import uuid
from datetime import datetime, timezone
from typing import Optional, TYPE_CHECKING
from sqlalchemy import String, Text, Boolean, DateTime, ForeignKey, 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.user import User


class FeatureFlag(Base):
    __tablename__ = "feature_flags"

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    flag_key: Mapped[str] = mapped_column(String(100), unique=True, nullable=False)
    display_name: Mapped[str] = mapped_column(String(255), nullable=False)
    description: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    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
    plan_defaults: Mapped[list["PlanFeatureDefault"]] = relationship("PlanFeatureDefault", back_populates="flag", cascade="all, delete-orphan")
    account_overrides: Mapped[list["AccountFeatureOverride"]] = relationship("AccountFeatureOverride", back_populates="flag", cascade="all, delete-orphan")


class PlanFeatureDefault(Base):
    __tablename__ = "plan_feature_defaults"
    __table_args__ = (
        UniqueConstraint("plan", "flag_id", name="uq_plan_feature_defaults_plan_flag"),
    )

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    plan: Mapped[str] = mapped_column(String(50), ForeignKey("plan_limits.plan"), nullable=False)
    flag_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("feature_flags.id", ondelete="CASCADE"),
        nullable=False
    )
    enabled: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)

    # Relationships
    flag: Mapped["FeatureFlag"] = relationship("FeatureFlag", back_populates="plan_defaults")


class AccountFeatureOverride(Base):
    __tablename__ = "account_feature_overrides"
    __table_args__ = (
        UniqueConstraint("account_id", "flag_id", name="uq_account_feature_overrides_account_flag"),
    )

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    account_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("accounts.id", ondelete="CASCADE"),
        nullable=False
    )
    flag_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("feature_flags.id", ondelete="CASCADE"),
        nullable=False
    )
    enabled: Mapped[bool] = mapped_column(Boolean, nullable=False)
    note: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    created_by_id: Mapped[Optional[uuid.UUID]] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("users.id"),
        nullable=True
    )
    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
    flag: Mapped["FeatureFlag"] = relationship("FeatureFlag", back_populates="account_overrides")
    created_by: Mapped[Optional["User"]] = relationship("User")