"""
Sharing models — cross-user access to heaps and folders.

HeapShare grants another user read or read+write access to a heap.
FolderShare does the same for a folder (or source root).
"""
import uuid

from sqlalchemy import (
    Column, DateTime, ForeignKey, Index, String, UniqueConstraint, func,
)

from app.database import Base


class HeapShare(Base):
    __tablename__ = "heap_shares"

    id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
    heap_id = Column(
        String, ForeignKey("heaps.id", ondelete="CASCADE"), nullable=False,
    )
    # Denormalized from heap.user_id for fast "shares I own" lookups.
    owner_id = Column(String, ForeignKey("users.id"), nullable=False)
    shared_with_id = Column(String, ForeignKey("users.id"), nullable=False)
    permission = Column(String, nullable=False, default="read")  # 'read' | 'write'
    created_at = Column(DateTime, server_default=func.now())

    __table_args__ = (
        UniqueConstraint("heap_id", "shared_with_id", name="uq_heap_share"),
        Index("ix_heap_shares_shared_with", "shared_with_id"),
        Index("ix_heap_shares_heap_id", "heap_id"),
    )


class FolderShare(Base):
    __tablename__ = "folder_shares"

    id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
    # Can reference either a Folder.id or a SourceRoot.id.
    folder_id = Column(String, nullable=False)
    folder_type = Column(String, nullable=False, default="folder")  # 'folder' | 'source_root'
    owner_id = Column(String, ForeignKey("users.id"), nullable=False)
    shared_with_id = Column(String, ForeignKey("users.id"), nullable=False)
    permission = Column(String, nullable=False, default="read")  # 'read' | 'write'
    created_at = Column(DateTime, server_default=func.now())

    __table_args__ = (
        UniqueConstraint("folder_id", "shared_with_id", name="uq_folder_share"),
        Index("ix_folder_shares_shared_with", "shared_with_id"),
        Index("ix_folder_shares_folder_id", "folder_id"),
    )