1 files changed, 97 insertions, 0 deletions
diff --git a/src/imap/imf_view.rs b/src/imap/imf_view.rs
new file mode 100644
index 0000000..4297769
--- /dev/null
+++ b/src/imap/imf_view.rs
@@ -0,0 +1,97 @@
+use imap_codec::imap_types::core::{IString, NString};
+use imap_codec::imap_types::envelope::{Address, Envelope};
+
+use eml_codec::imf;
+
+/// Envelope rules are defined in RFC 3501, section 7.4.2
+/// https://datatracker.ietf.org/doc/html/rfc3501#section-7.4.2
+///
+/// Some important notes:
+///
+/// If the Sender or Reply-To lines are absent in the [RFC-2822]
+/// header, or are present but empty, the server sets the
+/// corresponding member of the envelope to be the same value as
+/// the from member (the client is not expected to know to do
+/// this). Note: [RFC-2822] requires that all messages have a valid
+/// From header.  Therefore, the from, sender, and reply-to
+/// members in the envelope can not be NIL.
+///
+/// If the Date, Subject, In-Reply-To, and Message-ID header lines
+/// are absent in the [RFC-2822] header, the corresponding member
+/// of the envelope is NIL; if these header lines are present but
+/// empty the corresponding member of the envelope is the empty
+/// string.
+
+//@FIXME return an error if the envelope is invalid instead of panicking
+//@FIXME some fields must be defaulted if there are not set.
+pub fn message_envelope(msg: &imf::Imf) -> Envelope<'static> {
+    let from = msg.from.iter().map(convert_mbx).collect::<Vec<_>>();
+
+    Envelope {
+        date: NString(
+            msg.date
+                .as_ref()
+                .map(|d| IString::try_from(d.to_rfc3339()).unwrap()),
+        ),
+        subject: NString(
+            msg.subject
+                .as_ref()
+                .map(|d| IString::try_from(d.to_string()).unwrap()),
+        ),
+        sender: msg
+            .sender
+            .as_ref()
+            .map(|v| vec![convert_mbx(v)])
+            .unwrap_or(from.clone()),
+        reply_to: if msg.reply_to.is_empty() {
+            from.clone()
+        } else {
+            convert_addresses(&msg.reply_to)
+        },
+        from,
+        to: convert_addresses(&msg.to),
+        cc: convert_addresses(&msg.cc),
+        bcc: convert_addresses(&msg.bcc),
+        in_reply_to: NString(
+            msg.in_reply_to
+                .iter()
+                .next()
+                .map(|d| IString::try_from(d.to_string()).unwrap()),
+        ),
+        message_id: NString(
+            msg.msg_id
+                .as_ref()
+                .map(|d| IString::try_from(d.to_string()).unwrap()),
+        ),
+    }
+}
+
+pub fn convert_addresses(addrlist: &Vec<imf::address::AddressRef>) -> Vec<Address<'static>> {
+    let mut acc = vec![];
+    for item in addrlist {
+        match item {
+            imf::address::AddressRef::Single(a) => acc.push(convert_mbx(a)),
+            imf::address::AddressRef::Many(l) => acc.extend(l.participants.iter().map(convert_mbx)),
+        }
+    }
+    return acc;
+}
+
+pub fn convert_mbx(addr: &imf::mailbox::MailboxRef) -> Address<'static> {
+    Address {
+        name: NString(
+            addr.name
+                .as_ref()
+                .map(|x| IString::try_from(x.to_string()).unwrap()),
+        ),
+        // SMTP at-domain-list (source route) seems obsolete since at least 1991
+        // https://www.mhonarc.org/archive/html/ietf-822/1991-06/msg00060.html
+        adl: NString(None),
+        mailbox: NString(Some(
+            IString::try_from(addr.addrspec.local_part.to_string()).unwrap(),
+        )),
+        host: NString(Some(
+            IString::try_from(addr.addrspec.domain.to_string()).unwrap(),
+        )),
+    }
+}