From 10bef7df9bb224442b6e7873903ad729e0c83c6b Mon Sep 17 00:00:00 2001
From: Szepesi Tibor <smrtrfszm@proton.me>
Date: Sun, 3 Nov 2024 20:05:35 +0100
Subject: [PATCH] Unify order api and websocket problem sorting (#93)

---
 src/handlers/problem/order.rs | 26 ++++-----------------
 src/utils/problems.rs         | 43 +++++++++++++++++++++++++++++------
 2 files changed, 41 insertions(+), 28 deletions(-)

diff --git a/src/handlers/problem/order.rs b/src/handlers/problem/order.rs
index 14b7befc..64f6bb7e 100644
--- a/src/handlers/problem/order.rs
+++ b/src/handlers/problem/order.rs
@@ -2,7 +2,7 @@ use crate::{
     error::{self, DatabaseError, Result},
     extractors::Json,
     handlers::socket::Event,
-    utils::{execute_str, topics},
+    utils::{execute_str, sort_linked, topics},
     StateTrait,
 };
 use axum::{extract::State, http::StatusCode};
@@ -275,7 +275,7 @@ pub async fn change<S: StateTrait>(
 }
 
 pub async fn get<S: StateTrait>(State(state): State<S>) -> Result<Json<Vec<Uuid>>> {
-    let mut res = problems_order::Entity::find().all(state.db()).await?;
+    let res = problems_order::Entity::find().all(state.db()).await?;
 
     debug!("res: {res:?}");
 
@@ -283,26 +283,10 @@ pub async fn get<S: StateTrait>(State(state): State<S>) -> Result<Json<Vec<Uuid>
         return Ok(Json(Vec::new()));
     }
 
-    let Some(last_pos) = res.iter().position(|item| item.next.is_none()) else {
-        panic!("corrupted problem chain");
-    };
-
-    let length = res.len();
-    res.swap(last_pos, length - 1);
-
-    let mut last_id = res[length - 1].id;
-
-    for i in (0..(length - 1)).rev() {
-        for j in 0..i {
-            if res[j].next == Some(last_id) {
-                last_id = res[j].id;
-                res.swap(i, j);
-                break;
-            }
-        }
-    }
+    let sorted = sort_linked(res);
+    let ids = sorted.into_iter().map(|item| item.id).collect();
 
-    Ok(Json(res.into_iter().map(|item| item.id).collect()))
+    Ok(Json(ids))
 }
 
 pub(super) async fn delete_problem<T>(txn: &T, id: Uuid) -> Result<()>
diff --git a/src/utils/problems.rs b/src/utils/problems.rs
index cf23e7e1..cb1585cb 100644
--- a/src/utils/problems.rs
+++ b/src/utils/problems.rs
@@ -57,7 +57,7 @@ impl Problems {
             .await
             .expect("failed to query the problems");
 
-        let problems = Arc::new(RwLock::new(sort_initial_problems(res)));
+        let problems = Arc::new(RwLock::new(sort_linked(res)));
 
         let mut subscription = nats.subscribe(topics::problems()).await.unwrap();
 
@@ -211,8 +211,37 @@ impl Stream for ProblemStream {
     }
 }
 
-fn sort_initial_problems(problems: Vec<Problem>) -> Vec<Problem> {
-    let length = problems.len();
+pub trait Linked {
+    fn get_id(&self) -> Uuid;
+    fn get_next(&self) -> Option<Uuid>;
+}
+
+impl Linked for Problem {
+    #[inline]
+    fn get_id(&self) -> Uuid {
+        self.id
+    }
+
+    #[inline]
+    fn get_next(&self) -> Option<Uuid> {
+        self.next
+    }
+}
+
+impl Linked for problems_order::Model {
+    #[inline]
+    fn get_id(&self) -> Uuid {
+        self.id
+    }
+
+    #[inline]
+    fn get_next(&self) -> Option<Uuid> {
+        self.next
+    }
+}
+
+pub fn sort_linked<T: Linked>(list: Vec<T>) -> Vec<T> {
+    let length = list.len();
 
     if length == 0 {
         return Vec::new();
@@ -220,22 +249,22 @@ fn sort_initial_problems(problems: Vec<Problem>) -> Vec<Problem> {
 
     let mut map = HashMap::new();
 
-    for problem in problems {
-        map.insert(problem.next, problem);
+    for item in list {
+        map.insert(item.get_next(), item);
     }
 
     let mut result = Vec::with_capacity(length);
 
     let mut last_id = {
         let last = map.remove(&None).unwrap();
-        let last_id = last.id;
+        let last_id = last.get_id();
         result.push(last);
         last_id
     };
 
     while !map.is_empty() {
         let item = map.remove(&Some(last_id)).unwrap();
-        last_id = item.id;
+        last_id = item.get_id();
         result.push(item);
     }