"""
Command Service - 指令管理服务
Provides CRUD operations for device command logs.
"""

from datetime import datetime, timezone

from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models import CommandLog


async def get_commands(
    db: AsyncSession,
    device_id: int | None = None,
    status: str | None = None,
    page: int = 1,
    page_size: int = 20,
) -> tuple[list[CommandLog], int]:
    """
    获取指令列表（分页）/ Get paginated command logs.

    Parameters
    ----------
    db : AsyncSession
        Database session.
    device_id : int, optional
        Filter by device ID.
    status : str, optional
        Filter by command status (pending, sent, success, failed).
    page : int
        Page number (1-indexed).
    page_size : int
        Number of items per page.

    Returns
    -------
    tuple[list[CommandLog], int]
        (list of command logs, total count)
    """
    query = select(CommandLog)
    count_query = select(func.count(CommandLog.id))

    if device_id is not None:
        query = query.where(CommandLog.device_id == device_id)
        count_query = count_query.where(CommandLog.device_id == device_id)

    if status:
        query = query.where(CommandLog.status == status)
        count_query = count_query.where(CommandLog.status == status)

    total_result = await db.execute(count_query)
    total = total_result.scalar() or 0

    offset = (page - 1) * page_size
    query = query.order_by(CommandLog.created_at.desc()).offset(offset).limit(page_size)
    result = await db.execute(query)
    commands = list(result.scalars().all())

    return commands, total


async def create_command(
    db: AsyncSession,
    device_id: int,
    command_type: str,
    command_content: str,
    server_flag: str = "badge_admin",
) -> CommandLog:
    """
    创建指令记录 / Create a new command log entry.

    Parameters
    ----------
    db : AsyncSession
        Database session.
    device_id : int
        Target device ID.
    command_type : str
        Type of command.
    command_content : str
        Command payload content.
    server_flag : str
        Server flag identifier.

    Returns
    -------
    CommandLog
        The newly created command log.
    """
    command = CommandLog(
        device_id=device_id,
        command_type=command_type,
        command_content=command_content,
        server_flag=server_flag,
        status="pending",
    )
    db.add(command)
    await db.flush()
    await db.refresh(command)
    return command


async def get_command(db: AsyncSession, command_id: int) -> CommandLog | None:
    """
    按ID获取指令 / Get command log by ID.

    Parameters
    ----------
    db : AsyncSession
        Database session.
    command_id : int
        Command log primary key.

    Returns
    -------
    CommandLog | None
    """
    result = await db.execute(
        select(CommandLog).where(CommandLog.id == command_id)
    )
    return result.scalar_one_or_none()