import time
import logging
from typing import Dict, List, Optional

import requests
import numpy as np
import pandas as pd

from config import (
    OKX_BASE_URL,
    TIMEFRAME,
    CANDLE_LIMIT,
    REQUEST_DELAY,
    REQUEST_RETRIES,
    REQUEST_TIMEOUT,
)

logger = logging.getLogger(__name__)


def _parse_candle(bar: list) -> dict:
    return {
        "timestamp": pd.to_datetime(int(bar[0]), unit="ms", utc=True),
        "open": float(bar[1]),
        "high": float(bar[2]),
        "low": float(bar[3]),
        "close": float(bar[4]),
        "volume": float(bar[5]),
        "quote_volume": float(bar[6]) if len(bar) > 6 else np.nan,
    }


def fetch_ohlcv(
    symbol: str,
    timeframe: str = TIMEFRAME,
    limit: int = CANDLE_LIMIT,
) -> Optional[pd.DataFrame]:
    url = f"{OKX_BASE_URL}/api/v5/market/candles"
    params = {"instId": symbol, "bar": timeframe, "limit": str(limit)}

    for attempt in range(REQUEST_RETRIES):
        try:
            resp = requests.get(url, params=params, timeout=REQUEST_TIMEOUT)
            resp.raise_for_status()
            payload = resp.json()

            if payload.get("code") != "0":
                logger.warning(f"{symbol}: API error — {payload.get('msg', 'unknown')}")
                return None

            raw = payload.get("data")
            if not raw:
                logger.warning(f"{symbol}: empty data returned")
                return None

            records = [_parse_candle(bar) for bar in reversed(raw)]
            df = pd.DataFrame(records).set_index("timestamp").sort_index()
            time.sleep(REQUEST_DELAY)
            return df

        except requests.exceptions.Timeout:
            logger.warning(f"{symbol}: timeout on attempt {attempt + 1}")
        except requests.exceptions.RequestException as exc:
            logger.warning(f"{symbol}: request error on attempt {attempt + 1}: {exc}")

        time.sleep(REQUEST_DELAY * (attempt + 2))

    logger.error(f"{symbol}: all {REQUEST_RETRIES} fetch attempts failed")
    return None


def fetch_instruments(inst_type: str = "SPOT") -> List[str]:
    url = f"{OKX_BASE_URL}/api/v5/public/instruments"
    params = {"instType": inst_type}
    try:
        resp = requests.get(url, params=params, timeout=REQUEST_TIMEOUT)
        resp.raise_for_status()
        payload = resp.json()
        if payload.get("code") != "0":
            return []
        return [
            item["instId"]
            for item in payload.get("data", [])
            if item.get("quoteCcy") == "USDT" and item.get("state") == "live"
        ]
    except requests.exceptions.RequestException as exc:
        logger.error(f"Failed to fetch instruments: {exc}")
        return []


def fetch_multiple(
    symbols: List[str],
    timeframe: str = TIMEFRAME,
    limit: int = CANDLE_LIMIT,
    min_bars: int = 50,
    progress_callback=None,
) -> Dict[str, pd.DataFrame]:
    results: Dict[str, pd.DataFrame] = {}
    total = len(symbols)

    for i, sym in enumerate(symbols, 1):
        if progress_callback:
            progress_callback(i, total, sym)
        else:
            logger.info(f"Fetching {sym} ({i}/{total})")

        df = fetch_ohlcv(sym, timeframe=timeframe, limit=limit)
        if df is not None and len(df) >= min_bars:
            results[sym] = df
        else:
            logger.warning(f"{sym}: skipped (insufficient data)")

    return results