// Labels for the chart's times. Intraday times are New York wall-clock seconds read as UTC (see plan.ts),
// so formatting them in UTC shows New York time, daylight saving included. Dates are YYYY-MM-DD.

const MONTHS = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']

type AnyTime = number | string | { year: number; month: number; day: number }

function parts(time: AnyTime) {
  if (typeof time === 'number') {
    const d = new Date(time * 1000)
    return { y: d.getUTCFullYear(), m: d.getUTCMonth(), d: d.getUTCDate(), hh: d.getUTCHours(), mm: d.getUTCMinutes(), hasTime: true }
  }
  if (typeof time === 'string') {
    const [y, m, d] = time.split('-').map(Number)
    return { y, m: m - 1, d, hh: 0, mm: 0, hasTime: false }
  }
  return { y: time.year, m: time.month - 1, d: time.day, hh: 0, mm: 0, hasTime: false }
}

const pad = (n: number) => String(n).padStart(2, '0')

/** The crosshair's label: "Wed Oct 15 '26 09:30 ET" intraday, "Oct 15 '26" for a day. */
export function crosshairLabel(time: unknown): string {
  const p = parts(time as AnyTime)
  const date = `${MONTHS[p.m]} ${p.d} '${String(p.y).slice(2)}`
  if (!p.hasTime) return date
  const weekday = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'][new Date(Date.UTC(p.y, p.m, p.d)).getUTCDay()]
  return `${weekday} ${date} ${pad(p.hh)}:${pad(p.mm)} ET`
}

/** A tick on the time axis. markType is lightweight-charts' TickMarkType: 0 year, 1 month, 2 day, 3 and 4 time. */
export function tickLabel(time: unknown, markType: number): string {
  const p = parts(time as AnyTime)
  if (markType === 0) return String(p.y)
  if (markType === 1) return MONTHS[p.m]
  if (markType === 2 || !p.hasTime) return `${MONTHS[p.m]} ${p.d}`
  return `${pad(p.hh)}:${pad(p.mm)}`
}