"""
Celery 用：按批次将 transcript 写入 Story，并物化 Chapter canonical_markdown。
"""

from __future__ import annotations

import json
import uuid
from typing import Any

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

from app.agents.memoir.narrative_agent import NarrativeAgent
from app.agents.memoir.prompts import (
    STAGE_TO_ORDER,
    format_evidence_chunks_for_prompt,
    format_narrative_user_content,
)
from app.core.config import settings
from app.agents.memoir.story_route_agent import (
    PLAN_BATCH_MAX_SEGMENTS,
    StoryBatchPlan,
    StoryRouteAgent,
)
from app.agents.state_schema import MemoirStateSchema
from app.core.logging import get_logger
from app.features.memoir.cover_eligibility import chapter_needs_cover_enqueue
from app.features.memoir.memoir_images.settings import MemoirImageSettings
from app.features.memoir.models import Chapter
from app.features.memoir.narrative_to_markdown import narrative_to_markdown
from app.features.memoir.repo import (
    compose_chapter_from_story_links_sync,
    reorder_chapter_story_links_by_life_order_sync,
)
from app.features.memory.repo import retrieve_evidence_sync
from app.features.story.models import Story
from app.features.story.sync_write import (
    append_story_version_sync,
    create_story_with_version_sync,
    ensure_chapter_story_link_sync,
    list_active_stories_for_user_sync,
)

logger = get_logger(__name__)


def _fidelity_fallback_json(oral: str, existing_canonical: str | None) -> str:
    """忠实度未通过时的安全回退：续写场景保留旧文 + 本段口述，避免只剩一句。"""
    o = (oral or "").strip()[:15000]
    ex = (existing_canonical or "").strip()[:15000]
    if ex and o:
        return json.dumps(
            {"paragraphs": [{"content": ex}, {"content": o}]},
            ensure_ascii=False,
        )
    if ex:
        return json.dumps(
            {"paragraphs": [{"content": ex}]},
            ensure_ascii=False,
        )
    return json.dumps(
        {"paragraphs": [{"content": o}]},
        ensure_ascii=False,
    )


def _gate_narrative_fidelity(
    oral_text: str,
    narrative_raw: str,
    llm: Any,
    *,
    existing_canonical: str | None = None,
) -> str:
    """叙事 JSON 忠实度检查；不通过则回退为口述正文（续写时保留已有故事 + 口述）。"""
    from app.agents.memoir.fidelity_check_agent import FidelityCheckAgent

    if not settings.memoir_fidelity_check_enabled or not llm:
        return narrative_raw
    agent = FidelityCheckAgent()
    ex = (existing_canonical or "").strip() or None
    if agent.passes(
        oral_text=oral_text,
        narrative_json=narrative_raw,
        llm=llm,
        existing_canonical_markdown=ex,
    ):
        return narrative_raw
    logger.warning(
        "event=fidelity_gate_fallback oral_len={} merge={}",
        len((oral_text or "").strip()),
        bool(ex),
    )
    o = (oral_text or "").strip()
    if not o and not ex:
        return narrative_raw
    return _fidelity_fallback_json(o, ex)


def _should_fallback_to_transcript(md: str, oral: str) -> bool:
    """模型输出相对口述明显过短时回退为口述原文（防「1999」类压缩）。"""
    o = (oral or "").strip()
    if not o:
        return False
    m = (md or "").strip()
    if not m:
        return True
    if len(o) < 12:
        return len(m) < len(o)
    ratio = float(settings.memoir_narrative_fallback_body_ratio)
    min_abs = int(settings.memoir_narrative_fallback_min_chars)
    threshold = max(min_abs, int(len(o) * ratio))
    return len(m) < threshold


def _coalesce_story_markdown(
    md: str,
    oral: str,
    existing_for_narrative: str,
) -> str:
    """落库前对齐正文：空输出或过短回退时，续写场景保留「已有故事 + 本段口述」。"""
    o = (oral or "").strip()
    ex = (existing_for_narrative or "").strip()
    m = (md or "").strip()
    if not m:
        if ex and o:
            return f"{ex}\n\n{o}"
        if o:
            return o
        return ex
    if o and _should_fallback_to_transcript(m, o):
        if ex:
            return f"{ex}\n\n{o}"
        return o
    return m


