/**
 * @module tests/integration/level-field-shadow
 * @description The reserved-name shadow fix (VENUE-BRAINY-ORDERBY-NOOP,
 * 2026-08-03): `level` is HNSW plumbing, not an entity field — it must never
 * shadow user metadata of the same name. Pre-fix, STANDARD_ENTITY_FIELDS
 * listed `level`, so every by-name read returned the engine's internal 0
 * (all-equal → stable sort → insertion order, silently), and the indexing
 * views stamped level:0 into the same flattened column as user values
 * (multi-valued [0, real] poison). Laws:
 * (1) venue's exact repro sorts: three adds with metadata.level 3/9/6 →
 *     find({orderBy:'level'}) returns 9,6,3 desc and 3,6,9 asc;
 * (2) where {level: N} matches through filter AND egress guard;
 * (3) the index column carries the user value only (no 0 poison);
 * (4) update() keeps `level` readable (the update indexing view is clean too);
 * (5) the transact() update path never rewrites the noun record on a
 *     metadata-only patch (the planUpdate granularity completion).
 */
import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
import { Brainy } from '../../src/brainy.js'
import { NounType } from '../../src/types/graphTypes.js'
import { EXPECTED_INDEX_EPOCH } from '../../src/storage/brainFormat.js'

const stubEmbedding = async (text: string): Promise<number[]> => {
  const hash = text.split('').reduce((acc, char) => acc + char.charCodeAt(0), 0)
  return new Array(384).fill(0).map((_, i) => Math.sin(hash + i))
}

describe('level field shadow — user metadata named level is a real field', () => {
  let brain: Brainy

  beforeEach(async () => {
    brain = new Brainy({
      requireSubtype: false,
      storage: { type: 'memory' as const },
      embeddingFunction: stubEmbedding
    })
    await brain.init()
  })

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

  async function addProbeRows(): Promise<string[]> {
    const ids: string[] = []
    for (const level of [3, 9, 6]) {
      ids.push(
        await brain.add({
          data: `probe character level ${level}`,
          type: NounType.Person,
          subtype: 'probe-char',
          metadata: { name: `char-${level}`, level }
        })
      )
    }
    return ids
  }

  it("venue's exact repro: orderBy 'level' sorts desc and asc", async () => {
    await addProbeRows()

    const desc = await brain.find({
      type: NounType.Person,
      subtype: 'probe-char',
      orderBy: 'level',
      order: 'desc',
      limit: 100
    })
    expect(desc.map((r: any) => r.metadata?.level)).toEqual([9, 6, 3])

    const asc = await brain.find({
      type: NounType.Person,
      subtype: 'probe-char',
      orderBy: 'level',
      order: 'asc',
      limit: 100
    })
    expect(asc.map((r: any) => r.metadata?.level)).toEqual([3, 6, 9])
  })

  it('ordered reads are COMPLETE — no row dropped (the 2-of-3 face)', async () => {
    const ids = await addProbeRows()
    const desc = await brain.find({
      type: NounType.Person,
      subtype: 'probe-char',
      orderBy: 'level',
      order: 'desc',
      limit: 100
    })
    expect(desc).toHaveLength(3)
    expect(new Set(desc.map((r: any) => r.id))).toEqual(new Set(ids))
  })

  it('where {level: N} matches through the filter and the egress guard', async () => {
    const ids = await addProbeRows()
    const hit = await brain.find({ where: { level: 9 } })
    expect(hit).toHaveLength(1)
    expect(hit[0].id).toBe(ids[1])
    expect(hit[0].metadata?.level).toBe(9)
  })

  it('the index column carries ONLY the user value (no 0 poison)', async () => {
    const ids = await addProbeRows()
    const metadataIndex = (brain as any).metadataIndex
    const value = await metadataIndex.getFieldValueForEntity(ids[1], 'level')
    expect(value).toBe(9)

    // Zero must not match anything — pre-fix every entity carried a phantom 0.
    const phantom = await brain.find({ where: { level: 0 } })
    expect(phantom).toHaveLength(0)
  })

  it('update() keeps level readable (the update indexing view is clean)', async () => {
    const ids = await addProbeRows()
    await brain.update({ id: ids[0], metadata: { level: 12 } })
    const desc = await brain.find({
      type: NounType.Person,
      subtype: 'probe-char',
      orderBy: 'level',
      order: 'desc',
      limit: 100
    })
    expect(desc.map((r: any) => r.metadata?.level)).toEqual([12, 9, 6])
  })

  it('transact() metadata-only update never rewrites the noun record', async () => {
    const ids = await addProbeRows()
    const storage = (brain as any).storage
    const saveNounSpy = vi.spyOn(storage, 'saveNoun')

    await brain.transact([
      { op: 'update', id: ids[0], metadata: { level: 4 } },
      { op: 'update', id: ids[2], metadata: { level: 7 } }
    ])

    expect(saveNounSpy).not.toHaveBeenCalled()
    saveNounSpy.mockRestore()

    const after = await brain.get(ids[0], { includeVectors: true })
    expect(after?.metadata?.level).toBe(4)
    expect(Array.isArray(after?.vector) && after!.vector!.length).toBe(384)
  })

  it('this build runs index epoch 2 (the paired level-indexability rebuild)', () => {
    expect(EXPECTED_INDEX_EPOCH).toBe(2)
  })
})