"""
回忆录处理 Celery 任务
"""

import json
import uuid
from datetime import datetime, timezone
from typing import Dict, List, Set

import redis
from celery import shared_task
from sqlalchemy import select
from sqlalchemy.orm import Session

from app.agents.chat.prompts_profile import format_user_profile_context
from app.agents.memoir import MemoirOrchestrator
from app.agents.state_schema import MemoirStateSchema, SlotData, default_state
from app.core.db import get_sync_db
from app.core.dependencies import get_llm_provider
from app.core.logging import get_logger
from app.features.conversation.models import Segment
from app.features.memoir.cover_eligibility import (
    chapter_needs_cover_enqueue,
)
from app.features.memoir.memoir_images.parser import (
    build_initial_image_assets,
)
from app.features.memoir.memoir_images.schema import (
    IMAGE_STATUS_COMPLETED,
    IMAGE_STATUS_FAILED,
    IMAGE_STATUS_PENDING,
    normalize_image_assets,
)
from app.features.memoir.memoir_images.serializers import (
    image_dict_to_row_kwargs,
)
from app.features.memoir.memoir_images.settings import MemoirImageSettings
from app.features.memoir.models import (
    Book,
    MemoirImage,
    MemoirState,
)
from app.features.memoir.story_pipeline_sync import (
    run_story_pipeline_for_category_batch,
)
from app.features.user.models import User

logger = get_logger(__name__)
_REDIS_CLIENTS: dict[bool, redis.Redis] = {}


def _get_llm():
    """Celery 任务内获取 LangChain LLM（通过 port）"""
    try:
        return getattr(get_llm_provider(), "langchain_llm", None)
    except Exception:
        return None


def _get_redis_client(*, decode_responses: bool = False) -> redis.Redis:
    from app.core.config import settings

    client = _REDIS_CLIENTS.get(decode_responses)
    if client is None:
        client = redis.from_url(
            settings.redis_url,
            decode_responses=decode_responses,
        )
        _REDIS_CLIENTS[decode_responses] = client
    return client


def _acquire_chapter_lock(user_id: str, stage: str, timeout: int = 120) -> bool:
    """获取章节分布式锁，防止并发写入同一章节"""
    r = _get_redis_client()
    lock_key = f"lock:chapter:{user_id}:{stage}"
    return r.set(lock_key, "1", nx=True, ex=timeout)


def _release_chapter_lock(user_id: str, stage: str):
    """释放章节分布式锁"""
    r = _get_redis_client()
    lock_key = f"lock:chapter:{user_id}:{stage}"
    r.delete(lock_key)


def _update_task_status_sync(
    user_id: str, task_id: str, status: str, result: Dict = None
):
    """同步更新任务状态（在 Celery 任务中使用）"""
    try:
        r = _get_redis_client(decode_responses=True)

        key = f"task:user:{user_id}:tasks"

        # 获取现有任务信息
        data = r.hget(key, task_id)
        if data:
            task_info = json.loads(data)
        else:
            task_info = {"task_id": task_id}

        task_info["status"] = status
        task_info["updated_at"] = datetime.now(timezone.utc).isoformat()
        if result is not None:
            task_info["result"] = result

        r.hset(key, task_id, json.dumps(task_info))
        r.expire(key, 3600)  # 1小时过期

        logger.debug("任务状态已更新: task_id={} status={}", task_id, status)
    except Exception as e:
        logger.error(f"更新任务状态失败: {e}")


def _merge_chapter_image_assets(
    existing_images: list[dict] | None,
    placeholders: list[dict],
    provider: str,
    style: str,
    size: str,
    now_iso: str,
) -> list[dict]:
    normalized_existing_images = normalize_image_assets(existing_images)
    existing_by_placeholder = {
        item.get("placeholder"): dict(item)
        for item in normalized_existing_images
        if item.get("placeholder")
    }
    merged_assets: list[dict] = []

