import base64
import binascii
import json
import logging
import re
from functools import lru_cache
from pathlib import Path
from typing import Any

import gspread
from gspread.utils import InsertDataOption, ValueInputOption

from app import config

logger = logging.getLogger(__name__)

# Таймаут HTTP-запросов (сек): защита от зависания при проблемах с сетью/Google API
_SHEETS_HTTP_TIMEOUT = 30


def _load_service_account_info(raw: str) -> dict[str, Any]:
    """Разобрать ключ из переменной окружения: чистый JSON или его base64."""
    raw = raw.strip()
    if not raw.startswith("{"):
        try:
            raw = base64.b64decode(raw, validate=True).decode("utf-8")
        except (binascii.Error, UnicodeDecodeError) as e:
            raise ValueError(
                "GOOGLE_SERVICE_ACCOUNT_JSON: ожидается JSON ключа сервисного "
                "аккаунта или его base64"
            ) from e
    return json.loads(raw)


@lru_cache(maxsize=1)
def get_client() -> gspread.Client:
    """Клиент Google Sheets. Создаётся при первом обращении, не при импорте."""
    if config.GOOGLE_SERVICE_ACCOUNT_JSON:
        info = _load_service_account_info(config.GOOGLE_SERVICE_ACCOUNT_JSON)
        client = gspread.service_account_from_dict(info)
        logger.info("Google Sheets: ключ загружен из GOOGLE_SERVICE_ACCOUNT_JSON")
    else:
        key_path = Path(config.GOOGLE_SERVICE_ACCOUNT_FILE)
        if not key_path.is_file():
            raise FileNotFoundError(
                f"Ключ сервисного аккаунта Google не найден: {key_path}. "
                "Задайте GOOGLE_SERVICE_ACCOUNT_JSON или положите файл по пути "
                "GOOGLE_SERVICE_ACCOUNT_FILE"
            )
        client = gspread.service_account(filename=str(key_path))
        logger.info("Google Sheets: ключ загружен из файла %s", key_path)
    client.set_timeout(_SHEETS_HTTP_TIMEOUT)
    return client

# HTTP коды, при которых стоит сбросить кэш листа (устаревший объект)
_CACHE_INVALIDATE_CODES = frozenset({401, 403, 404, 429})


def parse_google_sheets_url(url: str) -> tuple[str, int | None]:
    spreadsheet_match = re.search(r"/d/([a-zA-Z0-9-_]+)", url)
    if not spreadsheet_match:
        raise ValueError("Invalid Google Sheets URL: Could not find spreadsheet ID")
    spreadsheet_id = spreadsheet_match.group(1)

    worksheet_match = re.search(r"[?&]gid=(\d+)", url)
    worksheet_id = int(worksheet_match.group(1)) if worksheet_match else None

    return spreadsheet_id, worksheet_id


@lru_cache
def get_sheet(sheet_link: str) -> gspread.Worksheet:
    spreadsheet_id, worksheet_id = parse_google_sheets_url(sheet_link)

    spreadsheet = get_client().open_by_key(spreadsheet_id)
    if worksheet_id is not None:
        return spreadsheet.get_worksheet_by_id(worksheet_id)
    return spreadsheet.sheet1


def add_rows_to_sheet(sheet_link: str, rows: list[list]) -> None:
    """Append rows to Google Sheet. Raises on failure so caller can retry."""
    sheet = get_sheet(sheet_link)
    try:
        sheet.append_rows(
            rows,
            value_input_option=ValueInputOption.user_entered,
            insert_data_option=InsertDataOption.insert_rows,
            table_range="A1",
        )
    except gspread.exceptions.APIError as e:
        http_code = getattr(e, "response", None)
        status_code = http_code.status_code if http_code else None
        error_detail = getattr(e, "error", {})
        error_msg = error_detail.get("message", str(e)) if isinstance(error_detail, dict) else str(e)
        logger.exception(
            "SHEETS_API_ERROR: type=APIError http_code=%s message=%r error=%s",
            status_code,
            error_msg,
            error_detail,
            extra={"sheet_link": sheet_link, "rows_count": len(rows)},
        )
        if status_code in _CACHE_INVALIDATE_CODES:
            get_sheet.cache_clear()
            logger.info("SHEETS_CACHE_CLEARED: сброшен кэш get_sheet после ошибки %s", status_code)
        raise
    except Exception as e:
        logger.exception(
            "SHEETS_ERROR: type=%s message=%s sheet_link=%s rows_count=%s",
            type(e).__name__,
            str(e),
            sheet_link,
            len(rows),
        )
        raise


def read_sheet(sheet_link: str) -> list[dict[str, Any]]:
    sheet = get_sheet(sheet_link)
    return sheet.get_all_records()