refine call states (#7179)

- sync declined calls from callee to caller, as usual in all larger
messengers
- introduce the call states "Missed call", "Declined call" and
"Cancelled all" ("Ended call" is gone)
- allow calling end_call()/accept_call() for already ended/accepted
calls, in practise, handling all cornercases is tricky in UI - and the
state needs anyways to be tracked.
- track and show the call duration

the duration calculation depends on local time, but it is displayed only
coarse and is not needed for any state. this can be improved as needed,
timestamps of the corresponding messages are probably better at some
point. or ending device sends its view of the time around. but for the
first throw, it seems good enough

if we finally want that set of states, it can be exposed to a json-info
in a subsequent call, so that the UI can render it more nicely. fallback
strings as follows will stay for now to make adaption in other UI easy,
and for debugging:

<img width="320" alt="IMG_0154"
src="https://github.com/user-attachments/assets/09a89bfb-66f4-4184-b05c-e8040b96cf44"
/>

successor of #6650

Author: r10s

deltachat-ffi/deltachat.h

@@ -1216,21 +1216,21 @@ uint32_t        dc_init_webxdc_integration    (dc_context_t* context, uint32_t c
 
 /**
  * Start an outgoing call.
- * This sends a message with all relevant information to the callee,
+ * This sends a message of type #DC_MSG_CALL with all relevant information to the callee,
  * who will get informed by an #DC_EVENT_INCOMING_CALL event and rings.
  *
  * Possible actions during ringing:
  *
  * - caller cancels the call using dc_end_call():
- *   callee receives #DC_EVENT_CALL_ENDED
+ *   callee receives #DC_EVENT_CALL_ENDED and has a "Missed Call"
  *
  * - callee accepts using dc_accept_incoming_call():
  *   caller receives #DC_EVENT_OUTGOING_CALL_ACCEPTED.
  *   callee's devices receive #DC_EVENT_INCOMING_CALL_ACCEPTED, call starts
  *
- * - callee rejects using dc_end_call():
- *   caller receives #DC_EVENT_CALL_ENDED after 1 minute timeout.
- *   callee's other devices receive #DC_EVENT_CALL_ENDED
+ * - callee declines using dc_end_call():
+ *   caller receives #DC_EVENT_CALL_ENDED and has a "Declinced Call".
+ *   callee's other devices receive #DC_EVENT_CALL_ENDED and have a "Cancelled Call",
  *
  * - callee is already in a call:
  *   in this case, UI may decide to show a notification instead of ringing.
@@ -1240,7 +1240,9 @@ uint32_t        dc_init_webxdc_integration    (dc_context_t* context, uint32_t c
  *   after 1 minute without action,
  *   caller and callee receive #DC_EVENT_CALL_ENDED
  *   to prevent endless ringing of callee
- *   in case caller got offline without being able to send cancellation message
+ *   in case caller got offline without being able to send cancellation message.
+ *   for caller, this is a "Cancelled Call";
+ *   for callee, this is a "Missed Call"
  *
  * Actions during the call:
  *
@@ -1276,13 +1278,15 @@ uint32_t        dc_place_outgoing_call       (dc_context_t* context, uint32_t ch
  * All affected devices will receive
  * either #DC_EVENT_OUTGOING_CALL_ACCEPTED or #DC_EVENT_INCOMING_CALL_ACCEPTED.
  *
+ * If the call is already accepted or ended, nothing happens.
+ *
  * @memberof dc_context_t
  * @param context The context object.
  * @param msg_id The ID of the call to accept.
  *     This is the ID reported by #DC_EVENT_INCOMING_CALL
  *     and equals to the ID of the corresponding info message.
  * @param accept_call_info any data that other devices receive
- *     in #DC_EVENT_OUTGOING_CALL_ACCEPTED or #DC_EVENT_INCOMING_CALL_ACCEPTED.
+ *     in #DC_EVENT_OUTGOING_CALL_ACCEPTED.
  * @return 1=success, 0=error
  */
  int            dc_accept_incoming_call      (dc_context_t* context, uint32_t msg_id, const char* accept_call_info);
@@ -1291,17 +1295,13 @@ uint32_t        dc_place_outgoing_call       (dc_context_t* context, uint32_t ch
  /**
   * End incoming or outgoing call.
   *
-  * From the view of the caller, a "cancellation",
-  * from the view of callee, a "rejection".
+  * For unaccepted calls ended by the caller, this is a "cancellation".
+  * Unaccepted calls ended by the callee are a "decline".
   * If the call was accepted, this is a "hangup".
   *
-  * For accepted calls,
-  * all participant devices get informed about the ended call via #DC_EVENT_CALL_ENDED.
-  * For not accepted calls, only the caller will inform the callee.
+  * All participant devices get informed about the ended call via #DC_EVENT_CALL_ENDED.
   *
-  * If the callee rejects, the caller will get a timeout or give up at some point -
-  * same as for all other reasons the call cannot be established: Device not in reach, device muted, connectivity etc.
-  * This is to protect privacy of the callee, avoiding to check if callee is online.
+  * If the call is already ended, nothing happens.
   *
   * @memberof dc_context_t
   * @param context The context object.
@@ -6724,29 +6724,27 @@ void dc_event_unref(dc_event_t* event);
  * or show a notification if there is already a call in some profile.
  *
  * Together with this event,
- * an info-message is added to the corresponding chat.
- * The info-message, however, is _not_ additionally notified using #DC_EVENT_INCOMING_MSG,
- * if needed, this has to be done by the UI explicitly.
+ * a message of type #DC_MSG_CALL is added to the corresponding chat;
+ * this message is announced and updated by the usual even as #DC_EVENT_MSGS_CHANGED.
  *
  * If user takes action, dc_accept_incoming_call() or dc_end_call() should be called.
  *
  * Otherwise, ringing should end on #DC_EVENT_CALL_ENDED
  * or #DC_EVENT_INCOMING_CALL_ACCEPTED
  *
- * @param data1 (int) msg_id ID of the info-message referring to the call.
+ * @param data1 (int) msg_id ID of the message referring to the call.
  * @param data2 (char*) place_call_info, text passed to dc_place_outgoing_call()
  */
 #define DC_EVENT_INCOMING_CALL                            2550
 
