"""库内数据浏览 API：排序、价格、类目（§5 矩阵）与店铺（精确）筛选。"""
from __future__ import annotations

from typing import Any

from django.db.models import F, Q, QuerySet
from django.db.models.expressions import OrderBy
from rest_framework.request import Request

SEARCH_SORT_FIELDS = frozenset(
    {
        "row_index",
        "price",
        "sku_id",
        "title",
        "leaf_category",
        "matrix_group_label",
        "total_sales",
        "comment_count",
    }
)
DETAIL_SORT_FIELDS = frozenset(
    {
        "row_index",
        "price",
        "sku_id",
        "detail_category_path",
        "detail_brand",
        "matrix_group_label",
    }
)
MERGED_SORT_FIELDS = frozenset(
    {
        "row_index",
        "price",
        "sku_id",
        "title",
        "leaf_category",
        "detail_category_path",
        "matrix_group_label",
        "total_sales",
        "comment_count",
    }
)


def _parse_opt_float(val: str | None) -> float | None:
    if val is None or not str(val).strip():
        return None
    try:
        return float(str(val).strip())
    except ValueError:
        return None


def parse_sort_meta(request: Request) -> tuple[str, bool]:
    sort = (request.query_params.get("sort") or "row_index").strip()
    order = (request.query_params.get("order") or "asc").strip().lower()
    desc = order == "desc"
    return sort, desc


def price_bounds_from_request(request: Request) -> tuple[float | None, float | None]:
    return (
        _parse_opt_float(request.query_params.get("price_min")),
        _parse_opt_float(request.query_params.get("price_max")),
    )


def report_group_from_request(request: Request) -> str:
    """与 §5 矩阵一致的类目名（如饼干、米）；查询参数 ``report_group``。"""
    return (request.query_params.get("report_group") or "").strip()


def shop_from_request(request: Request) -> str:
    """店铺名精确匹配（与摘要 ``shop_options`` 中某项一致）；查询参数 ``shop``。"""
    return (request.query_params.get("shop") or "").strip()


def detail_category_q_from_request(request: Request) -> str:
    return (request.query_params.get("detail_category_q") or "").strip()


def filter_echo(
    *,
    report_group: str,
    shop: str,
    price_min: float | None,
    price_max: float | None,
    detail_category_q: str,
    sort: str,
    desc: bool,
) -> dict[str, Any]:
    return {
        "report_group": report_group or None,
        "shop": shop or None,
        "price_min": price_min,
        "price_max": price_max,
        "detail_category_q": detail_category_q or None,
        "sort": sort,
        "order": "desc" if desc else "asc",
    }


def apply_search_filters(qs: QuerySet, request: Request) -> QuerySet:
    rg = report_group_from_request(request)
    if rg:
        qs = qs.filter(Q(matrix_group_label=rg) | Q(leaf_category=rg))
    sp = shop_from_request(request)
    if sp:
        qs = qs.filter(shop_name=sp)
    pmin, pmax = price_bounds_from_request(request)
    if pmin is not None:
        qs = qs.filter(price_value__gte=pmin)
    if pmax is not None:
        qs = qs.filter(price_value__lte=pmax)
    return qs


def apply_search_order(qs: QuerySet, sort: str, desc: bool) -> QuerySet:
    sort = sort if sort in SEARCH_SORT_FIELDS else "row_index"
    if sort == "price":
        return qs.order_by(
            OrderBy(F("price_value"), descending=desc, nulls_last=True),
            "row_index",
        )
    if sort == "total_sales":
        return qs.order_by(
            OrderBy(F("sales_sort_value"), descending=desc, nulls_last=True),
            "row_index",
        )
    if sort == "comment_count":
        return qs.order_by(
            OrderBy(F("comment_count_sort_value"), descending=desc, nulls_last=True),
            "row_index",
        )
    if sort == "row_index":
        return qs.order_by(OrderBy(F("row_index"), descending=desc))
    field = {
        "sku_id": "sku_id",
        "title": "title",
        "leaf_category": "leaf_category",
        "matrix_group_label": "matrix_group_label",
    }[sort]
    return qs.order_by(
        OrderBy(F(field), descending=desc, nulls_last=True),
        "row_index",
    )


def apply_detail_filters(qs: QuerySet, request: Request) -> QuerySet:
    rg = report_group_from_request(request)
    if rg:
        qs = qs.filter(matrix_group_label=rg)
    sp = shop_from_request(request)
    if sp:
        qs = qs.filter(detail_shop_name=sp)
    q = detail_category_q_from_request(request)
    if q:
        qs = qs.filter(detail_category_path__icontains=q)
    pmin, pmax = price_bounds_from_request(request)
    if pmin is not None:
        qs = qs.filter(detail_price_value__gte=pmin)
    if pmax is not None:
        qs = qs.filter(detail_price_value__lte=pmax)
    return qs


def apply_detail_order(qs: QuerySet, sort: str, desc: bool) -> QuerySet:
    sort = sort if sort in DETAIL_SORT_FIELDS else "row_index"
    if sort == "price":
        return qs.order_by(
            OrderBy(F("detail_price_value"), descending=desc, nulls_last=True),
            "row_index",
        )
    if sort == "row_index":
        return qs.order_by(OrderBy(F("row_index"), descending=desc))
    field = {
        "sku_id": "sku_id",
        "detail_category_path": "detail_category_path",
        "detail_brand": "detail_brand",
        "matrix_group_label": "matrix_group_label",
    }[sort]
    return qs.order_by(
        OrderBy(F(field), descending=desc, nulls_last=True),
        "row_index",
    )


def apply_merged_filters(qs: QuerySet, request: Request) -> QuerySet:
    rg = report_group_from_request(request)
    if rg:
        qs = qs.filter(matrix_group_label=rg)
    sp = shop_from_request(request)
    if sp:
        qs = qs.filter(Q(shop_name=sp) | Q(detail_shop_name=sp))
    q = detail_category_q_from_request(request)
    if q:
        qs = qs.filter(detail_category_path__icontains=q)
    pmin, pmax = price_bounds_from_request(request)
    if pmin is not None:
        qs = qs.filter(price_value__gte=pmin)
    if pmax is not None:
        qs = qs.filter(price_value__lte=pmax)
    return qs


def apply_merged_order(qs: QuerySet, sort: str, desc: bool) -> QuerySet:
    sort = sort if sort in MERGED_SORT_FIELDS else "row_index"
    if sort == "price":
        return qs.order_by(
            OrderBy(F("price_value"), descending=desc, nulls_last=True),
            "row_index",
        )
    if sort == "total_sales":
        return qs.order_by(
            OrderBy(F("sales_sort_value"), descending=desc, nulls_last=True),
            "row_index",
        )
    if sort == "comment_count":
        return qs.order_by(
            OrderBy(F("comment_count_sort_value"), descending=desc, nulls_last=True),
            "row_index",
        )
    if sort == "row_index":
        return qs.order_by(OrderBy(F("row_index"), descending=desc))
    field = {
        "sku_id": "sku_id",
        "title": "title",
        "leaf_category": "leaf_category",
        "detail_category_path": "detail_category_path",
        "matrix_group_label": "matrix_group_label",
    }[sort]
    return qs.order_by(
        OrderBy(F(field), descending=desc, nulls_last=True),
        "row_index",
    )