LLM switch refactored

Author: AdamBien

zsmith/src/main/java/airhacks/zsmith/llm/control/LLM.java

@@ -9,16 +9,35 @@
 
 public interface LLM {
 
-    static String provider() {
-        return ZCfg.string("llm.provider", "claude");
+    enum Provider {
+        CLAUDE {
+            @Override
+            public JSONObject invoke(String system, JSONArray messages, JSONArray tools, float temperature) {
+                return Claude.invoke(system, messages, tools, temperature);
+            }
+        },
+        OPENAI {
+            @Override
+            public JSONObject invoke(String system, JSONArray messages, JSONArray tools, float temperature) {
+                return OpenAI.invoke(system, messages, tools, temperature);
+            }
+        };
+
+        public abstract JSONObject invoke(String system, JSONArray messages, JSONArray tools, float temperature);
+
+        public static Provider fromConfig() {
+            var configured = ZCfg.string("llm.provider", "claude");
+            try {
+                return Provider.valueOf(configured.toUpperCase());
+            } catch (IllegalArgumentException e) {
+                throw new IllegalStateException(
+                        "unknown llm.provider '%s' — expected one of %s"
+                                .formatted(configured, java.util.Arrays.toString(values())));
+            }
+        }
     }
 
     static JSONObject invoke(String system, JSONArray messages, JSONArray tools, float temperature) {
-        return switch (provider()) {
-            case "openai" -> OpenAI.invoke(system, messages, tools, temperature);
-            case "claude" -> Claude.invoke(system, messages, tools, temperature);
-            default -> throw new IllegalStateException(
-                "unknown llm.provider '%s' — expected 'claude' or 'openai'".formatted(provider()));
-        };
+        return Provider.fromConfig().invoke(system, messages, tools, temperature);
     }
 }