Module-uo/server/test/assetBridge.test.js

const { test } = require('node:test')
const assert = require('node:assert/strict')

const uoLinkClient = require('../utils/uoLinkClient')
const bridge = require('../utils/assetBridge')

// The three walks over the asset plane, driven against a stubbed sidecar client
// (docs/link/v8.md §5, §6, §8 — protocol 8, phase 3).
//
// Two families of failure are asserted here and they are not the same shape.
//
// **The envelope failures** are ways the shard can be wrong that leave this side
// holding a catalogue it believes is complete. They are invisible downstream: a
// catalogue missing its last three hundred bodies renders as a site where some
// creatures have pictures and some do not, which is exactly what NO catalogue
// looks like. Each corresponds to a field §3.4 puts on the wire specifically so
// this side can tell the difference.
//
// **The absence failures** are the opposite mistake, and phase 3's more likely
// one: treating a body this client has no art for as an error. Two thirds of the
// playable ghost and gargoyle bodies are in that state on a stock client, and an
// import that failed — or even warned loudly — on them would teach an operator to
// ignore the panel.

const saved = {}

function stub({ sources, manifest = [], fetch = [], bodies = [] } = {}) {
  saved.getAssetSources = uoLinkClient.getAssetSources
  saved.getAssetManifest = uoLinkClient.getAssetManifest
  saved.fetchAssets = uoLinkClient.fetchAssets
  saved.resolveBodies = uoLinkClient.resolveBodies

  const calls = { manifest: [], fetch: [], bodies: [] }

  uoLinkClient.getAssetSources = async () => sources
  uoLinkClient.getAssetManifest = async ({ family, cursor } = {}) => {
    calls.manifest.push({ family: family ?? null, cursor: cursor ?? null })
    const next = manifest.shift()
    if (!next) throw new Error('the walk asked for more manifest pages than the test supplied')
    return next
  }
  uoLinkClient.fetchAssets = async ({ keys, catalog, cursor } = {}) => {
    calls.fetch.push({ keys, catalog: catalog ?? null, cursor: cursor ?? null })
    const next = fetch.shift()
    if (!next) throw new Error('the walk asked for more fetch pages than the test supplied')
    return next
  }
  uoLinkClient.resolveBodies = async (types) => {
    calls.bodies.push(types)
    const next = bodies.shift()
    if (!next) throw new Error('the walk asked for more body chunks than the test supplied')
    return next
  }

  return calls
}

function restore() {
  for (const [name, fn] of Object.entries(saved)) {
    if (fn) uoLinkClient[name] = fn
  }
}

const ok = (data) => ({ ok: true, status: 200, data })
const fail = (status, data) => ({ ok: false, status, data })

const CATALOG = 'a3f9c21d4b8e0771'

const manifestPage = (rows, extra = {}) =>
  ok({
    kind: 'assets.manifest.ok',
    family: 'body',
    catalog: CATALOG,
    extractorVersion: 1,
    playerBodies: [400, 401, 402, 403],
    scanned: rows.length,
    rows,
    more: false,
    cut: 'end',
    ...extra,
  })

const fetchPage = (rows, extra = {}) =>
  ok({
    kind: 'assets.fetch.ok',
    family: 'body',
    catalog: CATALOG,
    rows,
    more: false,
    cut: 'end',
    ...extra,
  })

const row = (body, sha = 'aa') => ({
  key: `body/${body}/a0`,
  sha256: sha,
  bytes: 900,
  width: 24,
  height: 63,
  body,
  direction: 1,
})

const png = Buffer.from([0x89, 0x50, 0x4e, 0x47]).toString('base64')

const sourcesReply = (extra = {}) =>
  ok({
    kind: 'assets.sources.ok',
    extractorVersion: 1,
    imaging: { ok: true },
    hashing: false,
    complete: true,
    files: [
      { name: 'anim.idx', size: 10, mtime: 1, sha256: 'a' },
      { name: 'anim.mul', size: 20, mtime: 2, sha256: 'b' },
      { name: 'body.def', size: 30, mtime: 3, sha256: 'c' },
      // Not a source this family reads: `art.mul` decides item pictures, not
      // creature ones, and folding it in would make every item-art change look
      // like a reason to re-import the whole body catalogue.
      { name: 'art.mul', size: 148000000, mtime: 4, sha256: 'd' },
    ],
    ...extra,
  })

