[Fix] User deletion & migration

src/state.rs

@@ -1,18 +1,47 @@
 use crate::sql::user_online_tracker::PresenceTracker;
 use std::sync::Arc;
+use dashmap::DashMap;
+use std::time::{Duration, Instant};
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum AccountChallengeOperation { Attach, Delete }
+
+#[derive(Clone, Debug)]
+pub struct AccountChallenge {
+    pub operation: AccountChallengeOperation,
+    pub user_id: i64,
+    pub requester_iota_id: i64,
+    pub nonce: u64,
+    pub created_at: Instant,
+}
 
 pub struct OmegaState {
     pub presence: Arc<PresenceTracker>,
+    challenges: DashMap<(AccountChallengeOperation, i64, i64), AccountChallenge>,
 }
 
 impl Default for OmegaState {
     fn default() -> Self {
         Self {
             presence: Arc::new(PresenceTracker::default()),
+            challenges: DashMap::new(),
         }
     }
 }
 
+impl OmegaState {
+    pub fn issue_challenge(&self, operation: AccountChallengeOperation, user_id: i64, requester_iota_id: i64) -> u64 {
+        let nonce = rand::random::<u64>();
+        self.challenges.insert((operation, user_id, requester_iota_id), AccountChallenge { operation, user_id, requester_iota_id, nonce, created_at: Instant::now() });
+        nonce
+    }
+
+    pub fn consume_challenge(&self, operation: AccountChallengeOperation, user_id: i64, requester_iota_id: i64, nonce: u64) -> bool {
+        self.challenges.remove(&(operation, user_id, requester_iota_id)).is_some_and(|(_, value)|
+            value.nonce == nonce && value.created_at.elapsed() <= Duration::from_secs(120))
+    }
+}
+
 impl OmegaState {
     pub fn new() -> Arc<Self> {
         Arc::new(Self::default())