"""Celery：story 变更后重组关联章节的 canonical_markdown（物化视图）。"""

import time
from datetime import datetime, timezone

from celery import shared_task

from app.core.chapter_pipeline_lock import (
    acquire_chapter_pipeline_lock,
    release_chapter_pipeline_lock,
)
from app.core.config import settings
from app.core.db import get_sync_db
from app.core.logging import get_logger
from app.core.memoir_pipeline_progress import merge_fanout_item
from app.core.memoir_pipeline_trace import new_memoir_correlation_id
from app.core.memory_compaction_schedule import schedule_memory_compaction_run
from app.features.memoir import repo as memoir_repo
from app.features.memoir.models import Chapter

logger = get_logger(__name__)


@shared_task(bind=True, max_retries=8, default_retry_delay=30)
def recompose_chapter(
    self, chapter_id: str, memoir_correlation_id: str | None = None
) -> dict:
    """
    按章节物化 canonical_markdown：仅当 markdown_compose_dirty 为 True 时执行；
    与 pipeline 共用章节级 Redis 锁，拿不到锁则跳过（依赖后续触发重试）。
    """
    lock_ttl = int(settings.chapter_pipeline_lock_ttl_seconds)
    tid = str(self.request.id)
    t0 = time.perf_counter()
    merge_fanout_item(
        memoir_correlation_id,
        list_name="recompose_chapters",
        id_field="chapter_id",
        item_id=chapter_id,
        task_id=tid,
        status="running",
    )
    user_id: str | None = None
    composed = False
    with get_sync_db() as session:
        chapter = session.get(Chapter, chapter_id)
        if not chapter:
            ms = (time.perf_counter() - t0) * 1000
            logger.info(
                "event=recompose_chapter status=not_found chapter_id={} duration_ms={:.1f} "
                "msg=章节重组跳过（章节不存在）",
                chapter_id,
                ms,
            )
            merge_fanout_item(
                memoir_correlation_id,
                list_name="recompose_chapters",
                id_field="chapter_id",
                item_id=chapter_id,
                task_id=tid,
                status="not_found",
            )
            return {"status": "not_found"}
        if chapter.markdown_compose_dirty is not True:
            ms = (time.perf_counter() - t0) * 1000
            logger.info(
                "event=recompose_chapter status=skip_not_dirty chapter_id={} duration_ms={:.1f} "
                "msg=章节重组跳过（无需重组）",
                chapter_id,
                ms,
            )
            merge_fanout_item(
                memoir_correlation_id,
                list_name="recompose_chapters",
                id_field="chapter_id",
                item_id=chapter_id,
                task_id=tid,
                status="skip_not_dirty",
            )
            return {"status": "skip_not_dirty"}
        uid = str(chapter.user_id)
        stage = str(chapter.category)
        lock_handle = acquire_chapter_pipeline_lock(uid, stage, ttl_seconds=lock_ttl)
        if lock_handle is None:
            ms = (time.perf_counter() - t0) * 1000
            logger.info(
                "event=recompose_chapter status=lock_busy_retry "
                "chapter_id={} user_id={} stage={} retry_on_lock={} duration_ms={:.1f} "
                "msg=章节重组等待锁或重试",
                chapter_id,
                uid,
                stage,
                settings.memoir_recompose_retry_on_lock_contention,
                ms,
            )
            if settings.memoir_recompose_retry_on_lock_contention:
                countdown = max(15, min(120, lock_ttl // 4))
                raise self.retry(countdown=countdown)
            merge_fanout_item(
                memoir_correlation_id,
                list_name="recompose_chapters",
                id_field="chapter_id",
                item_id=chapter_id,
                task_id=tid,
                status="skip_lock_contention",
            )
            return {"status": "skip_lock_contention"}
        try:
            composed = memoir_repo.compose_chapter_from_story_links_sync(
                session, chapter_id
            )
            session.commit()
            user_id = uid
        except Exception as exc:
            session.rollback()
            logger.warning(
                "recompose_chapter failed chapter_id={} err={}", chapter_id, exc
            )
            raise self.retry(exc=exc) from exc
        finally:
            release_chapter_pipeline_lock(lock_handle)

    if user_id:
        schedule_memory_compaction_run(
            user_id,
            {
                "trigger_source": "chapter_recompose",
                "trigger_time": datetime.now(timezone.utc).isoformat(),
                "pipeline_run_id": str(self.request.id),
                "memoir_correlation_id": new_memoir_correlation_id(),
                "recomposed_chapter_ids": [chapter_id],
            },
        )
    ms = (time.perf_counter() - t0) * 1000
    st = "composed" if composed else "empty"
    logger.info(
        "event=recompose_chapter status={} chapter_id={} user_id={} duration_ms={:.1f} "
        "msg=章节物化重组完成",
        st,
        chapter_id,
        user_id or "-",
        ms,
    )
    merge_fanout_item(
        memoir_correlation_id,
        list_name="recompose_chapters",
        id_field="chapter_id",
        item_id=chapter_id,
        task_id=tid,
        status="composed" if composed else "empty",
    )
    return {"status": "composed" if composed else "empty", "chapter_id": chapter_id}