1 files changed, 109 insertions, 0 deletions
diff --git a/aero-proto/imap/imf_view.rs b/aero-proto/imap/imf_view.rs
new file mode 100644
index 0000000..a4ca2e8
--- /dev/null
+++ b/aero-proto/imap/imf_view.rs
@@ -0,0 +1,109 @@
+use anyhow::{anyhow, Result};
+use chrono::naive::NaiveDate;
+
+use imap_codec::imap_types::core::{IString, NString};
+use imap_codec::imap_types::envelope::{Address, Envelope};
+
+use eml_codec::imf;
+
+pub struct ImfView<'a>(pub &'a imf::Imf<'a>);
+
+impl<'a> ImfView<'a> {
+    pub fn naive_date(&self) -> Result<NaiveDate> {
+        Ok(self.0.date.ok_or(anyhow!("date is not set"))?.date_naive())
+    }
+
+    /// 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(&self) -> Envelope<'static> {
+        let msg = self.0;
+        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(),
+        )),
+    }
+}