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

  # add date and id, save
  def save_activity(activity, box)
    date = Time.now.utc.iso8601
    activity['published'] ||= date # if box == OUTBOX
    basename = "#{activity['published']}_#{mention(activity['actor'])}.json"
    activity_rel_path = File.join(activity['type'].downcase, basename)
    activity_path = File.join(box[:dir], activity_rel_path)
    if box == OUTBOX
      # return unless activity['to'].include? 'https://www.w3.org/ns/activitystreams#Public' # save only public messages

      activity['id'] = File.join(box[:url], activity_rel_path)
      activity['object']['published'] = date unless activity['object'].is_a? String
      # save object
      save_object activity['object'], box if %w[Create Announce Update].include? activity['type']
    end
    # save activity
    FileUtils.mkdir_p File.dirname(activity_path)
    File.open(activity_path, 'w+') { |f| f.puts activity.to_json }
    activity_path
  end

  def save_object(object, box)
    object = fetch(object) if object.is_a? String and object.match(/^http/)
    return unless object and object['type'] != 'Person'
    return if box == INBOX and object['id'] and File.readlines(VISITED, chomp: true).include? object['id']

    object['@context'] = 'https://www.w3.org/ns/activitystreams'
    if object['attributedTo']
      basename = "#{object['published']}_#{mention(object['attributedTo'])}.json"
    else
      basename = "#{object['published']}.json"
      jj object
    end
    object_rel_path = File.join 'object', object['type'].downcase, basename
    object['id'] ||= File.join box[:url], object_rel_path # if box == OUTBOX
    object_path = File.join box[:dir], object_rel_path
    FileUtils.mkdir_p File.dirname(object_path)
    File.open(object_path, 'w+') { |f| f.puts object.to_json }
    if box == OUTBOX and 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
    elsif box == INBOX
      File.open(File.join(INBOX[:dir], 'visited'), 'a+') { |f| f.puts object['id'] }
    end
    object
  end

  def update_collection(path, objects, delete = false)
    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 delete
          collection['orderedItems'].delete_if { |o| o['id'] == id or o == id }
        else
          ids = collection['orderedItems'].collect { |i| i['id'] }
          collection['orderedItems'] << object unless ids.include?(id) or collection['orderedItems'].include?(id)
        end
      end
      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
    )
    response ? JSON.parse(response) : nil
  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 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.sub(/^@/, '').chomp
    actors = people.select { |p| p[0] == mention }
    if actors.empty?
      _, server = mention.split('@')
      a = fetch("https://#{server}/.well-known/webfinger?resource=acct:#{mention}", '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_file(id)
    Dir[File.join('*', 'object', '*', '*.json')].find do |f|
      JSON.load_file(f)['id'] == id
    end
  end

  def find_id(id, return_filename = true)
    Dir[File.join('**', '*.json')].find do |f|
      content = JSON.load_file(f)
      if content['id'] == id
        return_filename ? f : content
      end
    end
  end
end