button = m_clicked_mapping_buttons.front();
      auto* const control_reference = button->GetControlReference();

      control_reference->SetExpression(
          BuildExpression(detections, default_device, ciface::MappingCommon::Quote::On));
      m_parent->Save();

      m_parent->GetController()->UpdateSingleControlReference(g_controller_interface,
                                                              control_reference);
      UnQueueInputDetection(button);
    }
  }

  void UpdateInputDetectionStartTimer()
  {
    m_input_detector.reset();

    if (m_clicked_mapping_buttons.empty())
      m_input_detection_start_timer->stop();
    else
      m_input_detection_start_timer->start(INPUT_DETECT_INITIAL_DELAY);
  }

  void UnQueueInputDetection(MappingButton* button)
  {
    std::erase(m_clicked_mapping_buttons, button);
    button->ConfigChanged();
    UpdateInputDetectionStartTimer();
  }

  void QueueInputDetection(MappingButton* button)
  {
    // UnQueue if already queued.
    if (std::erase(m_clicked_mapping_buttons, button))
    {
      button->ConfigChanged();
      UpdateInputDetectionStartTimer();
      return;
    }

    button->setText(QStringLiteral("[ ... ]"));
    m_clicked_mapping_buttons.push_back(button);
    UpdateInputDetectionStartTimer();
  }

  void CancelMapping()
  {
    // Signal buttons to take on their proper input expression text.
    for (auto* button : m_clicked_mapping_buttons)
      button->ConfigChanged();

    m_clicked_mapping_buttons = {};
    UpdateInputDetectionStartTimer();
  }

private:
  std::deque<MappingButton*> m_clicked_mapping_buttons;
  std::unique_ptr<ciface::Core::InputDetector> m_input_detector;
  QTimer* m_input_detection_start_timer;
  MappingWindow* const m_parent;
};

void CreateMappingProcessor(MappingWindow* window)
{
  new MappingProcessor{window};
}

}  // namespace MappingCommon