/**
 * @module tests/integration/health-gate
 * @description Pins for the health-by-accounting read gate: the read gate stops
 * consulting an unnamed `isReady()` boolean and reads a NAMED, sync, O(1)
 * {@link HealthReport}; no read path may ever start a store walk; the open path
 * brings every provider to serving before it returns; an explicit operator door
 * (`repairIndex({ rebuild: [...] })`) rebuilds a named leg unconditionally.
 *
 * Providers here are white-box test doubles: a `healthReport()` (or, for the
 * interim-path pins, an `isReady()`) function assigned directly onto the LIVE
 * JS provider object, the same pattern `tests/unit/validate-invariants-delegation.test.ts`
 * uses for `validateInvariants`. This exercises brainy's real gate/verify code
 * against a controlled provider self-report — no engine mocks.
 */
import { describe, it, expect, afterEach, vi } from 'vitest'
import { mkdtempSync, rmSync } from 'node:fs'
import { tmpdir } from 'node:os'
import { join } from 'node:path'
import {
  Brainy,
  NounType,
  VerbType,
  GraphIndexNotReadyError,
  MetadataIndexNotReadyError,
  VectorIndexNotReadyError
} from '../../src/index.js'
import type { HealthReport, LedgerInvariantResult } from '../../src/plugin.js'
import { prodLog } from '../../src/utils/logger.js'
import { createTestConfig } from '../helpers/test-factory.js'

/** The white-box surface these pins drive on a live brain instance. */
interface BrainInternals {
  storage: {
    getNoun(id: string): Promise<unknown>
    getNounMetadata(id: string): Promise<unknown>
    getNouns(options?: unknown): Promise<unknown>
    getVerbs(options?: unknown): Promise<unknown>
  }
  index: { healthReport?: () => HealthReport; isReady?: () => boolean; rebuild(): Promise<void> }
  metadataIndex: {
    healthReport?: () => HealthReport
    isReady?: () => boolean
    rebuild(): Promise<void>
    validateInvariants?: () => Promise<unknown>
  }
  graphIndex: {
    healthReport?: () => HealthReport
    isReady?: () => boolean
    rebuild(): Promise<void>
    validateInvariants?: () => Promise<unknown>
  }
  rebuildIndexesIfNeeded(force?: boolean): Promise<void>
}

function internalsOf(brain: Brainy): BrainInternals {
  return brain as unknown as BrainInternals
}

function invariant(overrides: Partial<LedgerInvariantResult> = {}): LedgerInvariantResult {
  return {
    name: 'manifest-residency',
    holds: true,
    detail: 'ok',
    heal: 'none',
    source: 'ledger',
    ...overrides
  }
}

function healthReport(overrides: Partial<HealthReport> = {}): HealthReport {
  return {
    provider: 'vector',
    healthy: true,
    serving: true,
    invariants: [],
    checkedAt: Date.now(),
    durationMs: 1,
    generation: 1,
    unledgered: [],
    ...overrides
  }
}

const brains: Brainy[] = []
const dirs: string[] = []
afterEach(async () => {
  for (const b of brains.splice(0)) await b.close().catch(() => {})
  for (const d of dirs.splice(0)) rmSync(d, { recursive: true, force: true })
  vi.restoreAllMocks()
})

describe('health gate (a) — not-serving refuses loudly, ZERO canonical reads during the refusal', () => {
  it('metadata not-serving: find() throws MetadataIndexNotReadyError naming the failing invariant', async () => {
    const brain = new Brainy(createTestConfig({ silent: true }))
    await brain.init()
    brains.push(brain)
    await brain.add({ data: 'row', type: NounType.Document, metadata: { team: 'atlas' } })
    await brain.flush()

    const internals = internalsOf(brain)
    internals.metadataIndex.healthReport = () =>
      healthReport({
        provider: 'metadata',
        serving: false,
        healthy: false,
        invariants: [invariant({ name: 'posted-count-floor', holds: false, heal: 'rebuild', detail: 'posted 2 < canonical 5' })]
      })

    const getNounSpy = vi.spyOn(internals.storage, 'getNoun')
    const getNounMetadataSpy = vi.spyOn(internals.storage, 'getNounMetadata')
    const getNounsSpy = vi.spyOn(internals.storage, 'getNouns')

    await expect(brain.find({ where: { team: 'atlas' } })).rejects.toBeInstanceOf(MetadataIndexNotReadyError)
    await expect(brain.find({ where: { team: 'atlas' } })).rejects.toThrow(/posted-count-floor/)

    expect(getNounSpy).not.toHaveBeenCalled()
    expect(getNounMetadataSpy).not.toHaveBeenCalled()
    expect(getNounsSpy).not.toHaveBeenCalled()

    delete internals.metadataIndex.healthReport
  })

  it('graph not-serving: related() throws GraphIndexNotReadyError naming the failing invariant, no canonical reads', async () => {
    const brain = new Brainy(createTestConfig({ silent: true }))
    await brain.init()
    brains.push(brain)
    const a = await brain.add({ data: 'a', type: NounType.Person })
    const b = await brain.add({ data: 'b', type: NounType.Person })
    await brain.relate({ from: a, to: b, type: VerbType.Knows })
    await brain.flush()