    for item in placeholders:
        existing = existing_by_placeholder.get(item["placeholder"])
        if existing:
            merged_item = dict(existing)
            merged_item["index"] = item["index"]
            merged_item["placeholder"] = item["placeholder"]
            merged_item["description"] = item["description"]
            merged_item["provider"] = merged_item.get("provider") or provider
            merged_item["style"] = merged_item.get("style") or style
            merged_item["size"] = merged_item.get("size") or size
            merged_item["created_at"] = merged_item.get("created_at") or now_iso
            merged_item["updated_at"] = merged_item.get("updated_at") or now_iso
            if merged_item.get("status") == IMAGE_STATUS_COMPLETED and not (
                merged_item.get("storage_key") or merged_item.get("url")
            ):
                merged_item["status"] = IMAGE_STATUS_FAILED
                merged_item["error"] = merged_item.get("error") or "missing image url"
        else:
            merged_item = build_initial_image_assets(
                placeholders=[item],
                provider=provider,
                style=style,
                size=size,
                now_iso=now_iso,
            )[0]
        merged_assets.append(merged_item)

    return merged_assets


def chapter_has_images_to_generate(images: list[dict] | None) -> bool:
    return any(
        item.get("status") in {IMAGE_STATUS_PENDING, IMAGE_STATUS_FAILED}
        for item in normalize_image_assets(images)
    )


def _memoir_image_from_asset(
    chapter_id: str,
    order_index: int,
    image_asset: dict,
) -> MemoirImage:
    """从单条图片 dict 构建 MemoirImage 行（用于写入 memoir_images 表）。"""
    kwargs = image_dict_to_row_kwargs(image_asset)
    return MemoirImage(
        id=str(uuid.uuid4()).replace("-", "")[:32],
        chapter_id=chapter_id,
        order_index=order_index,
        **kwargs,
    )


def _coerce_state(model: MemoirState) -> MemoirStateSchema:
    """将数据库模型转换为 Schema"""
    return MemoirStateSchema.model_validate(
        {
            "stage_order": model.stage_order or default_state().stage_order,
            "current_stage": model.current_stage,
            "covered_stages": model.covered_stages or [],
            "slots": model.slots
            if isinstance(model.slots, dict)
            else default_state().slots,
        }
    )


def _get_or_create_state_sync(user_id: str, db: Session) -> MemoirStateSchema:
    """同步获取或创建状态"""
    stmt = select(MemoirState).where(MemoirState.user_id == user_id)
    result = db.execute(stmt)
    state = result.scalar_one_or_none()
    if state:
        return _coerce_state(state)

    default = default_state()
    state = MemoirState(
        id=str(uuid.uuid4()),
        user_id=user_id,
        stage_order=default.stage_order,
        current_stage=default.current_stage,
        covered_stages=default.covered_stages,
        slots={
            k: {sk: sv.model_dump() for sk, sv in v.items()}
            for k, v in default.slots.items()
        },
    )
    db.add(state)
    db.commit()
    db.refresh(state)
    return _coerce_state(state)


def _update_slot_sync(
    user_id: str,
    stage: str,
    slot_name: str,
    snippet: str,
    segment_ids: List[str],
    db: Session,
) -> MemoirStateSchema:
    """同步更新 slot"""
    stmt = select(MemoirState).where(MemoirState.user_id == user_id)
    result = db.execute(stmt)
    state = result.scalar_one_or_none()
    if not state:
        _get_or_create_state_sync(user_id, db)
        result = db.execute(stmt)
        state = result.scalar_one()

    slots: Dict[str, Dict] = state.slots or {}
    stage_slots = slots.get(stage, {})
    existing = stage_slots.get(slot_name, {})

    merged_segment_ids = list({*(existing.get("segment_ids") or []), *segment_ids})
    stage_slots[slot_name] = SlotData(
        snippet=snippet, segment_ids=merged_segment_ids
    ).model_dump()
    slots[stage] = stage_slots
    state.slots = slots
    state.current_stage = stage
    db.commit()
    db.refresh(state)
    return _coerce_state(state)


@shared_task(bind=True, max_retries=3, default_retry_delay=60)
def process_memoir_segments(self, user_id: str, segment_ids: List[str]):
    """
    处理回忆录段落的 Celery 任务

