import assert from 'node:assert/strict';
import test from 'node:test';
import {
  formatSessionStreamSseChunk,
  isSessionStreamReplayEnabled,
  isTerminalSessionEvent,
  parseSessionSseBlock,
  parseSessionStreamLastEventId,
  resolveUpstreamResumeEventId,
  shouldPersistSessionStreamEvent,
  shouldSkipUpstreamAfterSessionReplay,
} from './session-stream.mjs';

test('formatSessionStreamSseChunk includes id for replay cursor', () => {
  const chunk = formatSessionStreamSseChunk({
    id: 'evt-1',
    data: { type: 'Message', message: { role: 'assistant' } },
  });
  assert.match(chunk, /^id: evt-1\n/);
  assert.match(chunk, /"type":"Message"/);
});

test('parseSessionSseBlock extracts id and data', () => {
  const parsed = parseSessionSseBlock('id: upstream-1\ndata: {"type":"Finish"}\n\n');
  assert.equal(parsed.id, 'upstream-1');
  assert.equal(parsed.data, '{"type":"Finish"}');
});

test('terminal detection and upstream skip policy', () => {
  assert.equal(isTerminalSessionEvent({ type: 'Finish' }), true);
  assert.equal(isTerminalSessionEvent({ type: 'Message' }), false);
  assert.equal(
    shouldSkipUpstreamAfterSessionReplay([
      { payload: { type: 'Message' } },
      { payload: { type: 'Finish' } },
    ]),
    true,
  );
  assert.equal(
    shouldSkipUpstreamAfterSessionReplay([{ payload: { type: 'Message' } }]),
    false,
  );
  assert.equal(shouldPersistSessionStreamEvent({ type: 'Ping' }), false);
  assert.equal(shouldPersistSessionStreamEvent({ type: 'Message' }), true);
  assert.equal(isSessionStreamReplayEnabled({ MEMIND_SESSION_STREAM_REPLAY: '1' }), true);
  assert.equal(parseSessionStreamLastEventId(' abc '), 'abc');
});

test('upstream resume cursor never falls back to a Portal replay id', () => {
  assert.equal(
    resolveUpstreamResumeEventId([], {
      id: 'portal-uuid',
      upstreamEventId: null,
    }),
    null,
  );
  assert.equal(
    resolveUpstreamResumeEventId([], {
      id: 'portal-uuid',
      upstreamEventId: 'upstream-7',
    }),
    'upstream-7',
  );
});

test('upstream resume cursor uses the newest mappable replay event across turns', () => {
  assert.equal(
    resolveUpstreamResumeEventId(
      [
        { upstreamEventId: 'upstream-old-finish' },
        { upstreamEventId: 'upstream-new-message' },
        { upstreamEventId: null },
      ],
      { upstreamEventId: 'upstream-cursor' },
    ),
    'upstream-new-message',
  );
});