from typing import TYPE_CHECKING
from uuid import UUID

from sqlmodel import Field, Relationship, text

from .base import TableBase, SQLModelBase, UUIDTableBase

if TYPE_CHECKING:
    from .user import User
    from .policy import Policy


# ==================== Base 模型 ====================

class GroupBase(SQLModelBase):
    """用户组基础字段，供数据库模型和 DTO 共享"""

    name: str
    """用户组名称"""


class GroupOptionsBase(SQLModelBase):
    """用户组选项基础字段，供数据库模型和 DTO 共享"""

    share_download: bool = False
    """是否允许分享下载"""

    share_free: bool = False
    """是否免积分获取需要积分的内容"""

    relocate: bool = False
    """是否允许文件重定位"""

    source_batch: int = 0
    """批量获取源地址数量"""

    select_node: bool = False
    """是否允许选择节点"""

    advance_delete: bool = False
    """是否允许高级删除"""


# ==================== DTO 模型 ====================

class GroupResponse(GroupBase, GroupOptionsBase):
    """用户组响应 DTO"""

    id: UUID
    """用户组UUID"""

    allow_share: bool = False
    """是否允许分享"""

    allow_remote_download: bool = False
    """是否允许离线下载"""

    allow_archive_download: bool = False
    """是否允许打包下载"""

    compress: bool = False
    """是否允许压缩"""

    webdav: bool = False
    """是否允许WebDAV"""

    allow_webdav_proxy: bool = False
    """是否允许WebDAV代理"""


# ==================== 数据库模型 ====================

# GroupPolicyLink 定义在 policy.py 中以避免循环导入
from .policy import GroupPolicyLink


class GroupOptions(GroupOptionsBase, TableBase, table=True):
    """用户组选项模型"""

    group_id: UUID = Field(foreign_key="group.id", unique=True)
    """关联的用户组UUID"""

    archive_download: bool = False
    """是否允许打包下载"""

    archive_task: bool = False
    """是否允许创建打包任务"""

    webdav_proxy: bool = False
    """是否允许WebDAV代理"""

    aria2: bool = False
    """是否允许使用aria2"""

    redirected_source: bool = False
    """是否使用重定向源"""

    available_nodes: str = "[]"
    """可用节点ID列表（JSON数组）"""

    # 反向关系
    group: "Group" = Relationship(back_populates="options")


class Group(GroupBase, UUIDTableBase, table=True):
    """用户组模型"""

    name: str = Field(max_length=255, unique=True)
    """用户组名"""

    max_storage: int = Field(default=0, sa_column_kwargs={"server_default": "0"})
    """最大存储空间（字节）"""

    share_enabled: bool = Field(default=False, sa_column_kwargs={"server_default": text("false")})
    """是否允许创建分享"""

    web_dav_enabled: bool = Field(default=False, sa_column_kwargs={"server_default": text("false")})
    """是否允许使用WebDAV"""

    admin: bool = False
    """是否为管理员组"""

    speed_limit: int = Field(default=0, sa_column_kwargs={"server_default": "0"})
    """速度限制 (KB/s), 0为不限制"""

    # 一对一关系：用户组选项
    options: GroupOptions | None = Relationship(
        back_populates="group",
        sa_relationship_kwargs={"uselist": False}
    )

    # 多对多关系：用户组可以关联多个存储策略
    policies: list["Policy"] = Relationship(
        back_populates="groups",
        link_model=GroupPolicyLink,
    )

    # 关系：一个组可以有多个用户
    user: list["User"] = Relationship(
        back_populates="group",
        sa_relationship_kwargs={"foreign_keys": "User.group_id"}
    )
    previous_user: list["User"] = Relationship(
        back_populates="previous_group",
        sa_relationship_kwargs={"foreign_keys": "User.previous_group_id"}
    )

    def to_response(self) -> "GroupResponse":
        """转换为响应 DTO"""
        opts = self.options
        return GroupResponse(
            id=self.id,
            name=self.name,
            allow_share=self.share_enabled,
            webdav=self.web_dav_enabled,
            share_download=opts.share_download if opts else False,
            share_free=opts.share_free if opts else False,
            relocate=opts.relocate if opts else False,
            source_batch=opts.source_batch if opts else 0,
            select_node=opts.select_node if opts else False,
            advance_delete=opts.advance_delete if opts else False,
            allow_remote_download=opts.aria2 if opts else False,
            allow_archive_download=opts.archive_download if opts else False,
            allow_webdav_proxy=opts.webdav_proxy if opts else False,
        )