import EmberObject from '@ember/object';
import { assign } from '@ember/polyfills';
import wait from 'ember-test-helpers/wait';
import { module, test } from 'ember-qunit';
import sinon from 'sinon';
import Pretender from 'pretender';
import NodeStatsTracker, { stats } from 'nomad-ui/utils/classes/node-stats-tracker';
import fetch from 'nomad-ui/utils/fetch';

module('Unit | Util | NodeStatsTracker');

const refDate = Date.now();

const MockNode = overrides =>
  assign(
    {
      id: 'some-identifier',
      resources: {
        cpu: 2000,
        memory: 4096,
      },
    },
    overrides
  );

const mockFrame = step => ({
  CPUTicksConsumed: step + 1000,
  Memory: {
    Used: (step + 2048) * 1024 * 1024,
  },
  Timestamp: refDate + step,
});

test('the NodeStatsTracker constructor expects a fetch definition and a node', function(assert) {
  const tracker = NodeStatsTracker.create();
  assert.throws(
    () => {
      tracker.poll();
    },
    /StatsTrackers need a fetch method/,
    'Polling does not work without a fetch method provided'
  );
});

test('the url property is computed based off the node id', function(assert) {
  const node = MockNode();
  const tracker = NodeStatsTracker.create({ fetch, node });

  assert.equal(
    tracker.get('url'),
    `/v1/client/stats?node_id=${node.id}`,
    'Url is derived from the node id'
  );
});

test('reservedCPU and reservedMemory properties come from the node', function(assert) {
  const node = MockNode();
  const tracker = NodeStatsTracker.create({ fetch, node });

  assert.equal(tracker.get('reservedCPU'), node.resources.cpu, 'reservedCPU comes from the node');
  assert.equal(
    tracker.get('reservedMemory'),
    node.resources.memory,
    'reservedMemory comes from the node'
  );
});

test('poll results in requesting the url and calling append with the resulting JSON', function(assert) {
  const node = MockNode();
  const tracker = NodeStatsTracker.create({ fetch, node, append: sinon.spy() });
  const mockFrame = {
    Some: {
      data: ['goes', 'here'],
      twelve: 12,
    },
  };

  const server = new Pretender(function() {
    this.get('/v1/client/stats', () => [200, {}, JSON.stringify(mockFrame)]);
  });

  tracker.poll();

  assert.equal(server.handledRequests.length, 1, 'Only one request was made');
  assert.equal(
    server.handledRequests[0].url,
    `/v1/client/stats?node_id=${node.id}`,
    'The correct URL was requested'
  );

  return wait().then(() => {
    assert.ok(
      tracker.append.calledWith(mockFrame),
      'The JSON response was passed into append as a POJO'
    );

    server.shutdown();
  });
});

test('append appropriately maps a data frame to the tracked stats for cpu and memory for the node', function(assert) {
  const node = MockNode();
  const tracker = NodeStatsTracker.create({ fetch, node });

  assert.deepEqual(tracker.get('cpu'), [], 'No tracked cpu yet');
  assert.deepEqual(tracker.get('memory'), [], 'No tracked memory yet');

  tracker.append(mockFrame(1));

  assert.deepEqual(
    tracker.get('cpu'),
    [{ timestamp: refDate + 1, used: 1001, percent: 1001 / 2000 }],
    'One frame of cpu'
  );

  assert.deepEqual(
    tracker.get('memory'),
    [{ timestamp: refDate + 1, used: 2049 * 1024 * 1024, percent: 2049 / 4096 }],
    'One frame of memory'
  );

  tracker.append(mockFrame(2));

  assert.deepEqual(
    tracker.get('cpu'),
    [
      { timestamp: refDate + 1, used: 1001, percent: 1001 / 2000 },
      { timestamp: refDate + 2, used: 1002, percent: 1002 / 2000 },
    ],
    'Two frames of cpu'
  );

  assert.deepEqual(
    tracker.get('memory'),
    [
      { timestamp: refDate + 1, used: 2049 * 1024 * 1024, percent: 2049 / 4096 },
      { timestamp: refDate + 2, used: 2050 * 1024 * 1024, percent: 2050 / 4096 },
    ],
    'Two frames of memory'
  );
});

test('each stat list has maxLength equal to bufferSize', function(assert) {
  const node = MockNode();
  const bufferSize = 10;
  const tracker = NodeStatsTracker.create({ fetch, node, bufferSize });

  for (let i = 1; i <= 20; i++) {
    tracker.append(mockFrame(i));
  }

  assert.equal(
    tracker.get('cpu.length'),
    bufferSize,
    `20 calls to append, only ${bufferSize} frames in the stats array`
  );
  assert.equal(
    tracker.get('memory.length'),
    bufferSize,
    `20 calls to append, only ${bufferSize} frames in the stats array`
  );

  assert.equal(
    tracker.get('cpu')[0].timestamp,
    refDate + 11,
    'Old frames are removed in favor of newer ones'
  );
  assert.equal(
    tracker.get('memory')[0].timestamp,
    refDate + 11,
    'Old frames are removed in favor of newer ones'
  );
});

test('the stats computed property macro constructs a NodeStatsTracker based on a nodeProp and a fetch definition', function(assert) {
  const node = MockNode();
  const fetchSpy = sinon.spy();

  const SomeClass = EmberObject.extend({
    stats: stats('theNode', function() {
      return () => fetchSpy(this);
    }),
  });
  const someObject = SomeClass.create({
    theNode: node,
  });

  assert.equal(
    someObject.get('stats.url'),
    `/v1/client/stats?node_id=${node.id}`,
    'stats computed property macro creates a NodeStatsTracker'
  );

  someObject.get('stats').fetch();

  assert.ok(
    fetchSpy.calledWith(someObject),
    'the fetch factory passed into the macro gets called to assign a bound version of fetch to the NodeStatsTracker instance'
  );
});

test('changing the value of the nodeProp constructs a new NodeStatsTracker', function(assert) {
  const node1 = MockNode();
  const node2 = MockNode();
  const SomeClass = EmberObject.extend({
    stats: stats('theNode', () => fetch),
  });

  const someObject = SomeClass.create({
    theNode: node1,
  });

  const stats1 = someObject.get('stats');

  someObject.set('theNode', node2);
  const stats2 = someObject.get('stats');

  assert.notOk(
    stats1 === stats2,
    'Changing the value of the node results in creating a new NodeStatsTracker instance'
  );
});