import { Decision } from "@effect/core/io/Schedule/Decision"
import { Interval } from "@effect/core/io/Schedule/Interval"
import { makeWithState } from "@effect/core/io/Schedule/operations/_internal/makeWithState"
import {
  beginningOfHour,
  endOfHour,
  nextHour
} from "@effect/core/io/Schedule/operations/_internal/time"

/**
 * Cron-like schedule that recurs every specified `hour` of each day. It
 * triggers at zero minute of the hour. Producing a count of repeats: 0, 1, 2.
 *
 * NOTE: `hour` parameter is validated lazily. Must be in range 0...23.
 *
 * @tsplus static effect/core/io/Schedule.Ops hourOfDay
 */
export function hourOfDay(
  hour: number
): Schedule<readonly [number, number], never, unknown, number> {
  return makeWithState(
    [Number.MIN_SAFE_INTEGER, 0] as readonly [number, number],
    (now, _, state) => {
      if (!Number.isInteger(hour) || hour < 0 || 23 < hour) {
        return Effect.dieSync(
          new IllegalArgumentException(
            `Invalid argument in: hourOfDay(${hour}). Must be in range 0...23`
          )
        )
      }
      const [end0, n] = state
      const now0 = Math.max(end0, now)
      const hour0 = nextHour(now0, hour)
      const start = Math.max(beginningOfHour(hour0), now0)
      const end = endOfHour(hour0)
      const interval = Interval(start, end)
      return Effect.succeed([[end, n + 1] as const, n, Decision.continueWith(interval)] as const)
    }
  )
}