# -*- coding: utf-8 -*-
"""任务生命周期原语（启动 / 终态 / 文件收尾 / 结算）。

（自 services/runtime.py 拆出，行为与原实现一致。）
"""

import threading
import time
import traceback
from typing import Any

import auth_system
from core.state import (
    DOWNLOAD_TASKS,
    DOWNLOAD_TASKS_LOCK,
)

from .api_service import (
    api_service,
)


def _start_task_thread(task_id: str, target, args=()) -> str | None:
    """启动任务 worker（启动失败时收敛任务终态并按账本退费，不留僵尸 queued 记录）。
    退款只走账本（本处 settle 后装饰器看到账已关，不会重复退）。
    线程句柄存入任务字典——监控循环对 4h 超时任务若发现 worker 线程已死
    （无法自行走到终态结算），可代为按账本结算退款（settle 幂等，无双退）。"""
    try:
        th = threading.Thread(target=target, args=args, daemon=True)
        with DOWNLOAD_TASKS_LOCK:
            t = DOWNLOAD_TASKS.get(task_id)
            if t is not None:
                t['worker_thread'] = th
        th.start()
        return None
    except Exception as e:
        with DOWNLOAD_TASKS_LOCK:
            t = DOWNLOAD_TASKS.pop(task_id, None)
        if t:
            try:
                auth_system.ledger_settle(task_id, 0, 'submit_failed')
            except Exception:
                pass
        api_service.logger.error(f"任务线程启动失败: {task_id} {e}")
        return f'任务启动失败：{e}'


def _mark_task_terminal(task_id: str, status: str, msg: str = '') -> None:
    """任务进入终态的统一入口（记录 completed_at，保留期从完成时刻起算，
    而不是从提交时刻起算）。
    /F-E：置 error/canceled 终态时若 worker 线程已死（无人再走正常结算），
    代为按账本结算退款——ledger_settle 幂等，worker 已自行结算过则此处为 0。
    终态先到先得——已终态（done/error/canceled）的任务
    不再被覆盖（堵住 canceled→error 的非法迁移边：取消后解析阶段的自身失败
    不得把"已取消"改写成"失败"，completed_at 也不再刷新）。"""
    need_settle = False
    with DOWNLOAD_TASKS_LOCK:
        t = DOWNLOAD_TASKS.get(task_id)
        if t and t.get('status') in ('done', 'error', 'canceled'):
            return
        if t:
            t['status'] = status
            t['msg'] = msg or t.get('msg', '')
            t['completed_at'] = time.time()
            if status in ('canceled', 'error'):
                th = t.get('worker_thread')
                if th is not None and not th.is_alive():
                    need_settle = True
    # settle 移到任务锁外——ledger_settle 内部要抢 _DB_LOCK 写库
    # （busy 最长 15s），持任务锁调用会让全站进度/提交/取消/领取随库停摆；
    # settle 幂等，锁外调用无双退
    if need_settle:
        try:
            auth_system.ledger_settle(task_id, 0, status)
        except Exception:
            pass


def _task_files(task: dict[str, Any]) -> list[str]:
    """任务当前关联的可清理文件路径（交付 ZIP/交付副本；缓存文件不在此列）"""
    result = task.get('result') or {}
    files = []
    for f in (result.get('zip_path'), result.get('file_path')):
        if f:
            files.append(f)
    return files


def _settle_batch_billing(task_id: str, ok_count: int, final_status: str = 'settled') -> int:
    """批量任务结算（走持久账本，按实际预扣-实际交付幂等退款；
    重复调用/重启后调用都只会退一次）"""
    try:
        refund = auth_system.ledger_settle(task_id, ok_count, final_status)
    except Exception:
        # 本函数多在异常处理器内被调用——结算再抛错（库忙超时）
        # 会杀死 worker 收尾路径，跳过终态标记；失败留周期对账兜底（幂等）
        api_service.logger.error(
            f"批量结算异常（留对账兜底）: {task_id}\n{traceback.format_exc()}")
        return 0
    if refund:
        try:
            with DOWNLOAD_TASKS_LOCK:
                t = DOWNLOAD_TASKS.get(task_id) or {}
            uid = int(t.get('billing_user_id') or 0)
            u = auth_system.get_user_by_id(uid) if uid else None
            uname = u['username'] if u else 'system'
            remaining = u['duration_seconds'] if u else '?'
            auth_system.add_log('success', uname, 'system', '批量退费',
                                f'失败部分 {refund} 次已退回，剩余 {remaining} 次')
        except Exception:
            pass
    return refund