path: root/helpers.rb

require 'English'
helpers do
  def save_item(item, path)
    FileUtils.mkdir_p File.dirname(path)
    File.open(path, 'w+') { |f| f.puts item.to_json }
  end

  def create_activity(type, object, to)
    date = Time.now.utc.iso8601
    rel_path = File.join(type.downcase, "#{date}.json")
    activity = {
      '@context' => 'https://www.w3.org/ns/activitystreams',
      'id' => File.join(OUTBOX[:url], rel_path),
      'type' => type,
      'actor' => ACTOR,
      'published' => date,
      'to' => to,
      'object' => object
    }

    unless activity['object'].is_a? String
      object_rel_path = File.join('object', object['type'].downcase, "#{date}.json")
      object = activity['object']
      object['@context'] = 'https://www.w3.org/ns/activitystreams'
      object['id'] = File.join(OUTBOX[:url], object_rel_path)
      object['published'] = date
      save_item activity['object'], File.join(OUTBOX[:dir], object_rel_path)
      if object['tag']
        object['tag'].each do |tag|
          next unless tag['type'] == 'Hashtag'

          tag_path = File.join(TAGS[:dir], tag['name'].sub('#', '')) + '.json'
          tag_collection = if File.exist? tag_path
                             JSON.load_file(tag_path)
                           else
                             {
                               '@context' => 'https://www.w3.org/ns/activitystreams',
                               'id' => tag['href'],
                               'type' => 'OrderedCollection',
                               'totalItems' => 0,
                               'orderedItems' => []
                             }
                           end
          tag_collection['orderedItems'] << object['id']
          tag_collection['totalItems'] = tag_collection['orderedItems'].size
          File.open(tag_path, 'w+') do |f|
            f.puts tag_collection.to_json
          end
        end
      end
    end
    activity_path = File.join(OUTBOX[:dir], rel_path)
    save_item activity, activity_path
    send_activity activity, activity_path
  end

  def send_activity(activity, activity_path)
    to = activity['to'].is_a?(String) ? [activity['to']] : activity['to']
    inboxes = []
    to.uniq.each do |url|
      next if [ACTOR, 'https://www.w3.org/ns/activitystreams#Public'].include? url

      if url == FOLLOWERS_URL
        JSON.load_file(FOLLOWERS)['orderedItems'].each do |follower|
          inboxes << actor_inbox(follower)
        end
        next
      end
      inboxes << actor_inbox(url)
    end

    sha256 = OpenSSL::Digest.new('SHA256')
    digest = "SHA-256=#{sha256.base64digest(File.read(activity_path))}"
    keypair = OpenSSL::PKey::RSA.new(File.read('private.pem'))

    inboxes.compact.uniq.each do |inbox|
      uri = URI(inbox)
      httpdate = Time.now.utc.httpdate
      string = "(request-target): post #{uri.request_uri}\nhost: #{uri.host}\ndate: #{httpdate}\ndigest: #{digest}\ncontent-type: #{CONTENT_TYPE}"
      signature = Base64.strict_encode64(keypair.sign(OpenSSL::Digest.new('SHA256'), string))
      signed_header = "keyId=\"#{ACTOR}#main-key\",algorithm=\"rsa-sha256\",headers=\"(request-target) host date digest content-type\",signature=\"#{signature}\""

      # Net::HTTP fails with OpenSSL error
      curl(
        "-X POST -H 'Host: #{uri.host}' -H 'Date: #{httpdate}' -H 'Digest: #{digest}' -H 'Signature: #{signed_header}' --data-binary '@#{activity_path}'", inbox
      )
    end
  end

  def actor_inbox(url)
    actor = fetch url
    return unless actor

    if actor['endpoints'] and actor['endpoints']['sharedInbox']
      actor['endpoints']['sharedInbox']
    elsif actor['inbox']
      actor['inbox']
    end
  end

  def update_collection(path, objects, action = 'add')
    objects = [objects] unless objects.is_a? Array
    File.open(path, 'r+') do |f|
      f.flock(File::LOCK_EX)
      json = f.read
      collection = JSON.parse(json)
      objects.each do |object|
        id = object['id'] || object
        if action == 'delete'
          collection['orderedItems'].delete_if { |o| o['id'] == id or o == id }
        elsif action == 'add'
          ids = collection['orderedItems'].collect { |i| i['id'] }
          collection['orderedItems'] << object unless ids.include?(id) or collection['orderedItems'].include?(id)
        end
      end
      collection['orderedItems'].uniq!
      collection['totalItems'] = collection['orderedItems'].size
      f.rewind
      f.puts collection.to_json
      f.truncate(f.pos)
    end
  end

  def fetch(url, accept = 'application/activity+json')
    begin
      uri = URI(url)
    rescue StandardError => e
      p url, e
      return nil
    end
    httpdate = Time.now.utc.httpdate
    keypair = OpenSSL::PKey::RSA.new(File.read('private.pem'))
    string = "(request-target): get #{uri.request_uri}\nhost: #{uri.host}\ndate: #{httpdate}"
    signature = Base64.strict_encode64(keypair.sign(OpenSSL::Digest.new('SHA256'), string))
    signed_header = "keyId=\"#{ACTOR}#main-key\",algorithm=\"rsa-sha256\",headers=\"(request-target) host date\",signature=\"#{signature}\""
    response = curl(
      "-H 'Accept: #{accept}' -H 'Host: #{uri.host}' -H 'Date: #{httpdate}' -H 'Signature: #{signed_header}' ", url
    )
    return unless response

