"""
文件目录服务
"""

from __future__ import annotations

from typing import Optional, List
from sqlalchemy import select

from iti.applications.extensions import db
from iti.applications.models import SysFileDirectory
from iti.applications.common.enums import StatusEnum
from iti.applications.common.exceptions.biz_exp import BizException


def init_app(app):
    """初始化文件目录（系统启动时自动执行）"""
    with app.app_context():
        try:
            SysFileDirectoryService.ensure_default_directory()
        except Exception as e:
            print(f"⚠️  默认目录初始化失败: {e}")


class SysFileDirectoryService:
    """文件目录服务"""
    
    # 默认目录固定ID（使用标准UUID格式）
    DEFAULT_DIRECTORY_ID = "00000000000000000000000000000001"

    @classmethod
    def ensure_default_directory(cls) -> SysFileDirectory:
        """
        确保默认目录存在

        Returns:
            默认目录对象
        """
        # 使用固定ID查找默认目录
        default_dir = db.session.get(SysFileDirectory, cls.DEFAULT_DIRECTORY_ID)

        if not default_dir:
            # 创建默认目录，使用固定ID
            default_dir = SysFileDirectory(
                id=cls.DEFAULT_DIRECTORY_ID,
                name="默认目录",
                path="/default",
                parent_id=None,
                level=0,
                sort=0,
                icon="folder",
                description="系统默认文件目录",
                status=StatusEnum.ENABLED,
            )
            db.session.add(default_dir)
            db.session.commit()

        return default_dir

    @classmethod
    def get_default_directory_id(cls) -> str:
        """
        获取默认目录ID（直接返回固定ID，无需查询数据库）

        Returns:
            默认目录ID
        """
        return cls.DEFAULT_DIRECTORY_ID

    @classmethod
    def create_directory(
        cls,
        name: str,
        parent_id: Optional[str] = None,
        icon: Optional[str] = None,
        color: Optional[str] = None,
        description: Optional[str] = None,
    ) -> SysFileDirectory:
        """
        创建目录

        Args:
            name: 目录名称
            parent_id: 父目录ID
            icon: 图标
            color: 颜色
            description: 描述

        Returns:
            目录对象
        """
        # 计算路径和层级
        if parent_id:
            parent = db.session.get(SysFileDirectory, parent_id)
            if not parent:
                raise BizException("父目录不存在", code=404)
            path = f"{parent.path}/{name}"
            level = parent.level + 1
        else:
            path = f"/{name}"
            level = 0

        # 检查路径是否已存在
        existing = db.session.scalar(select(SysFileDirectory).filter_by(path=path))
        if existing:
            raise BizException("目录路径已存在", code=400)

        directory = SysFileDirectory(
            name=name,
            path=path,
            parent_id=parent_id,
            level=level,
            sort=0,
            icon=icon,
            color=color,
            description=description,
            status=StatusEnum.ENABLED,
        )
        db.session.add(directory)
        db.session.commit()

        return directory

    @classmethod
    def get_directory_tree(
        cls, parent_id: Optional[str] = None
    ) -> List[SysFileDirectory]:
        """
        获取目录树

        Args:
            parent_id: 父目录ID，None表示获取根目录

        Returns:
            目录列表
        """
        query = (
            select(SysFileDirectory)
            .filter_by(parent_id=parent_id, status=StatusEnum.ENABLED)
            .order_by(SysFileDirectory.sort, SysFileDirectory.created_at)
        )

        directories = db.session.scalars(query).all()
        return list(directories)

    @classmethod
    def delete_directory(cls, directory_id: str, force: bool = False) -> None:
        """
        删除目录

        Args:
            directory_id: 目录ID
            force: 是否强制删除（包括子目录和文件）
        """
        directory = db.session.get(SysFileDirectory, directory_id)
        if not directory:
            raise BizException("目录不存在", code=404)

        # 检查是否为默认目录
        if directory.path == "/default":
            raise BizException("不能删除默认目录", code=403)

        if not force:
            # 检查是否有子目录
            has_children = db.session.scalar(
                select(SysFileDirectory).filter_by(parent_id=directory_id).exists()
            )
            if has_children:
                raise BizException("目录下有子目录，无法删除", code=400)

            # 检查是否有文件
            from iti.applications.models import SysFile

            has_files = db.session.scalar(
                select(SysFile).filter_by(directory_id=directory_id).exists()
            )
            if has_files:
                raise BizException("目录下有文件，无法删除", code=400)

        # 删除目录
        db.session.delete(directory)
        db.session.commit()