"""
证据包组装：跨 memory + story 的检索结果合并（业务层，非纯 repo）。

Memory evidence 只保留 async 单链路：chunk 原文为首要证据，结构化事实/
摘要/故事均按本次 query 命中进入 evidence，不再做 rolling/recent 历史降级。
"""

from __future__ import annotations

from sqlalchemy.ext.asyncio import AsyncSession

from app.features.memory.repo import (
    list_summaries_for_evidence_async,
    search_facts_for_user_async,
)
from app.features.story.repo import list_recent_stories_for_evidence

EMPTY_EVIDENCE_BUNDLE: dict = {
    "relevant_chunks": [],
    "relevant_summaries": [],
    "relevant_facts": [],
    "relevant_stories": [],
}


def _facts_to_dicts(facts) -> list[dict]:
    return [
        {
            "id": f.id,
            "fact_type": f.fact_type,
            "subject": f.subject,
            "predicate": f.predicate,
            "object_json": f.object_json,
        }
        for f in facts
    ]


def _stories_to_dicts(story_rows) -> list[dict]:
    return [
        {
            "id": s.id,
            "title": s.title,
            "summary": s.summary,
            "stage": s.stage,
            "story_type": s.story_type,
        }
        for s in story_rows
    ]


async def fetch_evidence_metadata_async(
    db: AsyncSession, user_id: str, q: str, top_k: int
) -> dict:
    """非 chunk 证据（async）。"""
    facts = await search_facts_for_user_async(db, user_id, q, top_k)
    relevant_summaries = await list_summaries_for_evidence_async(
        db, user_id=user_id, q=q, limit=top_k
    )
    story_rows = await list_recent_stories_for_evidence(
        db, user_id=user_id, query=q, limit=top_k
    )
    return {
        "relevant_facts": _facts_to_dicts(facts),
        "relevant_summaries": relevant_summaries,
        "relevant_stories": _stories_to_dicts(story_rows),
    }


async def retrieve_evidence_bundle_async(
    db: AsyncSession,
    user_id: str,
    query: str,
    *,
    top_k: int = 10,
    merged_chunk_dicts: list[dict],
) -> dict:
    """
    异步路径：chunk 已由调用方（如 HybridRetriever）向量检索填入；此处只拼元数据。

    merged_chunk_dicts: [{"id","content","chunk_index"}, ...]
    """
    if not query or not query.strip():
        return dict(EMPTY_EVIDENCE_BUNDLE)
    q = query.strip()
    meta = await fetch_evidence_metadata_async(db, user_id, q, top_k)
    return {
        "relevant_chunks": merged_chunk_dicts,
        **meta,
    }