/**
 * @module tests/unit/brainy/find-orderby-pagek
 * @description CTX-BR-FIND-ORDERBY item (1) — `find({ where, orderBy, limit })` must
 * produce only the requested PAGE of sorted ids, not the full sorted match set. At
 * billion scale a broad filter + orderBy returning 20 rows previously materialized
 * every matching sorted id (O(matches) heap); the page bound (`offset+limit`) is now
 * threaded into `getSortedIdsForFilter` → the column store's top-K heap. Ordering
 * correctness is covered by orderby-sort-bug.test.ts; this locks the page bound.
 */

import { describe, it, expect, beforeEach, afterEach } from 'vitest'
import { Brainy } from '../../../src/index.js'
import { NounType } from '../../../src/types/graphTypes.js'
import { createTestConfig } from '../../helpers/test-factory.js'

describe('find({ where, orderBy }) bounds the sort to the page (CTX-BR-FIND-ORDERBY #1)', () => {
  let brain: Brainy
  const MATCHES = 50

  beforeEach(async () => {
    brain = new Brainy(createTestConfig())
    await brain.init()
    for (let i = 0; i < MATCHES; i++) {
      await brain.add({ type: NounType.Document, data: `doc ${i}`, metadata: { bucket: 'x', seq: i } })
    }
  })

  afterEach(async () => {
    await brain.close()
  })

  it('threads the page bound (offset+limit) into getSortedIdsForFilter, not the full match count', async () => {
    let capturedTopK: number | undefined
    const real = (brain as any).metadataIndex.getSortedIdsForFilter.bind((brain as any).metadataIndex)
    ;(brain as any).metadataIndex.getSortedIdsForFilter = async (
      f: any,
      ob: string,
      o: 'asc' | 'desc',
      topK?: number
    ) => {
      capturedTopK = topK
      return real(f, ob, o, topK)
    }

    const results = await brain.find({ where: { bucket: 'x' }, orderBy: 'createdAt', order: 'desc', limit: 5 })

    expect(results).toHaveLength(5)
    // Page-bounded: ~ limit (5) + a small hidden-tier over-fetch — NOT all 50 matches.
    expect(capturedTopK).toBeDefined()
    expect(capturedTopK!).toBeGreaterThanOrEqual(5)
    expect(capturedTopK!).toBeLessThan(MATCHES)
  })

  it('still returns the correct page with offset (sort + window unchanged)', async () => {
    // seq is a numeric metadata field; orderBy seq asc → 0,1,2,… ; page [10,15).
    const page = await brain.find({ where: { bucket: 'x' }, orderBy: 'seq', order: 'asc', limit: 5, offset: 10 })
    expect(page).toHaveLength(5)
    expect(page.map((r) => (r.metadata as { seq: number }).seq)).toEqual([10, 11, 12, 13, 14])
  })
})