feat: Support a way to define default model by adding DEFAULT_MODEL env.

app/utils/model.ts

@@ -1,5 +1,11 @@
 import { LLMModel } from "../client/api";
 
+const customProvider = (modelName: string) => ({
+  id: modelName,
+  providerName: "",
+  providerType: "custom",
+});
+
 export function collectModelTable(
   models: readonly LLMModel[],
   customModels: string,
@@ -11,6 +17,7 @@ export function collectModelTable(
       name: string;
       displayName: string;
       provider?: LLMModel["provider"]; // Marked as optional
+      isDefault?: boolean;
     }
   > = {};
 
@@ -22,12 +29,6 @@ export function collectModelTable(
     };
   });
 
-  const customProvider = (modelName: string) => ({
-    id: modelName,
-    providerName: "",
-    providerType: "custom",
-  });
-
   // server custom models
   customModels
     .split(",")
@@ -52,6 +53,27 @@ export function collectModelTable(
         };
       }
     });
+
+  return modelTable;
+}
+
+export function collectModelTableWithDefaultModel(
+  models: readonly LLMModel[],
+  customModels: string,
+  defaultModel: string,
+) {
+  let modelTable = collectModelTable(models, customModels);
+  if (defaultModel && defaultModel !== "") {
+    delete modelTable[defaultModel];
+    modelTable[defaultModel] = {
+      name: defaultModel,
+      displayName: defaultModel,
+      available: true,
+      provider:
+        modelTable[defaultModel]?.provider ?? customProvider(defaultModel),
+      isDefault: true,
+    };
+  }
   return modelTable;
 }
 
@@ -67,3 +89,17 @@ export function collectModels(
 
   return allModels;
 }
+
+export function collectModelsWithDefaultModel(
+  models: readonly LLMModel[],
+  customModels: string,
+  defaultModel: string,
+) {
+  const modelTable = collectModelTableWithDefaultModel(
+    models,
+    customModels,
+    defaultModel,
+  );
+  const allModels = Object.values(modelTable);
+  return allModels;
+}