feat: Audit Logs (#466)

* fix: squash audit log branch changes

Signed-off-by: Zomatree <me@zomatree.live>

* feat: emoji edit + pronoun

Signed-off-by: Zomatree <me@zomatree.live>

* fix: use tokio instead of async-std

Signed-off-by: Zomatree <me@zomatree.live>

* feat: add slowmode to audit log

Signed-off-by: Zomatree <me@zomatree.live>

* chore: update comments on permissions

Signed-off-by: Zomatree <me@zomatree.live>

---------

Signed-off-by: Zomatree <me@zomatree.live>

crates/delta/src/util/audit_log_reason.rs

@@ -0,0 +1,62 @@
+use revolt_result::{create_error, Error};
+use revolt_rocket_okapi::{OpenApiError, gen::OpenApiGenerator, request::{OpenApiFromRequest, RequestHeaderInput}, revolt_okapi::openapi3::{Parameter, ParameterValue}};
+use rocket::{
+    http::Status,
+    request::{FromRequest, Outcome, Request},
+};
+use schemars::schema::{InstanceType, SchemaObject, SingleOrVec};
+
+/// Newtype for an audit log reason.
+///
+/// Extracts the reason from the `X-Audit-Log-Reason` header if provided.
+pub struct AuditLogReason(pub Option<String>);
+
+#[async_trait]
+impl<'r> FromRequest<'r> for AuditLogReason {
+    type Error = Error;
+
+    async fn from_request(req: &'r Request<'_>) -> Outcome<Self, Self::Error> {
+        let reason = req.headers().get_one("x-audit-log-reason");
+
+        if reason.is_some_and(|str| str.len() > 512) {
+            return Outcome::Error((Status::BadRequest, create_error!(HeaderTooLarge)));
+        };
+
+        Outcome::Success(Self(reason.map(|str| str.to_string())))
+    }
+}
+
+impl OpenApiFromRequest<'_> for AuditLogReason {
+    fn from_request_input(
+        _gen: &mut OpenApiGenerator,
+        _name: String,
+        _required: bool,
+    ) -> Result<RequestHeaderInput, OpenApiError> {
+        Ok(RequestHeaderInput::Parameter(Parameter {
+            name: "X-Audit-Log-Reason".to_string(),
+            description: Some("Reason for action which is stored in the audit log.".to_string()),
+            allow_empty_value: false,
+            required: false,
+            deprecated: false,
+            extensions: schemars::Map::new(),
+            location: "header".to_string(),
+            value: ParameterValue::Schema {
+                allow_reserved: false,
+                example: None,
+                examples: None,
+                explode: None,
+                style: None,
+                schema: SchemaObject {
+                    instance_type: Some(SingleOrVec::Single(Box::new(InstanceType::String))),
+                    ..Default::default()
+                },
+            },
+        }))
+    }
+}
+
+impl From<AuditLogReason> for Option<String> {
+    fn from(value: AuditLogReason) -> Self {
+        value.0
+    }
+}

crates/delta/src/util/mod.rs

@@ -1,3 +1,4 @@
+pub mod audit_log_reason;
 pub mod ratelimits;
 
 #[cfg(test)]