"""Memoir repository — Book, Chapter, MemoirState data access."""

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import Session, joinedload

from app.features.memoir.models import Book, Chapter, ChapterSection, MemoirState


async def get_current_book(user_id: str, db: AsyncSession) -> Book | None:
    stmt = select(Book).where(Book.user_id == user_id).order_by(Book.updated_at.desc()).limit(1)
    result = await db.execute(stmt)
    return result.scalar_one_or_none()


async def get_chapters_with_sections(
    user_id: str,
    db: AsyncSession,
    *,
    active_only: bool = True,
    is_new_only: bool | None = None,
) -> list[Chapter]:
    stmt = (
        select(Chapter)
        .where(Chapter.user_id == user_id)
        .options(
            joinedload(Chapter.sections),
            joinedload(Chapter.images),
            joinedload(Chapter.sections).joinedload(ChapterSection.image_record),
        )
        .order_by(Chapter.order_index)
    )
    if active_only:
        stmt = stmt.where(Chapter.is_active == True)  # noqa: E712
    if is_new_only is True:
        stmt = stmt.where(Chapter.is_new == True)  # noqa: E712
    result = await db.execute(stmt)
    return list(result.unique().scalars().all())


async def get_chapter_by_id(chapter_id: str, db: AsyncSession) -> Chapter | None:
    stmt = (
        select(Chapter)
        .where(Chapter.id == chapter_id)
        .options(
            joinedload(Chapter.sections),
            joinedload(Chapter.images),
            joinedload(Chapter.sections).joinedload(ChapterSection.image_record),
        )
    )
    result = await db.execute(stmt)
    return result.unique().scalars().one_or_none()


async def get_memoir_state(user_id: str, db: AsyncSession) -> MemoirState | None:
    stmt = select(MemoirState).where(MemoirState.user_id == user_id)
    result = await db.execute(stmt)
    return result.scalar_one_or_none()


def get_archived_chapter_summaries_sync(
    session: Session, user_id: str, category: str
) -> list[tuple[str, str]]:
    """获取已删除（is_active=False）的同类别章节的标题与内容摘要，供 AI 参考。"""
    stmt = (
        select(Chapter)
        .where(
            Chapter.user_id == user_id,
            Chapter.category == category,
            Chapter.is_active == False,  # noqa: E712
        )
        .options(joinedload(Chapter.sections))
        .order_by(Chapter.updated_at.desc())
    )
    result = session.execute(stmt)
    chapters = list(result.unique().scalars().all())
    summaries: list[tuple[str, str]] = []
    for ch in chapters:
        sections = getattr(ch, "sections", None) or []
        parts = [
            (s.content or "").strip()
            for s in sorted(sections, key=lambda x: getattr(x, "order_index", 0))
        ]
        combined = "".join(parts)
        preview = (combined[:200] + "...") if len(combined) > 200 else combined
        if preview.strip():
            summaries.append((ch.title or "", preview))
    return summaries