Merge branch 'prop/rename-login-to-user'

1 files changed, 52 insertions, 0 deletions

diff --git a/src/user/history.rs b/src/user/history.rs
new file mode 100644
index 0000000..ae7a561
--- /dev/null
+++ b/src/user/history.rs
@@ -0,0 +1,52 @@
+use super::{
+    Id, User,
+    event::{Created, Event},
+};
+use crate::event::{Instant, Sequence};
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct History {
+    pub user: User,
+    pub created: Instant,
+}
+
+// State interface
+impl History {
+    pub fn id(&self) -> &Id {
+        &self.user.id
+    }
+
+    // Snapshot of this user as it was when created. (Note to the future: it's okay
+    // if this returns a redacted or modified version of the user. If we  implement
+    // renames by redacting the original name, then this should return the edited
+    // user, not the original, even if that's not how it was "as created.")
+    pub fn as_created(&self) -> User {
+        self.user.clone()
+    }
+
+    pub fn as_of(&self, resume_point: Sequence) -> Option<User> {
+        self.events()
+            .filter(Sequence::up_to(resume_point))
+            .collect()
+    }
+
+    // Snapshot of this user, as of all events recorded in this history.
+    pub fn as_snapshot(&self) -> Option<User> {
+        self.events().collect()
+    }
+}
+
+// Events interface
+impl History {
+    fn created(&self) -> Event {
+        Created {
+            instant: self.created,
+            user: self.user.clone(),
+        }
+        .into()
+    }
+
+    pub fn events(&self) -> impl Iterator<Item = Event> + use<> {
+        [self.created()].into_iter()
+    }
+}