"""
KRX Open API client wrapper.

Uses pykrx-openapi library to access KRX official REST API.
Activated when KRX_OPENAPI_KEY environment variable is set.
"""
import os
import logging
from datetime import datetime

import pandas as pd
from pykrx_openapi import KRXOpenAPI

logger = logging.getLogger(__name__)


class KRXClient:
    """Thin wrapper around pykrx-openapi with project defaults."""

    def __init__(self, api_key: str | None = None):
        key = api_key or os.getenv("KRX_OPENAPI_KEY")
        if not key:
            raise ValueError("KRX_OPENAPI_KEY is required for KRXClient")
        self.client = KRXOpenAPI(api_key=key)

    def _to_date_str(self, date_input: str) -> str:
        """Ensure date string is in YYYYMMDD format."""
        return date_input.replace("-", "")

    def _records_to_df(self, result: dict) -> pd.DataFrame:
        """Convert API response dict to DataFrame."""
        records = result.get("OutBlock_1", [])
        if not records:
            return pd.DataFrame()
        return pd.DataFrame(records)

    def get_etf_daily(self, bas_dd: str) -> pd.DataFrame:
        """Fetch all ETF daily trade data for a given date."""
        bas_dd = self._to_date_str(bas_dd)
        result = self.client.get_etf_daily_trade(bas_dd=bas_dd)
        return self._records_to_df(result)

    def get_stock_daily(self, bas_dd: str, market: str = "KOSPI") -> pd.DataFrame:
        """Fetch stock daily trade data for a given date and market."""
        bas_dd = self._to_date_str(bas_dd)
        if market == "KOSDAQ":
            result = self.client.get_kosdaq_stock_daily_trade(bas_dd=bas_dd)
        else:
            result = self.client.get_stock_daily_trade(bas_dd=bas_dd)
        return self._records_to_df(result)

    def get_stock_base_info(self, bas_dd: str, market: str = "KOSPI") -> pd.DataFrame:
        """Fetch stock base info for a given date and market."""
        bas_dd = self._to_date_str(bas_dd)
        if market == "KOSDAQ":
            result = self.client.get_kosdaq_stock_base_info(bas_dd=bas_dd)
        else:
            result = self.client.get_stock_base_info(bas_dd=bas_dd)
        return self._records_to_df(result)


def get_krx_client() -> KRXClient | None:
    """Return KRXClient if KRX_OPENAPI_KEY is set, else None."""
    key = os.getenv("KRX_OPENAPI_KEY")
    if key:
        return KRXClient(api_key=key)
    return None