import { expect, test } from "vitest"

import { Cron } from "#Source/cron/index.ts"

const internalCreateFutureMinute = (minutesAhead: number): Date => {
  const date = new Date(Date.now() + minutesAhead * 60_000)
  date.setSeconds(0, 0)
  return date
}

const internalCreatePastMinute = (minutesAgo: number): Date => {
  const date = new Date(Date.now() - minutesAgo * 60_000)
  date.setSeconds(0, 0)
  return date
}

test("Cron creates schedule models from both cron expressions and one-shot dates", () => {
  const expressionCron = new Cron({ pattern: "*/5 * * * *" })
  const singleShotCron = new Cron({ pattern: internalCreateFutureMinute(5) })

  expect(expressionCron).toBeInstanceOf(Cron)
  expect(singleShotCron).toBeInstanceOf(Cron)
})

test("Cron.prevRun returns undefined before a one-shot schedule is reached", () => {
  const scheduledAt = internalCreateFutureMinute(5)
  const cron = new Cron({ pattern: scheduledAt })

  expect(cron.prevRun()).toBeUndefined()
})

test("Cron.prevRuns returns historical one-shot runs that have already happened", () => {
  const scheduledAt = internalCreatePastMinute(5)
  const cron = new Cron({ pattern: scheduledAt })
  const previousRuns = cron.prevRuns(2)

  expect(previousRuns).toHaveLength(1)
  expect(previousRuns[0]?.getTime()).toBe(scheduledAt.getTime())
})

test("Cron.currentRun stays undefined when the model is only queried and not executing a task", () => {
  const cron = new Cron({ pattern: internalCreateFutureMinute(5) })

  expect(cron.currentRun()).toBeUndefined()
})

test("Cron.nextRun returns the next upcoming one-shot run", () => {
  const scheduledAt = internalCreateFutureMinute(5)
  const cron = new Cron({ pattern: scheduledAt })

  expect(cron.nextRun()?.getTime()).toBe(scheduledAt.getTime())
})

test("Cron.nextRuns returns upcoming expression runs in ascending order", () => {
  const cron = new Cron({ pattern: "*/5 * * * *" })
  const nextRuns = cron.nextRuns(2)

  expect(nextRuns).toHaveLength(2)
  expect(nextRuns[0]?.getTime()).toBeLessThan(nextRuns[1]?.getTime() ?? 0)
  expect(cron.match(nextRuns[0]!)).toBe(true)
  expect(cron.match(nextRuns[1]!)).toBe(true)
})

test("Cron.match reflects cron-expression semantics including domAndDow behavior", () => {
  const yearlyCron = new Cron({ pattern: "0 0 1 1 *" })
  const andCron = new Cron({ pattern: "0 0 1 * MON", domAndDow: true })
  const orCron = new Cron({ pattern: "0 0 1 * MON", domAndDow: false })
  const yearlyHit = new Date(2_026, 0, 1, 0, 0, 0, 0)
  const yearlyMiss = new Date(2_026, 0, 1, 0, 1, 0, 0)
  const mondayFirst = new Date(2_026, 5, 1, 0, 0, 0, 0)
  const mondayNotFirst = new Date(2_026, 5, 8, 0, 0, 0, 0)
  const firstNotMonday = new Date(2_026, 8, 1, 0, 0, 0, 0)

  expect(yearlyCron.match(yearlyHit)).toBe(true)
  expect(yearlyCron.match(yearlyMiss)).toBe(false)

  expect(andCron.match(mondayFirst)).toBe(true)
  expect(andCron.match(mondayNotFirst)).toBe(false)
  expect(andCron.match(firstNotMonday)).toBe(false)

  expect(orCron.match(mondayFirst)).toBe(true)
  expect(orCron.match(mondayNotFirst)).toBe(true)
  expect(orCron.match(firstNotMonday)).toBe(true)
})