def _is_json_narrative(text: str) -> bool:
    if not text or not text.strip():
        return False
    s = text.strip()
    return s.startswith("{") and "paragraphs" in s


def _ordered_text_for_segment_ids(
    category_segments: list, segment_ids: list[str]
) -> str:
    id_to_text = {seg.id: (seg.user_input_text or "") for seg in category_segments}
    return "\n\n".join(id_to_text.get(sid, "") for sid in segment_ids)


def _apply_narrative_fallbacks(
    narrative_raw: str,
    combined_unit_text: str,
    existing_for_narrative: str,
    *,
    chapter_category: str,
) -> str:
    # 整篇合并（JSON）输出异常缩水：回退为旧文 + 本段口述，避免覆盖丢失
    if existing_for_narrative and _is_json_narrative(narrative_raw):
        merged_md = narrative_to_markdown(narrative_raw).strip()
        ex = (existing_for_narrative or "").strip()
        if ex and len(ex) > 400 and len(merged_md) < len(ex) * 0.35:
            logger.warning(
                "event=narrative_fallback reason=merge_shrink action=append_oral "
                "chapter_category={}",
                chapter_category,
            )
            return f"{ex}\n\n{combined_unit_text.strip()}"

    if (
        existing_for_narrative
        and not _is_json_narrative(narrative_raw)
        and len(narrative_raw) < len(existing_for_narrative) * 0.8
    ):
        logger.warning(
            "event=narrative_fallback reason=length_anomaly action=append_raw "
            "chapter_category={}",
            chapter_category,
        )
        return f"{existing_for_narrative}\n\n{combined_unit_text}"

    # 禁止把「章节级 canonical」（多故事拼接）写进单条 Story：会把全章正文塞进一个故事，
    # 且该 story 若挂多章会导致各章阅读视图串台。新建故事时宁可短，也不拼接 existing_chapter_md。

    md_check = narrative_to_markdown(narrative_raw).strip()
    oral = (combined_unit_text or "").strip()
    ex_fb = (existing_for_narrative or "").strip()
    if oral and _should_fallback_to_transcript(md_check, oral):
        if ex_fb:
            logger.warning(
                "event=narrative_fallback reason=body_too_short_vs_oral_merge "
                "chapter_category={} oral_len={} md_len={}",
                chapter_category,
                len(oral),
                len(md_check),
            )
            return f"{ex_fb}\n\n{oral}"
        logger.warning(
            "event=narrative_fallback reason=body_too_short_vs_oral "
            "chapter_category={} oral_len={} md_len={}",
            chapter_category,
            len(oral),
            len(md_check),
        )
        return oral

    return narrative_raw


def _ensure_chapter_record(
    session: Session,
    *,
    user_id: str,
    chapter_category: str,
    title: str,
    source_ids: list[str],
    calculated_order_index: int,
) -> Chapter:
    stmt_chapter = (
        select(Chapter)
        .where(
            Chapter.user_id == user_id,
            Chapter.category == chapter_category,
            Chapter.is_active == True,  # noqa: E712
        )
        .options(
            joinedload(Chapter.images),
            joinedload(Chapter.story_links),
        )
    )
    chapter = session.execute(stmt_chapter).unique().scalar_one_or_none()
    if not chapter:
        chapter = Chapter(
            id=str(uuid.uuid4()),
            user_id=user_id,
            title=title,
            order_index=calculated_order_index,
            status="completed",
            category=chapter_category,
            is_new=True,
            source_segments=source_ids,
        )
        session.add(chapter)
        session.flush()
    else:
        chapter.source_segments = list(
            set((chapter.source_segments or []) + source_ids)
        )
        chapter.is_new = True
        session.flush()
    return chapter


def _run_batch_plan_writes(
    session: Session,
    *,
    plan: StoryBatchPlan,
    category_segments: list,
    chapter: Chapter,
    chapter_category: str,
    evidence_text: str,
    slot_snippets: dict[str, str],
    user_id: str,
    user_profile: str,
    user_birth_year: int | None,
    llm: Any,
    narrative_agent: NarrativeAgent,
) -> set[str]:
    dispatch_ids: set[str] = set()
    for unit in plan.units:
        unit_text = _ordered_text_for_segment_ids(category_segments, unit.segment_ids)
        new_content_input = format_narrative_user_content(unit_text, evidence_text)

