"""
Background tasks for document processing.
"""

import logging

from src.config.celery import celery_app

logger = logging.getLogger(__name__)


@celery_app.task(name="process_document", bind=True, max_retries=3)
def process_document(self, file_id: str, tenant_id: str) -> dict:
    """
    Process uploaded document for RAG.

    This task:
    1. Extracts text from document
    2. Chunks the text
    3. Generates embeddings
    4. Stores in vector database

    Args:
        file_id: File ID to process
        tenant_id: Tenant ID

    Returns:
        dict: Processing result
    """
    try:
        logger.info(f"Processing document {file_id} for tenant {tenant_id}")

        # Document processing is handled by the RAG service (rag_service.py)
        # This task is a placeholder for async processing via Celery
        # See: services/knowledge_base/rag_service.py for implementation

        return {
            "status": "success",
            "file_id": file_id,
            "chunks_created": 0,
        }

    except Exception as exc:
        logger.error(f"Error processing document {file_id}: {exc}")
        # Retry with exponential backoff
        raise self.retry(exc=exc, countdown=60 * (2**self.request.retries)) from exc


@celery_app.task(name="generate_embeddings", bind=True)
def generate_embeddings(_self, text_chunks: list[str], file_id: str) -> dict:
    """
    Generate embeddings for text chunks.

    Args:
        text_chunks: List of text chunks
        file_id: Source file ID

    Returns:
        dict: Embedding generation result
    """
    try:
        logger.info(f"Generating embeddings for {len(text_chunks)} chunks from file {file_id}")

        # Embedding generation is handled by the RAG service
        # See: services/knowledge_base/rag_service.py for implementation

        return {
            "status": "success",
            "embeddings_created": len(text_chunks),
        }

    except Exception as exc:
        logger.error(f"Error generating embeddings: {exc}")
        raise


@celery_app.task(name="cleanup_old_files")
def cleanup_old_files(days: int = 30) -> dict:
    """
    Clean up old temporary files.

    Args:
        days: Delete files older than this many days

    Returns:
        dict: Cleanup result
    """
    try:
        logger.info(f"Cleaning up files older than {days} days")

        # File cleanup can be extended here for scheduled maintenance
        # Current implementation returns placeholder - extend as needed

        return {
            "status": "success",
            "files_deleted": 0,
        }

    except Exception as exc:
        logger.error(f"Error during file cleanup: {exc}")
        raise


@celery_app.task(name="index_document")
def index_document(file_id: str, _tenant_id: str) -> dict:
    """
    Index document for search.

    Args:
        file_id: File ID to index
        tenant_id: Tenant ID

    Returns:
        dict: Indexing result
    """
    try:
        logger.info(f"Indexing document {file_id}")

        # Document indexing is handled during upload via the RAG service
        # This task is available for re-indexing operations

        return {
            "status": "success",
            "file_id": file_id,
        }

    except Exception as exc:
        logger.error(f"Error indexing document {file_id}: {exc}")
        raise
