"""Image repository for database operations."""

from collections.abc import Sequence
from uuid import UUID

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.database.models.board_image import BoardImage
from app.database.models.image import Image


class ImageRepository:
    """Repository for image database operations."""

    def __init__(self, db: AsyncSession):
        """Initialize repository with database session."""
        self.db = db

    async def create_image(
        self,
        user_id: UUID,
        filename: str,
        storage_path: str,
        file_size: int,
        mime_type: str,
        width: int,
        height: int,
        metadata: dict,
    ) -> Image:
        """
        Create new image record.

        Args:
            user_id: Owner user ID
            filename: Original filename
            storage_path: Path in MinIO
            file_size: File size in bytes
            mime_type: MIME type
            width: Image width in pixels
            height: Image height in pixels
            metadata: Additional metadata (format, checksum, thumbnails, etc)

        Returns:
            Created Image instance
        """
        image = Image(
            user_id=user_id,
            filename=filename,
            storage_path=storage_path,
            file_size=file_size,
            mime_type=mime_type,
            width=width,
            height=height,
            metadata=metadata,
        )
        self.db.add(image)
        await self.db.commit()
        await self.db.refresh(image)
        return image

    async def get_image_by_id(self, image_id: UUID) -> Image | None:
        """
        Get image by ID.

        Args:
            image_id: Image ID

        Returns:
            Image instance or None
        """
        result = await self.db.execute(select(Image).where(Image.id == image_id))
        return result.scalar_one_or_none()

    async def get_user_images(self, user_id: UUID, limit: int = 50, offset: int = 0) -> tuple[Sequence[Image], int]:
        """
        Get all images for a user with pagination.

        Args:
            user_id: User ID
            limit: Maximum number of images to return
            offset: Number of images to skip

        Returns:
            Tuple of (images, total_count)
        """
        # Get total count
        count_result = await self.db.execute(select(Image).where(Image.user_id == user_id))
        total = len(count_result.scalars().all())

        # Get paginated results
        result = await self.db.execute(
            select(Image).where(Image.user_id == user_id).order_by(Image.created_at.desc()).limit(limit).offset(offset)
        )
        images = result.scalars().all()

        return images, total

    async def delete_image(self, image_id: UUID) -> bool:
        """
        Delete image record.

        Args:
            image_id: Image ID

        Returns:
            True if deleted, False if not found
        """
        image = await self.get_image_by_id(image_id)
        if not image:
            return False

        await self.db.delete(image)
        await self.db.commit()
        return True

    async def increment_reference_count(self, image_id: UUID) -> None:
        """
        Increment reference count for image.

        Args:
            image_id: Image ID
        """
        image = await self.get_image_by_id(image_id)
        if image:
            image.reference_count += 1
            await self.db.commit()

    async def decrement_reference_count(self, image_id: UUID) -> int:
        """
        Decrement reference count for image.

        Args:
            image_id: Image ID

        Returns:
            New reference count
        """
        image = await self.get_image_by_id(image_id)
        if image and image.reference_count > 0:
            image.reference_count -= 1
            await self.db.commit()
            return image.reference_count
        return 0

    async def add_image_to_board(
        self,
        board_id: UUID,
        image_id: UUID,
        position: dict,
        transformations: dict,
        z_order: int = 0,
    ) -> BoardImage:
        """
        Add image to board.

        Args:
            board_id: Board ID
            image_id: Image ID
            position: Canvas position {x, y}
            transformations: Image transformations
            z_order: Layer order

        Returns:
            Created BoardImage instance
        """
        board_image = BoardImage(
            board_id=board_id,
            image_id=image_id,
            position=position,
            transformations=transformations,
            z_order=z_order,
        )
        self.db.add(board_image)

        # Increment reference count
        await self.increment_reference_count(image_id)

        await self.db.commit()
        await self.db.refresh(board_image)
        return board_image

    async def get_board_images(self, board_id: UUID) -> Sequence[BoardImage]:
        """
        Get all images for a board, ordered by z-order.

        Args:
            board_id: Board ID

        Returns:
            List of BoardImage instances
        """
        result = await self.db.execute(
            select(BoardImage).where(BoardImage.board_id == board_id).order_by(BoardImage.z_order.asc())
        )
        return result.scalars().all()

    async def remove_image_from_board(self, board_id: UUID, image_id: UUID) -> bool:
        """
        Remove image from board.

        Args:
            board_id: Board ID
            image_id: Image ID

        Returns:
            True if removed, False if not found
        """
        result = await self.db.execute(
            select(BoardImage).where(BoardImage.board_id == board_id, BoardImage.image_id == image_id)
        )
        board_image = result.scalar_one_or_none()

        if not board_image:
            return False

        await self.db.delete(board_image)

        # Decrement reference count
        await self.decrement_reference_count(image_id)

        await self.db.commit()
        return True