from __future__ import annotations

import httpx

from app.market.base import MarketData
from app.schemas import Candle

BASE_URL = "https://api.kraken.com"

# Kraken intervals are in minutes; map our timeframe strings to them.
INTERVALS: dict[str, int] = {
    "1m": 1,
    "5m": 5,
    "15m": 15,
    "30m": 30,
    "1h": 60,
    "4h": 240,
    "1d": 1440,
    "1w": 10080,
}


class KrakenMarketData(MarketData):
    """Public Kraken spot market data over REST (no API key required)."""

    def __init__(self, base_url: str = BASE_URL, timeout: float = 10.0) -> None:
        self._client = httpx.AsyncClient(base_url=base_url, timeout=timeout)

    @staticmethod
    def _interval(timeframe: str) -> int:
        try:
            return INTERVALS[timeframe]
        except KeyError:
            raise ValueError(
                f"unsupported timeframe '{timeframe}' for Kraken; use one of {sorted(INTERVALS)}"
            ) from None

    @staticmethod
    def _result(payload: dict) -> dict:
        errors = payload.get("error") or []
        if errors:
            raise ValueError(f"kraken error: {errors}")
        return payload.get("result", {})

    async def fetch_candles(self, symbol: str, timeframe: str, limit: int) -> list[Candle]:
        response = await self._client.get(
            "/0/public/OHLC",
            params={"pair": symbol, "interval": self._interval(timeframe)},
        )
        response.raise_for_status()
        result = self._result(response.json())
        rows = next((value for key, value in result.items() if key != "last"), [])
        candles = [
            Candle(
                ts=int(row[0]) * 1000,
                open=float(row[1]),
                high=float(row[2]),
                low=float(row[3]),
                close=float(row[4]),
                volume=float(row[6]),
            )
            for row in rows
        ]
        return candles[-limit:]

    async def fetch_price(self, symbol: str) -> float:
        response = await self._client.get("/0/public/Ticker", params={"pair": symbol})
        response.raise_for_status()
        result = self._result(response.json())
        ticker = next(iter(result.values()))
        return float(ticker["c"][0])

    async def close(self) -> None:
        await self._client.aclose()