import { computeSummary, toOcc, type ChainMeta, type ChainRow } from './math.ts'

export function filterStrikesNearSpot<T extends { strike: number }>(
  rows: T[],
  spot: number | null,
  maxStrikes: number,
): T[] {
  const sorted = [...rows].sort((a, b) => a.strike - b.strike)
  if (!maxStrikes || maxStrikes <= 0 || sorted.length <= maxStrikes) return sorted
  const ref = spot ?? sorted[Math.floor(sorted.length / 2)]!.strike
  return [...sorted]
    .sort((a, b) => Math.abs(a.strike - ref) - Math.abs(b.strike - ref) || a.strike - b.strike)
    .slice(0, maxStrikes)
    .sort((a, b) => a.strike - b.strike)
}

export function buildAlpacaChain(
  symbol: string,
  alpacaFeed: 'indicative' | 'opra',
  optRows: Record<string, unknown>[],
  snapRow: Record<string, unknown> | undefined,
  requestedExp: string | null | undefined,
  maxStrikes: number,
  allExpirations?: string[],
): { rows: ChainRow[]; meta: ChainMeta } {
  const sym = symbol.toUpperCase()
  const spot =
    typeof snapRow?.last === 'number'
      ? snapRow.last
      : typeof snapRow?.price === 'number'
        ? snapRow.price
        : typeof snapRow?.prev_close === 'number'
          ? snapRow.prev_close
          : typeof snapRow?.prevClose === 'number'
            ? snapRow.prevClose
            : null
  const change = typeof snapRow?.change === 'number' ? snapRow.change : null
  const changePct =
    typeof snapRow?.change_pct === 'number'
      ? snapRow.change_pct
      : typeof snapRow?.changePct === 'number'
        ? snapRow.changePct
        : null
  const dayHigh =
    typeof snapRow?.day_high === 'number'
      ? snapRow.day_high
      : typeof snapRow?.dayHigh === 'number'
        ? snapRow.dayHigh
        : null
  const dayLow =
    typeof snapRow?.day_low === 'number'
      ? snapRow.day_low
      : typeof snapRow?.dayLow === 'number'
        ? snapRow.dayLow
        : null
  const dayRange = dayLow != null && dayHigh != null ? `${dayLow.toFixed(2)}-${dayHigh.toFixed(2)}` : null
  const volume =
    typeof snapRow?.day_volume === 'number'
      ? snapRow.day_volume
      : typeof snapRow?.dayVolume === 'number'
        ? snapRow.dayVolume
        : null

  let sessionDate: string | null =
    typeof snapRow?.day_time === 'string'
      ? snapRow.day_time.slice(0, 10)
      : typeof snapRow?.last_time === 'string'
        ? snapRow.last_time.slice(0, 10)
        : null

  const expSet = new Set<string>(allExpirations ?? [])
  for (const r of optRows) {
    const e = typeof r.expiration === 'string' ? r.expiration : null
    if (e) expSet.add(e)
    const qt = typeof r.quote_time === 'string' ? r.quote_time.slice(0, 10) : null
    if (qt && (!sessionDate || qt > sessionDate)) sessionDate = qt
  }
  const expirations = [...expSet].sort()
  const selectedExpiration =
    (requestedExp && expSet.has(requestedExp) ? requestedExp : expirations[0]) ?? requestedExp ?? null

  const byStrike = new Map<number, ChainRow>()
  for (const r of optRows) {
    const exp = typeof r.expiration === 'string' ? r.expiration : null
    if (selectedExpiration && exp !== selectedExpiration) continue
    const strike = typeof r.strike === 'number' ? r.strike : Number(r.strike)
    if (!Number.isFinite(strike)) continue
    const type = r.type === 'put' ? 'put' : 'call'
    const expStr = exp ?? selectedExpiration ?? ''
    let row = byStrike.get(strike)
    if (!row) {
      const cc = toOcc(sym, expStr, 'C', strike)
      const pc = toOcc(sym, expStr, 'P', strike)
      row = {
        contract: `${cc} / ${pc}`,
        callContract: cc,
        putContract: pc,
        expiration: expStr,
        strike,
        callBid: null,
        callBidSize: null,
        callAsk: null,
        callAskSize: null,
        callLast: null,
        callLastTime: null,
        callChg: null,
        callVol: null,
        callOi: null,
        callIv: null,
        callDelta: null,
        callItm: spot != null ? strike < spot : false,
        putBid: null,
        putBidSize: null,
        putAsk: null,
        putAskSize: null,
        putLast: null,
        putLastTime: null,
        putChg: null,
        putVol: null,
        putOi: null,
        putIv: null,
        putDelta: null,
        putItm: spot != null ? strike > spot : false,
      }
      byStrike.set(strike, row)
    }
    const rawIv =
      typeof r.iv === 'number' ? (r.iv <= 5 ? Number((r.iv * 100).toFixed(2)) : Number(r.iv.toFixed(2))) : null
    const lastTime = typeof r.last_time === 'string' ? r.last_time : null
    const isCurrentSessionTrade =
      !sessionDate || (lastTime != null && lastTime.slice(0, 10) >= sessionDate)
    const rawLast =
      typeof r.last === 'number' ? r.last : typeof r.lastPrice === 'number' ? r.lastPrice : null
    const rawVol =
      typeof r.day_volume === 'number' ? r.day_volume : typeof r.volume === 'number' ? r.volume : null
    const rawOi =
      typeof r.open_interest === 'number' ? r.open_interest : typeof r.openInterest === 'number' ? r.openInterest : null
    const lastPx = isCurrentSessionTrade ? rawLast : null
    const volNum = isCurrentSessionTrade ? rawVol : null
    const bidSz = typeof r.bid_size === 'number' ? r.bid_size : typeof r.bidSize === 'number' ? r.bidSize : null
    const askSz = typeof r.ask_size === 'number' ? r.ask_size : typeof r.askSize === 'number' ? r.askSize : null

    if (type === 'call') {
      if (typeof r.symbol === 'string') row.callContract = r.symbol
      row.callBid = typeof r.bid === 'number' ? r.bid : null
      row.callBidSize = bidSz
      row.callAsk = typeof r.ask === 'number' ? r.ask : null
      row.callAskSize = askSz
      row.callLast = lastPx
      row.callLastTime = lastTime
      row.callVol = volNum
      row.callOi = rawOi
      row.callIv = rawIv
      row.callDelta = typeof r.delta === 'number' ? Number(r.delta.toFixed(3)) : null
    } else {
      if (typeof r.symbol === 'string') row.putContract = r.symbol
      row.putBid = typeof r.bid === 'number' ? r.bid : null
      row.putBidSize = bidSz
      row.putAsk = typeof r.ask === 'number' ? r.ask : null
      row.putAskSize = askSz
      row.putLast = lastPx
      row.putLastTime = lastTime
      row.putVol = volNum
      row.putOi = rawOi
      row.putIv = rawIv
      row.putDelta = typeof r.delta === 'number' ? Number(r.delta.toFixed(3)) : null
    }
    row.contract = `${row.callContract} / ${row.putContract}`
  }

  const filtered = filterStrikesNearSpot([...byStrike.values()], spot, maxStrikes)
  return computeSummary(filtered, {
    symbol: sym,
    provider: 'alpaca',
    feedLabel: `Alpaca (${alpacaFeed.toUpperCase()})`,
    spot,
    change,
    changePct,
    dayRange,
    volume,
    expirations,
    selectedExpiration,
  })
}