import EventEmitter from 'events'
import { defineStore } from 'pinia'
import { parse, Helpers } from 'nmea'

export class NMEADataSource extends EventEmitter {}


const verify = (value: String) => {
  if (!value) {
    return false
  }

  const dollar_index = value.indexOf('$')
  const star_index   = value.indexOf('*')
  if (value.indexOf('$') !== 0 || star_index <= dollar_index) {
    return false
  }
  
  const [sentence, checksum, ] = value.split('*')
  return Helpers.verifyChecksum(sentence, checksum)
}

export const useNMEAStore = defineStore('nmea', {
  state: () => ({
    GGA: null,
    GLL: null,
    GSA: {},
    GSV: {},
    RMC: null,
    VTG: null,
    ZDA: null,
    TXT: null,
    // ANT: null,
    // DHV: null,
    // LPS: null,
    // UTC: null,
    // GST: null,
    // INS: null,
    // TIM: null,
    handled: false,
  }),
  getters: {
    dateTime   () {
      if (!this.RMC || !this.RMC.date || !this.RMC.timestamp) return

      return Helpers.parseDateTime(this.RMC.date, this.RMC.timestamp)
    },
    longitude  () {
      if (!this.RMC || !this.RMC.lon || !this.RMC.lonPole) return
      
      return Helpers.parseLongitude(this.RMC.lon, this.RMC.lonPole)
    },
    latitude   () {
      if (!this.RMC || !this.RMC.lat || !this.RMC.latPole) return
      
      return Helpers.parseLatitude(this.RMC.lat, this.RMC.latPole)
    },
    altitude   () {
      if (!this.GGA || !this.GGA.alt || !this.GGA.altUnit) return
    
      return Helpers.parseAltitude(this.GGA.alt, this.GGA.altUnit)
    },
    satellites () {
      return (talker_id) => {
        const gsa  = this.GSA[talker_id]
        const gsvs = this.GSV[talker_id]

        if (!gsa || !gsvs ) return

        const satelliteArr = []

        const active_satellites = gsa.satellites

        gsvs.forEach(({ satellites }) => {
          satellites.forEach(satellite => {
            if (active_satellites.indexOf(parseInt(satellite.id)) < 0) {
              satellite.active = false
            } else {
              satellite.active = true
            }

            satelliteArr.push(satellite)
          })
        })

        return satelliteArr
      }
    },
  },
  actions: {
    bindDataSource(source: NMEADataSource) {
      source.on('open', () => this.$reset())

      let result;
      source.on('data', (data: String) => {
        if (!verify(data)) return

        result = parse(data)
        if (!result) return
        
        // 监控第一条语句，并重置所有state
        if (result.sentence === 'GGA') this.$reset()

        switch (result.sentence) {
          case 'GSA':
            this.GSA[result.talker_id] = result
            break;
          case 'GSV':
            if (!this.GSV[result.talker_id]) {
              this.GSV[result.talker_id] = []
            }

            this.GSV[result.talker_id].push(result)
            break;
          default:
            this.$state[result.sentence] = result
            break;
        }
        
        // 监听最后一条语句，并设置handled为true
        if (result.sentence === 'TXT') {
          this.handled = true
        }
      })
    },
  },
})