    Args:
        user_id: 用户 ID
        segment_ids: 段落 ID 列表
    """
    task_id = self.request.id
    logger.info(
        f"开始处理回忆录段落: user_id={user_id}, task_id={task_id}, segments={len(segment_ids)}"
    )

    # 更新任务状态为 running
    _update_task_status_sync(user_id, task_id, "running")

    try:
        with get_sync_db() as db:
            # 获取段落
            stmt = select(Segment).where(Segment.id.in_(segment_ids))
            result = db.execute(stmt)
            segments = result.scalars().all()

            if not segments:
                logger.warning(f"未找到段落: {segment_ids}")
                return {"status": "no_segments"}

            # Memory ingest 先于回忆录流水线 commit，保证后续 retrieve_evidence_sync 可见本批 chunk
            # （见 api/docs/memory-retrieval.md）
            conv_id = getattr(segments[0], "conversation_id", None) or ""
            transcript = "\n\n".join(seg.user_input_text or "" for seg in segments)
            if transcript.strip():
                try:
                    from app.features.memory.service import ingest_transcript_sync

                    source_id = ingest_transcript_sync(db, user_id, conv_id, transcript)
                    logger.info(
                        "event=memory_transcript_ingested user_id={} task_id={} "
                        "source_id={} conversation_id={} transcript_chars={} "
                        "segment_count={}",
                        user_id,
                        task_id,
                        source_id,
                        conv_id,
                        len(transcript),
                        len(segments),
                    )
                except Exception as e:
                    logger.warning(
                        "Memory ingest 跳过: {} exc_type={}",
                        e,
                        type(e).__name__,
                    )

            llm = _get_llm()
            image_settings = MemoirImageSettings.from_env()

            user_obj = db.get(User, user_id)
            user_profile = ""
            user_birth_year = None
            if user_obj:
                user_birth_year = user_obj.birth_year
                user_profile = format_user_profile_context(
                    birth_year=user_obj.birth_year,
                    birth_place=user_obj.birth_place,
                    grew_up_place=user_obj.grew_up_place,
                    occupation=user_obj.occupation,
                )

            story_dispatch_ids: Set[str] = set()

            memoir_orchestrator = MemoirOrchestrator()
            prepared = memoir_orchestrator.prepare_batches(
                segments=list(segments),
                llm=llm,
                get_or_create_state=lambda: _get_or_create_state_sync(user_id, db),
                update_slot=lambda stage, slot_name, snippet, seg_ids: (
                    _update_slot_sync(user_id, stage, slot_name, snippet, seg_ids, db)
                ),
            )

            chapters_to_enqueue: Set[str] = set()
            for (
                chapter_category,
                category_segments,
            ) in prepared.category_to_segments.items():
                if not _acquire_chapter_lock(user_id, chapter_category):
                    logger.warning(
                        "章节锁竞争: category={}, 延迟重试",
                        chapter_category,
                    )
                    raise self.retry(countdown=10)
                try:
                    chapter, needs_cover, disp = run_story_pipeline_for_category_batch(
                        db,
                        user_id=user_id,
                        chapter_category=chapter_category,
                        category_segments=category_segments,
                        state=prepared.state,
                        user_profile=user_profile,
                        user_birth_year=user_birth_year,
                        llm=llm,
                    )
                    story_dispatch_ids |= disp
                    db.flush()
                    db.refresh(chapter)

                    needs_cover_enqueue = (
                        image_settings.enabled and chapter_needs_cover_enqueue(chapter)
                    )

                    stmt_book = (
                        select(Book)
                        .where(Book.user_id == user_id)
                        .order_by(Book.updated_at.desc())
                    )
                    result_book = db.execute(stmt_book)
                    book = result_book.scalar_one_or_none()
                    if not book:
                        book = Book(
                            id=str(uuid.uuid4()),
                            user_id=user_id,
                            title="我的回忆录",
                            total_pages=0,
                            total_words=0,
                            cover_image_url=None,
                        )
                        db.add(book)
                    book.has_update = True
                    book.last_update_chapter_id = chapter.id

                    if chapter and needs_cover_enqueue:
                        chapters_to_enqueue.add(chapter.id)
                finally:
                    _release_chapter_lock(user_id, chapter_category)

