Add AI model integration and system prompt handling

agent/nodes.py

@@ -0,0 +1,73 @@
+from getpass import getpass
+import os
+from typing import Literal, cast
+from langchain_core.tools import StructuredTool
+from langchain_core.language_models.chat_models import BaseChatModel
+from langchain_core.runnables import Runnable
+from langchain_core.messages import BaseMessage
+from langchain_core.language_models.base import LanguageModelInput
+from langchain_google_genai import ChatGoogleGenerativeAI
+from langchain_openai import ChatOpenAI
+from pydantic import BaseModel, Field, SecretStr
+from agent.prompts import get_system_prompt
+from agent.state import State
+from langchain_core.messages import SystemMessage, HumanMessage
+from langgraph.prebuilt import ToolNode
+
+API_BASE_URL = "https://api.openrouter.ai/v1"
+MODEL_NAME = "qwen/qwen3-235b-a22b:free"
+API_KEY_ENV_VAR = "OPENROUTER_API_KEY"
+if API_KEY_ENV_VAR not in os.environ:
+    print(f"Please set the environment variable {API_KEY_ENV_VAR}.")
+    os.environ[API_KEY_ENV_VAR] = getpass(f"Enter your {API_KEY_ENV_VAR} (will not be echoed): ")
+
+### Helper functions ###
+
+def _get_model() -> BaseChatModel:
+
+    # api_key = os.getenv("GOOGLE_API_KEY")
+    # return ChatGoogleGenerativeAI(
+    #     api_key=SecretStr(api_key) if api_key else None,
+    #     model="gemini-2.5-pro"
+    # )
+
+    api_key = os.getenv(API_KEY_ENV_VAR)
+    return ChatOpenAI(
+        api_key=SecretStr(api_key) if api_key else None,
+        base_url=API_BASE_URL,
+        model=MODEL_NAME,
+        metadata={
+            "reasoning": {
+                "effort": "high"  # Use high reasoning effort
+            }
+        }
+    )
+
+def _get_tools() -> list[StructuredTool]:
+    from tools import get_all_tools
+    return get_all_tools()
+
+def _bind_model(model: BaseChatModel) -> Runnable[LanguageModelInput, BaseMessage]:
+    return model.bind_tools(_get_tools())
+
+### NODES ###
+# Call model node
+def call_model(state: State, config) -> dict[str, list[BaseMessage]]:
+    messages = state["messages"]
+    app_name = config.get('configurable', {}).get("app_name", "OracleBot")
+    
+    # Add system prompt if not already present
+    if not messages or messages[0].type != "system":
+        # Use dynamic system prompt if sports are mentioned
+        system_prompt = get_system_prompt()
+        system_message: BaseMessage = SystemMessage(content=system_prompt)
+        messages = [system_message] + list(messages)
+    
+    model = _get_model()
+    model = _bind_model(model)
+    response = model.invoke(messages)
+    
+    return {"messages": [response]}
+
+# Tool node
+tool_node = ToolNode(tools=_get_tools())