"""Procurement-order ledger import and supplier cooperation aggregation."""

from __future__ import annotations

import hashlib
import re
from datetime import date, datetime
from pathlib import Path
from typing import Any

from openpyxl import load_workbook
from sqlalchemy import func, select
from sqlalchemy.dialects.postgresql import insert
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.entities import PurchaseOrderLine


def clean_text(value: Any) -> str | None:
    if value is None:
        return None
    text = str(value).replace("\u200b", "").strip()
    return text or None


def parse_date(value: Any) -> date | None:
    if isinstance(value, datetime):
        return value.date()
    if isinstance(value, date):
        return value
    text = clean_text(value)
    if not text:
        return None
    text = re.sub(r"\s+.*$", "", text).replace("/", "-").replace("年", "-").replace("月", "-").replace("日", "")
    for fmt in ("%Y-%m-%d", "%Y.%m.%d"):
        try:
            return datetime.strptime(text, fmt).date()
        except ValueError:
            continue
    return None


def parse_datetime(value: Any) -> datetime | None:
    if isinstance(value, datetime):
        return value
    text = clean_text(value)
    if not text:
        return None
    for fmt in ("%Y/%m/%d %H:%M:%S", "%Y-%m-%d %H:%M:%S", "%Y/%m/%d", "%Y-%m-%d"):
        try:
            return datetime.strptime(text, fmt)
        except ValueError:
            continue
    return None


def fingerprint(file_name: str, row_number: int) -> str:
    return hashlib.sha256(f"{file_name}\x1fSheet1\x1f{row_number}".encode()).hexdigest()


def read_purchase_order_rows(path: Path) -> list[dict[str, Any]]:
    workbook = load_workbook(path, read_only=True, data_only=True)
    sheet = workbook.active
    headers = [clean_text(value) for value in next(sheet.iter_rows(values_only=True))]
    required = ["单据编号", "采购日期", "供应商"]
    missing = [name for name in required if name not in headers]
    if missing:
        raise ValueError(f"采购订单缺少必要字段：{', '.join(missing)}")
    indexes = {name: headers.index(name) for name in headers if name}

    def value(row: tuple[Any, ...], name: str) -> Any:
        index = indexes.get(name)
        return row[index] if index is not None and index < len(row) else None

    rows: list[dict[str, Any]] = []
    for row_number, raw in enumerate(sheet.iter_rows(min_row=2, values_only=True), start=2):
        document = clean_text(value(raw, "单据编号"))
        supplier = clean_text(value(raw, "供应商"))
        if not document or not supplier:
            continue
        rows.append(
            {
                "document_number": document,
                "purchase_date": parse_date(value(raw, "采购日期")),
                "supplier": supplier,
                "document_status": clean_text(value(raw, "单据状态")),
                "close_status": clean_text(value(raw, "关闭状态")),
                "material_code": clean_text(value(raw, "物料编码")),
                "material_name": clean_text(value(raw, "物料名称")),
                "purchase_unit": clean_text(value(raw, "采购单位")),
                "purchase_quantity": value(raw, "采购数量"),
                "delivery_date": parse_datetime(value(raw, "交货日期")),
                "tax_inclusive_unit_price": value(raw, "含税单价"),
                "is_gift": clean_text(value(raw, "是否赠品")),
                "business_close": clean_text(value(raw, "业务关闭")),
                "remark": clean_text(value(raw, "备注")),
                "source_file": path.name,
                "import_fingerprint": fingerprint(path.name, row_number),
            }
        )
    return rows


async def import_purchase_orders(session: AsyncSession, path: Path) -> dict[str, int]:
    rows = read_purchase_order_rows(path)
    inserted = 0
    for start in range(0, len(rows), 500):
        batch = rows[start : start + 500]
        result = await session.execute(
            insert(PurchaseOrderLine).values(batch).on_conflict_do_nothing(index_elements=["import_fingerprint"])
        )
        inserted += result.rowcount or 0
    await session.flush()
    return {"source_rows": len(rows), "inserted_rows": inserted, "skipped_rows": len(rows) - inserted}


async def supplier_order_counts(
    session: AsyncSession,
    supplier: str,
    start: date,
    end: date,
) -> int:
    value = await session.scalar(
        select(func.count(func.distinct(PurchaseOrderLine.document_number))).where(
            PurchaseOrderLine.supplier.ilike(f"%{supplier}%"),
            PurchaseOrderLine.purchase_date >= start,
            PurchaseOrderLine.purchase_date <= end,
        )
    )
    return int(value or 0)