"""SQLAlchemy implementation of PostRepository.

This module provides the concrete implementation of PostRepository
using SQLAlchemy ORM for data persistence.
"""

from uuid import UUID

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

from app.domain.entities import Post
from app.domain.entities.like import PostLike
from app.domain.repositories import PostRepository
from app.domain.value_objects import Content, Slug, Title
from app.infrastructure.database.models import PostLikeORM, PostORM


class SQLAlchemyPostRepository(PostRepository):
    """SQLAlchemy implementation of Post repository.

    Provides data access methods for Post entities using SQLAlchemy ORM.
    Handles conversion between domain entities and ORM models.

    Attributes:
        _session: SQLAlchemy async session for database operations.

    Example:
        >>> repo = SQLAlchemyPostRepository(session)
        >>> post = await repo.get_by_id(post_id)
    """

    def __init__(self, session: AsyncSession) -> None:
        """Initialize repository with session.

        Args:
            session: SQLAlchemy async session instance.
        """
        self._session = session

    def _to_domain(self, orm: PostORM) -> Post:
        """Convert ORM model to domain entity.

        Args:
            orm: SQLAlchemy ORM model instance.

        Returns:
            Domain Post entity with validated value objects.
        """
        return Post(
            id=UUID(orm.id),
            title=Title(orm.title),
            content=Content(orm.content),
            slug=Slug(orm.slug),
            author_id=orm.author_id,
            published=orm.published,
            like_count=orm.like_count,
            tags=orm.tags or [],
            created_at=orm.created_at,
            updated_at=orm.updated_at,
        )

    def _to_orm(self, post: Post) -> PostORM:
        """Convert domain entity to ORM model.

        Args:
            post: Domain Post entity.

        Returns:
            SQLAlchemy ORM model instance.
        """
        return PostORM(
            id=str(post.id),
            title=post.title.value,
            content=post.content.value,
            slug=post.slug.value,
            author_id=post.author_id,
            published=post.published,
            like_count=post.like_count,
            tags=post.tags,
            created_at=post.created_at,
            updated_at=post.updated_at,
        )

    async def get_by_id(self, entity_id: UUID) -> Post | None:
        """Get post by ID.

        Args:
            entity_id: Unique identifier of the post.

        Returns:
            Post entity if found, None otherwise.
        """
        result = await self._session.execute(select(PostORM).where(PostORM.id == str(entity_id)))
        orm = result.scalar_one_or_none()
        return self._to_domain(orm) if orm else None

    async def get_all(self) -> list[Post]:
        """Get all posts.

        Returns:
            List of all Post entities.
        """
        result = await self._session.execute(select(PostORM))
        orms = result.scalars().all()
        return [self._to_domain(orm) for orm in orms]

    async def add(self, entity: Post) -> None:
        """Add new post.

        Args:
            entity: Post entity to add.
        """
        orm = self._to_orm(entity)
        self._session.add(orm)

    async def update(self, entity: Post) -> None:
        """Update existing post.

        Args:
            entity: Post entity with updated data.
        """
        result = await self._session.execute(select(PostORM).where(PostORM.id == str(entity.id)))
        orm = result.scalar_one()

        orm.title = entity.title.value
        orm.content = entity.content.value
        orm.slug = entity.slug.value
        orm.published = entity.published
        orm.like_count = entity.like_count
        orm.tags = entity.tags
        orm.updated_at = entity.updated_at

    async def delete(self, entity_id: UUID) -> None:
        """Delete post by ID.

        Args:
            entity_id: Unique identifier of the post to delete.
        """
        result = await self._session.execute(select(PostORM).where(PostORM.id == str(entity_id)))
        orm = result.scalar_one_or_none()
        if orm:
            await self._session.delete(orm)

    async def exists(self, entity_id: UUID) -> bool:
        """Check if post exists.

        Args:
            entity_id: Unique identifier of the post.

        Returns:
            True if post exists, False otherwise.
        """
        result = await self._session.execute(select(PostORM).where(PostORM.id == str(entity_id)))
        return result.scalar_one_or_none() is not None

    async def get_by_slug(self, slug: str) -> Post | None:
        """Get post by slug.

        Args:
            slug: URL-friendly slug identifier.

        Returns:
            Post entity if found, None otherwise.
        """
        result = await self._session.execute(select(PostORM).where(PostORM.slug == slug))
        orm = result.scalar_one_or_none()
        return self._to_domain(orm) if orm else None

    async def get_by_author(
        self,
        author_id: str,
        limit: int | None = None,
        offset: int | None = None,
    ) -> list[Post]:
        """Get posts by author.

