/**
 * @module tests/unit/graph/graph-fastpath-honest-readiness
 * @description Pattern-A / Finding 2: getVerbsBySource/ByTarget gated the graph
 * fast path on `graphIndex.isInitialized` (a proxy that reads true once the
 * manifest/count loaded even if the source→target adjacency did NOT → the fast
 * path then returned a silent []). The honest gate skips the fast path when the
 * provider reports isReady()===false, falling to the correct canonical shard
 * scan; and a one-shot probe self-heals a no-isReady provider whose adjacency
 * did not cold-load.
 */
import { describe, it, expect, beforeEach } from 'vitest'
import { Brainy, NounType, VerbType } from '../../../src/index.js'

describe('graph fast-path honest readiness (Finding 2)', () => {
  let brain: any
  let storage: any
  let a: string
  let b: string
  let c: string

  beforeEach(async () => {
    process.env.BRAINY_DETERMINISTIC_EMBEDDINGS = 'true'
    brain = new Brainy({ requireSubtype: false, storage: { type: 'memory' }, dimensions: 384 })
    await brain.init()
    a = await brain.add({ data: 'a', type: NounType.Concept })
    b = await brain.add({ data: 'b', type: NounType.Concept })
    c = await brain.add({ data: 'c', type: NounType.Concept })
    await brain.relate({ from: a, to: b, type: VerbType.Contains })
    await brain.relate({ from: a, to: c, type: VerbType.Contains })
    await brain.flush()
    storage = brain.storage
    // Warm + wire the storage graph index (lazy) so we can stub it.
    await storage.getVerbsBySource(a)
  })

  it('not-ready provider → shard scan returns the REAL edges, not a silent []', async () => {
    const gi = storage.graphIndex
    // Simulate a cold native provider: count/manifest loaded (isInitialized) but
    // the source→target adjacency is NOT (isReady false; fast-path lookup empty).
    gi.isReady = () => false
    const origBySource = gi.getVerbIdsBySource.bind(gi)
    gi.getVerbIdsBySource = async () => [] // cold adjacency — old fast path trusted this
    storage._graphFastPathProbed = true // isolate the GATE (probe skips isReady-capable anyway)
    try {
      const verbs = await storage.getVerbsBySource(a)
      // Honest gate skipped the cold fast path → canonical shard scan → real edges.
      expect(verbs.length).toBe(2)
    } finally {
      delete gi.isReady
      gi.getVerbIdsBySource = origBySource
    }
  })

  it('ready provider → fast path is used and an empty result is trusted', async () => {
    const gi = storage.graphIndex
    gi.isReady = () => true
    let fastPathCalls = 0
    const origBySource = gi.getVerbIdsBySource.bind(gi)
    gi.getVerbIdsBySource = async (...args: any[]) => { fastPathCalls++; return origBySource(...args) }
    storage._graphFastPathProbed = true
    try {
      // `c` has no OUTGOING edges — a genuinely empty result via the fast path.
      const verbs = await storage.getVerbsBySource(c)
      expect(verbs).toEqual([])
      expect(fastPathCalls).toBeGreaterThan(0) // fast path was taken, not a shard scan
    } finally {
      delete gi.isReady
      gi.getVerbIdsBySource = origBySource
    }
  })

  it('no-isReady provider whose adjacency did not cold-load → probe rebuilds once', async () => {
    const gi = storage.graphIndex
    if ('isReady' in gi) delete gi.isReady // force the "unknown" (no honest signal) path
    // Force the probe to see a cold adjacency: a known edge resolves to no ints.
    const origBySource = gi.getVerbIdsBySource.bind(gi)
    let cold = true
    gi.getVerbIdsBySource = async (...args: any[]) => (cold ? [] : origBySource(...args))
    let rebuilds = 0
    const origRebuild = gi.rebuild.bind(gi)
    gi.rebuild = async (...args: any[]) => { rebuilds++; cold = false; return origRebuild(...args) }
    storage._graphFastPathProbed = false // re-arm the one-shot probe
    try {
      await storage.getVerbsBySource(a)
      expect(rebuilds).toBe(1)                    // probe detected cold adjacency + rebuilt once
      expect(storage._graphFastPathProbed).toBe(true) // latched — no second rebuild
      rebuilds = 0
      await storage.getVerbsByTarget(b)
      expect(rebuilds).toBe(0)                    // probe does not re-run
    } finally {
      gi.getVerbIdsBySource = origBySource
      gi.rebuild = origRebuild
    }
  })
})