"""部门管理"""
from typing import List, Optional
import asyncpg


class DepartmentService:
    @staticmethod
    async def list_by_enterprise(
        conn: asyncpg.Connection, enterprise_id: int
    ) -> List[dict]:
        rows = await conn.fetch(
            """
            SELECT id, enterprise_id, name, parent_id, created_at, updated_at
            FROM department
            WHERE enterprise_id = $1
            ORDER BY id ASC
            """,
            enterprise_id,
        )
        return [dict(r) for r in rows]

    @staticmethod
    async def get_by_id(
        conn: asyncpg.Connection, dept_id: int, enterprise_id: int
    ) -> Optional[dict]:
        row = await conn.fetchrow(
            """
            SELECT id, enterprise_id, name, parent_id, created_at, updated_at
            FROM department
            WHERE id = $1 AND enterprise_id = $2
            """,
            dept_id,
            enterprise_id,
        )
        return dict(row) if row else None

    @staticmethod
    async def create(
        conn: asyncpg.Connection,
        enterprise_id: int,
        name: str,
        parent_id: Optional[int] = None,
    ) -> dict:
        row = await conn.fetchrow(
            """
            INSERT INTO department (enterprise_id, name, parent_id)
            VALUES ($1, $2, $3)
            RETURNING id, enterprise_id, name, parent_id, created_at, updated_at
            """,
            enterprise_id,
            name,
            parent_id,
        )
        return dict(row)

    @staticmethod
    async def update(
        conn: asyncpg.Connection,
        dept_id: int,
        enterprise_id: int,
        name: Optional[str] = None,
        parent_id: Optional[int] = None,
    ) -> Optional[dict]:
        fields: List[str] = []
        params: List = []
        if name is not None:
            fields.append(f"name = ${len(params) + 1}")
            params.append(name)
        if parent_id is not None:
            fields.append(f"parent_id = ${len(params) + 1}")
            params.append(parent_id)
        if not fields:
            return await DepartmentService.get_by_id(conn, dept_id, enterprise_id)
        wid = len(params) + 1
        we = len(params) + 2
        params.extend([dept_id, enterprise_id])
        q = f"""
            UPDATE department SET {", ".join(fields)}, updated_at = CURRENT_TIMESTAMP
            WHERE id = ${wid} AND enterprise_id = ${we}
            RETURNING id, enterprise_id, name, parent_id, created_at, updated_at
        """
        row = await conn.fetchrow(q, *params)
        return dict(row) if row else None

    @staticmethod
    async def delete(
        conn: asyncpg.Connection, dept_id: int, enterprise_id: int
    ) -> Optional[str]:
        cnt = await conn.fetchval(
            """
            SELECT COUNT(*) FROM user_list
            WHERE department_id = $1 AND enterprise_id = $2
            """,
            dept_id,
            enterprise_id,
        )
        if cnt and int(cnt) > 0:
            return "部门下仍有用户，无法删除"
        row = await conn.fetchrow(
            """
            DELETE FROM department
            WHERE id = $1 AND enterprise_id = $2
            RETURNING id
            """,
            dept_id,
            enterprise_id,
        )
        return None if row else "部门不存在"