import { describe, expect, it } from 'vitest'
import {
  backgroundSyncReducer,
  initialBackgroundSyncState,
  planSync,
} from '../src/lib/sync'

describe('background-sync decision', () => {
  it('syncs a fresh foregrounded state', () => {
    expect(planSync(initialBackgroundSyncState, 1_000)).toBe(true)
  })

  it('does not sync again while a sync is already in flight', () => {
    const syncing = backgroundSyncReducer(initialBackgroundSyncState, { type: 'syncStarted', at: 1_000 })
    expect(planSync(syncing, 1_100)).toBe(false)
  })

  it('respects the interval gate after a recent attempt, but a forced pull bypasses it', () => {
    let s = backgroundSyncReducer(initialBackgroundSyncState, { type: 'syncStarted', at: 1_000 })
    s = backgroundSyncReducer(s, { type: 'syncSucceeded', at: 1_050 })
    // 1 minute later — inside the 5-minute interval → no auto sync…
    expect(planSync(s, 1_050 + 60_000)).toBe(false)
    // …but a manual pull forces it.
    expect(planSync(s, 1_050 + 60_000, true)).toBe(true)
    // 5+ minutes later the interval gate opens.
    expect(planSync(s, 1_050 + 6 * 60_000)).toBe(true)
  })

  it('does not auto-sync while backgrounded, but a forced sync still runs', () => {
    const bg = backgroundSyncReducer(initialBackgroundSyncState, { type: 'background' })
    expect(planSync(bg, 10_000)).toBe(false)
    expect(planSync(bg, 10_000, true)).toBe(true)
  })
})