import { type IndicatorData } from "../../types";
import { calculateSMA, calculateEMA, calculateRSI, calculateMACD, calculateBollingerBands, calculateATR, calculateVolumeAvg } from "../../utils/indicators";
import alpacaService from "../../lib/alpacaClient";

async function fetchBarsOnce(symbol: string): Promise<{ prices: number[]; volumes: number[]; highs: number[]; lows: number[] }> {
  const bars = await alpacaService.fetchBars(symbol, "1Day", { limit: 60 });
  const prices: number[] = [];
  const volumes: number[] = [];
  const highs: number[] = [];
  const lows: number[] = [];

  for (const b of bars) {
    const c = b.ClosePrice ?? b.c ?? 0;
    const v = b.Volume ?? b.v ?? 0;
    const h = b.HighPrice ?? b.h ?? 0;
    const l = b.LowPrice ?? b.l ?? 0;
    if (typeof c === "number" && c > 0) prices.push(c);
    if (typeof v === "number" && v > 0) volumes.push(v);
    if (typeof h === "number" && h > 0) highs.push(h);
    if (typeof l === "number" && l > 0) lows.push(l);
  }

  return { prices, volumes, highs, lows };
}

export async function loader({ request }: { request: Request }) {
  const url = new URL(request.url);
  const symbol = url.searchParams.get("symbol");

  if (!symbol) {
    return Response.json({ error: "Symbol is required" }, { status: 400 });
  }

  try {
    const { prices, volumes, highs, lows } = await fetchBarsOnce(symbol.toUpperCase());
    if (prices.length < 26) {
      return Response.json({ error: "Insufficient price data" }, { status: 404 });
    }

    const sma20 = calculateSMA(prices, 20);
    const sma50 = prices.length >= 50 ? calculateSMA(prices, 50) : 0;
    const ema12 = calculateEMA(prices, 12);
    const ema26 = calculateEMA(prices, 26);
    const rsi14 = calculateRSI(prices, 14);
    const macd = calculateMACD(prices);
    const bb = calculateBollingerBands(prices, 20);
    const atr = highs.length > 0 && lows.length > 0 ? calculateATR(highs, lows, prices, 14) : 0;
    const avgVol = volumes.length > 0 ? calculateVolumeAvg(volumes, 20) : 0;

    const data: IndicatorData = {
      symbol: symbol.toUpperCase(),
      indicators: {
        sma: sma20,
        sma50,
        ema12,
        ema26,
        rsi: rsi14,
        macd: macd.histogram,
        bbUpper: bb.upper,
        bbLower: bb.lower,
        bbMiddle: bb.middle,
        atr,
        avgVolume: avgVol,
      },
    };
    return Response.json(data);
  } catch (error) {
    console.error("Indicators error:", error);
    return Response.json({ error: "Failed to fetch indicators" }, { status: 500 });
  }
}