import test from 'brittle'
import { readFileSync } from 'node:fs'
import vm from 'node:vm'

const STATE_SRC = readFileSync(new URL('../lib/agent-state.js', import.meta.url), 'utf8')

function loadTrimHelpers() {
  const sandbox = { console, TextEncoder, TextDecoder }
  vm.createContext(sandbox)
  vm.runInContext(
    STATE_SRC +
      '\n;this.__exports = { bareAgentTrimMessages, bareAgentTrimMessagesForCtx, bareAgentEstimateTokens }',
    sandbox
  )
  return sandbox.__exports
}

test('trim for ctx shrinks system when tools consume budget', async (t) => {
  const { bareAgentTrimMessagesForCtx, bareAgentEstimateTokens } = loadTrimHelpers()
  const tools = [{ name: 'x', description: 'y'.repeat(8000), parameters: {} }]
  const msgs = [
    { role: 'system', content: 'S'.repeat(20_000) },
    { role: 'user', content: 'hello' }
  ]
  const out = bareAgentTrimMessagesForCtx(msgs, 4096, {
    tools,
    reserveCompletion: 512
  })
  t.is(out.length, 2)
  t.ok(String(/** @type {any} */ (out[0]).content).length < 20_000)
  t.ok(
    bareAgentEstimateTokens(out) + bareAgentEstimateTokens(tools) + 512 <=
      4096 + 200
  )
})