import { useState } from 'react'

export type TimeRange = '15m' | '1h' | '6h' | '24h'

const RANGE_MS: Record<TimeRange, number> = {
  '15m': 15 * 60_000,
  '1h': 60 * 60_000,
  '6h': 6 * 60 * 60_000,
  '24h': 24 * 60 * 60_000,
}

/** Roughly 40-60 bars per chart, which is where recharts stays readable. */
const RANGE_BUCKETS: Record<TimeRange, number> = {
  '15m': 30,
  '1h': 60,
  '6h': 72,
  '24h': 96,
}

export const TIME_RANGES: TimeRange[] = ['15m', '1h', '6h', '24h']

export interface TimeRangeState {
  range: TimeRange
  setRange: (range: TimeRange) => void
  rangeMs: number
  buckets: number
  /** ISO timestamp for the `since` query parameter. */
  since: () => string
}

export function useTimeRange(defaultRange: TimeRange = '1h'): TimeRangeState {
  const [range, setRange] = useState<TimeRange>(defaultRange)

  const rangeMs = RANGE_MS[range]
  const buckets = RANGE_BUCKETS[range]

  return {
    range,
    setRange,
    rangeMs,
    buckets,
    since: () => new Date(Date.now() - rangeMs).toISOString(),
  }
}