"""用户偏好 API"""
from fastapi import APIRouter, Depends, Query
from pydantic import BaseModel
from app.database import SessionLocalPMS

router = APIRouter(prefix="/api/pms/preference", tags=["用户偏好"])


class PreferenceResponse(BaseModel):
    user_id: int
    default_bom_target_id: int | None
    favorite_target_ids: list[str]   # 存储 bom_key 字符串列表


class PreferenceUpdate(BaseModel):
    default_bom_target_id: int | None
    favorite_target_ids: list[str] | None


def _parse_fav(raw) -> list[str]:
    """从 JSON 字段安全解析字符串列表（支持旧格式纯数字字符串）"""
    if raw is None:
        return []
    if isinstance(raw, list):
        return [str(x) for x in raw if x is not None]
    return []


def _get_or_create(db, user_id: int):
    from app.models import PmsUserPreference
    pref = db.query(PmsUserPreference).filter(
        PmsUserPreference.user_id == user_id
    ).first()
    if not pref:
        pref = PmsUserPreference(user_id=user_id)
        db.add(pref)
        db.commit()
        db.refresh(pref)
    return pref


# ── 1. 获取偏好 ────────────────────────────────────────────────────────
@router.get("", response_model=PreferenceResponse)
async def get_preference(user_id: int = Query(...)):
    from app.models import PmsUserPreference
    db = SessionLocalPMS()
    try:
        pref = db.query(PmsUserPreference).filter(
            PmsUserPreference.user_id == user_id
        ).first()
        if not pref:
            return PreferenceResponse(user_id=user_id, default_bom_target_id=None, favorite_target_ids=[])
        return PreferenceResponse(
            user_id=pref.user_id,
            default_bom_target_id=pref.default_bom_target_id,
            favorite_target_ids=_parse_fav(pref.favorite_target_ids)
        )
    finally:
        db.close()


# ── 2. 完整更新偏好 ────────────────────────────────────────────────────
@router.put("", response_model=PreferenceResponse)
async def put_preference(user_id: int = Query(...), data: PreferenceUpdate = ...):
    db = SessionLocalPMS()
    try:
        pref = _get_or_create(db, user_id)
        if data.default_bom_target_id is not None:
            pref.default_bom_target_id = data.default_bom_target_id
        if data.favorite_target_ids is not None:
            pref.favorite_target_ids = data.favorite_target_ids
        db.commit()
        db.refresh(pref)
        return PreferenceResponse(
            user_id=pref.user_id,
            default_bom_target_id=pref.default_bom_target_id,
            favorite_target_ids=_parse_fav(pref.favorite_target_ids)
        )
    finally:
        db.close()


# ── 3. 添加常看（bom_key）───────────────────────────────────────────────
@router.post("/favorite/add", response_model=PreferenceResponse)
async def add_favorite(user_id: int = Query(...), target_id: str = Query(..., description="bom_key")):
    """
    添加 bom_key 到用户常看列表
    路径: POST /api/pms/preference/favorite/add?user_id=1&target_id=181_v1_1
    """
    db = SessionLocalPMS()
    try:
        pref = _get_or_create(db, user_id)
        current: list[str] = _parse_fav(pref.favorite_target_ids)
        if target_id not in current:
            current.append(target_id)
            pref.favorite_target_ids = current
        db.commit()
        db.refresh(pref)
        return PreferenceResponse(
            user_id=pref.user_id,
            default_bom_target_id=pref.default_bom_target_id,
            favorite_target_ids=_parse_fav(pref.favorite_target_ids)
        )
    finally:
        db.close()


# ── 4. 移除常看（bom_key）───────────────────────────────────────────────
@router.post("/favorite/remove", response_model=PreferenceResponse)
async def remove_favorite(user_id: int = Query(...), target_id: str = Query(..., description="bom_key")):
    """
    从用户常看列表移除 bom_key
    路径: POST /api/pms/preference/favorite/remove?user_id=1&target_id=181_v1_1
    """
    db = SessionLocalPMS()
    try:
        pref = _get_or_create(db, user_id)
        current: list[str] = _parse_fav(pref.favorite_target_ids)
        if target_id in current:
            current.remove(target_id)
            pref.favorite_target_ids = current
        db.commit()
        db.refresh(pref)
        return PreferenceResponse(
            user_id=pref.user_id,
            default_bom_target_id=pref.default_bom_target_id,
            favorite_target_ids=_parse_fav(pref.favorite_target_ids)
        )
    finally:
        db.close()


# ── 5. 保存排序（替换全部顺序）────────────────────────────────────────
class ReorderRequest(BaseModel):
    favorite_keys: list[str]


@router.post("/favorite/reorder")
async def reorder_favorites(user_id: int = Query(...), data: ReorderRequest = ...):
    """
    用新数组完整替换用户常看列表的顺序
    路径: POST /api/pms/preference/favorite/reorder?user_id=1
    Body: {"favorite_keys": ["181_OF-L2_V1.0", "1784_KY*HPPA_V1.0"]}
    """
    from sqlalchemy.orm.attributes import flag_modified
    db = SessionLocalPMS()
    try:
        pref = _get_or_create(db, user_id)
        pref.favorite_target_ids = data.favorite_keys
        flag_modified(pref, "favorite_target_ids")
        db.commit()
        db.refresh(pref)
        return {
            "user_id": pref.user_id,
            "default_bom_target_id": pref.default_bom_target_id,
            "favorite_target_ids": _parse_fav(pref.favorite_target_ids)
        }
    finally:
        db.close()