var {h, computed, when, map, send} = require('mutant')
var nest = require('depnest')
var extend = require('xtend')
var moment = require('moment')

exports.needs = nest({
  'message.html.markdown': 'first',
  'message.html.layout': 'first',
  'message.html.decorate': 'reduce',
  'message.async.publish': 'first',
  'keys.sync.id': 'first',
  'about.html.image': 'first',
  'about.obs.latestValue': 'first',
  'about.obs.groupedValues': 'first',
  'about.obs.valueFrom': 'first',
  'about.obs.name': 'first',
  'contact.obs.following': 'first',
  'blob.sync.url': 'first',
  'gathering.sheet.edit': 'first'
})

exports.gives = nest('message.html.render')

exports.create = function (api) {
  var following = null

  return nest('message.html.render', function renderGathering (msg, opts) {
    if (msg.value.content.type !== 'gathering') return
    var yourId = api.keys.sync.id()
    var hidden = api.about.obs.valueFrom(msg.key, 'hidden', yourId)
    var image = api.about.obs.latestValue(msg.key, 'image')
    var title = api.about.obs.latestValue(msg.key, 'title')
    var description = api.about.obs.latestValue(msg.key, 'description')
    var location = api.about.obs.latestValue(msg.key, 'location')
    var startDateTime = api.about.obs.latestValue(msg.key, 'startDateTime')
    var endDateTime = api.about.obs.latestValue(msg.key, 'endDateTime')
    var attendees = computed([api.about.obs.groupedValues(msg.key, 'attendee')], getAttendees)
    if (!following) {
      following = api.contact.obs.following(yourId)
    }

    var imageUrl = computed(image, (id) => api.blob.sync.url(id))
    var imageId = computed(image, (link) => link && link.link || link)
    var content = h('GatheringCard', [
      h('div.title', [
        h('a', {href: msg.key}, title),
        h('button', {
          'ev-click': send(api.gathering.sheet.edit, msg.key)
        }, 'Edit Details')
      ]),
      h('div.time', computed(startDateTime, formatTime)),
      when(image, h('a.image', {
        href: imageId,
        style: {
          'background-image': computed(imageUrl, (url) => `url(${url})`)
        }
      })),
      h('div.attending', [
        h('div.title', ['Attendees', ' (', computed(attendees, (x) => x.length), ')']),
        h('div.attendees', [
          map(attendees, (attendee) => {
            return h('a.attendee', {
              href: attendee,
              title: nameAndFollowWarning(attendee)
            }, api.about.html.image(attendee))
          })
        ]),
        h('div.actions', [
          h('button -attend', {
            'ev-click': send(publishAttending, msg.key)
          }, `Attending`),
          h('button -attend', {
            'ev-click': send(publishNotAttending, msg.key)
          }, `Can't Attend`)
        ])
      ]),
      h('div.location', markdown(location)),
      when(description, h('div.description', markdown(description)))
    ])

    var element = api.message.html.layout(msg, extend({
      content,
      miniContent: 'Added a gathering',
      layout: 'mini'
    }, opts))

    // hide if no title set or hidden
    var visible = computed([title, hidden], (title, hidden) => {
      return title && !hidden
    })

    return when(visible, api.message.html.decorate(element, { msg }))
  })

  function publishAttending (id) {
    var yourId = api.keys.sync.id()

    // publish with confirm
    api.message.async.publish({
      type: 'about',
      about: id,
      attendee: {
        link: yourId
      }
    })
  }

  function publishNotAttending (id) {
    var yourId = api.keys.sync.id()

    // publish with confirm
    api.message.async.publish({
      type: 'about',
      about: id,
      attendee: {
        link: yourId,
        remove: true
      }
    })
  }

  function nameAndFollowWarning (id) {
    var yourId = api.keys.sync.id()
    return computed([api.about.obs.name(id), id, following], function nameAndFollowWarning (name, id, following) {
      if (id === yourId) {
        return `${name} (you)`
      } else if (following.includes(id)) {
        return `${name}`
      } else {
        return `${name} (not following)`
      }
    })
  }

  function markdown (obs) {
    return computed(obs, (text) => {
      if (typeof text === 'string') return api.message.html.markdown(text)
    })
  }
}

function formatTime (time) {
  if (time && time.epoch) {
    return moment(time.epoch).format('LLLL')
  }
}

function getAttendees (lookup) {
  return Object.keys(lookup)
}