        Args:
            author_id: Identifier of the author.
            limit: Maximum number of posts to return.
            offset: Number of posts to skip.

        Returns:
            List of Post entities by the author.
        """
        query = (
            select(PostORM)
            .where(PostORM.author_id == author_id)
            .order_by(PostORM.created_at.desc())
        )
        if limit is not None:
            query = query.limit(limit)
        if offset is not None:
            query = query.offset(offset)
        result = await self._session.execute(query)
        orms = result.scalars().all()
        return [self._to_domain(orm) for orm in orms]

    async def get_published(
        self,
        limit: int | None = None,
        offset: int | None = None,
    ) -> list[Post]:
        """Get published posts.

        Args:
            limit: Maximum number of posts to return.
            offset: Number of posts to skip.

        Returns:
            List of published Post entities.
        """
        query = (
            select(PostORM).where(PostORM.published.is_(True)).order_by(PostORM.created_at.desc())
        )
        if limit is not None:
            query = query.limit(limit)
        if offset is not None:
            query = query.offset(offset)
        result = await self._session.execute(query)
        orms = result.scalars().all()
        return [self._to_domain(orm) for orm in orms]

    async def get_by_tag(
        self,
        tag: str,
        limit: int | None = None,
        offset: int | None = None,
    ) -> list[Post]:
        """Get posts by tag.

        Args:
            tag: Tag to filter by.
            limit: Maximum number of posts to return.
            offset: Number of posts to skip.

        Returns:
            List of Post entities with the tag.
        """
        query = select(PostORM).where(PostORM.tags.contains([tag]))
        if limit is not None:
            query = query.limit(limit)
        if offset is not None:
            query = query.offset(offset)
        result = await self._session.execute(query)
        orms = result.scalars().all()
        return [self._to_domain(orm) for orm in orms]

    async def slug_exists(self, slug: str) -> bool:
        """Check if slug exists.

        Args:
            slug: Slug to check for existence.

        Returns:
            True if slug exists, False otherwise.
        """
        result = await self._session.execute(select(PostORM).where(PostORM.slug == slug))
        return result.scalar_one_or_none() is not None

    async def search(
        self,
        query: str,
        limit: int | None = None,
        offset: int | None = None,
    ) -> list[Post]:
        """Search posts.

        Args:
            query: Search query string.
            limit: Maximum number of posts to return.
            offset: Number of posts to skip.

        Returns:
            List of Post entities matching the query.
        """
        search_pattern = f"%{query}%"
        stmt = select(PostORM).where(
            or_(
                PostORM.title.ilike(search_pattern),
                PostORM.content.ilike(search_pattern),
            )
        )
        if limit is not None:
            stmt = stmt.limit(limit)
        if offset is not None:
            stmt = stmt.offset(offset)
        result = await self._session.execute(stmt)
        orms = result.scalars().all()
        return [self._to_domain(orm) for orm in orms]

    async def get_like(self, post_id: UUID, liked_by: str) -> PostLike | None:
        """Get a like by post and user/device.

        Args:
            post_id: UUID of the post.
            liked_by: User ID or device ID.

        Returns:
            PostLike if found, None otherwise.
        """
        result = await self._session.execute(
            select(PostLikeORM).where(
                PostLikeORM.post_id == str(post_id),
                PostLikeORM.liked_by == liked_by,
            )
        )
        orm = result.scalar_one_or_none()
        if not orm:
            return None
        return PostLike(
            id=UUID(orm.id),
            post_id=UUID(orm.post_id),
            liked_by=orm.liked_by,
            created_at=orm.created_at,
        )

    async def add_like(self, like: PostLike) -> None:
        """Add a new like.

        Args:
            like: PostLike entity to add.
        """
        orm = PostLikeORM(
            id=str(like.id),
            post_id=str(like.post_id),
            liked_by=like.liked_by,
            created_at=like.created_at,
        )
        self._session.add(orm)

    async def remove_like(self, post_id: UUID, liked_by: str) -> None:
        """Remove a like by post and user/device.

        Args:
            post_id: UUID of the post.
            liked_by: User ID or device ID.
        """
        result = await self._session.execute(
            select(PostLikeORM).where(
                PostLikeORM.post_id == str(post_id),
                PostLikeORM.liked_by == liked_by,
            )
        )
        orm = result.scalar_one_or_none()
        if orm:
            await self._session.delete(orm)