git ssb

1
var nest = require('depnest')
2
var sort = require('ssb-sort')
3
var ref = require('ssb-ref')
4
var { Array: MutantArray, Value, map, concat, computed } = require('mutant')
5
6
exports.needs = nest({
7
  'backlinks.obs.for': 'first',
8
  'sbot.async.get': 'first',
9
  'message.sync.unbox': 'first',
10
  'message.sync.root': 'first',
11
  'message.sync.isBlocked': 'first',
12
})
13
14
exports.gives = nest('feed.obs.thread')
15
16
exports.create = function (api) {
17
  return nest('feed.obs.thread', thread)
18
19
  function thread (rootId, { branch } = {}) {
20
    if (!ref.isLink(rootId)) throw new Error('an id must be specified')
21
    var sync = Value(false)
22
    const { isBlocked, unbox, root } = message.sync
23
24
    var prepend = MutantArray()
25
    api.sbot.async.get(rootId, (err, value) => {
26
      sync.set(true)
27
      if (!err) {
28
        var msg = unboxIfNeeded({key: rootId, value})
29
        if (isBlocked(msg)) msg.isBlocked = true
30
        prepend.push(Value(msg))
31
      }
32
    })
33
34
    var backlinks = api.backlinks.obs.for(rootId)
35
    var replies = map(computed(backlinks, (msgs) => {
36
      return msgs.filter(msg => {
37
        const { type, branch } = msg.value.content
38
        return type !== 'vote'
39
          && !isBlocked(msg)
40
          && (root(msg) === rootId || matchAny(branch, rootId))
41
      })
42
    }), x => Value(x), {
43
      // avoid refresh of entire list when items added
44
      comparer: (a, b) => a === b
45
    })
46
47
    var messages = concat([prepend, replies])
48
49
    var result = {
50
      messages,
51
      lastId: computed(messages, (messages) => {
52
        var branches = sort.heads(messages)
53
        if (branches.length <= 1) {
54
          branches = branches[0]
55
        }
56
        return branches
57
      }),
58
      rootId: computed(messages, (messages) => {
59
        if (branch && messages.length) {
60
          return messages[0].value.content.root
61
        } else {
62
          return rootId
63
        }
64
      }),
65
      branchId: computed(messages, (messages) => {
66
        if (branch) return rootId
67
      }),
68
      previousKey: function (msg) {
69
        return PreviousKey(result.messages, msg)
70
      },
71
      isPrivate: computed(messages, msgs => {
72
        if (!msgs[0]) return false
73
74
        return msgs[0].value.private || false
75
      }),
76
      channel: computed(messages, msgs => {
77
        if (!msgs[0]) return undefined
78
79
        return msgs[0].value.content.channel
80
      }),
81
      recps: computed(messages, msgs => {
82
        if (!msgs[0]) return undefined
83
84
        return msgs[0].value.content.recps
85
      })
86
    }
87
88
    result.sync = computed([backlinks.sync, sync], (a, b) => a && b, {idle: true})
89
    return result
90
  }
91
92
  function unboxIfNeeded (msg) {
93
    if (msg.value && typeof msg.value.content === 'string') {
94
      return unbox(msg) || msg
95
    } else {
96
      return msg
97
    }
98
  }
99
}
100
101
function PreviousKey (collection, item) {
102
  return computed(collection, (c) => {
103
    var index = collection.indexOf(item)
104
    if (~index) {
105
      var previous = c[index - 1]
106
      if (previous) {
107
        return previous.key
108
      }
109
    }
110
  })
111
}
112
113
function matchAny (valueOrArray, compare) {
114
  if (valueOrArray === compare) {
115
    return true
116
  } else if (Array.isArray(valueOrArray)) {
117
    return valueOrArray.includes(compare)
118
  }
119
}
120