import uuid
from datetime import datetime, timezone
from typing import Optional, TYPE_CHECKING
from sqlalchemy import String, Text, DateTime, ForeignKey, Boolean, Integer, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship
from sqlalchemy.dialects.postgresql import UUID
from app.core.database import Base

if TYPE_CHECKING:
    from app.models.account import Account
    from app.models.tree import Tree
    from app.models.category import TreeCategory


class Workspace(Base):
    """Workspaces are the top-level organizational context for trees/flows.

    They sit above the folder system — a workspace scopes which trees/flows
    are visible, while folders remain for personal organization within.
    """
    __tablename__ = "workspaces"
    __table_args__ = (
        UniqueConstraint('slug', 'account_id', name='uq_workspaces_slug_account'),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4
    )
    name: Mapped[str] = mapped_column(String(100), nullable=False)
    slug: Mapped[str] = mapped_column(String(100), nullable=False, index=True)
    description: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    icon: Mapped[Optional[str]] = mapped_column(String(10), nullable=True)
    accent_color: Mapped[Optional[str]] = mapped_column(String(7), nullable=True)
    account_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("accounts.id", ondelete="CASCADE"),
        nullable=False,
        index=True
    )
    is_default: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
    sort_order: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc)
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc),
        onupdate=lambda: datetime.now(timezone.utc)
    )

    # Relationships
    account: Mapped["Account"] = relationship("Account", back_populates="workspaces")
    trees: Mapped[list["Tree"]] = relationship("Tree", back_populates="workspace")
    categories: Mapped[list["TreeCategory"]] = relationship("TreeCategory", back_populates="workspace")