import re

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

from app.models.attachment import (
    AttachmentCategory,
    FinishedGoodsAttachment,
    FinishedGoodsAttachmentItem,
    FinishedGoodsAttachmentLocation,
    FinishedGoodsBoxAttachmentItem,
)
from app.services.box_service import InvalidZongpaiError

ZONGPAI_PATTERN = re.compile(r"^(\d{2}(B|C|T)\d+|\d{2}(BW|CW)\d{4})$")


class CategoryNotFoundError(Exception):
    pass


class AttachmentItemNotFoundError(Exception):
    pass


class DuplicateAttachmentLocationError(Exception):
    def __init__(self, location_code: str, registered_at: str):
        self.location_code = location_code
        self.registered_at = registered_at


class AlreadyOffShelfAttachmentError(Exception):
    def __init__(self, location_code: str, registered_at: str):
        self.location_code = location_code
        self.registered_at = registered_at


class DuplicateAttachmentBoxItemError(Exception):
    def __init__(self, paichan_no: str, box_no: int):
        self.paichan_no = paichan_no
        self.box_no = box_no


class CategoryHasBoxesError(Exception):
    """配置中删除已有装箱记录的类型时抛出。"""

    def __init__(self, category_name: str):
        self.category_name = category_name


def _validate_zongpai(zongpai_no: str) -> str:
    zongpai_no = zongpai_no.strip().upper()
    if not ZONGPAI_PATTERN.match(zongpai_no):
        raise InvalidZongpaiError()
    return zongpai_no


def _boxed_qty_map(db: Session, zongpai_no: str) -> dict[int, int]:
    """按 category_id 汇总已装数量。"""
    rows = db.execute(
        select(
            FinishedGoodsBoxAttachmentItem.category_id,
            func.sum(FinishedGoodsBoxAttachmentItem.quantity),
        )
        .where(FinishedGoodsBoxAttachmentItem.zongpai_no == zongpai_no)
        .group_by(FinishedGoodsBoxAttachmentItem.category_id)
    ).all()
    return {row[0]: int(row[1] or 0) for row in rows}


def _location_map(db: Session, zongpai_no: str) -> dict[int, str]:
    rows = (
        db.query(FinishedGoodsAttachmentLocation)
        .filter(FinishedGoodsAttachmentLocation.zongpai_no == zongpai_no)
        .all()
    )
    return {r.category_id: r.location_code for r in rows}


def _category_name_map(db: Session, category_ids: list[int]) -> dict[int, str]:
    if not category_ids:
        return {}
    rows = (
        db.query(AttachmentCategory)
        .filter(AttachmentCategory.id.in_(category_ids))
        .all()
    )
    return {r.id: r.name for r in rows}


def get_attachment_status(db: Session, zongpai_no: str) -> dict:
    zongpai_no = _validate_zongpai(zongpai_no)

    att = (
        db.query(FinishedGoodsAttachment)
        .filter(FinishedGoodsAttachment.zongpai_no == zongpai_no)
        .first()
    )
    determination = att.determination if att else "undetermined"

    items_db = (
        db.query(FinishedGoodsAttachmentItem)
        .filter(FinishedGoodsAttachmentItem.zongpai_no == zongpai_no)
        .all()
    )
    category_ids = [i.category_id for i in items_db]
    names = _category_name_map(db, category_ids)
    boxed = _boxed_qty_map(db, zongpai_no)
    locations = _location_map(db, zongpai_no)

    items = []
    for it in items_db:
        boxed_qty = boxed.get(it.category_id, 0)
        items.append(
            {
                "category_id": it.category_id,
                "name": names.get(it.category_id, "(已删除类型)"),
                "expected_qty": it.expected_qty,
                "boxed_qty": boxed_qty,
                "location_code": locations.get(it.category_id),
                "complete": boxed_qty >= it.expected_qty,
            }
        )

    items.sort(key=lambda x: x["category_id"])
    all_complete = determination == "has" and bool(items) and all(i["complete"] for i in items)
    return {
        "zongpai_no": zongpai_no,
        "determination": determination,
        "all_complete": all_complete,
        "items": items,
    }