require 'openssl'
require 'digest/sha2'
require 'base64'
require "cloudfront-private/version"
require 'cloudfront-private/configuration'

require 'rails'


module Cloudfront
	module Private
		module Streaming
			module Base
				extend ActiveSupport::Concern
				include Cloudfront::Private::Configuration
				
				module ClassMethods
				  def get_url(_request, _resource)
				    url = get_signed_url(_resource, _request)
				    # Escape characters for proper embedding in Flash parameters
				    return url.gsub("?","%3F").gsub("=","%3D").gsub("&","%26")
				  end

				  protected				
				    def get_signed_url(_resource, _request)
				      pk_file        = Rails.root.join('certs',pem_file)
				      key            = OpenSSL::PKey::RSA.new(File.readlines(pk_file).join(""))
				      policy         = create_policy(_resource, _request)
				      sigcrypt       = key.sign(OpenSSL::Digest::SHA1.new, policy)
				      urlsig         = escape_string(Base64.encode64(sigcrypt))
				      encoded_policy = escape_string(Base64.encode64(policy))
				      return "#{_resource}?Policy=#{encoded_policy}&Signature=#{urlsig}&Key-Pair-Id=#{key_pair_id}"
				    end
				
				    def create_policy(_resource, _request)
				      expires = 1.hour.from_now.to_i
				      # Skip IP check for localhost (AWS:SourceIp does not work with localhost)
				      if Rails.env.development?
				        policy = %{ {"Statement":
				          [{ 
				            "Resource": "#{_resource}",
				            "Condition": { 
				              "DateLessThan": { "AWS:EpochTime": #{expires} }
				            }
				          }]}
				        }
				      else
				        ip = "#{_request.remote_ip}/24"
				        policy = %{ {"Statement":
				          [{ 
				            "Resource": "#{_resource}",
				            "Condition": { 
				              "DateLessThan": { "AWS:EpochTime": #{expires} },
				              "IpAddress": { "AWS:SourceIp": "#{ip}" }
				            }
				          }]}
				        }
				      end
				      return policy
				    end
				
				    def escape_string(_str)
				      _str.gsub('+','-').gsub('=','_').gsub('/','~').gsub(/\n/,'')
				    end
					
				end
			
			end
		end
	end
end