var pull = require('pull-stream')
var ref = require('ssb-ref')
var msum = require('markdown-summary')
var sort = require('ssb-sort')
var u = require('yap-util')

var toUrl = u.toUrl

function uniqueRecps (recps) {
  if(!recps || !recps.length) return
  recps = recps.map(function (e) {
    return 'string' === typeof e ? e : e.link
  })
  .filter(Boolean)
  return recps.filter(function (id, i) {
    return !~recps.indexOf(id, i+1)
  })
}

function getThread(sbot, id, cb) {
  pull(
    sbot.query.read({
      //hack so that ssb-query filters on post but uses
      //indexes for root.
      query: [{$filter: {
        value: { content: {root: id} }
      }},{$filter: {
        value: { content: {type: 'post'} }
      }}]
    }),
    pull.collect(function (err, ary) {
      if(err) return cb(err)
      cb(null, ary)
    })
  )
}

function isObject(o) {
  return o && 'object' === typeof o
}
var isArray = Array.isArray

module.exports = function (sbot) {
  return function (opts, apply, req) {
    var context = req.cookies
    var since = apply.since
    var tr = require('./translations')(context.lang)
    return function (cb) {
      var cacheTime = 0
      if(!ref.isMsg(opts.id))
        return cb(new Error('expected valid msg id as id'))
      sbot.get({id:opts.id, private: true}, function (err, msg) {
        if(err) return cb(err)
        var data = {key: opts.id, value: msg, timestamp: msg.timestamp || Date.now() }
        if(data.value.content.root)
          cb(null, apply('message', data)) //just show one message
        else if(data.value.content.type != 'post')
          cb(null, apply('message', data)) //just show one message
        else
          getThread(sbot, opts.id, function (err, ary) {
            var root = opts.id
            ary = [data].concat(ary || [])
            var branch = sort.heads(ary)
            var recps = uniqueRecps(ary[0].value.content.recps)

            ary.unshift(data)
            var o = {}, cacheTime
            ary = ary.filter(function (e) {
              if(o[e.key]) return false
              return o[e.key] = true
            })
            sort(ary)
            var recipients = ' '
            if(ary[0].value.content.recps)
                recipients = ['div.Recipients', tr('ThreadRecipients'),
                  ary[0].value.content.recps.map(function (e) {
                    return apply('avatar', e)
                  })]
            cb(null,
              ['div.thread',
                apply.cacheAttrs(apply.toUrl('patch/thread', opts), data.key, since),
                ary[0].value.content.text && ['title', msum.title(ary[0].value.content.text)],
                recipients,
                ary.map(function (data) {
                  var msg = apply('messageLayout', {
                    id: data.key,
                    author: data.value.author,
                    content: u.markdown(data.value.content),
                    root: root, branch: branch,
                    ts: data.value.timestamp || data.timestamp,
                    meta: [],
                    extra: true
                  })
                  return msg
                }),
                apply('compose', {
                  content: {
                    type: 'post',
                    root: root,
                    recps: recps,
                    branch: branch,
                    channel: ary[0].value.content.channel
                  }
                })
              ]
            )
          })
      })
    }
  }
}