#ifndef LLARP_H_
#define LLARP_H_
#include <stdint.h>
#include <unistd.h>

#ifdef __cplusplus
extern "C"
{
#endif

  /// ensure configuration exists
  /// populate with defaults
  /// return if this succeeded
  /// if overwrite is true then overwrite old config file
  /// if basedir is not nullptr then use basedir as an absolute
  /// base path for all files in config
  bool
  llarp_ensure_config(const char*, const char*, bool overwrite, bool asrouter);

  /// llarp application context for C api
  struct llarp_main;

  /// runtime options for main context from cli
  struct llarp_main_runtime_opts
  {
    bool background = false;
    bool debug = false;
    bool singleThreaded = false;
  };

  /// llarp_application config
  struct llarp_config;

  /// get default config for current platform
  struct llarp_config*
  llarp_default_config();

  /// free previously allocated configuration
  void
  llarp_config_free(struct llarp_config*);

  /// packet writer to send packets to lokinet internals
  struct llarp_vpn_writer_pipe;
  /// packet reader to recv packets from lokinet internals
  struct llarp_vpn_reader_pipe;

  /// vpn io api
  /// all hooks called in native code
  /// for use with a vpn interface managed by external code
  /// the external vpn interface MUST be up and have addresses set
  struct llarp_vpn_io
  {
    /// private implementation
    void* impl;
    /// user data
    void* user;
    /// hook set by user called by lokinet core when lokinet is done with the
    /// vpn io
    void (*closed)(struct llarp_vpn_io*);
    /// hook set by user called from lokinet core after attempting to inject
    /// into endpoint passed a bool set to true if we were injected otherwise
    /// set to false
    void (*injected)(struct llarp_vpn_io*, bool);
    /// hook set by user called every event loop tick
    void (*tick)(struct llarp_vpn_io*);
  };

  /// info about the network interface that we give to lokinet core
  struct llarp_vpn_ifaddr_info
  {
    /// name of the network interface
    char ifname[64];
    /// interface's address as string
    char ifaddr[128];
    /// netmask number of bits set
    uint8_t netmask;
  };

  /// initialize llarp_vpn_io private implementation
  /// returns false if either parameter is nullptr
  bool
  llarp_vpn_io_init(struct llarp_main* m, struct llarp_vpn_io* io);

  /// get the packet pipe for writing IP packets to lokinet internals
  /// returns nullptr if llarp_vpn_io is nullptr or not initialized
  struct llarp_vpn_pkt_writer*
  llarp_vpn_io_packet_writer(struct llarp_vpn_io* io);

  /// get the packet pipe for reading IP packets from lokinet internals
  /// returns nullptr if llarp_vpn_io is nullptr or not initialized
  struct llarp_vpn_pkt_reader*
  llarp_vpn_io_packet_reader(struct llarp_vpn_io* io);

  /// blocking read on packet reader from lokinet internals
  /// returns -1 on error, returns size of packet read
  /// thread safe
  ssize_t
  llarp_vpn_io_readpkt(struct llarp_vpn_pkt_reader* r, unsigned char* dst, size_t dstlen);

  /// blocking write on packet writer to lokinet internals
  /// returns false if we can't write this packet
  /// return true if we wrote this packet
  /// thread safe
  bool
  llarp_vpn_io_writepkt(struct llarp_vpn_pkt_writer* w, unsigned char* pktbuf, size_t pktlen);

  /// close vpn io and free private implementation after done
  /// operation is async and calls llarp_vpn_io.closed after fully closed
  /// after fully closed the llarp_vpn_io MUST be re-initialized by
  /// llarp_vpn_io_init if it is to be used again
  void
  llarp_vpn_io_close_async(struct llarp_vpn_io* io);

  /// get the default endpoint's name for injection
  const char*
  llarp_main_get_default_endpoint_name(struct llarp_main* m);

  /// give main context a vpn io for mobile when it is reader to do io with
  /// associated info tries to give the vpn io to endpoint with name epName a
  /// deferred call to llarp_vpn_io.injected is queued unconditionally
  /// thread safe
  bool
  llarp_main_inject_vpn_by_name(
      struct llarp_main* m,
      const char* epName,
      struct llarp_vpn_io* io,
      struct llarp_vpn_ifaddr_info info);

  /// give main context a vpn io on its default endpoint
  static bool
  llarp_main_inject_default_vpn(
      struct llarp_main* m, struct llarp_vpn_io* io, struct llarp_vpn_ifaddr_info info)
  {
    return llarp_main_inject_vpn_by_name(m, llarp_main_get_default_endpoint_name(m), io, info);
  }

  /// load config from file by name
  /// allocates new config and puts it into c
  /// return false on failure
  bool
  llarp_config_load_file(const char* fname, struct llarp_config** c);

  /// loads config from file by name
  /// uses already allocated config
  /// return false on failure
  bool
  llarp_config_read_file(struct llarp_config* c, const char* f);

  /// make a main context from configuration
  /// copies config contents
  struct llarp_main*
  llarp_main_init_from_config(struct llarp_config* conf);

  /// initialize application context and load config
  static struct llarp_main*
  llarp_main_init(const char* fname)
  {
    struct llarp_main* m = 0;
    struct llarp_config* conf = 0;
    if (!llarp_config_load_file(fname, &conf))
      return 0;
    if (conf == NULL)
      return 0;
    m = llarp_main_init_from_config(conf);
    llarp_config_free(conf);
    return m;
  }

  /// initialize applicatin context with all defaults
  static struct llarp_main*
  llarp_main_default_init()
  {
    struct llarp_main* m;
    struct llarp_config* conf;
    conf = llarp_default_config();
    if (conf == 0)
      return 0;
    m = llarp_main_init_from_config(conf);
    llarp_config_free(conf);
    return m;
  }

  /// (re)configure main context
  /// return true if (re)configuration was successful
  bool
  llarp_main_configure(struct llarp_main* ptr, struct llarp_config* conf);

  /// return true if this main context is running
  /// return false otherwise
  bool
  llarp_main_is_running(struct llarp_main* ptr);

  /// handle signal for main context
  void
  llarp_main_signal(struct llarp_main* ptr, int sig);

  /// setup main context, returns 0 on success
  int
  llarp_main_setup(struct llarp_main* ptr);

  /// run main context, returns 0 on success, blocks until program end
  int
  llarp_main_run(struct llarp_main* ptr, struct llarp_main_runtime_opts opts);

  /// tell main context to stop and wait for complete stop
  /// after calling this you can call llarp_main_free safely
  void
  llarp_main_stop(struct llarp_main* ptr);

  /// free main context and end all operations
  void
  llarp_main_free(struct llarp_main* ptr);

  /// get version string
  const char*
  llarp_version();

  /// return sizeof(llarp_main); for jni
  size_t
  llarp_main_size();

  /// return sizeof(llarp_config); for jni
  size_t
  llarp_config_size();

#ifdef __cplusplus
}
#endif
#endif