    const internals = internalsOf(brain)
    internals.graphIndex.healthReport = () =>
      healthReport({
        provider: 'graph',
        serving: false,
        healthy: false,
        invariants: [invariant({ name: 'adjacency-residency', holds: false, heal: 'rebuild', detail: 'edges not loaded' })]
      })

    const getNounSpy = vi.spyOn(internals.storage, 'getNoun')
    const getVerbsSpy = vi.spyOn(internals.storage, 'getVerbs')

    await expect(brain.related({ from: a })).rejects.toBeInstanceOf(GraphIndexNotReadyError)
    await expect(brain.related({ from: a })).rejects.toThrow(/adjacency-residency/)

    expect(getNounSpy).not.toHaveBeenCalled()
    expect(getVerbsSpy).not.toHaveBeenCalled()

    delete internals.graphIndex.healthReport
  })
})

describe('health gate (b) — unledgered is unknown: never blocks a serving provider', () => {
  it('serving:true with an unledgered family and no failing invariant serves normally; at most one narration', async () => {
    const brain = new Brainy(createTestConfig({ silent: true }))
    await brain.init()
    brains.push(brain)
    await brain.add({ data: 'row', type: NounType.Document, metadata: { team: 'atlas' } })
    await brain.flush()

    const internals = internalsOf(brain)
    internals.metadataIndex.healthReport = () =>
      healthReport({
        provider: 'metadata',
        serving: true,
        healthy: true,
        invariants: [],
        unledgered: ['canonical-verb-coverage']
      })

    const warnSpy = vi.spyOn(prodLog, 'warn')

    const r1 = await brain.find({ where: { team: 'atlas' } })
    const r2 = await brain.find({ where: { team: 'atlas' } })
    expect(r1.length).toBe(1)
    expect(r2.length).toBe(1)

    const narrations = warnSpy.mock.calls.filter(
      ([msg]) => typeof msg === 'string' && msg.includes('canonical-verb-coverage')
    )
    expect(narrations.length).toBe(1) // one narration at most across both reads (same generation)

    delete internals.metadataIndex.healthReport
  })
})

describe('health gate (c) — degraded-but-serving narrates once per generation', () => {
  // PER-FAMILY LAW (10.4.1): a metadata find() consults the METADATA leg only — the
  // degraded report lives on the family the read actually consults.
  it('a heal:"repair" failure serves; narrates once per DISTINCT VERDICT, not once per generation bump', async () => {
    const brain = new Brainy(createTestConfig({ silent: true }))
    await brain.init()
    brains.push(brain)
    await brain.add({ data: 'row', type: NounType.Document, metadata: { team: 'atlas' } })
    await brain.flush()

    const internals = internalsOf(brain)
    let generation = 1
    let detail = 'counter drift'
    internals.metadataIndex.healthReport = () =>
      healthReport({
        provider: 'vector',
        serving: true,
        healthy: false,
        invariants: [invariant({ name: 'stale-vector-counter', holds: false, heal: 'repair', detail })],
        generation
      })

    const warnSpy = vi.spyOn(prodLog, 'warn')
    const countNarrations = () =>
      warnSpy.mock.calls.filter(([msg]) => typeof msg === 'string' && msg.includes('stale-vector-counter')).length

    await expect(brain.find({ where: { team: 'atlas' } })).resolves.toHaveLength(1)
    await expect(brain.find({ where: { team: 'atlas' } })).resolves.toHaveLength(1)
    expect(countNarrations()).toBe(1) // same verdict both times — one narration

    // THE DEDUPE KEY IS THE VERDICT, NOT THE COUNTER. A provider's `generation`
    // bumps on every ledger mutation and every rebuild boundary, so keying the
    // narration on it re-printed an UNCHANGED health line on every read that
    // consulted a busy provider — and, in the other direction, let a provider
    // that never bumped suppress a line whose reasons had genuinely changed.
    // An unchanged verdict is silent however the counter moves:
    generation = 2
    await expect(brain.find({ where: { team: 'atlas' } })).resolves.toHaveLength(1)
    expect(countNarrations()).toBe(1) // generation bumped, verdict identical — still silent

