1 files changed, 168 insertions, 0 deletions
diff --git a/src/uidindex.rs b/src/uidindex.rs
new file mode 100644
index 0000000..7c5500f
--- /dev/null
+++ b/src/uidindex.rs
@@ -0,0 +1,168 @@
+use im::OrdMap;
+use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
+
+use crate::bayou::*;
+
+type ImapUid = u32;
+type ImapUidvalidity = u32;
+
+/// A Mail UUID is composed of two components:
+/// - a process identifier, 128 bits
+/// - a sequence number, 64 bits
+#[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq)]
+pub struct MailUuid(pub [u8; 24]);
+
+#[derive(Clone)]
+pub struct UidIndex {
+    mail_uid: OrdMap<MailUuid, ImapUid>,
+    mail_flags: OrdMap<MailUuid, Vec<String>>,
+
+    mails_by_uid: OrdMap<ImapUid, MailUuid>,
+
+    uidvalidity: ImapUidvalidity,
+    uidnext: ImapUid,
+    internalseq: ImapUid,
+}
+
+#[derive(Clone, Serialize, Deserialize)]
+pub enum UidIndexOp {
+    MailAdd(MailUuid, ImapUid, Vec<String>),
+    MailDel(MailUuid),
+}
+
+impl Default for UidIndex {
+    fn default() -> Self {
+        Self {
+            mail_flags: OrdMap::new(),
+            mail_uid: OrdMap::new(),
+            mails_by_uid: OrdMap::new(),
+            uidvalidity: 1,
+            uidnext: 1,
+            internalseq: 1,
+        }
+    }
+}
+
+impl BayouState for UidIndex {
+    type Op = UidIndexOp;
+
+    fn apply(&self, op: &UidIndexOp) -> Self {
+        let mut new = self.clone();
+        match op {
+            UidIndexOp::MailAdd(uuid, uid, flags) => {
+                if *uid < new.internalseq {
+                    new.uidvalidity += new.internalseq - *uid;
+                }
+                let new_uid = new.internalseq;
+
+                if let Some(prev_uid) = new.mail_uid.get(uuid) {
+                    new.mails_by_uid.remove(prev_uid);
+                } else {
+                    new.mail_flags.insert(*uuid, flags.clone());
+                }
+                new.mails_by_uid.insert(new_uid, *uuid);
+                new.mail_uid.insert(*uuid, new_uid);
+
+                new.internalseq += 1;
+                new.uidnext = new.internalseq;
+            }
+            UidIndexOp::MailDel(uuid) => {
+                if let Some(uid) = new.mail_uid.get(uuid) {
+                    new.mails_by_uid.remove(uid);
+                    new.mail_uid.remove(uuid);
+                    new.mail_flags.remove(uuid);
+                }
+                new.internalseq += 1;
+            }
+        }
+        new
+    }
+}
+
+// ---- CUSTOM SERIALIZATION AND DESERIALIZATION ----
+
+#[derive(Serialize, Deserialize)]
+struct UidIndexSerializedRepr {
+    mails: Vec<(ImapUid, MailUuid, Vec<String>)>,
+    uidvalidity: ImapUidvalidity,
+    uidnext: ImapUid,
+    internalseq: ImapUid,
+}
+
+impl<'de> Deserialize<'de> for UidIndex {
+    fn deserialize<D>(d: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let val: UidIndexSerializedRepr = UidIndexSerializedRepr::deserialize(d)?;
+
+        let mut uidindex = UidIndex {
+            mail_flags: OrdMap::new(),
+            mail_uid: OrdMap::new(),
+            mails_by_uid: OrdMap::new(),
+            uidvalidity: val.uidvalidity,
+            uidnext: val.uidnext,
+            internalseq: val.internalseq,
+        };
+
+        for (uid, uuid, flags) in val.mails {
+            uidindex.mail_flags.insert(uuid, flags);
+            uidindex.mail_uid.insert(uuid, uid);
+            uidindex.mails_by_uid.insert(uid, uuid);
+        }
+
+        Ok(uidindex)
+    }
+}
+
+impl Serialize for UidIndex {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut mails = vec![];
+        for (uid, uuid) in self.mails_by_uid.iter() {
+            mails.push((
+                *uid,
+                *uuid,
+                self.mail_flags.get(uuid).cloned().unwrap_or_default(),
+            ));
+        }
+
+        let val = UidIndexSerializedRepr {
+            mails,
+            uidvalidity: self.uidvalidity,
+            uidnext: self.uidnext,
+            internalseq: self.internalseq,
+        };
+
+        val.serialize(serializer)
+    }
+}
+
+impl<'de> Deserialize<'de> for MailUuid {
+    fn deserialize<D>(d: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let v = String::deserialize(d)?;
+        let bytes = hex::decode(v).map_err(|_| D::Error::custom("invalid hex"))?;
+
+        if bytes.len() != 24 {
+            return Err(D::Error::custom("bad length"));
+        }
+
+        let mut tmp = [0u8; 24];
+        tmp[..].copy_from_slice(&bytes);
+        Ok(Self(tmp))
+    }
+}
+
+impl Serialize for MailUuid {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&hex::encode(self.0))
+    }
+}