var MutantMap = require('@mmckegg/mutant/map')
var computed = require('@mmckegg/mutant/computed')
var when = require('@mmckegg/mutant/when')
var send = require('@mmckegg/mutant/send')
var pull = require('pull-stream')
var extend = require('xtend')

var plugs = require('patchbay/plugs')
var h = require('../lib/h')
var message_compose = plugs.first(exports.message_compose = [])
var sbot_log = plugs.first(exports.sbot_log = [])
var sbot_feed = plugs.first(exports.sbot_feed = [])
var sbot_user_feed = plugs.first(exports.sbot_user_feed = [])

var feed_summary = plugs.first(exports.feed_summary = [])
var obs_channels = plugs.first(exports.obs_channels = [])
var obs_subscribed_channels = plugs.first(exports.obs_subscribed_channels = [])
var get_id = plugs.first(exports.get_id = [])
var publish = plugs.first(exports.sbot_publish = [])
var obs_following = plugs.first(exports.obs_following = [])
var obs_recently_updated_feeds = plugs.first(exports.obs_recently_updated_feeds = [])
var avatar_image = plugs.first(exports.avatar_image = [])
var avatar_name = plugs.first(exports.avatar_name = [])
var obs_local = plugs.first(exports.obs_local = [])
var obs_connected = plugs.first(exports.obs_connected = [])

exports.screen_view = function (path, sbot) {
  if (path === '/public') {
    var id = get_id()
    var channels = computed(obs_channels(), items => items.slice(0, 8), {comparer: arrayEq})
    var subscribedChannels = obs_subscribed_channels(id)
    var loading = computed(subscribedChannels.sync, x => !x)
    var connectedPeers = obs_connected()
    var localPeers = obs_local()
    var connectedPubs = computed([connectedPeers, localPeers], (c, l) => c.filter(x => !l.includes(x)))
    var following = obs_following(id)

    var oldest = Date.now() - (2 * 24 * 60 * 60e3)
    getFirstMessage(id, (_, msg) => {
      if (msg) {
        // fall back to timestamp stream before this, give 48 hrs for feeds to stabilize
        if (msg.value.timestamp > oldest) {
          oldest = Date.now()
        }
      }
    })

    var whoToFollow = computed([obs_following(id), obs_recently_updated_feeds(200)], (following, recent) => {
      return Array.from(recent).filter(x => x !== id && !following.has(x)).slice(0, 10)
    })

    var feedSummary = feed_summary(getFeed, [
      message_compose({type: 'post'}, {placeholder: 'Write a public message'})
    ], {
      waitUntil: computed([
        following.sync,
        subscribedChannels.sync
      ], x => x.every(Boolean)),
      windowSize: 500,
      filter: (item) => {
        return (
          id === item.author ||
          following().has(item.author) ||
          subscribedChannels().has(item.channel) ||
          (item.repliesFrom && item.repliesFrom.has(id)) ||
          item.digs && item.digs.has(id)
        )
      },
      bumpFilter: (msg, group) => {
        if (!group.message) {
          return (
            isMentioned(id, msg.value.content.mentions) ||
            msg.value.author === id || (
              fromDay(msg, group.fromTime) && (
                following().has(msg.value.author) ||
                group.repliesFrom.has(id)
              )
            )
          )
        }
        return true
      }
    })

    var result = h('SplitView', [
      h('div.side', [
        h('h2', 'Active Channels'),
        when(loading, [ h('Loading') ]),
        h('ChannelList', {
          hidden: loading
        }, [
          MutantMap(channels, (channel) => {
            var subscribed = subscribedChannels.has(channel.id)
            return h('a.channel', {
              href: `##${channel.id}`,
              classList: [
                when(subscribed, '-subscribed')
              ]
            }, [
              h('span.name', '#' + channel.id),
              when(subscribed,
                h('a -unsubscribe', {
                  'ev-click': send(unsubscribe, channel.id)
                }, 'Unsubscribe'),
                h('a -subscribe', {
                  'ev-click': send(subscribe, channel.id)
                }, 'Subscribe')
              )
            ])
          }, {maxTime: 5})
        ]),

        when(computed(localPeers, x => x.length), h('h2', 'Local')),
        h('ProfileList', [
          MutantMap(localPeers, (id) => {
            return h('a.profile', {
              classList: [
                when(computed([connectedPeers, id], (p, id) => p.includes(id)), '-connected')
              ],
              href: `#${id}`
            }, [
              h('div.avatar', [avatar_image(id)]),
              h('div.main', [
                h('div.name', [ avatar_name(id) ])
              ])
            ])
          })
        ]),

        when(computed(whoToFollow, x => x.length), h('h2', 'Who to follow')),
        h('ProfileList', [
          MutantMap(whoToFollow, (id) => {
            return h('a.profile', {
              href: `#${id}`
            }, [
              h('div.avatar', [avatar_image(id)]),
              h('div.main', [
                h('div.name', [ avatar_name(id) ])
              ])
            ])
          })
        ]),

        when(computed(connectedPubs, x => x.length), h('h2', 'Connected Pubs')),
        h('ProfileList', [
          MutantMap(connectedPubs, (id) => {
            return h('a.profile', {
              classList: [ '-connected' ],
              href: `#${id}`
            }, [
              h('div.avatar', [avatar_image(id)]),
              h('div.main', [
                h('div.name', [ avatar_name(id) ])
              ])
            ])
          })
        ])
      ]),
      h('div.main', [ feedSummary ])
    ])

    result.pendingUpdates = feedSummary.pendingUpdates
    result.reload = feedSummary.reload

    return result
  }

  // scoped

  function getFeed (opts) {
    if (opts.lt && opts.lt < oldest) {
      opts = extend(opts, {lt: parseInt(opts.lt, 10)})
      return pull(
        sbot_feed(opts),
        pull.map((msg) => {
          if (msg.sync) {
            return msg
          } else {
            return {key: msg.key, value: msg.value, timestamp: msg.value.timestamp}
          }
        })
      )
    } else {
      return sbot_log(opts)
    }
  }
}

function fromDay (msg, fromTime) {
  return (fromTime - msg.timestamp) < (24 * 60 * 60e3)
}

function isMentioned (id, list) {
  if (Array.isArray(list)) {
    return list.includes(id)
  } else {
    return false
  }
}

function subscribe (id) {
  publish({
    type: 'channel',
    channel: id,
    subscribed: true
  })
}

function unsubscribe (id) {
  publish({
    type: 'channel',
    channel: id,
    subscribed: false
  })
}

function arrayEq (a, b) {
  if (Array.isArray(a) && Array.isArray(b) && a.length === b.length && a !== b) {
    return a.every((value, i) => value === b[i])
  }
}

function getFirstMessage (feedId, cb) {
  sbot_user_feed({id: feedId, gte: 0, limit: 1})(null, cb)
}