// ── the source gate (§6 stage 1) ──────────────────────────────────────────

test('the source fingerprint keeps only the files the body catalogue reads', async (t) => {
  stub({ sources: sourcesReply() })
  t.after(restore)

  const fingerprint = await bridge.sourceFingerprint()

  assert.deepEqual(Object.keys(fingerprint.files).sort(), ['anim.idx', 'anim.mul', 'body.def'])
  assert.equal(fingerprint.extractorVersion, 1)
})

test('a bumped extractor version is drift even when every client file is identical', () => {
  const files = { 'anim.mul': { size: 1, mtime: 2, sha256: 'x' } }

  assert.equal(
    bridge.sameSources({ files, extractorVersion: 1 }, { files, extractorVersion: 1 }),
    true,
  )
  // §7: a corrected frame offset changes every derived byte while every source
  // file stays byte-identical. If this returned true the fix would never reach
  // an install whose client never moves.
  assert.equal(
    bridge.sameSources({ files, extractorVersion: 2 }, { files, extractorVersion: 1 }),
    false,
  )
})

test('a client that GAINED an anim file is drift, not a match', () => {
  const before = { files: { 'anim.mul': { size: 1, mtime: 2, sha256: 'x' } }, extractorVersion: 1 }
  const after = {
    files: {
      'anim.mul': { size: 1, mtime: 2, sha256: 'x' },
      // A client that grows an anim5.mul is a client whose gargoyles suddenly
      // resolve. Comparing only the files present in both would call that
      // unchanged and never import them.
      'anim5.mul': { size: 9, mtime: 9, sha256: 'y' },
    },
    extractorVersion: 1,
  }

  assert.equal(bridge.sameSources(before, after), false)
})

test('a null hash falls back to size and mtime rather than reading as changed', () => {
  // The shard hashes 195 MB anim files off the request path, so a null sha256 is
  // "not computed yet". Treating it as a difference would re-import the whole
  // catalogue on every restart until the background pass finished.
  const a = { files: { 'anim.mul': { size: 5, mtime: 7, sha256: null } }, extractorVersion: 1 }
  const b = { files: { 'anim.mul': { size: 5, mtime: 7, sha256: 'later' } }, extractorVersion: 1 }

  assert.equal(bridge.sameSources(a, b), true)
})

// ── the manifest walk (§6 stage 2) ────────────────────────────────────────

test('the manifest walks every page and stops only on cut: end', async (t) => {
  const calls = stub({
    manifest: [
      manifestPage([row(12), row(34)], { more: true, cursor: 'b:34', cut: 'limit' }),
      manifestPage([row(400)]),
    ],
  })
  t.after(restore)

  const result = await bridge.readManifest()

  assert.equal(result.rows.length, 3)
  assert.equal(result.catalog, CATALOG)
  assert.deepEqual(result.playerBodies, [400, 401, 402, 403])
  assert.deepEqual(
    calls.manifest.map((c) => c.cursor),
    [null, 'b:34'],
  )
})

test('a short page that did not end the catalogue is refused', async (t) => {
  // `cut: 'limit'` with `more: false` is the shard saying it stopped for its own
  // reason. Importing what arrived would silently drop every body after it, and
  // the result is indistinguishable from a client with fewer creatures.
  stub({ manifest: [manifestPage([row(12)], { more: false, cut: 'limit' })] })
  t.after(restore)

  await assert.rejects(() => bridge.readManifest(), /stopped sending assets/)
})

test('a cursor that does not advance is refused rather than looped on', async (t) => {
  stub({
    manifest: [
      manifestPage([row(12)], { more: true, cursor: 'b:12', cut: 'budget' }),
      manifestPage([row(13)], { more: true, cursor: 'b:12', cut: 'budget' }),
    ],
  })
  t.after(restore)

  await assert.rejects(() => bridge.readManifest(), /without advancing its cursor/)
})

test('the client files changing mid-walk aborts the whole import', async (t) => {
  // The catalogue id is derived from the client files themselves, so a change
  // between two pages means half of what we hold describes files that no longer
  // exist — and nothing later can tell which half.
  stub({
    manifest: [
      manifestPage([row(12)], { more: true, cursor: 'b:12', cut: 'limit' }),
      manifestPage([row(34)], { catalog: 'something-else' }),
    ],
  })
  t.after(restore)

  await assert.rejects(() => bridge.readManifest(), /changed while the manifest was being read/)
})

