aboutsummaryrefslogtreecommitdiff
path: root/lib/about.js
blob: 5f1c6181b21540576b77d92d42f5d3e9bd77ba10 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
var pull = require('pull-stream')
var multicb = require('multicb')
var cat = require('pull-cat')
var u = require('./util')

module.exports = About

function About(app, myId, follows) {
  this.app = app
  this.myId = myId
  this.follows = follows
}

About.prototype.createAboutOpStream = function (id) {
  return pull(
    this.app.sbot.links({dest: id, rel: 'about', values: true, reverse: true}),
    pull.map(function (msg) {
      var c = msg.value.content || {}
      return Object.keys(c).filter(function (key) {
        return key !== 'about'
          && key !== 'type'
          && key !== 'recps'
      }).map(function (key) {
        var value = c[key]
        return {
          id: msg.key,
          author: msg.value.author,
          timestamp: msg.value.timestamp,
          prop: key,
          value: value,
          remove: value && value.remove,
        }
      })
    }),
    pull.flatten()
  )
}

About.prototype.createAboutStreams = function (id) {
  var ops = this.createAboutOpStream(id)
  var scalars = {/* author: {prop: value} */}
  var sets = {/* author: {prop: {link}} */}

  var setsDone = multicb({pluck: 1, spread: true})
  setsDone()(null, pull.values([]))
  return {
    scalars: pull(
      ops,
      pull.unique(function (op) {
        return op.author + '-' + op.prop + '-'
      }),
      pull.filter(function (op) {
        return !op.remove
      })
    ),
    sets: u.readNext(setsDone)
  }
}

function computeTopAbout(aboutByFeed) {
  var propValueCounts = {/* prop: {value: count} */}
  var topValues = {/* prop: value */}
  var topValueCounts = {/* prop: count */}
  for (var feed in aboutByFeed) {
    var feedAbout = aboutByFeed[feed]
    for (var prop in feedAbout) {
      var value = feedAbout[prop]
      var valueCounts = propValueCounts[prop] || (propValueCounts[prop] = {})
      var count = (valueCounts[value] || 0) + 1
      valueCounts[value] = count
      if (count > (topValueCounts[prop] || 0)) {
        topValueCounts[prop] = count
        topValues[prop] = value
      }
    }
  }
  return topValues
}

About.prototype.get = function (dest, cb) {
  var self = this
  var myAbout = []
  var aboutByFeed = {}
  var aboutByFeedFollowed = {}
  this.follows.getFollows(this.myId, function (err, follows) {
    if (err) return cb(err)
    pull(
      cat([
        dest[0] === '%' && self.app.pullGetMsg(dest),
        self.app.sbot.links({
          rel: 'about',
          dest: dest,
          values: true,
        })
      ]),
      self.app.unboxMessages(),
      pull.drain(function (msg) {
        var author = msg.value.author
        var c = msg.value.content
        if (!c) return
        if (msg.key === dest && c.type === 'about') {
          // don't describe an about message with itself
          return
        }
        var about = author === self.myId ? myAbout :
          follows[author] ?
            aboutByFeedFollowed[author] || (aboutByFeedFollowed[author] = {}) :
            aboutByFeed[author] || (aboutByFeed[author] = {})

        if (c.name) about.name = c.name
        if (c.title) about.title = c.title
        if (c.image) {
          about.image = u.linkDest(c.image)
          about.imageLink = u.toLink(c.image)
        }
        if (c.description) about.description = c.description
        if (c.publicWebHosting) about.publicWebHosting = c.publicWebHosting
      }, function (err) {
        if (err) return cb(err)
        var destAbout = aboutByFeedFollowed[dest] || aboutByFeed[dest]
        // bias the author's choices by giving them an extra vote
        if (destAbout) {
          if (follows[dest]) aboutByFeedFollowed._author = destAbout
          else aboutByFeed._author = destAbout
        }
        var about = {}
        var followedAbout = computeTopAbout(aboutByFeedFollowed)
        var topAbout = computeTopAbout(aboutByFeed)
        for (var k in topAbout) about[k] = topAbout[k]
        // prefer followed feeds' choices
        for (var k in followedAbout) about[k] = followedAbout[k]
        // if we follow the destination/author feed, prefer its choices
        if (follows[dest]) for (var k in destAbout) about[k] = destAbout[k]
        // always prefer own choices
        for (var k in myAbout) about[k] = myAbout[k]
        cb(null, about)
      })
    )
  })
}