    begin
      JSON.parse(response)
    rescue StandardError => e
      p url, e
      nil
    end
  end

  def curl(ext, url)
    response = `/run/current-system/sw/bin/curl -H 'Content-Type: #{CONTENT_TYPE}' -H 'Accept: #{CONTENT_TYPE}' --fail-with-body -sSL #{ext} #{url}`
    if $CHILD_STATUS.success?
      response
    else
      p 'Curl Error:', url, response
      nil
    end
  end

  def mention(actor)
    person = people.select { |p| p[1] == actor }
    if person.empty?
      a = fetch(actor)
      return nil unless a

      mention = "@#{a['preferredUsername']}@#{URI(actor).host}"
      cache mention, actor, a
      mention
    else
      person[0][0]
    end
  end

  def actor(mention)
    mention = mention.chomp
    actors = people.select { |p| p[0] == mention }
    if actors.empty?
      server = mention.split('@').last
      a = fetch("https://#{server}/.well-known/webfinger?resource=acct:#{mention.sub(/^@/, '')}",
                'application/jrd+json')
      return nil unless a

      actor = a['links'].select do |l|
        l['rel'] == 'self'
      end[0]['href']
      cache mention, actor, a
      actor
    else
      actors[0][1]
    end
  end

  def people
    File.read('public/people.tsv').split("\n").collect { |l| l.chomp.split("\t") }
  end

  def cache(mention, actor, a)
    sharedInbox = a['endpoints']['sharedInbox'] if a['endpoints'] && a['endpoints']['sharedInbox']
    File.open('public/people.tsv', 'a') { |f| f.puts "#{mention}\t#{actor}\t#{sharedInbox}" }
  end

  def media_type(url) # TODO: extend extensions
    extensions = {
      image: %w[jpeg jpg png tiff webp],
      audio: %w[flac wav mp3 ogg aiff],
      video: %w[mp4 webm]
    }
    ext = File.extname(url).sub('.', '').downcase
    type = extensions.find { |_k, v| v.include? ext }
    "#{type[0]}/#{ext}"
  end

  def find_object(id)
    Dir[File.join('*', '**', '*.json')].each do |file|
      object = JSON.load_file(file)
      return [file, object] if object['id'] == id
    end
  end

  def outbox_html(activity)
    html = File.read('/home/ch/src/publish/html/head.html')
    html += '<nav>'
    html += "<a id='logo' href='/about.html'><img src='/pdp8.png' alt='pdp8'></a>"
    %w[music pictures videos climbing code contact].each do |c|
      html += "&nbsp;<a class='item' href='/#{c}.html'>#{c}</a>"
    end
    html += "&nbsp;<a class='item current' href='/social/create.html'>social</a>"
    html += "&nbsp;<a class='item' href='/rss.xml'>rss</a>"
    html += "&nbsp;<a id='menu' href='#' onclick='show_vertical_menu()'>&equiv;</a>"
    html += "</nav><div class='post'><h1><a href='https://social.pdp8.info/pdp8'>@pdp8@social.pdp8.info</a></h1><h2>"
    html += if activity == 'create'
              "posts&nbsp;|&nbsp;<a href='/social/announce.html'>boosts</a>"
            elsif activity == 'announce'
              "<a href='/social/create.html'>posts</a>&nbsp;|&nbsp;boosts"
            end
    html += '</h2></div>'
    Dir[File.join(SOCIAL_DIR, 'outbox', activity, '*.json')].collect do |f|
      JSON.load_file(f)
    end.select { |a| a['to'].include?('https://www.w3.org/ns/activitystreams#Public') }.sort_by { |a| a['published'] }.reverse.collect { |a| a['object'] }.each do |object|
      object = fetch(object) if object.is_a? String
      mention = mention object['attributedTo']
      html += "<div class='post'>"
      if activity == 'announce'
        html += "<b><a href='#{object['attributedTo']}' target='_blank'>#{mention}</a></b>&nbsp;"
      end
      html += "<em>#{object['published']}</em>
          #{object['content']}"
      if object['attachment']
        object['attachment'].each do |att|
          w = 1024
          h = 768
          case att['mediaType']
          when /audio/
            html += "<br><audio controls><source src='#{att['url']}' type='#{att['mediaType']}'></audio>"
          when /image/
            if activity == 'create'
              w, h = `/etc/profiles/per-user/ch/bin/identify -format "%w %h" #{att['url'].sub(
                'https://media.pdp8.info', '/srv/media'
              )}`.chomp.split(' ') end
            html += "<br><a href='#{att['url']}'><img loading='lazy' width='#{w}' height='#{h}' "
            alt = att['name'] ? att['name'].gsub("'", '&apos;').gsub('"', '&quot;') : ''
            html += "alt='#{alt}' src='#{att['url']}'></a>"
          when /video/
            if activity == 'create'
              w, h = `ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=p=0 #{att['url'].sub(
                'https://media.pdp8.info', '/srv/media'
              )}`.chomp.split(',')
            end
            html += "<br><video width='#{w}' height='#{h}' controls><source src='#{att['url']}' type='#{att['mediaType']}'></video>"
          end
        end
      end
      html += '</div>'
    end
    html += File.read('/home/ch/src/publish/html/tail.html')
    %w[pdp8 pdp8-test].each do |d|
      outdir = "/srv/www/#{d}/social"
      out = File.join(outdir, activity + '.html')
      File.open(out, 'w+') { |f| f.puts(html) }
      puts `/etc/profiles/per-user/ch/bin/tidy -iqm -w 0 #{out} 2>&1`
    end
  end
end