const assert = require('assert');
const { JhmDecoder, additiveChecksum } = require('../decoder');

function buildJhmFrame(command, payload) {
  const cy = (command + payload[0] + payload[1] + payload[2] + payload[3]) & 0xFF;
  return Buffer.from([0xEE, 0x55, command, ...payload, cy]);
}

function buildBloodPressureFrame({ systolic, diastolic, pulse, timeBytes }) {
  const frameWithoutChecksum = Buffer.from([
    0xAA,
    0x55,
    0x0E,
    0xBA,
    (systolic >> 8) & 0xFF,
    systolic & 0xFF,
    diastolic & 0xFF,
    pulse & 0xFF,
    ...timeBytes,
  ]);

  return Buffer.concat([
    frameWithoutChecksum,
    Buffer.from([additiveChecksum(frameWithoutChecksum)]),
  ]);
}

describe('decoder', () => {
  it('parses blood pressure frame and publishes N/O/P', () => {
    const decoder = new JhmDecoder({ alModelPath: './alModel.json' });
    const frame = buildBloodPressureFrame({
      systolic: 120,
      diastolic: 80,
      pulse: 89,
      timeBytes: [0x1A, 0x04, 0x0F, 0x09, 0x1E],
    });

    const results = decoder.push(frame);

    assert.strictEqual(results.length, 1);
    assert.strictEqual(results[0].publish, true);
    assert.deepStrictEqual(results[0].metric, {
      N: 120,
      O: 80,
      P: 89,
    });
  });

  it('keeps legacy JHM protocol parsing intact', () => {
    const decoder = new JhmDecoder({ alModelPath: './alModel.json' });
    const frame = buildJhmFrame(0x01, [0x00, 0x00, 0x01, 0x72]);

    const results = decoder.push(frame);

    assert.strictEqual(results.length, 1);
    assert.strictEqual(results[0].publish, true);
    assert.deepStrictEqual(results[0].metric, { F: 37 });
  });

  it('can parse mixed protocol frames from one stream', () => {
    const decoder = new JhmDecoder({ alModelPath: './alModel.json' });
    const jhmFrame = buildJhmFrame(0x0E, [0x00, 0x00, 0x00, 0x8C]);
    const bpFrame = buildBloodPressureFrame({
      systolic: 118,
      diastolic: 76,
      pulse: 72,
      timeBytes: [0x1A, 0x04, 0x0F, 0x0A, 0x05],
    });

    const results = decoder.push(Buffer.concat([jhmFrame, bpFrame]));

    assert.strictEqual(results.length, 2);
    assert.deepStrictEqual(results[0].metric, { Na: 140 });
    assert.deepStrictEqual(results[1].metric, {
      N: 118,
      O: 76,
      P: 72,
    });
  });

  it('can disable blood pressure time publishing', () => {
    const decoder = new JhmDecoder({
      alModelPath: './alModel.json',
      publishBloodPressureTime: false,
    });
    const frame = buildBloodPressureFrame({
      systolic: 120,
      diastolic: 80,
      pulse: 89,
      timeBytes: [0x1A, 0x04, 0x0F, 0x09, 0x1E],
    });

    const results = decoder.push(frame);

    assert.strictEqual(results.length, 1);
    assert.strictEqual(results[0].publish, true);
    assert.deepStrictEqual(results[0].metric, {
      N: 120,
      O: 80,
      P: 89,
    });
  });
});