1 files changed, 39 insertions, 5 deletions
diff --git a/src/conversation/history.rs b/src/conversation/history.rs
index 746a1b0..5cba9ca 100644
--- a/src/conversation/history.rs
+++ b/src/conversation/history.rs
@@ -4,13 +4,49 @@ use super::{
     Conversation, Id,
     event::{Created, Deleted, Event},
 };
-use crate::event::Sequence;
+use crate::{
+    event::{Instant, Sequence},
+    name::Name,
+};
 
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct History {
     pub conversation: Conversation,
 }
 
+// Lifecycle interface
+impl History {
+    pub fn begin(name: &Name, created: Instant) -> Self {
+        Self {
+            conversation: Conversation {
+                id: Id::generate(),
+                name: name.clone(),
+                created,
+                deleted: None,
+            },
+        }
+    }
+
+    pub fn delete(self, deleted: Instant) -> Result<Self, DeleteError> {
+        if self.conversation.deleted.is_none() {
+            Ok(Self {
+                conversation: Conversation {
+                    deleted: Some(deleted),
+                    ..self.conversation
+                },
+            })
+        } else {
+            Err(DeleteError::Deleted(self))
+        }
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum DeleteError {
+    #[error("conversation {} already deleted", .0.conversation.id)]
+    Deleted(History),
+}
+
 // State interface
 impl History {
     pub fn id(&self) -> &Id {
@@ -30,9 +66,7 @@ impl History {
     where
         S: Into<Sequence>,
     {
-        self.events()
-            .filter(Sequence::up_to(sequence.into()))
-            .collect()
+        self.events().filter(Sequence::up_to(sequence)).collect()
     }
 
     // Snapshot of this conversation as of all events recorded in this history.
@@ -43,7 +77,7 @@ impl History {
 
 // Event factories
 impl History {
-    pub fn events(&self) -> impl Iterator<Item = Event> + use<> {
+    pub fn events(&self) -> impl Iterator<Item = Event> + Clone + use<> {
         [self.created()]
             .into_iter()
             .merge_by(self.deleted(), Sequence::merge)