class AuthorizationsController < ApplicationController
  include OAuth2::Provider::Rack::AuthorizationCodesSupport
  before_filter :authenticate_user!, :except => :token
  before_filter :block_invalid_authorization_code_requests, :except => [:token, :index, :destroy]

  skip_before_filter :verify_authenticity_token, :only => :token

  def new
    @requested_scopes = params["scope"].split(',')
    @client = oauth2_authorization_request.client
    render :layout => "popup" if params[:popup]
  end

  def create
    if params[:commit] == "Authorize"
      grant_authorization_code(current_user)
    else
      deny_authorization_code
    end
  end

  def token
    if(params[:type] == 'client_associate' && params[:manifest_url])
      manifest = JSON.parse(RestClient.get(params[:manifest_url]).body)

      message = verify(params[:signed_string], params[:signature], manifest['public_key'])
      unless message =='ok' 
        render :text => message, :status => 403
      else
        client = OAuth2::Provider.client_class.create_from_manifest!(manifest)

        render :json => {:client_id => client.oauth_identifier,
                         :client_secret => client.oauth_secret,
                         :expires_in => 0,
                         :flows_supported => "",
                        }

      end
    else
      render :text => "bad request", :status => 403
    end
  end

  def index
    @authorizations = current_user.authorizations
    @applications = current_user.applications
  end

  def destroy
    ## ID is actually the id of the client
    auth = current_user.authorizations.where(:client_id => params[:id]).first
    auth.revoke
    redirect_to authorizations_path
  end

  # @param [String] enc_signed_string A Base64 encoded string with app_url;pod_url;time;nonce
  # @param [String] sig A Base64 encoded signature of the decoded signed_string with public_key.
  # @param [String] public_key The application's public key to verify sig with.
  def verify( enc_signed_string, sig, public_key)
    signed_string = Base64.decode64(enc_signed_string)
    split = signed_string.split(';')
    time = split[2]
    nonce = split[3]

    return 'blank public key' if public_key.blank?
    return "invalid time" unless valid_time?(time)
    return 'invalid nonce' unless valid_nonce?(nonce)
    return 'invalid signature' unless verify_signature(signed_string, Base64.decode64(sig), public_key)
    'ok'
  end

  def verify_signature(challenge, signature, serialized_pub_key)
    public_key = OpenSSL::PKey::RSA.new(serialized_pub_key) 
    public_key.verify(OpenSSL::Digest::SHA256.new, signature, challenge)
  end

  def valid_time?(time)
    time.to_i > (Time.now - 5.minutes).to_i
  end

  def valid_nonce?(nonce)
    !OAuth2::Provider.client_class.exists?(:nonce => nonce)
  end
end

OAuth2::Provider.client_class.instance_eval do
  def self.create_from_manifest! manifest
    create!(manifest)
  end
end