from typing import Tuple
import time
import pandas as pd
import requests
from fastapi import HTTPException

from app.config import get_settings
from app.indicators import add_technical_indicators

settings = get_settings()

ALPHA_VANTAGE_URL = "https://www.alphavantage.co/query"

_CACHE: dict[str, dict] = {}
_CACHE_TTL = 60  # seconds (safe for AV free tier)


# -------------------------
# Helpers
# -------------------------
def is_crypto(ticker: str) -> bool:
    t = ticker.upper()
    return "-" in t or t in {"BTC", "ETH", "SOL", "BNB", "XRP", "DOGE"}


def _safe_get_json(params: dict) -> dict:
    try:
        resp = requests.get(ALPHA_VANTAGE_URL, params=params, timeout=10)
        return resp.json()
    except Exception:
        raise HTTPException(
            status_code=503,
            detail="Market data provider unavailable",
        )


def _detect_ohlcv_columns(df: pd.DataFrame) -> pd.DataFrame:
    """
    Robust OHLCV resolver for Alpha Vantage crypto.
    Works for:
    - 1a / 1b
    - USD / non-USD
    - future schema changes
    """
    def find(keywords):
        for c in df.columns:
            name = c.lower()
            if all(k in name for k in keywords):
                return c
        return None

    open_col  = find(["open"])
    high_col  = find(["high"])
    low_col   = find(["low"])
    close_col = find(["close"])
    volume_col = find(["volume"])

    if not all([open_col, high_col, low_col, close_col, volume_col]):
        raise HTTPException(
            status_code=500,
            detail=f"Unsupported crypto data format from Alpha Vantage: {list(df.columns)}",
        )

    df = df[[open_col, high_col, low_col, close_col, volume_col]]
    df.columns = ["Open", "High", "Low", "Close", "Volume"]
    return df


# -------------------------
# STOCK DATA
# -------------------------
def _fetch_stock_history(ticker: str) -> pd.DataFrame:
    params = {
        "function": "TIME_SERIES_DAILY",
        "symbol": ticker,
        "apikey": settings.alpha_vantage_api_key,
        "outputsize": "compact",  # FREE tier only
    }

    data = _safe_get_json(params)

    if "Time Series (Daily)" not in data:
        if "Note" in data or "Information" in data:
            raise HTTPException(429, "Alpha Vantage rate limit exceeded")
        raise HTTPException(400, "Invalid stock ticker symbol")

    df = pd.DataFrame.from_dict(
        data["Time Series (Daily)"], orient="index"
    )

    df.rename(
        columns={
            "1. open": "Open",
            "2. high": "High",
            "3. low": "Low",
            "4. close": "Close",
            "5. volume": "Volume",
        },
        inplace=True,
    )

    df = df[["Open", "High", "Low", "Close", "Volume"]]
    df = df.apply(pd.to_numeric, errors="coerce").dropna()

    df.index = pd.to_datetime(df.index)
    df.sort_index(inplace=True)

    if len(df) < settings.history_window + 50:
        raise HTTPException(400, "Not enough historical stock data")

    return df


# -------------------------
# CRYPTO DATA
# -------------------------
def _fetch_crypto_history(ticker: str) -> pd.DataFrame:
    if "-" in ticker:
        symbol, market = ticker.split("-", 1)
    else:
        symbol, market = ticker, "USD"

    params = {
        "function": "DIGITAL_CURRENCY_DAILY",
        "symbol": symbol.upper(),
        "market": market.upper(),
        "apikey": settings.alpha_vantage_api_key,
    }

    data = _safe_get_json(params)

    if "Time Series (Digital Currency Daily)" not in data:
        if "Note" in data or "Information" in data:
            raise HTTPException(429, "Alpha Vantage rate limit exceeded")
        raise HTTPException(400, "Invalid crypto ticker symbol")

    df = pd.DataFrame.from_dict(
        data["Time Series (Digital Currency Daily)"], orient="index"
    )

    df = _detect_ohlcv_columns(df)

    df = df.apply(pd.to_numeric, errors="coerce")
    df.dropna(subset=["Open", "High", "Low", "Close"], inplace=True)

    df.index = pd.to_datetime(df.index)
    df.sort_index(inplace=True)

    if len(df) < settings.history_window + 50:
        raise HTTPException(400, "Not enough historical crypto data")

    return df


# -------------------------
# Cached unified fetcher
# -------------------------
def fetch_raw_history(ticker: str) -> pd.DataFrame:
    key = ticker.upper()
    now = time.time()

    if key in _CACHE and now - _CACHE[key]["ts"] < _CACHE_TTL:
        return _CACHE[key]["df"]

    df = (
        _fetch_crypto_history(key)
        if is_crypto(key)
        else _fetch_stock_history(key)
    )

    _CACHE[key] = {"df": df, "ts": now}
    return df


# -------------------------
# Public API
# -------------------------
def get_enriched_history(ticker: str) -> Tuple[pd.DataFrame, pd.DataFrame]:
    df_raw = fetch_raw_history(ticker)
    df_tech = add_technical_indicators(df_raw)

    if len(df_tech) < settings.history_window:
        raise HTTPException(
            status_code=400,
            detail="Insufficient data after technical indicator calculation",
        )

    return df_raw, df_tech


def last_n_candles(df: pd.DataFrame, n: int) -> list[dict]:
    return [
        {
            "date": idx.strftime("%Y-%m-%d"),
            "price": float(row["Close"]),
        }
        for idx, row in df.tail(n).iterrows()
    ]