# -*- coding: utf-8 -*-
"""
租约续期服务

后台线程定期为正在执行的任务续期租约。
"""

import logging
import threading
import time
from typing import TYPE_CHECKING, Any, Optional

if TYPE_CHECKING:
    from services.api_client import APIClientV2
    from util.tracing import TaskTraceContext

from util.tracing import bind_trace_context, start_span

logger = logging.getLogger(__name__)


class LeaseService:
    """
    租约续期服务

    在后台线程中定期调用 API 延长任务租约，
    防止长时间任务因租约过期被回收。
    """

    def __init__(
        self,
        api_client: 'APIClientV2',
        task_id: str,
        interval: int = 60,
        extension: int = 300,
        parent_otel_context: Any = None,
        task_trace_context: Optional['TaskTraceContext'] = None,
    ):
        """
        初始化租约服务

        Args:
            api_client: API 客户端
            task_id: 任务 ID
            interval: 续期间隔（秒），默认 60 秒
            extension: 每次续期时长（秒），默认 300 秒
        """
        self.api_client = api_client
        self.task_id = task_id
        self.interval = interval
        self.extension = extension
        self.parent_otel_context = parent_otel_context
        self.task_trace_context = task_trace_context
        self.running = False
        self.thread: threading.Thread = None
        self._stop_event = threading.Event()

    def start(self):
        """启动租约续期线程"""
        if self.running:
            logger.warning(f"[task:{self.task_id}] Lease service already running")
            return

        self.running = True
        self._stop_event.clear()
        self.thread = threading.Thread(
            target=self._run,
            name=f"LeaseService-{self.task_id}",
            daemon=True
        )
        self.thread.start()
        logger.debug(f"[task:{self.task_id}] Lease service started (interval={self.interval}s)")

    def stop(self):
        """停止租约续期线程"""
        if not self.running:
            return

        self.running = False
        self._stop_event.set()

        if self.thread and self.thread.is_alive():
            self.thread.join(timeout=5)

        logger.debug(f"[task:{self.task_id}] Lease service stopped")

    def _run(self):
        """续期线程主循环"""
        with bind_trace_context(self.parent_otel_context, self.task_trace_context):
            while self.running:
                if self._stop_event.wait(timeout=self.interval):
                    break

                if self.running:
                    self._extend_lease()

    def _extend_lease(self):
        """执行租约续期"""
        with start_span(
            "render.task.lease.extend",
            task_id=self.task_id,
            attributes={"render.lease.extension_seconds": self.extension},
        ):
            try:
                success = self.api_client.extend_lease(self.task_id, self.extension)
                if success:
                    logger.debug(f"[task:{self.task_id}] Lease extended by {self.extension}s")
                else:
                    logger.warning(f"[task:{self.task_id}] Failed to extend lease")
            except Exception as e:
                logger.warning(f"[task:{self.task_id}] Lease extension error: {e}")

    def __enter__(self):
        """上下文管理器入口"""
        self.start()
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        """上下文管理器出口"""
        self.stop()
        return False