import logging
import os
from langchain_core.tools import StructuredTool
from pydantic import BaseModel, Field
from typing import Optional

logger = logging.getLogger(__name__)

class DocumentRetrieverInput(BaseModel):
    task_id: str = Field(description="Task identifier")
    query: str = Field(description="Search query")
    file_path: Optional[str] = Field(description="Path to document file", default=None)

async def document_retriever_func(task_id: str, query: str, file_path: Optional[str] = None) -> str:
    """
    Retrieve content from documents for a given task and query.
    
    Args:
        task_id (str): Task identifier.
        query (str): Search query.
        file_path (Optional[str]): Path to document file.
    
    Returns:
        str: Retrieved document content or error message.
    """
    try:
        if file_path and os.path.exists(file_path):
            logger.info(f"Retrieving document from {file_path} for task {task_id}")
            if file_path.endswith('.pdf'):
                import PyPDF2
                with open(file_path, 'rb') as f:
                    reader = PyPDF2.PdfReader(f)
                    text = "".join(page.extract_text() or "" for page in reader.pages)
                return text[:500] if text else "No text extracted"
            return "Unsupported file format"
        logger.warning(f"No valid documents found for task {task_id}")
        return "Document not found"
    except Exception as e:
        logger.error(f"Error retrieving document for task {task_id}: {e}")
        return f"Error: {str(e)}"

document_retriever_tool = StructuredTool.from_function(
    func=document_retriever_func,
    name="document_retriever_tool",
    args_schema=DocumentRetrieverInput,
    coroutine=document_retriever_func
)