            # 标记段落为已处理
            for seg in segments:
                seg.processed = True

            db.commit()

            from app.tasks.chapter_compose_tasks import recompose_chapters_for_story
            from app.tasks.story_image_tasks import generate_story_image

            for sid in story_dispatch_ids:
                try:
                    generate_story_image.delay(sid)
                except Exception as exc:
                    logger.warning("generate_story_image delay: {}", exc)
                try:
                    recompose_chapters_for_story.delay(sid)
                except Exception as exc:
                    logger.warning("recompose_chapters_for_story delay: {}", exc)

            from app.tasks.chapter_cover_enqueue import (
                try_enqueue_generate_chapter_cover,
            )

            for chapter_id in sorted(chapters_to_enqueue):
                if try_enqueue_generate_chapter_cover(chapter_id, source="pipeline"):
                    logger.info(f"派发章节封面任务: chapter={chapter_id}")

            categories_processed = sorted(prepared.category_to_segments.keys())
            logger.info(
                "回忆录处理完成: user_id={} task_id={} segment_count={} "
                "categories_processed={}",
                user_id,
                task_id,
                len(segments),
                categories_processed,
            )

            # 更新任务状态为成功
            _update_task_status_sync(
                user_id,
                task_id,
                "success",
                {
                    "processed": len(segments),
                    "categories_processed": categories_processed,
                },
            )

            return {
                "status": "success",
                "processed": len(segments),
                "categories_processed": categories_processed,
            }

    except Exception as e:
        logger.error(f"回忆录处理失败: {e}")

        # 更新任务状态为失败
        _update_task_status_sync(user_id, task_id, "failure", {"error": str(e)})

        # 重试
        raise self.retry(exc=e) from e


@shared_task(bind=True, max_retries=3, default_retry_delay=30)
def generate_chapter_content(self, user_id: str, stage: str, new_content: str):
    """
    单独生成章节内容的任务（用于实时更新）

    Args:
        user_id: 用户 ID
        stage: 阶段
        new_content: 新内容
    """
    logger.info(f"生成章节内容: user_id={user_id}, stage={stage}")

    try:
        with get_sync_db() as db:
            llm = _get_llm()
            user_obj = db.get(User, user_id)
            user_profile = ""
            user_birth_year = None
            if user_obj:
                user_birth_year = user_obj.birth_year
                user_profile = format_user_profile_context(
                    birth_year=user_obj.birth_year,
                    birth_place=user_obj.birth_place,
                    grew_up_place=user_obj.grew_up_place,
                    occupation=user_obj.occupation,
                )

            class _Seg:
                def __init__(self, text: str):
                    self.id = str(uuid.uuid4())
                    self.user_input_text = text

            state = _get_or_create_state_sync(user_id, db)
            chapter, _, dispatch_ids = run_story_pipeline_for_category_batch(
                db,
                user_id=user_id,
                chapter_category=stage,
                category_segments=[_Seg(new_content)],
                state=state,
                user_profile=user_profile,
                user_birth_year=user_birth_year,
                llm=llm,
            )
            db.commit()
            db.refresh(chapter)

            from app.tasks.chapter_compose_tasks import recompose_chapters_for_story
            from app.tasks.story_image_tasks import generate_story_image

            for sid in dispatch_ids:
                try:
                    generate_story_image.delay(sid)
                except Exception as exc:
                    logger.warning("generate_story_image delay: {}", exc)
                try:
                    recompose_chapters_for_story.delay(sid)
                except Exception as exc:
                    logger.warning("recompose_chapters_for_story delay: {}", exc)

            image_settings = MemoirImageSettings.from_env()
            if (
                image_settings.enabled
                and chapter
                and chapter_needs_cover_enqueue(chapter)
            ):
                from app.tasks.chapter_cover_enqueue import (
                    try_enqueue_generate_chapter_cover,
                )

                try_enqueue_generate_chapter_cover(chapter.id, source="pipeline")
            return {"status": "success"}

    except Exception as e:
        logger.error(f"章节生成失败: {e}")
        raise self.retry(exc=e) from e