const axios = require('axios')
const cheerio = require('cheerio')
const SafeEval = require('safe-eval')
const baseURL = 'https://www.instagram.com'

const obj = {}
module.exports = obj

/**
 * get post link
 * @param {string} shortcode ig post shortcode
 */
const getPostLink = (shortcode = '') => {
  if (typeof shortcode !== 'string' || shortcode.trim().length === 0) return ''
  return `${baseURL.replace(/\/$/, '')}/p/${shortcode}`
}

/**
 * @param {string} data instagram source html
 */
const getInstagramData = (data) => {
  // console.log(data)
  if (typeof data !== 'string' || data.trim().length === 0) return null
  let $ = cheerio.load(data)

  let dataArr = []
  $('script').each((idx, el) => {
    let e = cheerio.load(el)
    // console.log(e('script').html())
    if (/^window._sharedData/i.test(e('script').html())) {
      // console.log('aaa')
      dataArr.push(e('script').html())
    }
  })

  // console.log(dataArr)
  if (dataArr.length === 0) return null
  let context = { window: {} }
  SafeEval(dataArr[0], context)
  let posts = context.window._sharedData.entry_data.ProfilePage[0].graphql.user.edge_owner_to_timeline_media.edges
  let lastPost = posts[0].node
  // console.log(JSON.stringify(lastPost, null, 2))
  let postData = {}
  postData.id = lastPost.id
  postData.timestamp = lastPost.taken_at_timestamp
  postData.link = getPostLink(lastPost.shortcode)
  try {
    postData.text = lastPost.edge_media_to_caption.edges.length > 0 ? lastPost.edge_media_to_caption.edges[0].node.text : ''
  } catch (err) {
    postData.text = ''
  }
  lastPost = null
  posts = null
  delete context.window
  return postData
}

/**
 * @param {string} id ig user page id
 */
obj.getLastPost = async (id) => {
  if (typeof id !== 'string' || id.trim().length === 0) return null
  let param = {
    baseURL,
    method: 'get',
    url: `/${id}`,
    headers: {
      'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Gecko/20100101 Firefox/68.0'
      // 'Referer': 'https://wiki.trj.tw'
    }
  }

  try {
    let result = await axios(param)
    if (!('data' in result) || typeof result.data !== 'string') return null
    let data = getInstagramData(result.data)
    return data
  } catch (err) {
    console.log(err.response.data || 'no response error data')
    return null
  }
}