/**
 * Service scrapes Instagram for pictures since they've ruined their API.
 * Set it up in services config with the following options:
    instagram: {
      username: 'annapurnapics',
      frequency: 60 * 60 * 1000,
    },
 */

var request = require('request')

function OKInstagram (options) {
  if (!(this instanceof OKInstagram)) return new OKInstagram(options)
  options = options || {}
  if (!options.express)
    throw new Error('Express not provided to OKInstagram');
  if (!options.config || !options.config.username)
    throw new Error('Username not provided to OKInstagram');

  var express = options.express
  var router = express.Router()
  
  var username = options.config.username
  var frequency = options.config.frequency || 60 * 60 * 1000 // hourly
  
  var posts = []

  router.get('/', function (req, res) {
    res.set('Content-Type', 'application/json; charset=utf-8')
    res.send(posts)
  })
  router.get('/fetch', function (req, res) {
    res.send('Fetching now')
    setTimeout(fetch)
  })
  
  function go () {
    fetch(function(){
      setTimeout(go, frequency)
    })
  }
  function fetch (cb) {
    request('https://www.instagram.com/' + username + '/', function (err, response, body) {
      if (err || response.statusCode !== 200) {
        console.error("error fetching instagrams")
        cb && cb()
        return
      }
      if (! body.match(/"nodes": \[/)) {
        console.error("instagram format has changed")
        cb && cb()
        return
      }
      var node_first = body.split(/"nodes": \[/)[1]
      var node_list = node_first.split(/\]/)[0]
      var nodes = JSON.parse("[" + node_list + "]")
      posts = nodes.map(function(node){
        var post = {
          url: "https://www.instagram.com/p/" + node.code,
          img: node.thumbnail_src,
          caption: node.caption || "",
        }
        return post
      })
      cb && cb()
    })
  }

  router.post('*', function (req, res) {
    throw new Error('OKInstagram POST requests not implemented')
  })

  if (frequency)
    go()

  this._router = router
}

OKInstagram.prototype.middleware = function () {
  return this._router
}

module.exports = OKInstagram