"""
Example using the sugar: create_qwen_react_agent(...)

Prereqs:
  uv pip install -e '.[openai,custom]'

Env:
  export QWEN_API_KEY=sk-...
  export QWEN_BASE_URL=https://dashscope-intl.aliyuncs.com/compatible-mode/v1
  export QWEN_MODEL=qwen3-coder-flash
"""

from langchain_core.messages import HumanMessage

try:
    from langchain.tools import tool
except Exception:
    from langchain_core.tools import tool  # type: ignore

from langgraph_qwen import create_qwen_react_agent


@tool
def echo(text: str) -> str:
    """Echo back the given text."""
    return text


def main():
    agent = create_qwen_react_agent(
        [echo],
        prefer="custom",  # use our custom BaseChatModel by default
        model_kwargs={"temperature": 0},
    )

    res = agent.invoke({"messages": [HumanMessage(content="调用 echo 工具返回：你好，LangGraph！")]})
    print("\n=== Final ===\n")
    print(res["messages"][-1].content)


if __name__ == "__main__":
    main()