import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { summarizeRtt, RttWindow } from '../src/rtt.js';
import { pickMachine } from '../src/machines.js';

describe('RTT planning stats', () => {
  it('computes min, avg, p50, p90 in order', () => {
    const s = summarizeRtt([10, 20, 30, 40, 50, 60, 70, 80, 90, 100]);
    assert.equal(s.count, 10);
    assert.equal(s.minMs, 10);
    assert.equal(s.avgMs, 55);
    assert.ok(s.p50Ms >= s.minMs && s.p50Ms <= s.p90Ms);
    assert.ok(s.p90Ms <= 100);
  });

  it('empty window is nulls', () => {
    const s = new RttWindow().stats();
    assert.equal(s.count, 0);
    assert.equal(s.minMs, null);
  });
});

describe('machine placement', () => {
  it('spreads onto the least-loaded eligible host', () => {
    const machines = [
      { id: 'a', enabled: true, capacity: 4, roles: ['*'] },
      { id: 'b', enabled: true, capacity: 4, roles: ['*'] },
    ];
    const instances = [{ machine: 'a', pid: 1 }];
    const pick = pickMachine(machines, instances, 'tree-node', 'tree-node');
    assert.equal(pick.id, 'b');
  });

  it('skips machines that do not allow the role', () => {
    const machines = [
      { id: 'edge', enabled: true, capacity: 8, roles: ['zappier-edge'] },
      { id: 'trees', enabled: true, capacity: 8, roles: ['tree-node'] },
    ];
    const pick = pickMachine(machines, [], 'tree-node', 'tree-node');
    assert.equal(pick.id, 'trees');
  });
});