# Source code for scrapy.extensions.logstats

    from __future__ import annotations

    import logging
    from typing import TYPE_CHECKING

    from twisted.internet import task

    from scrapy import Spider, signals
    from scrapy.exceptions import NotConfigured

    if TYPE_CHECKING:
        # typing.Self requires Python 3.11
        from typing_extensions import Self

        from scrapy.crawler import Crawler
        from scrapy.statscollectors import StatsCollector

    logger = logging.getLogger(__name__)

    class LogStats:
        """Log basic scraping stats periodically like:
        * RPM - Requests per Minute
        * IPM - Items per Minute
        """

        def __init__(self, stats: StatsCollector, interval: float = 60.0):
            self.stats: StatsCollector = stats
            self.interval: float = interval
            self.multiplier: float = 60.0 / self.interval
            self.task: task.LoopingCall | None = None

        @classmethod
        def from_crawler(cls, crawler: Crawler) -> Self:
            interval: float = crawler.settings.getfloat("LOGSTATS_INTERVAL")
            if not interval:
                raise NotConfigured
            assert crawler.stats
            o = cls(crawler.stats, interval)
            crawler.signals.connect(o.spider_opened, signal=signals.spider_opened)
            crawler.signals.connect(o.spider_closed, signal=signals.spider_closed)
            return o

        def spider_opened(self, spider: Spider) -> None:
            self.pagesprev: int = 0
            self.itemsprev: int = 0

            self.task = task.LoopingCall(self.log, spider)
            self.task.start(self.interval)

        def log(self, spider: Spider) -> None:
            self.calculate_stats()

            msg = (
                "Crawled %(pages)d pages (at %(pagerate)d pages/min), "
                "scraped %(items)d items (at %(itemrate)d items/min)"
            )
            log_args = {
                "pages": self.pages,
                "pagerate": self.prate,
                "items": self.items,
                "itemrate": self.irate,
            }
            logger.info(msg, log_args, extra={"spider": spider})

        def calculate_stats(self) -> None:
            self.items: int = self.stats.get_value("item_scraped_count", 0)
            self.pages: int = self.stats.get_value("response_received_count", 0)
            self.irate: float = (self.items - self.itemsprev) * self.multiplier
            self.prate: float = (self.pages - self.pagesprev) * self.multiplier
            self.pagesprev, self.itemsprev = self.pages, self.items

        def spider_closed(self, spider: Spider, reason: str) -> None:
            if self.task and self.task.running:
                self.task.stop()

            rpm_final, ipm_final = self.calculate_final_stats(spider)
            self.stats.set_value("responses_per_minute", rpm_final)
            self.stats.set_value("items_per_minute", ipm_final)

        def calculate_final_stats(
            self, spider: Spider
        ) -> tuple[None, None] | tuple[float, float]:
            start_time = self.stats.get_value("start_time")
            finished_time = self.stats.get_value("finished_time")

            if not start_time or not finished_time:
                return None, None

            mins_elapsed = (finished_time - start_time).seconds / 60

            items = self.stats.get_value("item_scraped_count", 0)
            pages = self.stats.get_value("response_received_count", 0)

            return (pages / mins_elapsed), (items / mins_elapsed)