"""ZIP file extraction handler for batch image uploads."""

import io
import zipfile
from collections.abc import AsyncIterator

from fastapi import HTTPException, UploadFile, status


async def extract_images_from_zip(zip_file: UploadFile) -> AsyncIterator[tuple[str, bytes]]:
    """
    Extract image files from ZIP archive.

    Args:
        zip_file: Uploaded ZIP file

    Yields:
        Tuples of (filename, contents) for each image file

    Raises:
        HTTPException: If ZIP is invalid or too large
    """
    # Read ZIP contents
    zip_contents = await zip_file.read()

    # Check ZIP size (max 200MB for ZIP)
    max_zip_size = 200 * 1024 * 1024  # 200MB
    if len(zip_contents) > max_zip_size:
        raise HTTPException(
            status_code=status.HTTP_413_REQUEST_ENTITY_TOO_LARGE,
            detail=f"ZIP file too large. Maximum size is {max_zip_size / 1_048_576:.1f}MB",
        )

    try:
        # Open ZIP file
        with zipfile.ZipFile(io.BytesIO(zip_contents)) as zip_ref:
            # Get list of image files (filter by extension)
            image_extensions = {".jpg", ".jpeg", ".png", ".gif", ".webp", ".svg"}
            image_files = [
                name
                for name in zip_ref.namelist()
                if not name.startswith("__MACOSX/")  # Skip macOS metadata
                and not name.startswith(".")  # Skip hidden files
                and any(name.lower().endswith(ext) for ext in image_extensions)
            ]

            if not image_files:
                raise HTTPException(
                    status_code=status.HTTP_400_BAD_REQUEST,
                    detail="No valid image files found in ZIP archive",
                )

            # Extract each image
            for filename in image_files:
                # Skip directories
                if filename.endswith("/"):
                    continue

                # Get just the filename without path
                base_filename = filename.split("/")[-1]

                # Read file contents
                file_contents = zip_ref.read(filename)

                yield base_filename, file_contents

    except zipfile.BadZipFile as e:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Invalid ZIP file") from e
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Error processing ZIP file: {str(e)}",
        ) from e