        target_story_id: str | None = None
        existing_for_narrative = ""
        if unit.decision == "append_story" and unit.target_story_id:
            st = session.get(Story, unit.target_story_id)
            if st and st.user_id == user_id:
                target_story_id = st.id
                existing_for_narrative = (st.canonical_markdown or "").strip()

        narrative_raw = narrative_agent.generate_narrative(
            stage=chapter_category,
            slots=slot_snippets,
            new_content=new_content_input,
            existing_content=existing_for_narrative,
            user_profile=user_profile,
            birth_year=user_birth_year,
            llm=llm,
        )
        narrative_raw = _gate_narrative_fidelity(
            unit_text,
            narrative_raw,
            llm,
            existing_canonical=existing_for_narrative or None,
        )
        narrative_raw = _apply_narrative_fallbacks(
            narrative_raw,
            unit_text,
            existing_for_narrative,
            chapter_category=chapter_category,
        )

        md = _coalesce_story_markdown(
            narrative_to_markdown(narrative_raw).strip(),
            unit_text.strip(),
            existing_for_narrative or "",
        )

        if target_story_id:
            append_story_version_sync(session, target_story_id, md)
            dispatch_ids.add(target_story_id)
            ensure_chapter_story_link_sync(
                session, chapter_id=chapter.id, story_id=target_story_id
            )
        else:
            story_title = (unit.new_story_title or "").strip()
            if not story_title:
                story_title = narrative_agent.generate_title(
                    stage=chapter_category,
                    emotion="neutral",
                    slots=slot_snippets,
                    user_profile=user_profile,
                    birth_year=user_birth_year,
                    llm=llm,
                )
            st = create_story_with_version_sync(
                session,
                user_id=user_id,
                title=story_title,
                canonical_markdown=md,
                stage=chapter_category,
            )
            dispatch_ids.add(st.id)
            ensure_chapter_story_link_sync(
                session, chapter_id=chapter.id, story_id=st.id
            )
    return dispatch_ids


def run_story_pipeline_for_category_batch(
    session: Session,
    *,
    user_id: str,
    chapter_category: str,
    category_segments: list,
    state: MemoirStateSchema,
    user_profile: str,
    user_birth_year: int | None,
    llm: Any,
) -> tuple[Chapter | None, bool, set[str]]:
    """
    返回 (chapter, needs_cover_enqueue, story_ids_to_dispatch_after_commit)。
    """
    narrative_agent = NarrativeAgent()
    route_agent = StoryRouteAgent()
    dispatch_ids: set[str] = set()

    segment_texts = [seg.user_input_text or "" for seg in category_segments]
    combined_text = "\n\n".join(segment_texts)
    source_ids = [seg.id for seg in category_segments]

    try:
        evidence = retrieve_evidence_sync(session, user_id, combined_text, top_k=10)
    except Exception as e:
        logger.warning("Evidence 检索跳过: {}", e)
        evidence = {
            "relevant_chunks": [],
            "relevant_summaries": [],
            "relevant_facts": [],
            "timeline_hints": [],
            "relevant_stories": [],
        }

    evidence_text = format_evidence_chunks_for_prompt(evidence)
    new_content_input = format_narrative_user_content(combined_text, evidence_text)

    stmt_chapter = (
        select(Chapter)
        .where(
            Chapter.user_id == user_id,
            Chapter.category == chapter_category,
            Chapter.is_active == True,  # noqa: E712
        )
        .options(
            joinedload(Chapter.images),
            joinedload(Chapter.story_links),
        )
    )
    chapter = session.execute(stmt_chapter).unique().scalar_one_or_none()

    slot_snippets: dict[str, str] = {}
    stage_slots = state.slots.get(chapter_category, {}) or {}
    for key, value in stage_slots.items():
        snip = getattr(value, "snippet", None) or (
            value.get("snippet") if isinstance(value, dict) else None
        )
        if snip:
            slot_snippets[key] = snip

    title = chapter.title if chapter else f"{chapter_category} 回忆"