    // ...and a CHANGED verdict is always heard, bump or no bump:
    detail = 'counter drift widened to 12 rows'
    await expect(brain.find({ where: { team: 'atlas' } })).resolves.toHaveLength(1)
    expect(countNarrations()).toBe(2) // the reasons changed — a new narration

    delete internals.metadataIndex.healthReport
  })
})

describe('health gate (d) — interim isReady()-only path (no healthReport) is unchanged', () => {
  it('isReady() === true serves; isReady() === false refuses via the typed NotReady error', async () => {
    const brain = new Brainy(createTestConfig({ silent: true }))
    await brain.init()
    brains.push(brain)
    await brain.add({ data: 'row', type: NounType.Document, metadata: { team: 'atlas' } })
    await brain.flush()

    const internals = internalsOf(brain)
    internals.metadataIndex.isReady = () => true
    await expect(brain.find({ where: { team: 'atlas' } })).resolves.toHaveLength(1)

    internals.metadataIndex.isReady = () => false
    await expect(brain.find({ where: { team: 'atlas' } })).rejects.toBeInstanceOf(MetadataIndexNotReadyError)

    delete internals.metadataIndex.isReady
  })
})

describe('health gate (e) — open builds; the first read never does', () => {
  it('disableAutoRebuild:true on a populated store: open narrates + builds; the first find() triggers zero rebuilds', async () => {
    const dir = mkdtempSync(join(tmpdir(), 'brainy-healthgate-open-'))
    dirs.push(dir)

    const writer = new Brainy({
      storage: { type: 'filesystem', path: dir },
      requireSubtype: false,
      silent: true,
      disableAutoRebuild: true
    })
    await writer.init()
    brains.push(writer)
    await writer.add({ data: 'row one', type: NounType.Document, metadata: { team: 'atlas' } })
    await writer.flush()
    await brains.pop()!.close()

    const warnSpy = vi.spyOn(prodLog, 'warn')
    const reader = new Brainy({
      storage: { type: 'filesystem', path: dir },
      requireSubtype: false,
      silent: true,
      disableAutoRebuild: true
    })
    const internals = internalsOf(reader)
    const rebuildSpy = vi.spyOn(internals, 'rebuildIndexesIfNeeded')

    await reader.init()
    brains.push(reader)

    expect(rebuildSpy).toHaveBeenCalledTimes(1) // open() built it, exactly once
    expect(
      warnSpy.mock.calls.some(
        ([msg]) => typeof msg === 'string' && msg.includes('open() is building')
      )
    ).toBe(true)

    rebuildSpy.mockClear()
    const rows = await reader.find({ where: { team: 'atlas' } })
    expect(rebuildSpy).toHaveBeenCalledTimes(0) // the read never builds
    expect(rows.length).toBe(1)
  }, 30000)
})

describe('health gate (f) — the ceremony door: explicit rebuild bypasses invariant consultation', () => {
  it("repairIndex({ rebuild: ['graph'] }) rebuilds unconditionally without consulting validateInvariants", async () => {
    const brain = new Brainy(createTestConfig({ silent: true }))
    await brain.init()
    brains.push(brain)
    await brain.add({ data: 'x', type: NounType.Concept })
    await brain.flush()

    const internals = internalsOf(brain)
    let validateCalls = 0
    internals.graphIndex.validateInvariants = async () => {
      validateCalls++
      return healthReport({ provider: 'graph' })
    }
    const rebuildSpy = vi.spyOn(internals.graphIndex, 'rebuild')

    const report = await brain.repairIndex({ rebuild: ['graph'] })

    expect(rebuildSpy).toHaveBeenCalledTimes(1)
    expect(validateCalls).toBe(0) // the door never consults validateInvariants to decide

    const graphFamily = report.families.find((f) => f.family === 'provider:graph')
    expect(graphFamily?.rebuilt).toBe(true)
    expect(graphFamily?.checked).toBe(true)
    expect(graphFamily?.reason).toBe('explicit rebuild requested')

    delete internals.graphIndex.validateInvariants
  })

  it('bare repairIndex() on a healthy provider calls no rebuild()', async () => {
    const brain = new Brainy(createTestConfig({ silent: true }))
    await brain.init()
    brains.push(brain)
    await brain.add({ data: 'x', type: NounType.Concept })
    await brain.flush()

    const internals = internalsOf(brain)
    internals.graphIndex.validateInvariants = async () => healthReport({ provider: 'graph', healthy: true, serving: true })
    const rebuildSpy = vi.spyOn(internals.graphIndex, 'rebuild')

    await brain.repairIndex()

    expect(rebuildSpy).not.toHaveBeenCalled()

    delete internals.graphIndex.validateInvariants
  })
})

describe('health gate (g) — a throwing healthReport() is a contract violation, never read as healthy', () => {
  // PER-FAMILY LAW (10.4.1): the throwing report sits on the family the read consults.
  it('healthReport() that throws refuses loudly with the typed NotReady error naming the throw', async () => {
    const brain = new Brainy(createTestConfig({ silent: true }))
    await brain.init()
    brains.push(brain)
    await brain.add({ data: 'row', type: NounType.Document, metadata: { team: 'atlas' } })
    await brain.flush()

    const internals = internalsOf(brain)
    internals.metadataIndex.healthReport = () => {
      throw new Error('accelerator: mmap window busy')
    }

    await expect(brain.find({ where: { team: 'atlas' } })).rejects.toBeInstanceOf(MetadataIndexNotReadyError)
    await expect(brain.find({ where: { team: 'atlas' } })).rejects.toThrow(/mmap window busy/)

    delete internals.metadataIndex.healthReport
  })
})