const fetch = require('isomorphic-unfetch')

function getStreaminfoUrl (siteurl) {
  return siteurl + '/streaminfo.json' // XXX: improve this logic
}
function getManifestUrl (siteurl) {
  return siteurl + '/radiomanifest.xml' // XXX: improve this logic
}

function getAttribute(el, attr, default_value) {
  if(el.hasAttribute(attr))
    return el.getAttribute(attr);
  return default_value;
}

class Radio {
  constructor (sources, schedule, shows, feed) {
    this.streaming = new RadioStreaming(sources)
    this.schedule = schedule
    this.shows = shows
    this.feed = feed
    this.name = ''
  }

  getStreaming () {
    return this.streaming
  }

  setName (name) {
    this.name = name
  }

  getShowByName (showName) {
  }

  getSchedule () {
  }

  getShowAtTime () {
  }

  static fromDOM (xml) {
    const doc = xml.cloneNode(true)
    let res = doc.evaluate('/radio-manifest/streaming/source', doc, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null)
    const sources = []
    for (let i = 0; i < res.snapshotLength; i++) {
      const src = res.snapshotItem(i)

      if (!src.hasAttribute('priority')) {
        src.setAttribute('priority', '0')
      } else if (parseInt(src.getAttribute('priority'), 10) < 0) {
        continue
      }
      sources.push(src)
    }

    res = doc.evaluate('/radio-manifest/schedule', doc)
    const scheduleEl = res.iterateNext()
    let schedule = null
    if (scheduleEl !== null) {
      schedule = scheduleEl.getAttribute('src')
    }

    res = xml.evaluate('/radio-manifest/shows', xml)
    const showsEl = res.iterateNext()
    let shows = null
    if (showsEl !== null) {
      shows = showsEl.getAttribute('src')
    }

    res = xml.evaluate('/radio-manifest/feed', xml)
    const feedEl = res.iterateNext()
    let feed = null
    if (feedEl !== null) {
      feed = feedEl.getAttribute('src')
    }

    const manifest = new Radio(sources, schedule, shows, feed)
    return manifest
  }
}

class RadioStreaming {
  constructor (sources) {
    this.sources = sources.sort(
        (a,b) => this.getPriority(a) < this.getPriority(a) 
        )
  }

  getOptions() {
    return this.sources.map(function (x) {
        return x.getAttribute('name')
        })
  }
  // this is private
  getPriority(element) {
    return parseInt(getAttribute(element, 'priority', '1'))
  }
  // this is private
  getTopPrioritySources() {
    var topPriority = this.getPriority(this.sources[0])
    return this.sources.filter(
        (src) => parseInt(src.getAttribute('priority'), 10) === topPriority
        )
  }
  getSource(name) {
    if (name === undefined) {
      return this.getTopPrioritySources()[0]
    }
    const s = this.sources.find(function (x) {
        return x.getAttribute('name') === name
        })
    if (s === undefined) return s
      return s.getAttribute('src')
  }
  
  async pickURLs() {
    var allSources = this.getTopPrioritySources()
    var allAudios = []
    for(let src of allSources) {
      let url = src.getAttribute('src')
      let resp = await fetch(url)
      allAudios.unshift(... parseM3U(await resp.text()))
    }
    return allAudios
  }
  async pickURL() {
    var allAudios = await this.pickURLs()
    return allAudios[0]
  }
}

async function get (siteurl, options) {
  let resp = await fetch(getManifestUrl(siteurl))
  let text = await resp.text()

  const parser = new DOMParser()
  const dom = parser.parseFromString(text, 'text/xml')
  const manifest = Radio.fromDOM(dom)

  resp = null
  try {
    resp = await fetch(getStreaminfoUrl(siteurl))
  } catch (e) {
    true
  }
  if(resp !== null) {
    try {
      text = await resp.text()

        const data = JSON.parse(text)
        const name = data['icy-name']
        if (name !== undefined) {
          manifest.setName(name)
        }
    } catch (e) {
      if (e instanceof SyntaxError) {
        true
      } else {
        console.error('Error', e)
          throw e
      }
    }
  }

  // XXX: in base alle options fai fetch anche di altra roba
  return manifest
}

function parseM3U (body) {
  return body.split('\n').filter((line) => {
    if (line.startsWith('#')) {
      return false
    } else {
      try {
        new URL(line); return true
      } catch {
        return false
      }
    }
  })
}

module.exports = {
  get: get,
  objs: {
    Radio: Radio,
    RadioStreaming: RadioStreaming
  },
  parsers: {
    M3U: parseM3U,
    radioManifest: Radio.fromDOM
  }
}