1 files changed, 93 insertions, 0 deletions
diff --git a/src/imap/capability.rs b/src/imap/capability.rs
new file mode 100644
index 0000000..631c3e2
--- /dev/null
+++ b/src/imap/capability.rs
@@ -0,0 +1,93 @@
+use imap_codec::imap_types::core::NonEmptyVec;
+use imap_codec::imap_types::extensions::enable::{CapabilityEnable, Utf8Kind};
+use imap_codec::imap_types::response::Capability;
+use std::collections::HashSet;
+
+fn capability_unselect() -> Capability<'static> {
+    Capability::try_from("UNSELECT").unwrap()
+}
+
+fn capability_condstore() -> Capability<'static> {
+    Capability::try_from("CONDSTORE").unwrap()
+}
+
+fn capability_qresync() -> Capability<'static> {
+    Capability::try_from("QRESYNC").unwrap()
+}
+
+#[derive(Debug, Clone)]
+pub struct ServerCapability(HashSet<Capability<'static>>);
+
+impl Default for ServerCapability {
+    fn default() -> Self {
+        Self(HashSet::from([
+            Capability::Imap4Rev1,
+            Capability::Move,
+            Capability::LiteralPlus,
+            capability_unselect(),
+            //capability_condstore(),
+            //capability_qresync(),
+        ]))
+    }
+}
+
+impl ServerCapability {
+    pub fn to_vec(&self) -> NonEmptyVec<Capability<'static>> {
+        self.0
+            .iter()
+            .map(|v| v.clone())
+            .collect::<Vec<_>>()
+            .try_into()
+            .unwrap()
+    }
+
+    #[allow(dead_code)]
+    pub fn support(&self, cap: &Capability<'static>) -> bool {
+        self.0.contains(cap)
+    }
+}
+
+enum ClientStatus {
+    NotSupportedByServer,
+    Disabled,
+    Enabled,
+}
+
+pub struct ClientCapability {
+    condstore: ClientStatus,
+    utf8kind: Option<Utf8Kind>,
+}
+
+impl ClientCapability {
+    pub fn new(sc: &ServerCapability) -> Self {
+        Self {
+            condstore: match sc.0.contains(&capability_condstore()) {
+                true => ClientStatus::Disabled,
+                _ => ClientStatus::NotSupportedByServer,
+            },
+            utf8kind: None,
+        }
+    }
+
+    pub fn try_enable(
+        &mut self,
+        caps: &[CapabilityEnable<'static>],
+    ) -> Vec<CapabilityEnable<'static>> {
+        let mut enabled = vec![];
+        for cap in caps {
+            match cap {
+                CapabilityEnable::CondStore if matches!(self.condstore, ClientStatus::Disabled) => {
+                    self.condstore = ClientStatus::Enabled;
+                    enabled.push(cap.clone());
+                }
+                CapabilityEnable::Utf8(kind) if Some(kind) != self.utf8kind.as_ref() => {
+                    self.utf8kind = Some(kind.clone());
+                    enabled.push(cap.clone());
+                }
+                _ => (),
+            }
+        }
+
+        enabled
+    }
+}