"""
回忆录状态服务：get_or_create_state、update_slot、mark_stage_complete 等。
供 memoir service、conversation ws 使用；Celery 任务内使用同步版本。
"""

import uuid
from typing import Dict, List

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

from app.agents.stage_constants import (
    chat_bucket,
    normalize_chat_stage,
)
from app.agents.state_schema import MemoirStateSchema, SlotData, default_state
from app.core.config import settings
from app.features.memoir.models import MemoirState as MemoirStateModel


def _slots_snapshot_for_merge(raw: Dict[str, Dict] | None) -> Dict[str, Dict]:
    """浅拷贝 slots，避免就地改 JSON 列同一 dict 引用导致 ORM 不标记 dirty。"""
    if not raw or not isinstance(raw, dict):
        return {}
    return {k: dict(v or {}) for k, v in raw.items()}


def coerce_memoir_state(model: MemoirStateModel) -> MemoirStateSchema:
    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,
        }
    )


async def get_or_create_state(user_id: str, db: AsyncSession) -> MemoirStateSchema:
    stmt = select(MemoirStateModel).where(MemoirStateModel.user_id == user_id)
    result = await db.execute(stmt)
    state = result.scalar_one_or_none()
    if state:
        return coerce_memoir_state(state)

    default = default_state()
    state = MemoirStateModel(
        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)
    await db.commit()
    await db.refresh(state)
    return coerce_memoir_state(state)


def _apply_current_stage_policy(
    state: MemoirStateModel,
    stage_norm: str,
    *,
    memoir_batch: bool,
) -> None:
    """按 memoir_extraction_updates_current_stage 与 chat_bucket 真值表更新 current_stage。"""
    current_from_db = state.current_stage or "childhood"
    if not memoir_batch:
        state.current_stage = stage_norm
        return

    if not settings.memoir_extraction_updates_current_stage:
        return
    cur_b = chat_bucket(state.current_stage or current_from_db)
    new_b = chat_bucket(stage_norm)
    if new_b == cur_b:
        state.current_stage = stage_norm


async def update_slot(
    user_id: str,
    stage: str,
    slot_name: str,
    snippet: str,
    segment_ids: List[str],
    db: AsyncSession,
    *,
    memoir_batch: bool = False,
) -> MemoirStateSchema:
    stmt = (
        select(MemoirStateModel)
        .where(MemoirStateModel.user_id == user_id)
        .with_for_update()
    )
    result = await db.execute(stmt)
    state = result.scalar_one_or_none()
    if not state:
        await get_or_create_state(user_id, db)
        result = await db.execute(stmt)
        state = result.scalar_one()

    current_from_db = state.current_stage or "childhood"
    stage_norm = normalize_chat_stage(
        stage,
        fallback=current_from_db,
        log_context={"user_id": user_id},
    )

    slots = _slots_snapshot_for_merge(
        state.slots if isinstance(state.slots, dict) else None
    )
    stage_slots = dict(slots.get(stage_norm, {}) or {})
    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_norm] = stage_slots
    state.slots = slots
    _apply_current_stage_policy(state, stage_norm, memoir_batch=memoir_batch)
    await db.commit()
    await db.refresh(state)
    return coerce_memoir_state(state)


async def mark_stage_complete(
    user_id: str, stage: str, db: AsyncSession
) -> MemoirStateSchema:
    """推进 covered_stages 并在当前阶段匹配时尝试进入下一阶段。当前无调用方，预留未来阶段推进逻辑。"""
    stmt = select(MemoirStateModel).where(MemoirStateModel.user_id == user_id)
    result = await db.execute(stmt)
    state = result.scalar_one_or_none()
    if not state:
        return await get_or_create_state(user_id, db)

    covered = state.covered_stages or []
    if stage not in covered:
        covered.append(stage)
    state.covered_stages = covered

    stage_order = state.stage_order or default_state().stage_order
    if state.current_stage == stage:
        try:
            idx = stage_order.index(stage)
            state.current_stage = stage_order[min(idx + 1, len(stage_order) - 1)]
        except ValueError:
            state.current_stage = default_state().current_stage
    await db.commit()
    await db.refresh(state)
    return coerce_memoir_state(state)


async def get_empty_slots(user_id: str, db: AsyncSession) -> List[str]:
    state = await get_or_create_state(user_id, db)
    return state.empty_slots_for_current_stage()


async def switch_stage(
    user_id: str, new_stage: str, db: AsyncSession
) -> MemoirStateSchema:
    stmt = (
        select(MemoirStateModel)
        .where(MemoirStateModel.user_id == user_id)
        .with_for_update()
    )
    result = await db.execute(stmt)
    state = result.scalar_one_or_none()
    if not state:
        await get_or_create_state(user_id, db)
        result = await db.execute(stmt)
        state = result.scalar_one()

    fb = state.current_stage or "childhood"
    state.current_stage = normalize_chat_stage(
        new_stage, fallback=fb, log_context={"user_id": user_id}
    )
    await db.commit()
    await db.refresh(state)
    return coerce_memoir_state(state)


def get_or_create_state_sync(user_id: str, db: Session) -> MemoirStateSchema:
    stmt = select(MemoirStateModel).where(MemoirStateModel.user_id == user_id)
    result = db.execute(stmt)
    state = result.scalar_one_or_none()
    if state:
        return coerce_memoir_state(state)

    default = default_state()
    state = MemoirStateModel(
        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_memoir_state(state)


def update_slot_sync(
    user_id: str,
    stage: str,
    slot_name: str,
    snippet: str,
    segment_ids: List[str],
    db: Session,
    *,
    memoir_batch: bool = True,
) -> MemoirStateSchema:
    stmt = (
        select(MemoirStateModel)
        .where(MemoirStateModel.user_id == user_id)
        .with_for_update()
    )
    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()

    current_from_db = state.current_stage or "childhood"
    stage_norm = normalize_chat_stage(
        stage,
        fallback=current_from_db,
        log_context={"user_id": user_id},
    )

    slots = _slots_snapshot_for_merge(
        state.slots if isinstance(state.slots, dict) else None
    )
    stage_slots = dict(slots.get(stage_norm, {}) or {})
    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_norm] = stage_slots
    state.slots = slots
    _apply_current_stage_policy(state, stage_norm, memoir_batch=memoir_batch)
    db.commit()
    db.refresh(state)
    return coerce_memoir_state(state)