//===-- DarwinLogCollector.h ------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef DarwinLogCollector_h
#define DarwinLogCollector_h

#include <sys/types.h>

#include <memory>
#include <mutex>
#include <unordered_map>

#include "ActivityStore.h"
#include "ActivityStreamSPI.h"
#include "DNBDefs.h"
#include "DarwinLogEvent.h"
#include "DarwinLogInterfaces.h"
#include "JSON.h"

class DarwinLogCollector;
typedef std::shared_ptr<DarwinLogCollector> DarwinLogCollectorSP;

class DarwinLogCollector
    : public std::enable_shared_from_this<DarwinLogCollector>,
      public ActivityStore {
public:
  //------------------------------------------------------------------
  /// Return whether the os_log and activity tracing SPI is available.
  ///
  /// @return \b true if the activity stream support is available,
  /// \b false otherwise.
  //------------------------------------------------------------------
  static bool IsSupported();

  //------------------------------------------------------------------
  /// Return a log function suitable for DNBLog to use as the internal
  /// logging function.
  ///
  /// @return a DNBLog-style logging function if IsSupported() returns
  ///      true; otherwise, returns nullptr.
  //------------------------------------------------------------------
  static DNBCallbackLog GetLogFunction();

  static bool StartCollectingForProcess(nub_process_t pid,
                                        const JSONObject &config);

  static bool CancelStreamForProcess(nub_process_t pid);

  static DarwinLogEventVector GetEventsForProcess(nub_process_t pid);

  ~DarwinLogCollector();

  pid_t GetProcessID() const { return m_pid; }

  //------------------------------------------------------------------
  // ActivityStore API
  //------------------------------------------------------------------
  const char *GetActivityForID(os_activity_id_t activity_id) const override;

  std::string
  GetActivityChainForID(os_activity_id_t activity_id) const override;

private:
  DarwinLogCollector() = delete;
  DarwinLogCollector(const DarwinLogCollector &) = delete;
  DarwinLogCollector &operator=(const DarwinLogCollector &) = delete;

  explicit DarwinLogCollector(nub_process_t pid,
                              const LogFilterChainSP &filter_chain_sp);

  void SignalDataAvailable();

  void SetActivityStream(os_activity_stream_t activity_stream);

  bool HandleStreamEntry(os_activity_stream_entry_t entry, int error);

  DarwinLogEventVector RemoveEvents();

  void CancelActivityStream();

  void GetActivityChainForID_internal(os_activity_id_t activity_id,
                                      std::string &result, size_t depth) const;

  struct ActivityInfo {
    ActivityInfo(const char *name, os_activity_id_t activity_id,
                 os_activity_id_t parent_activity_id)
        : m_name(name), m_id(activity_id), m_parent_id(parent_activity_id) {}

    const std::string m_name;
    const os_activity_id_t m_id;
    const os_activity_id_t m_parent_id;
  };

  using ActivityMap = std::unordered_map<os_activity_id_t, ActivityInfo>;

  const nub_process_t m_pid;
  os_activity_stream_t m_activity_stream;
  DarwinLogEventVector m_events;
  std::mutex m_events_mutex;
  LogFilterChainSP m_filter_chain_sp;

  /// Mutex to protect activity info (activity name and parent structures)
  mutable std::mutex m_activity_info_mutex;
  /// Map of activity id to ActivityInfo
  ActivityMap m_activity_map;
};

#endif /* LogStreamCollector_h */