#pragma once
#include <list>
#include <memory>
#include <mutex>
#include <thread>

#include "lasp_daq.h"
#include "lasp_siggen.h"
#include "lasp_thread.h"

/** \addtogroup device
 * @{
 */
class StreamMgr;
class InDataHandler;

class SeriesBiquad;

/**
 * @brief Stream manager. Used to manage the input and output streams.
 * Implemented as a singleton: only one stream manager can be in existance for
 * a given program. The thread that instantiates a stream manager is the only
 * thread that should interact with the stream manager. If this is not true,
 * undefined behavior can be expected. If LASP is compiled in debug mode, this
 * fact is asserted.
 */
class StreamMgr {
  mutable std::recursive_mutex _mtx;

  /**
   * @brief Storage for streams.
   */
  std::unique_ptr<Daq> _inputStream, _outputStream;

  std::atomic<bool> _scanningDevices{false};

  GlobalThreadPool _pool;

  /**
   * @brief All indata handlers are called when input data is available. Note
   * that they can be called from different threads and should take care of
   * thread-safety.
   */
  std::list<InDataHandler *> _inDataHandlers;

  /**
   * @brief Signal generator in use to generate output data. Currently
   * implemented as to generate the same data for all output channels.
   */
  std::shared_ptr<Siggen> _siggen;

  /**
   * @brief Filters on input stream. For example, a digital high pass filter.
   */
  std::vector<std::unique_ptr<SeriesBiquad>> _inputFilters;

  /**
   * @brief Current storage for the device list
   */
  DeviceInfoList _devices;

  // Singleton, no public constructor. Can only be obtained using
  // getInstance();
  StreamMgr();

  friend class InDataHandler;
  friend class Siggen;

 public:
  ~StreamMgr();

  enum class StreamType : us {
    /**
     * @brief Input stream
     */
    input = 1 << 0,
    /**
     * @brief Output stream
     */
    output = 1 << 1,
  };

  StreamMgr(const StreamMgr &) = delete;
  StreamMgr &operator=(const StreamMgr &) = delete;

  /**
   * @brief Get access to stream manager instance
   *
   * @return Reference to stream manager.
   */
  static std::shared_ptr<StreamMgr> getInstance();

  /**
   * @brief Obtain a list of devices currently available. When the StreamMgr is
   * first created, this
   *
   * @return A copy of the internal stored list of devices
   */
  DeviceInfoList getDeviceInfo() const {
    std::scoped_lock lck(_mtx);
    DeviceInfoList d2;
    for (const auto &dev : _devices) {
      assert(dev != nullptr);
      d2.push_back(dev->clone());
    }
    return d2;
  }

  /**
   * @brief Triggers a background scan of the DAQ devices, which updates the
   * internally stored list of devices. Throws a runtime error when a
   * background thread is already scanning for devices, or if a stream is
   * running.
   *
   * @param background Perform searching for DAQ devices in the background. If
   * set to true, the function returns immediately.
   * @param callback Function to call when complete.
   */
  void rescanDAQDevices(
      bool background = false,
      std::function<void()> callback = std::function<void()>());

  /**
   * @brief Start a stream based on given configuration.
   *
   * @param config Configuration of a device
   */
  void startStream(const DaqConfiguration &config);

  /**
   * @brief Check if a certain stream is running. If running with no errors, it
   * returns true. If an error occured, or the stream is not running, it gives
   * false.
   *
   * @param type The type of stream to check for.
   */
  bool isStreamRunningOK(const StreamType type) const {
    return getStreamStatus(type).runningOK();
  }
  bool isStreamRunning(const StreamType type) const {
    switch (type) {
      case (StreamType::input):
        return bool(_inputStream);
        break;
      case (StreamType::output):
        return bool(_outputStream);
        break;
    }
    return false;
  }

  /**
   * @brief Get the streamstatus object corresponding to a given stream.
   *
   * @param type  Type of stream, input, inputType, etc.
   *
   * @return status object.
   */
  Daq::StreamStatus getStreamStatus(const StreamType type) const;

  /**
   * @brief Get DAQ pointer for a given stream. Gives a nullptr if stream is
   * not running.
   *
   * @param type The stream type to get a DAQ ptr for.
   *
   * @return Pointer to DAQ
   */
  const Daq *getDaq(StreamType type) const;

  /**
   * @brief Stop stream of given type (input / output/ duplex);
   *
   * @param stype The stream type to stop.
   */
  void stopStream(const StreamType stype);

  /**
   * @brief Stop and delete all streams. Also called on destruction of the
   * StreamMgr.
   */
  void stopAllStreams();

  /**
   * @brief Set active signal generator for output streams. Only one `Siggen'
   * is active at the same time. Siggen controls its own data race protection
   * using a mutex. If no Siggen is there, and an output stream is running, it
   * will send a default signal of 0.
   *
   * @param s New Siggen pointer
   */
  void setSiggen(std::shared_ptr<Siggen> s);

 private:
  void inCallback(const DaqData &data);
  void outCallback(DaqData &data);

  /**
   * @brief Add an input data handler. The handler's inCallback() function is
   * called with data when available. This function should *NOT* be called by
   * the user, instead, an InDataHandler can only be created with the StreamMgr
   * as argument.
   *
   * @param handler The handler to add.
   */
  void addInDataHandler(InDataHandler *handler);

  /**
   * @brief Remove InDataHandler from the list.
   *
   * @param handler
   */
  void removeInDataHandler(InDataHandler &handler);
  /**
   * @brief Do the actual rescanning.
   *
   * @param callback
   */
  void rescanDAQDevices_impl(std::function<void()> callback);

#if LASP_DEBUG == 1
  const std::thread::id main_thread_id;
  void checkRightThread() const;
#else
  void checkRightThread() const {}
#endif
};

/** @} */