 /**
- * The callee accepted an incoming call on another device using dc_accept_incoming_call().
+ * The callee accepted an incoming call on this or another device using dc_accept_incoming_call().
  * The caller gets the event #DC_EVENT_OUTGOING_CALL_ACCEPTED at the same time.
  *
  * The event is sent unconditionally when the corresponding message is received.
  * UI should only take action in case call UI was opened before, otherwise the event should be ignored.
  *
- * @param data1 (int) msg_id ID of the info-message referring to the call
- * @param data2 (char*) accept_call_info, text passed to dc_place_outgoing_call()
+ * @param data1 (int) msg_id ID of the message referring to the call
  */
  #define DC_EVENT_INCOMING_CALL_ACCEPTED                  2560
 
@@ -6756,7 +6754,7 @@ void dc_event_unref(dc_event_t* event);
  * The event is sent unconditionally when the corresponding message is received.
  * UI should only take action in case call UI was opened before, otherwise the event should be ignored.
  *
- * @param data1 (int) msg_id ID of the info-message referring to the call
+ * @param data1 (int) msg_id ID of the message referring to the call
  * @param data2 (char*) accept_call_info, text passed to dc_accept_incoming_call()
  */
 #define DC_EVENT_OUTGOING_CALL_ACCEPTED                   2570
@@ -6768,7 +6766,7 @@ void dc_event_unref(dc_event_t* event);
  * The event is sent unconditionally when the corresponding message is received.
  * UI should only take action in case call UI was opened before, otherwise the event should be ignored.
  *
- * @param data1 (int) msg_id ID of the info-message referring to the call
+ * @param data1 (int) msg_id ID of the message referring to the call
  */
 #define DC_EVENT_CALL_ENDED                               2580
 

deltachat-ffi/src/lib.rs

@@ -779,17 +779,15 @@ pub unsafe extern "C" fn dc_event_get_data2_str(event: *mut dc_event_t) -> *mut
         | EventType::ChatlistChanged
         | EventType::AccountsChanged
         | EventType::AccountsItemChanged
+        | EventType::IncomingCallAccepted { .. }
         | EventType::WebxdcRealtimeAdvertisementReceived { .. } => ptr::null_mut(),
         EventType::IncomingCall {
             place_call_info, ..
         } => {
             let data2 = place_call_info.to_c_string().unwrap_or_default();
             data2.into_raw()
         }
-        EventType::IncomingCallAccepted {
-            accept_call_info, ..
-        }
-        | EventType::OutgoingCallAccepted {
+        EventType::OutgoingCallAccepted {
             accept_call_info, ..
         } => {
             let data2 = accept_call_info.to_c_string().unwrap_or_default();

deltachat-jsonrpc/src/api/types/events.rs

@@ -430,8 +430,6 @@ pub enum EventType {
     IncomingCallAccepted {
         /// ID of the info message referring to the call.
         msg_id: u32,
-        /// User-defined info passed to dc_accept_incoming_call()
-        accept_call_info: String,
     },
 
     /// Outgoing call accepted.
@@ -604,12 +602,8 @@ impl From<CoreEventType> for EventType {
                 msg_id: msg_id.to_u32(),
                 place_call_info,
             },
-            CoreEventType::IncomingCallAccepted {
-                msg_id,
-                accept_call_info,
-            } => IncomingCallAccepted {
+            CoreEventType::IncomingCallAccepted { msg_id } => IncomingCallAccepted {
                 msg_id: msg_id.to_u32(),
-                accept_call_info,
             },
             CoreEventType::OutgoingCallAccepted {
                 msg_id,