var ble = require('./ble')
var http = require('../utils/request')

var syncing = false

function commandPayload(command) {
  return command.payload || {}
}

function execute(command) {
  var payload = commandPayload(command)
  switch (Number(command.opcode)) {
    case ble.CMD.SET_PARAMS:
      return ble.setParams({
        region_mask: payload.region_mask,
        wavelength: payload.wavelength,
        brightness: payload.brightness,
        duration_ms: payload.duration_ms,
        mode: payload.mode,
        control: payload.control,
        current_gain: payload.current_gain,
        hold_time: payload.hold_time
      })
    case ble.CMD.START:
      return ble.startTreatment(payload.region_mask)
    case ble.CMD.STOP:
      return ble.stopTreatment()
    case ble.CMD.QUERY_STATUS:
      return ble.queryStatus()
    default:
      return Promise.reject({ error_code: 0xFE, error_msg: 'unsupported opcode' })
  }
}

function report(command, success, result) {
  return http.post('/api/v1/device/command/result', {
    command_id: command.seq || command.command_id,
    seq: command.seq || command.command_id,
    success: success,
    opcode: command.opcode,
    result: result || null
  }).catch(function (err) { console.error('[command-sync] report failed:', err) })
}

function runOne(command) {
  return execute(command).then(function (result) {
    return report(command, true, result)
  }).catch(function (err) {
    return report(command, false, err)
  })
}

function sync(deviceId) {
  if (syncing || !deviceId || !ble.isConnected()) return Promise.resolve()
  syncing = true
  return http.get('/api/v1/device/command/pending', { device_id: deviceId }).then(function (data) {
    var chain = Promise.resolve()
    var commands = data.commands || []
    commands.forEach(function (command) {
      chain = chain.then(function () { return runOne(command) })
    })
    return chain
  }).catch(function () {}).then(function () {
    syncing = false
  })
}

module.exports = {
  sync: sync,
  execute: execute
}