// ── the fetch (§5) ────────────────────────────────────────────────────────

test('a fetch passes the catalogue id and decodes the PNG', async (t) => {
  const calls = stub({
    fetch: [fetchPage([{ key: 'body/12/a0', status: 'ok', sha256: 'aa', bytes: 4, width: 24, height: 63, body: 12, direction: 1, png }])],
  })
  t.after(restore)

  const { assets } = await bridge.fetchAssets({ keys: ['body/12/a0'], catalog: CATALOG })

  assert.equal(calls.fetch[0].catalog, CATALOG)
  assert.equal(assets.get('body/12/a0').png.length, 4)
  assert.equal(assets.get('body/12/a0').width, 24)
})

test('an absent asset is a counted row, not a failed fetch', async (t) => {
  // The whole reason this is not an error: two thirds of the playable ghost and
  // gargoyle bodies have no art on a stock client (§5.2), and an import that
  // failed on them could never succeed.
  stub({
    fetch: [
      fetchPage([
        { key: 'body/12/a0', status: 'ok', sha256: 'aa', bytes: 4, png },
        { key: 'body/666/a0', status: 'absent' },
        { key: 'body/400/a2/f3', status: 'unsupported' },
      ]),
    ],
  })
  t.after(restore)

  const { assets, missing } = await bridge.fetchAssets({
    keys: ['body/12/a0', 'body/666/a0', 'body/400/a2/f3'],
    catalog: CATALOG,
  })

  assert.equal(assets.size, 1)
  // Counted apart, because they mean different things: `absent` is a gap in the
  // operator's client and `unsupported` is a bug on this side.
  assert.equal(missing.absent, 1)
  assert.equal(missing.unsupported, 1)
})

test('a busy shard is retried rather than failing the walk', async (t) => {
  saved.fetchAssets = uoLinkClient.fetchAssets
  t.after(restore)

  let attempts = 0

  uoLinkClient.fetchAssets = async () => {
    attempts++
    if (attempts < 3) return fail(425, { reason: 'busy' })
    return fetchPage([{ key: 'body/12/a0', status: 'ok', sha256: 'aa', bytes: 4, png }])
  }

  const { assets } = await bridge.fetchAssets({ keys: ['body/12/a0'], catalog: CATALOG })

  assert.equal(attempts, 3)
  assert.equal(assets.size, 1)
})

test('a shard host with no libgdiplus is named, not reported as a dead shard', async (t) => {
  saved.getAssetManifest = uoLinkClient.getAssetManifest
  t.after(restore)

  uoLinkClient.getAssetManifest = async () =>
    fail(503, { reason: "this shard host cannot render images - Mono's System.Drawing needs libgdiplus" })

  await assert.rejects(
    () => bridge.readManifest(),
    (err) => err.code === 'NO_IMAGING',
  )
})

// ── the body pass (§8) ────────────────────────────────────────────────────

test('body resolution chunks to the shard cap and records every outcome', async (t) => {
  const creatures = []

  for (let i = 0; i < bridge.BODY_CHUNK + 5; i++) {
    creatures.push({ slug: `c-${i}`, name: `Creature${i}` })
  }

  const reply = (types) =>
    ok({
      kind: 'assets.bodies.ok',
      rows: types.map((type, i) => (i === 0 ? { type, status: 'unknown' } : { type, status: 'ok', body: 100 + i })),
      more: false,
      cut: 'end',
    })

  const calls = stub({ bodies: [] })
  t.after(restore)

  uoLinkClient.resolveBodies = async (types) => {
    calls.bodies.push(types)
    return reply(types)
  }

  const rows = await bridge.resolveBodies({ creatures })

  // Two chunks, and neither over the cap: the shard REFUSES an over-long list
  // rather than truncating it, so a chunk size above its cap does not degrade —
  // every request fails.
  assert.equal(calls.bodies.length, 2)
  assert.ok(calls.bodies.every((chunk) => chunk.length <= bridge.BODY_CHUNK))

  assert.equal(rows.length, creatures.length)
  // The negative answers are kept. Without them the next pass asks again, and
  // the pass costs a real constructor per name on the shard's Core thread.
  assert.equal(rows.filter((r) => r.status === 'unknown').length, 2)
})

test('two slugs sharing a class name are asked once and both get the answer', async (t) => {
  const calls = stub({
    bodies: [
      ok({ kind: 'assets.bodies.ok', rows: [{ type: 'GiantSpider', status: 'ok', body: 28 }], more: false, cut: 'end' }),
    ],
  })
  t.after(restore)

  const rows = await bridge.resolveBodies({
    creatures: [
      { slug: 'giant-spider', name: 'GiantSpider' },
      { slug: 'giantspider', name: 'GiantSpider' },
    ],
  })

  assert.deepEqual(calls.bodies[0], ['GiantSpider'])
  assert.equal(rows.length, 2)
  assert.ok(rows.every((r) => r.body === 28))
})