Rewrite from mongodb to sqlx (#1)

Reviewed-on: #1

src/routes/mod.rs

@@ -1,10 +1,7 @@
 use axum::response::Html;
 use axum::{Json, extract::State, http::StatusCode};
-use futures_util::stream::TryStreamExt;
-use mongodb::Database;
-use mongodb::bson::doc;
-use mongodb::bson::oid::ObjectId;
 use serde::{Deserialize, Serialize};
+use sqlx::{Sqlite, SqlitePool, Transaction};
 
 use crate::models::Character;
 use crate::utils::calculate_elo;
@@ -15,7 +12,7 @@ pub struct RateRequest {
     loser_id: String,
 }
 
-#[derive(Deserialize, Serialize)]
+#[derive(Serialize)]
 pub struct RateResponse {
     winner: Character,
     loser: Character,
@@ -24,94 +21,74 @@ pub struct RateResponse {
 static K_FACTOR: f64 = 32.0; // K-factor for Elo rating system
 
 pub async fn get_characters(
-    State(db): State<Database>,
+    State(db): State<SqlitePool>,
 ) -> Result<Json<Vec<Character>>, StatusCode> {
-    let collection = db.collection::<Character>("characters");
-    let pipeline = vec![doc! { "$sort": { "elo_rating": -1 } }];
-
-    let mut cursor = collection
-        .aggregate(pipeline)
-        .await
-        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
-
-    let mut characters = Vec::new();
-    while let Some(result) = cursor
-        .try_next()
-        .await
-        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
-    {
-        let character: Character =
-            mongodb::bson::from_document(result).map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
-        characters.push(character);
-    }
-
-    tracing::info!(count = characters.len(), "Fetched characters from DB");
+    let characters =
+        sqlx::query_as::<_, Character>("SELECT * FROM characters ORDER BY elo_rating DESC")
+            .fetch_all(&db)
+            .await
+            .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
 
     Ok(Json(characters))
 }
 
 #[axum::debug_handler]
 pub async fn rate(
-    State(db): State<Database>,
+    State(db): State<SqlitePool>,
     Json(req): Json<RateRequest>,
 ) -> Result<Json<RateResponse>, StatusCode> {
-    let collection = db.collection::<Character>("characters");
-
-    let winner_oid = ObjectId::parse_str(&req.winner_id).map_err(|_| StatusCode::BAD_REQUEST)?;
-    let loser_oid = ObjectId::parse_str(&req.loser_id).map_err(|_| StatusCode::BAD_REQUEST)?;
-
-    let winner = collection
-        .find_one(doc! { "_id": winner_oid })
+    // 1. Fetch characters by ID
+    let winner: Character = sqlx::query_as("SELECT * FROM characters WHERE id = ?")
+        .bind(&req.winner_id)
+        .fetch_optional(&db)
         .await
-        .ok()
-        .flatten()
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
         .ok_or(StatusCode::NOT_FOUND)?;
-    let loser = collection
-        .find_one(doc! { "_id": loser_oid })
+
+    let loser: Character = sqlx::query_as("SELECT * FROM characters WHERE id = ?")
+        .bind(&req.loser_id)
+        .fetch_optional(&db)
         .await
-        .ok()
-        .flatten()
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
         .ok_or(StatusCode::NOT_FOUND)?;
 
     let (new_winner_elo, new_loser_elo) =
         calculate_elo(winner.elo_rating, loser.elo_rating, K_FACTOR);
 
-    collection
-        .update_one(
-            doc! {"_id": &winner_oid},
-            doc! { "$set": { "elo_rating": new_winner_elo } },
-        )
+    let mut tx: Transaction<'_, Sqlite> = db
+        .begin()
         .await
         .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
 
-    collection
-        .update_one(
-            doc! {"_id": &loser_oid},
-            doc! { "$set": { "elo_rating": new_loser_elo } },
-        )
+    sqlx::query("UPDATE characters SET elo_rating = ? WHERE id = ?")
+        .bind(new_winner_elo)
+        .bind(&req.winner_id)
+        .execute(&mut *tx)
         .await
         .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
 
-    // return resposnse with characters' new Elo ratings
-    let updated_winner = collection
-        .find_one(doc! { "_id": winner_oid })
+    sqlx::query("UPDATE characters SET elo_rating = ? WHERE id = ?")
+        .bind(new_loser_elo)
+        .bind(&req.loser_id)
+        .execute(&mut *tx)
         .await
-        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
-        .ok_or(StatusCode::NOT_FOUND)?;
-    let updated_loser = collection
-        .find_one(doc! { "_id": loser_oid })
-        .await
-        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
-        .ok_or(StatusCode::NOT_FOUND)?;
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
 
-    tracing::info!(
-        "Rated characters: winner_id = {}, loser_id = {}, new_winner_elo =
-    {}, new_loser_elo = {}",
-        req.winner_id,
-        req.loser_id,
-        new_winner_elo,
-        new_loser_elo
-    );
+    tx.commit()
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    let updated_winner: Character = sqlx::query_as("SELECT * FROM characters WHERE id = ?")
+        .bind(&req.winner_id)
+        .fetch_one(&db)
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    let updated_loser: Character = sqlx::query_as("SELECT * FROM characters WHERE id = ?")
+        .bind(&req.loser_id)
+        .fetch_one(&db)
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
 
     Ok(Json(RateResponse {
         winner: updated_winner,