meli/src/mail/compose.rs

@@ -207,6 +207,14 @@ impl Composer {
                 .iter()
                 .any(|hn| hn.as_str() == h.name())
         });
+
+        for h in context.accounts[&account_hash]
+            .backend_capabilities
+            .extra_submission_headers
+        {
+            ret.draft.set_header(h.clone(), String::new());
+        }
+
         for (h, v) in
             account_settings!(context[account_hash].composing.default_header_values).iter()
         {
@@ -582,6 +590,33 @@ To: {}
         self.form.set_cursor(old_cursor);
         let headers = self.draft.headers();
         let account_hash = self.account_hash;
+        for k in context.accounts[&account_hash]
+            .backend_capabilities
+            .extra_submission_headers
+        {
+            if matches!(*k, HeaderName::NEWSGROUPS) {
+                self.form.push_cl((
+                    k.into(),
+                    headers[k].to_string(),
+                    Box::new(move |c, term| {
+                        c.accounts[&account_hash]
+                            .mailbox_entries
+                            .values()
+                            .filter_map(|v| {
+                                if v.path.starts_with(term) {
+                                    Some(v.path.to_string())
+                                } else {
+                                    None
+                                }
+                            })
+                            .map(AutoCompleteEntry::from)
+                            .collect::<Vec<AutoCompleteEntry>>()
+                    }),
+                ));
+            } else {
+                self.form.push((k.into(), headers[k].to_string()));
+            }
+        }
         for k in &[
             HeaderName::DATE,
             HeaderName::FROM,
@@ -590,7 +625,7 @@ To: {}
             HeaderName::BCC,
             HeaderName::SUBJECT,
         ] {
-            if k == HeaderName::TO || k == HeaderName::CC || k == HeaderName::BCC {
+            if matches!(*k, HeaderName::TO | HeaderName::CC | HeaderName::BCC) {
                 self.form.push_cl((
                     k.into(),
                     headers[k].to_string(),

melib/src/backends.rs

@@ -37,7 +37,7 @@ use super::email::{Envelope, EnvelopeHash, Flag};
 use crate::{
     conf::AccountSettings,
     error::{Error, ErrorKind, Result},
-    LogLevel,
+    HeaderName, LogLevel,
 };
 
 #[macro_export]
@@ -328,6 +328,7 @@ pub struct MailBackendCapabilities {
     pub supports_search: bool,
     pub supports_tags: bool,
     pub supports_submission: bool,
+    pub extra_submission_headers: &'static [HeaderName],
 }
 
 #[derive(Debug, Copy, Clone)]

melib/src/imap/mod.rs

@@ -292,6 +292,7 @@ impl MailBackend for ImapType {
             extensions: Some(extensions),
             supports_tags: true,
             supports_submission: false,
+            extra_submission_headers: &[],
         }
     }
 

melib/src/jmap/mod.rs

@@ -299,6 +299,7 @@ impl MailBackend for JmapType {
             extensions: None,
             supports_tags: true,
             supports_submission: true,
+            extra_submission_headers: &[],
         };
         let supports_submission: bool = self
             .store

melib/src/maildir/backend.rs

@@ -186,6 +186,7 @@ impl MailBackend for MaildirType {
             extensions: None,
             supports_tags: false,
             supports_submission: false,
+            extra_submission_headers: &[],
         };
         CAPABILITIES
     }

melib/src/mbox/mod.rs

@@ -836,6 +836,7 @@ impl MailBackend for MboxType {
             extensions: None,
             supports_tags: false,
             supports_submission: false,
+            extra_submission_headers: &[],
         };
         CAPABILITIES
     }

melib/src/nntp/mod.rs

@@ -217,6 +217,7 @@ impl MailBackend for NntpType {
             extensions: Some(extensions),
             supports_tags: false,
             supports_submission,
+            extra_submission_headers: &[HeaderName::NEWSGROUPS],
         }
     }
 

melib/src/notmuch/mod.rs

@@ -603,6 +603,7 @@ impl MailBackend for NotmuchDb {
             extensions: None,
             supports_tags: true,
             supports_submission: false,
+            extra_submission_headers: &[],
         };
         CAPABILITIES
     }