"""Deep agent: web search + virtual files → real filesystem export."""
import os
import asyncio
from pathlib import Path

from dotenv import load_dotenv
from langchain_openai import ChatOpenAI
from langchain_core.messages import HumanMessage
from langchain.tools import tool
from deepagents import create_deep_agent
from deepagents.backends import LocalShellBackend, CompositeBackend

load_dotenv()

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,
)

WORKSPACE = Path("./workspace")
REAL_OUT = Path("./output")


@tool
def web_search(query: str) -> str:
    """Search the web for information and return snippets."""
    try:
        from duckduckgo_search import DDGS
        with DDGS() as ddgs:
            results = list(ddgs.text(query, max_results=5))
        return "\n".join(f"{r['title']}: {r['body']}" for r in results)
    except Exception as exc:
        return f"Search error: {exc}"


backend = CompositeBackend(
    default=LocalShellBackend(
        root_dir=str(WORKSPACE),
        virtual_mode=True,
        inherit_env=True,
    ),
)

agent = create_deep_agent(
    model=llm,
    tools=[web_search],
    backend=backend,
    system_prompt=(
        "You are a research agent. "
        "Use web_search to find information, then create virtual files with write_file. "
        "When done, export all virtual files to real filesystem by calling execute with "
        "a shell command that copies /virtual/ contents to the output directory."
    ),
)


async def main(query: str = "Python LangChain agent best practices 2024") -> None:
    WORKSPACE.mkdir(parents=True, exist_ok=True)
    REAL_OUT.mkdir(parents=True, exist_ok=True)

    config = {"configurable": {"thread_id": "research-session-1"}}
    result = await agent.ainvoke(
        {"messages": [HumanMessage(
            content=(
                f"Search the web for: {query}\n"
                "Save your findings to results.txt as a virtual file.\n"
                "Then export the virtual file results.txt to the real filesystem "
                f"at {REAL_OUT}/results.txt"
            )
        )]},
        config,
    )
    print(result["messages"][-1].content)


if __name__ == "__main__":
    import sys
    q = " ".join(sys.argv[1:]) if len(sys.argv) > 1 else "Python LangChain agent best practices 2024"
    asyncio.run(main(q))