import pandas as pd
from datetime import datetime

from services.contractors import get_contractors


def _find_column(df, aliases):
    for name in aliases:
        if name in df.columns:
            return name
    return None


def import_sbis_excel(file, conn):
    contractors = {
        name: contractor_id
        for contractor_id, name in get_contractors(conn)
    }

    cursor = conn.cursor()
    df = pd.read_excel(file)

    required = {
        "contractor": _find_column(
            df, ["Контрагент", "Наименование контрагента", "Организация"]
        ),
        "doc_date": _find_column(df, ["Дата", "Дата документа"]),
        "doc_number": _find_column(df, ["Номер", "Номер документа"]),
        "doc_type": _find_column(df, ["Вид документа", "Тип документа", "Тип"]),
        "amount": _find_column(df, ["Сумма"]),
        "state": _find_column(df, ["Состояние", "Статус", "Состояние документа"]),
    }

    missing = [key for key, col in required.items() if col is None]
    if missing:
        raise ValueError(
            f"В файле не найдены обязательные колонки: {', '.join(missing)}"
        )

    responsible_col = _find_column(
        df, ["Ответственный", "Ответственный сотрудник"]
    )
    description_col = _find_column(df, ["Описание", "Комментарий", "Примечание"])

    imported = 0
    updated = 0
    skipped = 0
    now = datetime.now().strftime("%Y-%m-%d %H:%M:%S")

    # Получаем максимальный row_order для новых записей
    cursor.execute("SELECT COALESCE(MAX(row_order), 0) FROM documents_sbis")
    max_order = cursor.fetchone()[0] or 0
    
    for idx, (_, row) in enumerate(df.iterrows()):
        contr = str(row[required["contractor"]]).strip()

        if contr not in contractors:
            skipped += 1
            continue

        doc_type = row[required["doc_type"]]
        doc_date = row[required["doc_date"]]
        number = row[required["doc_number"]]
        summ = row[required["amount"]]
        state = row[required["state"]]

        amount = float(summ) if pd.notna(summ) else 0
        responsible = (
            str(row[responsible_col]).strip()
            if responsible_col and pd.notna(row[responsible_col])
            else None
        )
        description = (
            str(row[description_col]).strip()
            if description_col and pd.notna(row[description_col])
            else None
        )

        # Проверяем существование документа
        cursor.execute(
            """
            SELECT id
            FROM documents_sbis
            WHERE contractor = ?
              AND doc_type = ?
              AND doc_date = ?
              AND doc_number = ?
              AND amount = ?
            """,
            (
                contr,
                str(doc_type),
                str(doc_date),
                str(number),
                amount,
            ),
        )

        document = cursor.fetchone()

        if document:
            cursor.execute(
                """
                UPDATE documents_sbis
                SET state = ?,
                    responsible = COALESCE(?, responsible),
                    description = COALESCE(?, description),
                    updated_at = ?
                WHERE id = ?
                """,
                (str(state), responsible, description, now, document[0]),
            )
            updated += 1
        else:
            row_order = max_order + idx + 1
            cursor.execute(
                """
                INSERT INTO documents_sbis (
                    raw_text,
                    doc_date,
                    doc_number,
                    contractor,
                    doc_type,
                    amount,
                    description,
                    state,
                    responsible,
                    created_at,
                    updated_at,
                    row_order
                )
                VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
                """,
                (
                    None,
                    str(doc_date),
                    str(number),
                    contr,
                    str(doc_type),
                    amount,
                    description,
                    str(state),
                    responsible,
                    now,
                    now,
                    row_order,
                ),
            )
            imported += 1

    conn.commit()
    return imported, updated, skipped