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_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"]),
        "doc_type": _find_column(df, ["Вид документа", "Тип документа"]),
        "doc_date": _find_column(df, ["Дата", "Дата документа"]),
        "doc_number": _find_column(df, ["Номер", "Номер документа"]),
        "amount": _find_column(df, ["Сумма"]),
        "state": _find_column(df, ["Состояние ЭДО", "Состояние", "Статус"]),
    }

    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)}"
        )

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

    for _, row in df.iterrows():
        contr = str(row[required["contractor"]]).strip()

        if contr not in contractors:
            skipped += 1
            continue

        contractor_id = contractors[contr]
        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

        cursor.execute(
            """
            SELECT id
            FROM documents_1c
            WHERE contractor_id = ?
              AND doc_type = ?
              AND doc_date = ?
              AND doc_number = ?
              AND amount = ?
            """,
            (
                contractor_id,
                str(doc_type),
                str(doc_date),
                str(number),
                amount,
            ),
        )

        document = cursor.fetchone()

        if document:
            cursor.execute(
                """
                UPDATE documents_1c
                SET state = ?, updated_at = ?
                WHERE id = ?
                """,
                (str(state), now, document[0]),
            )
            updated += 1
        else:
            cursor.execute(
                """
                INSERT INTO documents_1c (
                    contractor_id,
                    doc_type,
                    doc_date,
                    doc_number,
                    amount,
                    state,
                    comment,
                    created_at,
                    updated_at
                )
                VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
                """,
                (
                    contractor_id,
                    str(doc_type),
                    str(doc_date),
                    str(number),
                    amount,
                    str(state),
                    "",
                    now,
                    now,
                ),
            )
            imported += 1

    conn.commit()
    return imported, updated, skipped