feat: webxdc notify (#6230)

this PR adds support for the property `update.notify` to notify about
changes in `update.info` or `update.summary`. the property can be set to
an array of addresses [^1]

core emits then the event `IncomingWebxdcNotify`, resulting in all UIs
to display a system notification, maybe even via PUSH.

for using the existing `update.info` and `update.summary`: the message
is no secret and should be visible to all group members as usual, to not
break the UX of having same group messages on all devices of all users -
as known already from the normal messages.

also, that way, there is no question what happens if user have disabled
notifications as the change is presented in the chat as well

doc counterpart at https://github.com/webxdc/website/pull/90

closes #6217 

[^1]: addresses come in either via the payload as currently or as an
explicit sender in the future - this does not affect this PR. same for
translations, see discussions at #6217 and #6097

---------

Co-authored-by: adb <asieldbenitez@gmail.com>
Co-authored-by: l <link2xt@testrun.org>

deltachat-ffi/deltachat.h

@@ -1154,7 +1154,13 @@ uint32_t dc_send_videochat_invitation (dc_context_t* context, uint32_t chat_id);
  * @memberof dc_context_t
  * @param context The context object.
  * @param msg_id The ID of the message with the webxdc instance.
- * @param json program-readable data, the actual payload
+ * @param json program-readable data, this is created in JS land as:
+ *     - `payload`: any JS object or primitive.
+ *     - `info`: optional informational message. Will be shown in chat and may be added as system notification.
+ *       note that also users that are not notified explicitly get the `info` or `summary` update shown in the chat.
+ *     - `document`: optional document name. shown eg. in title bar.
+ *     - `summary`: optional summary. shown beside app icon.
+ *     - `notify`: optional array of other users `selfAddr` to be notified e.g. by a sound about `info` or `summary`.
  * @param descr The user-visible description of JSON data,
  *     in case of a chess game, e.g. the move.
  * @return 1=success, 0=error
@@ -6080,12 +6086,29 @@ void dc_event_unref(dc_event_t* event);
 #define DC_EVENT_INCOMING_REACTION        2002
 
 
+
+/**
+ * A webxdc wants an info message or a changed summary to be notified.
+ *
+ * @param data1 contact_id ID of the contact sending.
+ * @param data2 (int) msg_id + (char*) text_to_notify.
+ *      msg_id in dc_event_get_data2_int(), referring to webxdc-info-message
+ *      or webxdc-instance in case of summary change.
+ *      text_to_notify in dc_event_get_data2_str().
+ *      string must be passed to dc_str_unref() afterwards.
+ */
+#define DC_EVENT_INCOMING_WEBXDC_NOTIFY   2003
+
+
 /**
  * There is a fresh message. Typically, the user will show an notification
  * when receiving this message.
  *
  * There is no extra #DC_EVENT_MSGS_CHANGED event send together with this event.
  *
+ * If the message is a webxdc info message,
+ * dc_msg_get_parent() returns the webxdc instance the notification belongs to.
+ *
  * @param data1 (int) chat_id
  * @param data2 (int) msg_id
  */

deltachat-ffi/src/lib.rs

@@ -542,6 +542,7 @@ pub unsafe extern "C" fn dc_event_get_id(event: *mut dc_event_t) -> libc::c_int
         EventType::MsgsChanged { .. } => 2000,
         EventType::ReactionsChanged { .. } => 2001,
         EventType::IncomingReaction { .. } => 2002,
+        EventType::IncomingWebxdcNotify { .. } => 2003,
         EventType::IncomingMsg { .. } => 2005,
         EventType::IncomingMsgBunch { .. } => 2006,
         EventType::MsgsNoticed { .. } => 2008,
@@ -602,7 +603,8 @@ pub unsafe extern "C" fn dc_event_get_data1_int(event: *mut dc_event_t) -> libc:
         | EventType::ErrorSelfNotInGroup(_)
         | EventType::AccountsBackgroundFetchDone => 0,
         EventType::ChatlistChanged => 0,
-        EventType::IncomingReaction { contact_id, .. } => contact_id.to_u32() as libc::c_int,
+        EventType::IncomingReaction { contact_id, .. }
+        | EventType::IncomingWebxdcNotify { contact_id, .. } => contact_id.to_u32() as libc::c_int,
         EventType::MsgsChanged { chat_id, .. }
         | EventType::ReactionsChanged { chat_id, .. }
         | EventType::IncomingMsg { chat_id, .. }
@@ -681,6 +683,7 @@ pub unsafe extern "C" fn dc_event_get_data2_int(event: *mut dc_event_t) -> libc:
         EventType::MsgsChanged { msg_id, .. }
         | EventType::ReactionsChanged { msg_id, .. }
         | EventType::IncomingReaction { msg_id, .. }
+        | EventType::IncomingWebxdcNotify { msg_id, .. }
         | EventType::IncomingMsg { msg_id, .. }
         | EventType::MsgDelivered { msg_id, .. }
         | EventType::MsgFailed { msg_id, .. }
@@ -775,6 +778,9 @@ pub unsafe extern "C" fn dc_event_get_data2_str(event: *mut dc_event_t) -> *mut
             .to_c_string()
             .unwrap_or_default()
             .into_raw(),
+        EventType::IncomingWebxdcNotify { text, .. } => {
+            text.to_c_string().unwrap_or_default().into_raw()
+        }
         #[allow(unreachable_patterns)]
         #[cfg(test)]
         _ => unreachable!("This is just to silence a rust_analyzer false-positive"),