Proper asset id

src/engine/fetch.rs

@@ -3,6 +3,8 @@ use pulse_sdk::prelude::*;
 use serde_json::Value;
 use std::collections::HashMap;
 
+use crate::engine::WatchList;
+
 fn number(value: &Value, field: &str) -> Result<Decimal, String> {
     let raw = value[field]
         .as_str()
@@ -15,7 +17,7 @@ fn number(value: &Value, field: &str) -> Result<Decimal, String> {
 pub async fn fetch_watch_list(
     client: &hypersdk::hypercore::HttpClient,
     symbols: &[String],
-) -> Result<Vec<MarketItem>, String> {
+) -> Result<WatchList, String> {
     let response = client
         .meta_and_asset_ctxs(None)
         .await
@@ -35,6 +37,7 @@ pub async fn fetch_watch_list(
     let universe = response[0]["universe"]
         .as_array()
         .ok_or("metaAndAssetCtxs response is missing meta.universe")?;
+
     let contexts = response[1]
         .as_array()
         .ok_or("metaAndAssetCtxs response contexts must be an array")?;
@@ -47,12 +50,27 @@ pub async fn fetch_watch_list(
         ));
     }
 
-    let mut by_symbol = HashMap::with_capacity(universe.len());
+    // Build symbol -> perp asset index
+    let mut name_to_index = HashMap::with_capacity(universe.len());
 
-    for (meta, context) in universe.iter().zip(contexts) {
+    for (index, meta) in universe.iter().enumerate() {
         let symbol = meta["name"]
             .as_str()
             .ok_or("instrument metadata is missing a name")?;
+
+        name_to_index.insert(symbol.to_owned(), index);
+    }
+
+    // Now only process requested symbols
+    let mut items = Vec::with_capacity(symbols.len());
+
+    for symbol in symbols {
+        let index = *name_to_index
+            .get(symbol)
+            .ok_or_else(|| format!("{symbol} is not in the Hyperliquid perpetual universe"))?;
+
+        let context = &contexts[index];
+
         let price = number(context, "markPx")?;
         let previous_day_price = number(context, "prevDayPx")?;
         let volume_24h = number(context, "dayNtlVlm")?;
@@ -61,24 +79,17 @@ pub async fn fetch_watch_list(
             return Err(format!("{symbol} has an invalid previous-day price"));
         }
 
-        by_symbol.insert(
-            symbol,
-            MarketItem {
-                symbol: Symbol(symbol.to_owned()),
-                price: USD(price),
-                volume_24h: USD(volume_24h),
-                trend: ((price / previous_day_price) - <Decimal as From<i32>>::from(1))
-                    * <Decimal as From<i32>>::from(100),
-            },
-        );
+        items.push(MarketItem {
+            symbol: Symbol(symbol.clone()),
+            price: USD(price),
+            volume_24h: USD(volume_24h),
+            trend: ((price / previous_day_price) - <Decimal as From<i32>>::from(1))
+                * <Decimal as From<i32>>::from(100),
+        });
     }
 
-    symbols
-        .iter()
-        .map(|symbol| {
-            by_symbol
-                .remove(symbol.as_str())
-                .ok_or_else(|| format!("{symbol} is not in the Hyperliquid perpetual universe"))
-        })
-        .collect()
+    Ok(WatchList {
+        items,
+        name_to_index,
+    })
 }