init

src/routes/mod.rs

@@ -0,0 +1,125 @@
+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 crate::models::Character;
+use crate::utils::calculate_elo;
+
+#[derive(Deserialize)]
+pub struct RateRequest {
+    winner_id: String,
+    loser_id: String,
+}
+
+#[derive(Deserialize, Serialize)]
+pub struct RateResponse {
+    winner: Character,
+    loser: Character,
+}
+
+static K_FACTOR: f64 = 32.0; // K-factor for Elo rating system
+
+pub async fn get_characters(
+    State(db): State<Database>,
+) -> Result<Json<Vec<Character>>, StatusCode> {
+    let collection = db.collection::<Character>("characters");
+    let pipeline = vec![doc! { "$sort": { "elo_rating": -1 } }];
+
+    let mut cursor = collection
+        .aggregate(pipeline)
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    let mut characters = Vec::new();
+    while let Some(result) = cursor
+        .try_next()
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
+    {
+        let character: Character =
+            mongodb::bson::from_document(result).map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+        characters.push(character);
+    }
+
+    tracing::info!(count = characters.len(), "Fetched characters from DB");
+
+    Ok(Json(characters))
+}
+
+#[axum::debug_handler]
+pub async fn rate(
+    State(db): State<Database>,
+    Json(req): Json<RateRequest>,
+) -> Result<Json<RateResponse>, StatusCode> {
+    let collection = db.collection::<Character>("characters");
+
+    let winner_oid = ObjectId::parse_str(&req.winner_id).map_err(|_| StatusCode::BAD_REQUEST)?;
+    let loser_oid = ObjectId::parse_str(&req.loser_id).map_err(|_| StatusCode::BAD_REQUEST)?;
+
+    let winner = collection
+        .find_one(doc! { "_id": winner_oid })
+        .await
+        .ok()
+        .flatten()
+        .ok_or(StatusCode::NOT_FOUND)?;
+    let loser = collection
+        .find_one(doc! { "_id": loser_oid })
+        .await
+        .ok()
+        .flatten()
+        .ok_or(StatusCode::NOT_FOUND)?;
+
+    let (new_winner_elo, new_loser_elo) =
+        calculate_elo(winner.elo_rating, loser.elo_rating, K_FACTOR);
+
+    collection
+        .update_one(
+            doc! {"_id": &winner_oid},
+            doc! { "$set": { "elo_rating": new_winner_elo } },
+        )
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    collection
+        .update_one(
+            doc! {"_id": &loser_oid},
+            doc! { "$set": { "elo_rating": new_loser_elo } },
+        )
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    // return resposnse with characters' new Elo ratings
+    let updated_winner = collection
+        .find_one(doc! { "_id": winner_oid })
+        .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)?;
+
+    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
+    );
+
+    Ok(Json(RateResponse {
+        winner: updated_winner,
+        loser: updated_loser,
+    }))
+}
+
+pub async fn index() -> Html<&'static str> {
+    tracing::info!("Serving index page");
+    Html("<h1>Welcome to the Rick and Morty Character Rating API</h1>")
+}