import base64ToArrayBuffer from 'base64-arraybuffer';
import { hexToBase64, decimalArrayAsBigEndianNumber } from '../../parsing/binary';
import { sendCommand } from '../sendCommands';
import { BluetoothProbeEmitter } from '../emitter/BluetoothProbeEmitter';
import { DummyProbeEmitter } from '../emitter/DummyProbeEmitter';

const isCommandCorrect = responseArray => responseArray[0] === 0x7e && responseArray[1] === 0x08;

export const parseBatteryPercentage = aBase64String => {
  const arrayBuffer = new Uint8Array(base64ToArrayBuffer.decode(aBase64String));

  if (arrayBuffer.length < 4 || !isCommandCorrect(arrayBuffer)) {
    return null;
  }
  const voltage = Number(decimalArrayAsBigEndianNumber(arrayBuffer.slice(2, 4))) / 1000;

  return Math.max(Math.min(Math.round((voltage - 3.0) / 0.009), 100), 0);
};

export const BATTERY_PROBE_COMMAND = hexToBase64('7E 08');

export const getProbeBatteryStatus = ({ bluetoothContext }) => {
  const probeEmitter = bluetoothContext.mockProbe
    ? new DummyProbeEmitter(true)
    : new BluetoothProbeEmitter(bluetoothContext.connectedDevice, bluetoothContext.manager);
  const receiver = ({ timeoutId }) => ({
    appendString: commandResult => {
      clearTimeout(timeoutId);
      probeEmitter.cancel().finally(() => bluetoothContext.mutex.release());

      const batteryPercentage = parseBatteryPercentage(commandResult);
      bluetoothContext.setBatteryPercentage(batteryPercentage);
    },
    reject: _anErrorObject => {
      clearTimeout(timeoutId);
      probeEmitter.cancel().finally(() => bluetoothContext.mutex.release());
    },
  });

  const task = () => {
    sendCommand({
      bluetoothContext,
      probeEmitter,
      receiver,
      probeCommand: BATTERY_PROBE_COMMAND,
      timeOutInMs: bluetoothContext.timeOuts.probeBatteryTimeOutInMs,
    });
  };

  return task;
};