// This file is under GNU General Public License 3.0

 // see LICENSE.txt

 #pragma once

 #include "message.h"

 #ifdef __cplusplus

 extern "C" {

 #endif

 typedef enum _sync_handshake_signal {

     SYNC_NOTIFY_UNDEFINED = 0,

     // request show handshake dialog

     SYNC_NOTIFY_INIT_ADD_OUR_DEVICE,

     SYNC_NOTIFY_INIT_ADD_OTHER_DEVICE,

     SYNC_NOTIFY_INIT_FORM_GROUP,

     SYNC_NOTIFY_INIT_MOVE_OUR_DEVICE,

     // handshake process timed out

     SYNC_NOTIFY_TIMEOUT,

     // handshake accepted by user

     SYNC_NOTIFY_ACCEPTED_DEVICE_ADDED,

     SYNC_NOTIFY_ACCEPTED_GROUP_CREATED,

     SYNC_NOTIFY_ACCEPTED_DEVICE_MOVED,

     // handshake dialog must be closed

     SYNC_NOTIFY_OVERTAKEN

 } sync_handshake_signal;

 // notifyHandshake() - notify UI about sync handshaking process

 //

 //  parameters:

 //      obj (in)        object handle (implementation defined)

 //      me (in)         own identity

 //      partner (in)    identity of partner

 //      signal (in)     reason of the notification

 //

 //  return value:

 //      PEP_STATUS_OK or any other value on error

 //

 //  caveat:

 //      ownership of self and partner go to the callee

 typedef PEP_STATUS (*notifyHandshake_t)(

         pEp_identity *me,

         pEp_identity *partner,

         sync_handshake_signal signal

     );

 typedef enum _sync_handshake_result {

     SYNC_HANDSHAKE_CANCEL = -1,

     SYNC_HANDSHAKE_ACCEPTED = 0,

     SYNC_HANDSHAKE_REJECTED = 1

 } sync_handshake_result;

 // deliverHandshakeResult() - give the result of the handshake dialog

 //

 //  parameters:

 //      session (in)        session handle

 //      result (in)         handshake result

 DYNAMIC_API PEP_STATUS deliverHandshakeResult(

         PEP_SESSION session,

         pEp_identity *partner,

         sync_handshake_result result

     );

 // retrieve_next_sync_event - receive next sync event

 //

 //  parameters:

 //      management (in)     application defined; usually a locked queue

 //      threshold (in)      threshold in seconds for timeout

 //

 //  return value:

 //      next event

 //

 //  caveat:

 //      an implementation of retrieve_next_sync_event must return

 //      new_sync_timeout_event() in case of timeout

 typedef SYNC_EVENT (*retrieve_next_sync_event_t)(void *management,

         unsigned threshold);

 // register_sync_callbacks() - register adapter's callbacks

 //

 //  parameters:

 //      session (in)                    session where to store obj handle

 //      management (in)                 application defined; usually a locked queue

 //      notifyHandshake (in)            callback for doing the handshake

 //      retrieve_next_sync_event (in)   callback for receiving sync event

 //

 //  return value:

 //      PEP_STATUS_OK or any other value on errror

 //

 //  caveat:

 //      call that BEFORE you're using any other part of the engine

 DYNAMIC_API PEP_STATUS register_sync_callbacks(

         PEP_SESSION session,

         void *management,

         notifyHandshake_t notifyHandshake,

         retrieve_next_sync_event_t retrieve_next_sync_event

     );

 DYNAMIC_API void unregister_sync_callbacks(PEP_SESSION session);

 // do_sync_protocol() - function to be run on an extra thread

 //

 //  parameters:

 //      session                 pEp session to use

 //      retrieve_next_sync_msg  pointer to retrieve_next_identity() callback

 //                              which returns at least a valid address field in

 //                              the identity struct

 //      obj                     application defined sync object

 //

 //  return value:

 //      PEP_STATUS_OK if thread has to terminate successfully or any other

 //      value on failure

 DYNAMIC_API PEP_STATUS do_sync_protocol(

         PEP_SESSION session,

         void *obj

     );

 // do_sync_protocol_step() - function for single threaded implementations

 //

 //  parameters:

 //      session                 pEp session to use

 //      retrieve_next_sync_msg  pointer to retrieve_next_identity() callback

 //                              which returns at least a valid address field in

 //                              the identity struct

 //      obj                     application defined sync object

 //      event                   Sync event to process

 DYNAMIC_API PEP_STATUS do_sync_protocol_step(

         PEP_SESSION session,

         void *obj,

         SYNC_EVENT event

     );

 // is_sync_thread() - determine if this is sync thread's session

 //

 //  paramters:

 //      session                 pEp session to test

 //

 //  return value:

 //      true if this is sync thread's session, false otherwise

 DYNAMIC_API bool is_sync_thread(PEP_SESSION session);

 // new_sync_timeout_event() - create a Sync timeout event

 //

 //  return value:

 //      returns a new Sync timeout event, or NULL on failure

 DYNAMIC_API SYNC_EVENT new_sync_timeout_event();

 #ifdef __cplusplus

 }

 #endif