prototype a device-chat

Author: r10s

deltachat-ffi/deltachat.h

@@ -2715,6 +2715,42 @@ int             dc_chat_is_unpromoted        (const dc_chat_t* chat);
 int             dc_chat_is_self_talk         (const dc_chat_t* chat);
 
 
+/**
+ * Check if a chat is a device-talk.
+ * Device-talks contain update information
+ * and some hints that are added during the program runs, multi-device etc.
+ * The only sender in these chats is usually the contact DC_CONTACT_ID_DEVICE (5).
+ *
+ * From the ui view, device-talks are not very special,
+ * the user can delete and forward messages, archive the chat, set notifications etc.
+ *
+ * How to create a device-talk and add messages to it:
+ * ```
+ * device_chat_id = dc_create_chat_by_contact_id(context, DC_CONTACT_ID_DEVICE);
+ * dc_send_text_msg(context, device_chat_id, "recent changes ...");
+ * ```
+ *
+ * @memberof dc_chat_t
+ * @param chat The chat object.
+ * @return 1=chat is device-talk, 0=chat is no device-talk
+ */
+int             dc_chat_is_device_talk       (const dc_chat_t* chat);
+
+
+/**
+ * Check if messages can be sent to a give chat.
+ * This is not true eg. for the deaddrop or for the device-talk, cmp. dc_chat_is_device_talk().
+ *
+ * Calling dc_send_msg() for these chats will fail
+ * and the ui may decide to hide input controls therefore.
+ *
+ * @memberof dc_chat_t
+ * @param chat The chat object.
+ * @return 1=chat is writable, 0=chat is not writable
+ */
+int             dc_chat_is_writable           (const dc_chat_t* chat);
+
+
 /**
  * Check if a chat is verified.  Verified chats contain only verified members
  * and encryption is alwasy enabled.  Verified chats are created using
@@ -3370,7 +3406,8 @@ void            dc_msg_latefiling_mediasize   (dc_msg_t* msg, int width, int hei
 
 
 #define         DC_CONTACT_ID_SELF           1
-#define         DC_CONTACT_ID_INFO           2
+#define         DC_CONTACT_ID_INFO           2 // centered messages as "member added", used in all chats
+#define         DC_CONTACT_ID_DEVICE         5 // messages "update info" in the device-chat
 #define         DC_CONTACT_ID_LAST_SPECIAL   9