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

if TYPE_CHECKING:
    from app.models.user import User
    from app.models.team import Team
    from app.models.session import Session
    from app.models.category import TreeCategory
    from app.models.tag import TreeTag
    from app.models.folder import UserFolder


class Tree(Base):
    __tablename__ = "trees"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4
    )
    name: Mapped[str] = mapped_column(String(255), nullable=False)
    description: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    # Legacy category field - kept for backward compatibility
    # New code should use category_id instead
    category: Mapped[Optional[str]] = mapped_column(String(100), nullable=True, index=True)
    # New category relationship
    category_id: Mapped[Optional[uuid.UUID]] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("tree_categories.id", ondelete="SET NULL"),
        nullable=True,
        index=True
    )
    tree_structure: Mapped[dict[str, Any]] = mapped_column(JSONB, nullable=False)
    author_id: Mapped[Optional[uuid.UUID]] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("users.id"),
        nullable=True
    )
    team_id: Mapped[Optional[uuid.UUID]] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("teams.id"),
        nullable=True,
        index=True
    )
    is_active: Mapped[bool] = mapped_column(Boolean, default=True)
    is_public: Mapped[bool] = mapped_column(Boolean, default=False, index=True)
    is_default: Mapped[bool] = mapped_column(Boolean, default=False, index=True)
    version: Mapped[int] = mapped_column(Integer, default=1)
    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)
    )
    usage_count: Mapped[int] = mapped_column(Integer, default=0)

    # Relationships
    author: Mapped[Optional["User"]] = relationship("User", back_populates="trees")
    team: Mapped[Optional["Team"]] = relationship("Team", back_populates="trees")
    sessions: Mapped[list["Session"]] = relationship("Session", back_populates="tree")

    # New organization relationships
    category_rel: Mapped[Optional["TreeCategory"]] = relationship("TreeCategory", back_populates="trees")
    tags: Mapped[list["TreeTag"]] = relationship(
        "TreeTag",
        secondary="tree_tag_assignments",
        back_populates="trees"
    )
    folders: Mapped[list["UserFolder"]] = relationship(
        "UserFolder",
        secondary="user_folder_trees",
        back_populates="trees"
    )

    # Full-text search index will be created in migration

    @property
    def tag_names(self) -> list[str]:
        """Returns list of tag names for this tree."""
        return [tag.name for tag in self.tags] if self.tags else []