"""Image serving with quality-based thumbnail selection."""

from fastapi import HTTPException, status
from fastapi.responses import StreamingResponse

from app.database.models.image import Image


def get_thumbnail_path(image: Image, quality: str) -> str:
    """
    Get thumbnail path for specified quality level.

    Args:
        image: Image model instance
        quality: Quality level ('low', 'medium', 'high', 'original')

    Returns:
        Storage path to thumbnail

    Raises:
        ValueError: If quality level is invalid
    """
    if quality == "original":
        return image.storage_path

    # Get thumbnail paths from metadata
    thumbnails = image.image_metadata.get("thumbnails", {})

    # Map quality to thumbnail size
    if quality == "low":
        thumbnail_path = thumbnails.get("low")
    elif quality == "medium":
        thumbnail_path = thumbnails.get("medium")
    elif quality == "high":
        thumbnail_path = thumbnails.get("high")
    else:
        raise ValueError(f"Invalid quality level: {quality}")

    # Fall back to original if thumbnail doesn't exist
    if not thumbnail_path:
        return image.storage_path

    return thumbnail_path


async def serve_image_with_quality(
    image: Image, quality: str = "medium", filename: str | None = None
) -> StreamingResponse:
    """
    Serve image with specified quality level.

    Args:
        image: Image model instance
        quality: Quality level ('low', 'medium', 'high', 'original')
        filename: Optional custom filename for download

    Returns:
        StreamingResponse with image data

    Raises:
        HTTPException: If image cannot be served
    """
    from app.images.download import download_single_image

    try:
        # Get appropriate thumbnail path
        storage_path = get_thumbnail_path(image, quality)

        # Use original filename if not specified
        if filename is None:
            filename = image.filename

        # Serve the image
        return await download_single_image(storage_path, filename)

    except ValueError as e:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=str(e),
        ) from e
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to serve image: {str(e)}",
        ) from e


def determine_quality_from_speed(speed_mbps: float) -> str:
    """
    Determine appropriate quality level based on connection speed.

    Args:
        speed_mbps: Connection speed in Mbps

    Returns:
        Quality level string
    """
    if speed_mbps < 1.0:
        return "low"
    elif speed_mbps < 5.0:
        return "medium"
    else:
        return "high"