from datetime import datetime
from enum import Enum
from typing import Optional
from uuid import UUID, uuid4

from sqlalchemy import JSON, Boolean, DateTime, Enum as SQLEnum, ForeignKey, Integer, String, UniqueConstraint, func
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.db.base_class import Base


class TemplateType(str, Enum):
    ROLE = "ROLE"
    SCENARIO = "SCENARIO"
    CUSTOM = "CUSTOM"


class PermissionTemplate(Base):
    __tablename__ = "permission_templates"

    id: Mapped[UUID] = mapped_column(primary_key=True, default=uuid4)
    name: Mapped[str] = mapped_column(String(100), nullable=False)
    description: Mapped[Optional[str]] = mapped_column(String(500), nullable=True)
    template_type: Mapped[TemplateType] = mapped_column(SQLEnum(TemplateType), nullable=False)
    is_system: Mapped[bool] = mapped_column(Boolean, nullable=False, server_default="false")
    created_by: Mapped[Optional[UUID]] = mapped_column(nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, server_default=func.now(), onupdate=func.now())

    # 权限配置 JSON: {role: {endpoint_key: allowed}}
    permissions: Mapped[dict] = mapped_column(JSON, nullable=False)

    # 元数据
    tags: Mapped[Optional[str]] = mapped_column(String(200), nullable=True)
    category: Mapped[Optional[str]] = mapped_column(String(50), nullable=True)
    recommended_roles: Mapped[Optional[str]] = mapped_column(String(200), nullable=True)

    # 关系
    versions: Mapped[list["PermissionTemplateVersion"]] = relationship(
        "PermissionTemplateVersion",
        back_populates="template",
        cascade="all, delete-orphan",
    )


class PermissionTemplateVersion(Base):
    __tablename__ = "permission_template_versions"
    __table_args__ = (
        UniqueConstraint("template_id", "version", name="uq_template_versions"),
    )

    id: Mapped[UUID] = mapped_column(primary_key=True, default=uuid4)
    template_id: Mapped[UUID] = mapped_column(ForeignKey("permission_templates.id"), nullable=False)
    version: Mapped[int] = mapped_column(Integer, nullable=False)
    permissions: Mapped[dict] = mapped_column(JSON, nullable=False)
    change_log: Mapped[Optional[str]] = mapped_column(String(500), nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, server_default=func.now())

    # 关系
    template: Mapped["PermissionTemplate"] = relationship(
        "PermissionTemplate",
        back_populates="versions",
    )