import test from 'brittle'
import { readFile } from 'node:fs/promises'
import { dirname, join } from 'node:path'
import { fileURLToPath } from 'node:url'
import { createContext, runInContext } from 'node:vm'

const __dirname = dirname(fileURLToPath(import.meta.url))
const helpersPath = join(__dirname, '../lib/baretop/baretop-ui-helpers.js')
const composePath = join(__dirname, '../lib/baretop/baretop-compose.js')
const fixturePath = join(__dirname, 'fixtures/baretop-process-table.json')

test('bareTopComposeSmokeTestFrame golden lines', async (t) => {
  const helpers = await readFile(helpersPath, 'utf8')
  const compose = await readFile(composePath, 'utf8')
  const ctx = createContext({})
  runInContext(helpers, ctx)
  runInContext(compose, ctx)
  const raw = await readFile(fixturePath, 'utf8')
  const pt = JSON.parse(raw)
  const snap = { extra: { processTable: pt } }
  const fr = ctx.bareTopComposeSmokeTestFrame(snap, 80)
  t.ok(Array.isArray(fr.lines))
  t.is(fr.lines[0], 'baretop-compose-smoke cols=80')
  t.ok(fr.lines.some((l) => l.startsWith('process_rows=')))
  t.ok(fr.meta && fr.meta.layoutVersion)
})

test('bareTopEmitFrame skips hashing on tiny frames', async (t) => {
  const helpers = await readFile(helpersPath, 'utf8')
  const compose = await readFile(composePath, 'utf8')
  const ctx = createContext({})
  runInContext(helpers, ctx)
  runInContext(compose, ctx)
  const out = 'a\r\nb\r\nc'
  const prev = ['x', 'y', 'z']
  const em = ctx.bareTopEmitFrame(
    {},
    { write() {} },
    out,
    {
      prevLines: prev,
      rows: 4,
      cols: 80,
      incrementalFrameDiff: true,
      useLineHash: true,
      fullscreenPanel: false,
      cup: (r, c) => `\\x1b[${r};${c}H`
    }
  )
  t.ok(em.consideredPatch)
})

test('bareTopEmitFrame enters hysteresis after near-full patch miss', async (t) => {
  const helpers = await readFile(helpersPath, 'utf8')
  const compose = await readFile(composePath, 'utf8')
  const ctx = createContext({})
  runInContext(helpers, ctx)
  runInContext(compose, ctx)
  const prev = Array.from({ length: 20 }, (_, i) => 'L' + i)
  const next = Array.from({ length: 20 }, (_, i) => 'X' + i).join('\r\n')
  const first = ctx.bareTopEmitFrame(
    {},
    { write() {} },
    next,
    {
      prevLines: prev,
      rows: 24,
      cols: 80,
      incrementalFrameDiff: true,
      useLineHash: false,
      fullscreenPanel: false,
      cup: (r, c) => `\\x1b[${r};${c}H`
    }
  )
  t.ok(!first.wrotePatch)
  const second = ctx.bareTopEmitFrame(
    {},
    { write() {} },
    next,
    {
      prevLines: prev,
      rows: 24,
      cols: 80,
      incrementalFrameDiff: true,
      useLineHash: false,
      fullscreenPanel: false,
      cup: (r, c) => `\\x1b[${r};${c}H`
    }
  )
  t.is(second.fallbackReason, 'patch_hysteresis_full')
})