const nest = require('depnest')
const { h, Array: MutantArray, Value, map, computed, when, resolve, throttle } = require('mutant')
const get = require('lodash/get')

exports.gives = nest('app.html.comments')

exports.needs = nest({
  'about.html.avatar': 'first',
  'about.obs.name': 'first',
  'backlinks.obs.for': 'first',
  'feed.obs.thread': 'first',
  'message.html.compose': 'first',
  'message.html.markdown': 'first',
  'message.html.timeago': 'first',
  'message.html.likes': 'first',
  'unread.sync.markRead': 'first',
  'unread.sync.isUnread': 'first',
  'translations.sync.strings': 'first',
})

exports.create = (api) => {
  return nest('app.html.comments', comments)

  function comments (thread) {
    const { messages, channel, lastId: branch } = thread
    const strings = api.translations.sync.strings()

    // TODO - move this up into Patchcore
    const messagesTree = computed(throttle(messages, 200), msgs => {
      return msgs
        .filter(msg => forkOf(msg) === undefined)
        .map(threadMsg => { 
          const nestedReplies = msgs.filter(msg => forkOf(msg) === threadMsg.key)
          threadMsg.replies = nestedReplies
          return threadMsg
        })
    })

    const root = computed(messages, ary => ary[0].key)

    const meta = {
      type: 'post',
      root,
      branch,
      channel
    }
    // const twoComposers = computed(messages, messages => {
    //   return messages.length > 5
    // })
    const { compose } = api.message.html


    return h('Comments', [
      // when(twoComposers, compose({ meta, shrink: true, canAttach: false })),
      map(messagesTree, msg => Comment(msg, root, branch)),
      compose({ meta, shrink: false, canAttach: true, placeholder: strings.writeComment }),
    ])
  }

  function Comment (msgObs, root, branch) {
    const strings = api.translations.sync.strings()
    const msg = resolve(msgObs)

    const raw = get(msg, 'value.content.text')
    var className = api.unread.sync.isUnread(msg) ? ' -unread' : ' -read'
    api.unread.sync.markRead(msg)

    if (!get(msg, 'value.content.root')) return

    const { author, content } = msg.value

    // // TODO - move this upstream into patchcore:feed.obs.thread ??
    // // OR change strategy to use forks
    // const backlinks = api.backlinks.obs.for(msg.key) 
    // const nestedReplies = computed(backlinks, backlinks => {
    //   return backlinks.filter(backlinker => {
    //     const { type, root } = backlinker.value.content
    //     return type === 'post' && root === msg.key
    //   })
    // })

    var nestedReplyCompose = Value(false)
    const toggleCompose = () => nestedReplyCompose.set(!nestedReplyCompose())
    const nestedReplyComposer = api.message.html.compose({
      meta: {
        type: 'post',
        root,
        fork: msg.key,
        branch,
        channel: content.channel
      },
      shrink: false,
      canAttach: true,
      canPreview: false,
      placeholder: strings.writeComment 
    }, toggleCompose)

    return h('Comment', { className }, [
      h('div.left', api.about.html.avatar(author, 'tiny')),
      h('div.right', [
        h('section.context', [
          h('div.name', api.about.obs.name(author)),
          api.message.html.timeago(msg)
        ]),
        h('section.content', api.message.html.markdown(raw)),
        when(msgObs.replies, 
          h('section.replies', 
            map(msgObs.replies, NestedComment)
          )
        ),
        h('section.actions', [
          h('div.reply', { 'ev-click': toggleCompose }, [ 
            h('i.fa.fa-commenting-o'),
          ]),
          api.message.html.likes(msg)
        ]),
        when(nestedReplyCompose, nestedReplyComposer),
      ])
    ])
  }

  function NestedComment (msgObs) {
    const msg = resolve(msgObs)
    const raw = get(msg, 'value.content.text')
    if (!raw) return

    const { author } = msg.value

    return h('Comment -nested', [
      h('div.left'),
      h('div.right', [
        h('section.context', [
          h('div.name', api.about.obs.name(author)),
          api.message.html.timeago(msg)
        ]),
        h('section.content', api.message.html.markdown(raw)),
      ])
    ])

    api.message.html.markdown(raw)
  }
}

function forkOf (msg) {
  return get(msg, 'value.content.fork')
}