/**
 * Mirrors lib/agent-sse-parse.js + parsing behavior used in agent-openai.js.
 * Keep in sync when editing SSE helpers.
 */
import test from 'brittle'

function bareAgentParseSseDataPayload(dataLine) {
  const t = String(dataLine).trim()
  if (t === '[DONE]') return { kind: 'done' }
  try {
    const j = JSON.parse(t)
    return { kind: 'json', value: j }
  } catch {
    return { kind: 'raw', value: t }
  }
}

function bareAgentSplitSseLines(buf) {
  const lines = []
  let start = 0
  for (let i = 0; i < buf.length; i++) {
    if (buf.charCodeAt(i) === 10) {
      lines.push(buf.slice(start, i))
      start = i + 1
    }
  }
  return { lines, rest: buf.slice(start) }
}

test('SSE data payload [DONE]', async (t) => {
  t.is(bareAgentParseSseDataPayload('[DONE]').kind, 'done')
})

test('SSE data payload JSON', async (t) => {
  const r = bareAgentParseSseDataPayload('{"x":1}')
  t.is(r.kind, 'json')
  t.is(r.value.x, 1)
})

test('SSE split preserves tail', async (t) => {
  const sp = bareAgentSplitSseLines('a\nb\nc\n')
  t.is(sp.lines.length, 3)
  t.is(sp.rest, '')
  const sp2 = bareAgentSplitSseLines('partial')
  t.is(sp2.lines.length, 0)
  t.is(sp2.rest, 'partial')
})