import { describe, it, expect } from 'vitest'
import { bucketIncidentsByMonth, topRootCauses } from '@/lib/dashboard/trends'

describe('bucketIncidentsByMonth', () => {
  const now = new Date('2026-07-15T12:00:00Z')

  it('returns one bucket per month, oldest first', () => {
    const buckets = bucketIncidentsByMonth([], 3, now)
    expect(buckets.map(b => b.month)).toEqual(['2026-05', '2026-06', '2026-07'])
  })

  it('counts leading and lagging types into the right month', () => {
    const buckets = bucketIncidentsByMonth(
      [
        { reported_at: '2026-07-01T08:00:00Z', incident_type: 'near_miss' },
        { reported_at: '2026-07-02T08:00:00Z', incident_type: 'hazard' },
        { reported_at: '2026-07-03T08:00:00Z', incident_type: 'injury' },
        { reported_at: '2026-06-03T08:00:00Z', incident_type: 'fire' },
      ],
      3,
      now,
    )
    const july = buckets.find(b => b.month === '2026-07')!
    expect(july).toMatchObject({ total: 3, leading: 2, lagging: 1 })
    expect(buckets.find(b => b.month === '2026-06')).toMatchObject({ total: 1, leading: 0, lagging: 0 })
  })

  it('ignores incidents outside the window', () => {
    const buckets = bucketIncidentsByMonth(
      [{ reported_at: '2025-01-01T08:00:00Z', incident_type: 'injury' }],
      3,
      now,
    )
    expect(buckets.every(b => b.total === 0)).toBe(true)
  })
})

describe('topRootCauses', () => {
  it('groups normalized duplicates and sorts by count', () => {
    const result = topRootCauses([
      { root_cause_summary: 'Inadequate forklift training.' },
      { root_cause_summary: 'inadequate  forklift training' },
      { root_cause_summary: 'Blocked walkway' },
      { root_cause_summary: null },
      { root_cause_summary: '' },
    ])
    expect(result).toHaveLength(2)
    expect(result[0]).toMatchObject({ count: 2 })
    expect(result[0].cause.toLowerCase()).toContain('forklift')
  })

  it('limits to top N', () => {
    const invs = ['a', 'b', 'c', 'd', 'e', 'f'].map(c => ({ root_cause_summary: c }))
    expect(topRootCauses(invs, 5)).toHaveLength(5)
  })
})