add main.py

main.py

@@ -0,0 +1,91 @@
+import os
+from langchain_openai import ChatOpenAI
+from langchain_core.messages import HumanMessage, SystemMessage
+from langchain.tools import tool
+from langgraph.checkpoint.memory import MemorySaver
+from langgraph.types import Command
+from langgraph.graph import StateGraph, START, END
+from langgraph.graph.message import add_messages
+from rich.console import Console
+
+# LLM setup
+llm = ChatOpenAI(
+    model="openai/gpt-oss-20b:free",
+    base_url="https://openrouter.ai/api/v1",
+    api_key=os.getenv("OPENAI_API_KEY"),
+    temperature=0.0,
+)
+
+console = Console()
+
+# Dummy tool – can be replaced by real implementation
+@tool
+def get_price(query: str) -> str:
+    """Return a fake price for demonstration."""
+    return f"Цена для {query} – 100₽"
+
+# State definition
+class ChatState(dict):
+    messages: list = add_messages
+    location: str = "start"
+    inventory: list = []
+
+# Agent graph
+builder = StateGraph(ChatState)
+
+# Node that runs the LLM and returns tool calls
+async def llm_node(state: ChatState):
+    system = SystemMessage(content="You are a helpful assistant. Use the get_price tool if needed.")
+    response = await llm.ainvoke([system] + state["messages"], config={"configurable": {"thread_id": "chat-1"}})
+    return {"messages": [response]}
+
+# Node that handles tool calls (only get_price)
+async def tool_node(state: ChatState):
+    last_msg = state["messages"][-1]
+    if hasattr(last_msg, "tool_calls") and last_msg.tool_calls:
+        tool_call = last_msg.tool_calls[0]
+        name = tool_call["name"]
+        args = tool_call["args"]
+        if name == "get_price":
+            result = get_price(args)
+            # Append tool result to messages
+            state["messages"].append(HumanMessage(content=result))
+    return state
+
+builder.add_node("llm", llm_node)
+builder.add_node("tool", tool_node)
+builder.add_edge(START, "llm")
+builder.add_edge("llm", "tool")
+builder.add_edge("tool", END)
+
+chat = builder.compile(checkpointer=MemorySaver(), interrupt_before=["tool"])
+
+# Main loop
+while True:
+    user_input = console.input("\nВы: ")
+    if user_input.lower() in {"exit", "quit"}:
+        break
+    # Add user message
+    chat.add_state({"messages": [HumanMessage(content=user_input)]})
+    # Run graph with interrupt handling
+    state = chat.get_state({"configurable": {"thread_id": "chat-1"}})
+    while True:
+        result = await chat.ainvoke(state, {"configurable": {"thread_id": "chat-1"}})
+        # If interrupted before tool
+        if "__interrupt__" in result and result["__interrupt__"][0]["name"] == "tool":
+            console.print("\nАгент хочет вызвать инструмент: get_price")
+            ans = console.input("Разрешить? (Y/n): ")
+            if ans.lower() in {"", "y", "yes"}:
+                # resume
+                state = chat.get_state({"configurable": {"thread_id": "chat-1"}})
+                continue
+            else:
+                console.print("Отменено")
+                break
+        # Print assistant response
+        for msg in result["messages"]:
+            if msg.role == "assistant":
+                console.print(msg.content)
+        break
+
+console.print("\nДо свидания!")