    if not chapter:
        title = narrative_agent.generate_title(
            stage=chapter_category,
            emotion="neutral",
            slots=slot_snippets,
            user_profile=user_profile,
            birth_year=user_birth_year,
            llm=llm,
        )

    candidates = list_active_stories_for_user_sync(session, user_id)
    valid_ids = {s.id for s in candidates}

    batch_for_route = (
        f"{combined_text}\n\n{evidence_text}"
        if evidence_text.strip()
        else combined_text
    )

    calculated_order_index = STAGE_TO_ORDER.get(chapter_category, 999)

    use_batch_plan = (
        llm
        and len(category_segments) >= 2
        and len(category_segments) <= PLAN_BATCH_MAX_SEGMENTS
    )
    plan: StoryBatchPlan | None = None
    if use_batch_plan:
        segs = [(seg.id, seg.user_input_text or "") for seg in category_segments]
        plan = route_agent.plan_batch(
            chapter_category=chapter_category,
            chapter_title=title,
            segments=segs,
            candidate_stories=candidates,
            llm=llm,
            valid_story_ids=valid_ids,
        )

    chapter = _ensure_chapter_record(
        session,
        user_id=user_id,
        chapter_category=chapter_category,
        title=title,
        source_ids=source_ids,
        calculated_order_index=calculated_order_index,
    )

    if plan is not None:
        dispatch_ids = _run_batch_plan_writes(
            session,
            plan=plan,
            category_segments=category_segments,
            chapter=chapter,
            chapter_category=chapter_category,
            evidence_text=evidence_text,
            slot_snippets=slot_snippets,
            user_id=user_id,
            user_profile=user_profile,
            user_birth_year=user_birth_year,
            llm=llm,
            narrative_agent=narrative_agent,
        )
    else:
        route = route_agent.decide(
            chapter_category=chapter_category,
            chapter_title=title,
            batch_transcript=batch_for_route,
            candidate_stories=candidates,
            llm=llm,
            valid_story_ids=valid_ids,
        )

        target_story_id: str | None = None
        existing_for_narrative = ""
        if route.decision == "append_story" and route.target_story_id:
            st = session.get(Story, route.target_story_id)
            if st and st.user_id == user_id:
                target_story_id = st.id
                existing_for_narrative = (st.canonical_markdown or "").strip()

        narrative_raw = narrative_agent.generate_narrative(
            stage=chapter_category,
            slots=slot_snippets,
            new_content=new_content_input,
            existing_content=existing_for_narrative,
            user_profile=user_profile,
            birth_year=user_birth_year,
            llm=llm,
        )
        narrative_raw = _gate_narrative_fidelity(
            combined_text,
            narrative_raw,
            llm,
            existing_canonical=existing_for_narrative or None,
        )

        narrative_raw = _apply_narrative_fallbacks(
            narrative_raw,
            combined_text,
            existing_for_narrative,
            chapter_category=chapter_category,
        )

        md = _coalesce_story_markdown(
            narrative_to_markdown(narrative_raw).strip(),
            combined_text.strip(),
            existing_for_narrative or "",
        )

        do_append = target_story_id is not None

        if do_append:
            append_story_version_sync(session, target_story_id, md)
            dispatch_ids.add(target_story_id)
            ensure_chapter_story_link_sync(
                session, chapter_id=chapter.id, story_id=target_story_id
            )
        else:
            story_title = (route.new_story_title or "").strip()
            if not story_title:
                story_title = narrative_agent.generate_title(
                    stage=chapter_category,
                    emotion="neutral",
                    slots=slot_snippets,
                    user_profile=user_profile,
                    birth_year=user_birth_year,
                    llm=llm,
                )
            st = create_story_with_version_sync(
                session,
                user_id=user_id,
                title=story_title,
                canonical_markdown=md,
                stage=chapter_category,
            )
            dispatch_ids.add(st.id)
            ensure_chapter_story_link_sync(
                session, chapter_id=chapter.id, story_id=st.id
            )

    reorder_chapter_story_links_by_life_order_sync(session, chapter.id)
    compose_chapter_from_story_links_sync(session, chapter.id)
    session.flush()

    image_settings = MemoirImageSettings.from_env()
    needs_cover = image_settings.enabled and chapter_needs_cover_enqueue(chapter)

    return chapter, needs_cover, dispatch_ids