# server-server
post "/inbox" do 
  request.body.rewind # in case someone already read it
  @body = request.body.read
  @action = JSON.parse @body
  verify!

  case @action["type"]

  when "Create"
    create @action["object"]

  when "Delete"
    delete @action["object"]

  when "Update"
    delete @action["object"]
    create @action["object"]

  when "Follow"
    File.open(File.join("public", "followers", mention(@action["actor"]) + ".json"), "w+") { |f| f.puts @body }
    accept = { "@context" => "https://www.w3.org/ns/activitystreams",
               "id" => File.join(SOCIAL_URL + "#accepts", SecureRandom.uuid),
               "type" => "Accept",
               "actor" => ACTOR,
               "object" => @action }
    send_signed accept, @action["actor"]

  when "Undo"
    o = @action["object"]
    case o["type"]
    when "Follow"
      Dir["public/followers/*.json"].each do |follower|
        FileUtils.rm follower if JSON.parse(File.read(follower))["actor"] == o["actor"]
      end
    end

  when "Accept"
    o = @action["object"]
    case o["type"]
    when "Follow"
      File.open(File.join("public","following",mention(o['object'])+".json"),"w+"){|f| f.puts o.to_json}
    end

  when "Announce"
    download @action["object"]
  #when "Move"
  #when "Add"
  #when "Remove"
  #when "Like"
  #when "Block"

  else
    p "Unknown @action: #{@action['type']}"
    p @body
  end
end

# public
get "/.well-known/webfinger" do
  request["resource"] == "acct:#{ACCOUNT}" ? send_file("./public/webfinger", :type => "application/jrd+json") : halt(404)
end

get "/pdp8", :provides => 'html' do
 redirect 'https://pdp8.info'
end

get "/pdp8" do
  send_file "pdp8.json", :type => 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'
end

["/outbox","/following","/followers"].each do |path|
  get path do 
    ordered_collection(path).to_json
  end
end

helpers do

  # https://github.com/mastodon/mastodon/blob/main/app/controllers/concerns/signature_verification.rb
  def verify!

    # verify digest
    sha256 = OpenSSL::Digest::SHA256.new
    digest = "SHA-256=" + sha256.base64digest(@body)
    halt 403 unless digest == request.env["HTTP_DIGEST"]

    signature_params = {}
    request.env["HTTP_SIGNATURE"].split(',').each do |pair|
      k, v = pair.split('=')
      signature_params[k] = v.gsub('"', '')
    end

    key_id = signature_params['keyId']
    headers = signature_params['headers']
    signature = Base64.decode64(signature_params['signature'])

    if @action["type"] == "Delete" # deleted users do not return actors
      delete @action["object"]
      halt 200
    end

    jj @action
    actor = fetch key_id
    halt 403 unless actor
    key = OpenSSL::PKey::RSA.new(actor['publicKey']['publicKeyPem'])

    comparison = headers.split(' ').map do |signed_params_name|
      if signed_params_name == '(request-target)'
        '(request-target): post /inbox'
      elsif signed_params_name == 'content-type'
        "#{signed_params_name}: #{request.env["CONTENT_TYPE"]}"
      else
        "#{signed_params_name}: #{request.env["HTTP_" + signed_params_name.upcase]}"
      end
    end.join("\n")

    halt 403 unless key.verify(OpenSSL::Digest.new('SHA256'), signature, comparison)
  end

  def create object
    unless object['type'] == 'Person'
      doc = File.join("inbox", "#{Time.now.strftime('%Y-%m-%dT%H:%M:%S.%N')}.json")
      File.open(doc, "w+") { |f| f.puts object.to_json }
      if object['inReplyTo']
        @dir = 'inbox'
        items
        if @items.select{|it| it[:id] == object['inReplyTo'] }.empty?
           download object['inReplyTo']
        end
      end
    end
  end

  def download object_url
    object = fetch(object_url)
    object and object["type"] ? create(object) : p(object_url, object)
  end

  def delete object
    Dir["inbox/*.json"].each do |doc|
      FileUtils.rm doc if JSON.parse(File.read(doc))["id"] == object["id"]
    end
  end

  def ordered_collection dir
    posts = Dir[File.join("public",dir, "*.json")].collect { |f| JSON.parse(File.read f) }.sort_by { |o| o["published"] }
    {
      "@context" => "https://www.w3.org/ns/activitystreams",
      "summary" => "#{USER} #{dir}",
      "type" => "OrderedCollection",
      "totalItems" => posts.size,
      "orderedItems" => posts,
    }
  end

end