"""
Story 同步写入（Celery / sync Session）。

与 StoryService 行为对齐：版本链、主图 intent、章节 dirty；不 commit，由调用方提交。
"""

from __future__ import annotations

import uuid
from datetime import datetime, timezone

from sqlalchemy import delete, func, select
from sqlalchemy.orm import Session, joinedload

from app.core.db import utc_now
from app.core.logging import get_logger
from app.features.memoir.asset_resolver import strip_asset_image_refs_from_markdown
from app.features.memoir.models import ChapterStoryLink
from app.features.memoir import repo as memoir_repo
from app.features.story.image_intent_extractor import extract_primary_image_intent
from app.features.story.models import Story, StoryImageIntent, StoryVersion

logger = get_logger(__name__)


def count_story_versions_sync(session: Session, story_id: str) -> int:
    stmt = select(func.count(StoryVersion.id)).where(StoryVersion.story_id == story_id)
    return int(session.execute(stmt).scalar() or 0)


def _delete_pending_failed_intents_sync(session: Session, story_id: str) -> None:
    session.execute(
        delete(StoryImageIntent).where(
            StoryImageIntent.story_id == story_id,
            StoryImageIntent.intent_role == "primary",
            StoryImageIntent.status.in_(["pending", "failed"]),
        )
    )


def _get_primary_intent_sync(
    session: Session, story_id: str
) -> StoryImageIntent | None:
    stmt = select(StoryImageIntent).where(
        StoryImageIntent.story_id == story_id,
        StoryImageIntent.intent_role == "primary",
    )
    return session.execute(stmt).scalar_one_or_none()


def _extract_and_store_image_intent_sync(
    session: Session,
    *,
    story: Story,
    version: StoryVersion,
    markdown: str,
) -> None:
    _delete_pending_failed_intents_sync(session, story.id)
    result = extract_primary_image_intent(
        markdown,
        title=story.title or "",
        stage=story.stage,
        summary=story.summary,
        people_refs=story.people_refs or [],
        place_refs=story.place_refs or [],
        time_start=story.time_start,
        time_end=story.time_end,
    )
    existing = _get_primary_intent_sync(session, story.id)
    now = datetime.now(timezone.utc)

    if existing and existing.story_version_id == version.id:
        st = (existing.status or "").strip()
        if st in ("processing", "completed"):
            return
        existing.caption = result.caption
        existing.prompt_brief = result.prompt_brief
        existing.style_profile = result.style_profile
        existing.status = "pending"
        existing.error = None
        existing.asset_id = None
        existing.updated_at = now
        return

    if existing and existing.story_version_id != version.id:
        existing.story_version_id = version.id
        existing.caption = result.caption
        existing.prompt_brief = result.prompt_brief
        existing.style_profile = result.style_profile
        existing.status = "pending"
        existing.error = None
        existing.asset_id = None
        existing.updated_at = now
        return

    session.add(
        StoryImageIntent(
            id=str(uuid.uuid4()),
            story_id=story.id,
            story_version_id=version.id,
            intent_role="primary",
            caption=result.caption,
            prompt_brief=result.prompt_brief,
            style_profile=result.style_profile,
            status="pending",
        )
    )


def create_story_with_version_sync(
    session: Session,
    *,
    user_id: str,
    title: str,
    canonical_markdown: str,
    stage: str | None = None,
) -> Story:
    md = strip_asset_image_refs_from_markdown(canonical_markdown or "")
    story = Story(
        id=str(uuid.uuid4()),
        user_id=user_id,
        title=title,
        stage=stage,
        canonical_markdown=md,
    )
    session.add(story)
    session.flush()
    vid = str(uuid.uuid4())
    version = StoryVersion(
        id=vid,
        story_id=story.id,
        version_no=1,
        markdown_snapshot=md,
        actor_type="ai",
        source_type="generate",
    )
    session.add(version)
    session.flush()
    story.current_version_id = vid
    if md.strip():
        _extract_and_store_image_intent_sync(
            session, story=story, version=version, markdown=md
        )
        memoir_repo.mark_chapters_dirty_for_story_sync(session, story.id)
    return story


def append_story_version_sync(
    session: Session,
    story_id: str,
    markdown_snapshot: str,
    *,
    actor_type: str = "ai",
    source_type: str = "generate",
) -> StoryVersion:
    story = session.get(Story, story_id)
    if not story:
        raise ValueError(f"Story {story_id} not found")
    md = strip_asset_image_refs_from_markdown(markdown_snapshot or "")
    parent_id = story.current_version_id
    version_no = count_story_versions_sync(session, story_id) + 1
    vid = str(uuid.uuid4())
    version = StoryVersion(
        id=vid,
        story_id=story_id,
        version_no=version_no,
        markdown_snapshot=md,
        actor_type=actor_type,
        source_type=source_type,
        parent_version_id=parent_id,
    )
    session.add(version)
    session.flush()
    story.current_version_id = vid
    story.canonical_markdown = md
    _extract_and_store_image_intent_sync(
        session, story=story, version=version, markdown=md
    )
    memoir_repo.mark_chapters_dirty_for_story_sync(session, story_id)
    return version


def ensure_chapter_story_link_sync(
    session: Session,
    *,
    chapter_id: str,
    story_id: str,
) -> None:
    """若章节尚未关联该 story，则在末尾追加一条 chapter_story_link。"""
    exists = session.scalars(
        select(ChapterStoryLink)
        .where(
            ChapterStoryLink.chapter_id == chapter_id,
            ChapterStoryLink.story_id == story_id,
        )
        .limit(1)
    ).first()
    if exists is not None:
        return
    max_stmt = select(func.coalesce(func.max(ChapterStoryLink.order_index), -1)).where(
        ChapterStoryLink.chapter_id == chapter_id
    )
    max_idx = int(session.execute(max_stmt).scalar() or -1)
    session.add(
        ChapterStoryLink(
            id=str(uuid.uuid4()),
            chapter_id=chapter_id,
            story_id=story_id,
            order_index=max_idx + 1,
        )
    )
    session.flush()


def list_active_stories_for_user_sync(session: Session, user_id: str) -> list[Story]:
    stmt = (
        select(Story)
        .where(Story.user_id == user_id, Story.status == "active")
        .options(
            joinedload(Story.chapter_links).joinedload(ChapterStoryLink.chapter),
        )
        .order_by(Story.updated_at.desc())
    )
    return list(session.execute(stmt).unique().scalars().all())