"""角色、权限及其关联模型（RBAC 标准五表的后四张）。

权限与角色是多对多：一个权限（如「计提参数配置」）可授予多个角色，
因此关联必须独立成表，不能把 role_id 塞进 permissions 表。
"""

from datetime import datetime
from typing import TYPE_CHECKING

from sqlalchemy import DateTime, ForeignKey, Index, Integer, String, UniqueConstraint, text
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.models.base import BIGINT_UNSIGNED, TINYINT_TYPE, Base, TimestampMixin, mysql_table_args

if TYPE_CHECKING:
    from app.models.user import UserRole


class Role(Base, TimestampMixin):
    """角色表。本期仅 admin / user 两个角色，数据随迁移脚本初始化。"""

    __tablename__ = "roles"
    __table_args__ = mysql_table_args("角色表")

    id: Mapped[int] = mapped_column(
        BIGINT_UNSIGNED, primary_key=True, autoincrement=True, comment="主键ID"
    )
    role_code: Mapped[str] = mapped_column(
        String(32), nullable=False, unique=True, comment="角色编码：admin系统管理员 user普通用户"
    )
    role_name: Mapped[str] = mapped_column(String(64), nullable=False, comment="角色名称")
    description: Mapped[str | None] = mapped_column(String(255), comment="角色说明")
    sort_order: Mapped[int] = mapped_column(
        Integer, nullable=False, server_default="0", comment="显示排序"
    )
    status: Mapped[int] = mapped_column(
        TINYINT_TYPE, nullable=False, server_default="1", comment="状态：1启用 0禁用"
    )

    user_roles: Mapped[list["UserRole"]] = relationship(back_populates="role")


class Permission(Base, TimestampMixin):
    """权限表。

    perm_type 区分菜单/按钮/接口三类，parent_id 支撑树形结构。
    本期只建表不填数据 —— 具体权限清单待需求澄清后确定。
    """

    __tablename__ = "permissions"
    __table_args__ = mysql_table_args("权限表")

    id: Mapped[int] = mapped_column(
        BIGINT_UNSIGNED, primary_key=True, autoincrement=True, comment="主键ID"
    )
    perm_code: Mapped[str] = mapped_column(
        String(128), nullable=False, unique=True, comment="权限编码，如 system:user:create"
    )
    perm_name: Mapped[str] = mapped_column(String(64), nullable=False, comment="权限名称")
    perm_type: Mapped[int] = mapped_column(
        TINYINT_TYPE, nullable=False, server_default="1", comment="类型：1菜单 2按钮 3接口"
    )
    parent_id: Mapped[int | None] = mapped_column(
        BIGINT_UNSIGNED,
        ForeignKey("permissions.id", ondelete="CASCADE"),
        comment="父权限ID（permissions.id），顶级为空",
    )
    sort_order: Mapped[int] = mapped_column(
        Integer, nullable=False, server_default="0", comment="显示排序"
    )
    status: Mapped[int] = mapped_column(
        TINYINT_TYPE, nullable=False, server_default="1", comment="状态：1启用 0禁用"
    )


class RolePermission(Base):
    """角色-权限关联表。"""

    __tablename__ = "role_permissions"
    __table_args__ = mysql_table_args(
        "角色权限关联表",
        UniqueConstraint(
            "role_id", "permission_id", name="uk_role_permissions_role_id_permission_id"
        ),
        Index("idx_role_permissions_permission_id", "permission_id"),
    )

    id: Mapped[int] = mapped_column(
        BIGINT_UNSIGNED, primary_key=True, autoincrement=True, comment="主键ID"
    )
    role_id: Mapped[int] = mapped_column(
        BIGINT_UNSIGNED,
        ForeignKey("roles.id", ondelete="CASCADE"),
        nullable=False,
        comment="角色ID（roles.id）",
    )
    permission_id: Mapped[int] = mapped_column(
        BIGINT_UNSIGNED,
        ForeignKey("permissions.id", ondelete="CASCADE"),
        nullable=False,
        comment="权限ID（permissions.id）",
    )
    create_time: Mapped[datetime] = mapped_column(
        DateTime, nullable=False, server_default=text("CURRENT_TIMESTAMP"), comment="创建时间"
    )