#!/usr/bin/env python3
"""Deep agent that searches the web using Perplexity and writes results to a file.

Usage:
    python main.py "search query"

The agent will:
1. Query Perplexity via LangChain's Perplexity wrapper.
2. Store the answer in a virtual file `output.txt`.
3. Write the virtual file to the real filesystem.
"""

import argparse
import os
from pathlib import Path

from langchain_community.utilities import Perplexity
from langchain_core.prompts import ChatPromptTemplate
from langchain_core.output_parsers import StrOutputParser

# Configure Perplexity API key via environment variable
# Users should set PERPLEXITY_API_KEY in their environment

PERPLEXITY_API_KEY = os.getenv("PERPLEXITY_API_KEY")
if not PERPLEXITY_API_KEY:
    raise RuntimeError("PERPLEXITY_API_KEY environment variable not set")

# Create a simple chain: prompt -> Perplexity -> output parser
prompt = ChatPromptTemplate.from_messages([
    ("system", "You are a helpful assistant that answers questions based on web search."),
    ("human", "{question}")
])

llm = Perplexity(api_key=PERPLEXITY_API_KEY, temperature=0.7)
chain = prompt | llm | StrOutputParser()


def search_and_write(query: str, output_path: Path) -> None:
    """Search the web for *query* and write the answer to *output_path*.

    The function creates a virtual file in memory and then writes it to disk.
    """
    print(f"Searching for: {query}")
    answer = chain.invoke({"question": query})
    # Virtual file content
    virtual_file_content = f"Query: {query}\n\nAnswer:\n{answer}\n"
    # Write to real filesystem
    output_path.write_text(virtual_file_content, encoding="utf-8")
    print(f"Result written to {output_path.resolve()}")


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Deep agent search tool")
    parser.add_argument("query", type=str, help="Search query")
    parser.add_argument(
        "--output",
        type=str,
        default="output.txt",
        help="Path to write the result file (default: output.txt)",
    )
    args = parser.parse_args()

    output_path = Path(args.output)
    search_and_write(args.query, output_path)