git ssb

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var pull = require('pull-stream')
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var asyncMemo = require('asyncmemo')
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module.exports = function (sbot) {
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  var votes = {}
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  pull(
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    sbot.links({rel: 'vote', values: true, old: false}),
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    pull.drain(processMsg, function (err) {
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      if (err) console.error('vote', err)
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    })
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  )
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  return asyncMemo(function (id, cb) {
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    var result = votes[id] = {
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      upvoters: {},
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      downvoters: {},
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      upvotes: 0,
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      downvotes: 0
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    }
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    pull(
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      sbot.links({dest: id, rel: 'vote', values: true}),
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      pull.drain(processMsg, function (err) {
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        cb(err, result)
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      })
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    )
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  })
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  function processMsg(msg) {
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    var c = msg.value.content
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    if (!c || !c.vote) return
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    var result = votes[c.vote.link]
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    if (!result) return
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    var vote = c.vote.value
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    var author = msg.value.author
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    // remove old vote, if any
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    if (author in result.upvoters) {
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      result.upvotes--
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      delete result.upvoters[author]
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    } else if (author in result.downvoters) {
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      result.downvotes--
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      delete result.downvoters[author]
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    }
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    // add new vote
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    if (vote > 0) {
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      result.upvoters[author] = vote
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      result.upvotes++
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    } else if (vote < 0) {
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      result.downvoters[author] = vote
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      result.downvotes++
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    }
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  }
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}
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