// Library searches run a few at a time rather than one behind another, and
// the session is renewed before it expires.
const test = require('node:test');
const assert = require('node:assert/strict');
const fs = require('node:fs');
const path = require('node:path');
const src = fs.readFileSync(path.join(__dirname, '..', 'src/utils/clinicalMcpClient.js'), 'utf8');

test('a bounded number of calls run at once; the rest wait their turn', async () => {
  // The slot logic on its own, with the environment's default bound.
  const slice = src.slice(src.indexOf('function acquireSlot'), src.indexOf('async function callMcpTool'));
  const fn = new Function('MCP_CONCURRENCY', 'var _inFlight = 0, _waiting = [];' + slice + '; return { acquireSlot, releaseSlot, count: () => _inFlight, waiting: () => _waiting.length };')(3);
  await fn.acquireSlot(); await fn.acquireSlot(); await fn.acquireSlot();
  assert.equal(fn.count(), 3);
  let fourthStarted = false;
  const fourth = fn.acquireSlot().then(() => { fourthStarted = true; });
  await new Promise(r => setTimeout(r, 5));
  assert.equal(fourthStarted, false, 'the fourth waits');
  assert.equal(fn.waiting(), 1);
  fn.releaseSlot();
  await fourth;
  assert.equal(fourthStarted, true, 'and runs when a slot frees');
  assert.equal(fn.count(), 3, 'the slot passed hands rather than being freed');
  fn.releaseSlot(); fn.releaseSlot(); fn.releaseSlot();
  assert.equal(fn.count(), 0);
});

test('the serial promise chain is gone, the session is kept warm, and the split is logged', () => {
  assert.doesNotMatch(src, /_mcpCallQueue = queued\.catch/, 'no more one-at-a-time chain');
  assert.match(src, /var MCP_CONCURRENCY = positiveInt\(process\.env\.CLINICAL_ASSISTANT_MCP_CONCURRENCY, 3\)/);
  assert.match(src, /setInterval\(function\(\) \{[\s\S]*?getMcpSession\(\)\.catch/, 'renewed on a timer');
  assert.match(src, /_warmTimer\.unref/, 'the timer never keeps the process alive');
  assert.match(src, /mcp ' \+ name \+ ': session=' \+ sessionMs \+ 'ms total='/);
});